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Your patient is a 30-year-old man who has frequent episodes of herpes labialis. He asks you to tell him something about herpes simplex virus type 1 (HSV-1). Which one of the following would be the most accurate statement to make?
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(A) Acyclovir can eradicate the latent state of HSV-1 but not HSV-2.
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(B) The main site of latency by HSV-1 is the neurons in the sensory ganglia of the face.
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(C) HSV-1 is an enveloped virus that has a DNA genome and a DNA polymerase in the virion.
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(D) The lesions of primary HSV-1 infections are less extensive and less severe than the lesions of recurrent HSV-1 infections.
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(E) The laboratory diagnosis of HSV-1 infections typically involves the detection of a greater than fourfold rise in antibody titer against the virus.
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Your patient is a woman who is due to give birth next week. She asks you about the risk of her baby becoming infected with herpes simplex virus type 2 (HSV-2). Which one of the following is the most accurate response?
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(A) HSV-2 is a significant cause of congenital abnormalities.
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(B) The risk is higher if the mother has visible lesions than if she does not.
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(C) The risk is higher if the mother has IgG antibody to HSV-2 than if she has IgM antibody.
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(D) The risk is higher if the delivery occurs by cesarean section than if the delivery is performed vaginally.
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(E) The risk is higher if the mother is having an episode of recurrent disease caused by HSV-2 than if it were a primary episode.
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Regarding varicella-zoster virus (VZV), which one of the following is most accurate?
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(A) High-dose acyclovir can eliminate the latent state caused by VZV.
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(B) The principal site of latency of VZV is in the nucleus of motor neurons.
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(C) Domestic animals, such as pigs and chickens, are the main reservoir for VZV.
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(D) The vaccine against varicella contains all three serotypes of formalin-killed VZV as the immunogen.
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(E) When zoster occurs in an immunocompromised patient, acyclovir should be given to prevent disseminated infection.
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Regarding cytomegalovirus (CMV), which one of the following is most accurate?
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(A) CMV is usually acquired by the fecal–oral route in adults.
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(B) Neonates born from infected mothers should be given the subunit vaccine.
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(C) Reactivation of CMV in sensory ganglion cells leads to painful vesicles along nerves.
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(D) Lamivudine should be used to treat CMV infections in immunocompromised patients.
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(E) CMV infection of a fetus during the first trimester results in more congenital abnormalities than infection in the third trimester.
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Regarding Epstein–Barr virus (EBV) and infectious mononucleosis, which one of the following is most accurate?
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(A) EBV enters the latent state primarily in CD4-positive helper T cells.
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(B) Approximately 10% of people in the United States have been exposed to EBV.
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(C) People with infectious mononucleosis produce antibodies that agglutinate sheep red cells.
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(D) The atypical lymphs in the blood of people with infectious mononucleosis are EBV-infected T helper cells.
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(E) Patients with deficient cell-mediated immunity should receive passive–active immunization against EBV.
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Naturally occurring smallpox disease has been eradicated from the face of the Earth. Eradication was achieved by the use of the vaccine. Regarding this vaccine, which one of the following is the most accurate?
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(A) The vaccine should be given in conjunction with preformed antibody to the virus.
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(B) Administration of the vaccine 1 day after exposure to the virus does not protect against disease.
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(C) The vaccine contains killed smallpox virus so the virus in the vaccine does not cause adverse effects.
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(D) Smallpox virus has a single stable serotype, so new formulations of the vaccine do not have to be made each year.
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(E) Because domestic animals such as cows are the main reservoir for smallpox virus, the vaccine must interrupt transmission from these sources.
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Your patient is a 35-year-old man who had a grand-mal seizure this morning. Magnetic resonance imaging revealed a lesion in the temporal lobe. A brain biopsy showed multinucleated giant cells with intranuclear inclusion bodies. Which one of the following is the most likely cause of this disease?
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(C) Herpes simplex virus type 1
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(E) Varicella-zoster virus
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Your patient is a 35-year-old man who had a grand-mal seizure this morning. Magnetic resonance imaging revealed a lesion in the temporal lobe. A brain biopsy showed multinucleated giant cells with intranuclear inclusion bodies. Which one of the following is the best choice of drug to treat his infection?
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Your patient is a 22-year-old woman with several episodes of bloody diarrhea. She is HIV antibody positive with a CD4 count of 50. Stool cultures for Shigella, Salmonella, and Campylobacter were negative. An assay for Clostridium difficile toxin was negative. Colonoscopy revealed many ulcerated lesions. Biopsy revealed cells with “owl’s eye” inclusions in the nucleus. Which one of the following is the most likely cause of this disease?
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(C) Herpes simplex virus type 1
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(E) Varicella-zoster virus
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Your patient is a 22-year-old woman with several episodes of bloody diarrhea. She is HIV antibody positive with a CD4 count of 50. Stool cultures for Shigella, Salmonella, and Campylobacter were negative. An assay for Clostridium difficile toxin was negative. Colonoscopy revealed many ulcerated lesions. Biopsy revealed cells with “owl’s eye” inclusions in the nucleus. Which one of the following is the best choice of drug to treat her infection?
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Regarding human papillomavirus (HPV), which one of the following statements is most accurate?
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(A) There is no vaccine available against HPV.
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(B) Acyclovir is effective in preventing lesions caused by HPV but does not cure the latent state.
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(C) Antigen–antibody complexes play an important role in the pathogenesis of warts caused by HPV.
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(D) The early proteins of HPV play a more important role in malignant transformation than the late proteins.
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(E) The diagnosis of HPV infection is usually made by detecting cytoplasmic inclusions within giant cells in the lesions.
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A 24-year-old woman is seen by her gynecologist for a routine Pap smear. The smear shows cervical intraepithelial neoplasia grade 3 (CIN 3). You decide to examine her long-term male sexual partner. Which one of the following is the most likely finding?
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(B) Condylomata acuminata
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(C) Penile intraepithelial neoplasia associated with HPV-6
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(D) Penile intraepithelial neoplasia associated with HPV-16
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Regarding influenza virus, which one of the following statements is most accurate?
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(A) The virion contains an RNA-dependent DNA polymerase.
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(B) Its surface proteins, hemagglutinin and neuraminidase, have multiple serologic types.
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(C) The protein that undergoes antigenic variation most often is the internal ribonucleoprotein.
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(D) Antigenic drift involves major changes in antigenicity that result from reassortment of the segments of its RNA genome.
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(E) The neuraminidase on the virion surface mediates the interaction of the virus with the receptors on the respiratory tract epithelium.
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Regarding influenza virus and the disease influenza, which one of the following statements is most accurate?
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(A) Both the killed and the live, attenuated vaccines induce lifelong immunity.
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(B) Influenza A virus causes more severe disease and more widespread epidemics than does influenza B virus.
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(C) The genome of influenza A virus has eight segments, but the genome of influenza B virus is in one piece.
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(D) The classification of influenza viruses into A, B, and C viruses is based on antigenic differences in their hemagglutinin.
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(E) Chronic carriers (i.e., patients from whom influenza virus is isolated at least 6 months after the acute disease) are an important source of human infection.
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(F) This virus has only one antigenic type, and lifelong immunity occurs in patients who have had measles.
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Regarding respiratory syncytial virus (RSV), which one of the following statements is most accurate?
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(A) RSV is an important cause of bronchiolitis in infants.
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(B) RSV causes tumors in newborn animals but not in humans.
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(C) The RSV vaccine is recommended for all children prior to entering school.
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(D) Amantadine should be given to elderly nursing home residents to prevent outbreaks of disease caused by RSV.
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(E) RSV forms intranuclear inclusion bodies within neutrophils that are important in diagnosis by the clinical laboratory.
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Your patient is a 75-year-old woman with fever, chills, and myalgias that began yesterday. It is January and an outbreak of influenza is occurring in the retirement community in which she lives. A rapid test for influenza antigen is positive. Which one of the following is the best choice of drug to treat the infection?
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Regarding rhinoviruses, which one of the following is most accurate?
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(A) Rhinoviruses are an important cause of viral meningitis and myocarditis.
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(B) The rhinovirus vaccine is recommended for all children over 2 years of age.
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(C) Rhinoviruses have many serologic types, so a person can have many infections caused by these viruses.
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(D) Rhinoviruses are not inactivated by stomach acid, so they infect the upper gastrointestinal tract and are one of the causes of viral diarrhea.
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(E) An important feature of the laboratory diagnosis of rhinoviruses is finding cytopathic effect in cell culture consisting of multinucleated giant cells.
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Regarding adenoviruses, which one of the following statements is most accurate?
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(A) Acyclovir is the drug of choice for life-threatening infections.
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(B) They cause pharyngitis, pneumonia, and conjunctivitis (“pink eye”).
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(C) They are often transmitted across the placenta and cause hydrocephalus in the fetus.
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(D) The adenovirus vaccine is recommended for all children prior to entering first grade.
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(E) Laboratory diagnosis depends on seeing multinucleated giant cells on biopsy as the virus has not been grown in cell culture.
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Regarding measles virus and the disease measles, which one of the following statements is most accurate?
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(A) The measles vaccine contains killed virus as the immunogen.
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(B) One of the main sequelae of measles is autoimmune glomerulonephritis and kidney failure.
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(C) Measles is unlikely to be eradicated because there is a significant animal reservoir for this virus.
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(D) Fecal–oral transmission during the diaper stage is the main mode of acquisition of measles virus.
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(E) This virus has only one antigenic type, and lifelong immunity occurs in patients who have had measles.
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Regarding rubella virus, which one of the following statements is most accurate?
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(A) Systemic infection with rubella virus often causes severe liver damage resulting in cirrhosis.
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(B) If a pregnant woman is infected during the first trimester, significant fetal abnormalities typically result.
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(C) The main source of virus is adults who have recovered from the disease but are chronic carriers of the virus.
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(D) Immunization of both male and female healthcare workers with the formalin-inactivated vaccine is recommended.
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(E) The significant changes in the antigenicity of this virus are attributed to reassortment of the segments of its genome.
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Regarding parvovirus B19, which one of the following statements is most accurate?
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(A) A vaccine is available that contains killed virus as the immunogen.
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(B) Patients infected by parvovirus B19 can be diagnosed in the laboratory using the cold agglutinin test.
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(C) Parvovirus B19 causes a severe anemia because it preferentially infects erythrocyte precursors such as erythroblasts.
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(D) It commonly infects neutrophils, resulting in an immunodeficiency that predisposes to infections by pyogenic bacteria.
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(E) Parvoviruses have a double-stranded DNA genome but require a DNA polymerase in the virion because they replicate in the cytoplasm.
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Regarding rabies virus and the disease rabies, which one of the following statements is most accurate?
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(A) Finding intranuclear inclusion bodies within macrophages is presumptive evidence of rabies virus infection.
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(B) Lamivudine is used to treat rabies because it inhibits the RNA-dependent DNA polymerase in the virion.
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(C) In the United States, skunks and bats are more likely to transmit rabies virus to people than are dogs and cats.
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(D) The incubation period of the disease is usually 2 to 4 days, leading to the rapid progression of the encephalitis and death.
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(E) After the animal bite, rabies virus enters the bloodstream, replicates in internal organs such as the liver, and then reaches the central nervous system during the secondary viremia.
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A woman was hiking in an isolated area when a skunk appeared and bit her on the leg. She now presents to your emergency room about an hour after the bite. Which one of the following is the most appropriate action to take?
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(A) Give rabies vaccine and hyperimmune globulin immediately.
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(B) Reassure her that rabies is not a problem because skunks do not carry rabies.
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(C) Quarantine the animal for 10 days and only treat her if signs of rabies appear in the animal.
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(D) Test the patient’s serum for antibodies now and in 10 days to see if there is a rise in antibody titer before treating her.
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(E) Administer ribavirin intravenously.
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Regarding Ebola virus, which one of the following is most accurate?
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(A) Skunks and raccoons are the main natural reservoirs for Ebola virus.
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(B) In endemic areas, most people are latently infected with Ebola virus.
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(C) People known to be exposed to Ebola virus should be given ganciclovir to prevent disease.
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(D) Ebola hemorrhagic fever occurs primarily in people with deficient cell-mediated immunity.
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(E) The appearance of Ebola virus in the electron microscope is that of a long thread, which often has a curved end.
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Regarding poliovirus and the disease poliomyelitis, which one of the following is most accurate?
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(A) Poliovirus is transmitted primarily by the fecal–oral route.
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(B) New antigenic variants arise by coinfection with animal strains of poliovirus.
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(C) Paralytic poliomyelitis is the most common manifestation of poliovirus infection.
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(D) Poliovirus has single-stranded RNA as its genome and a polymerase in the virion that synthesizes its mRNA.
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(E) The current vaccine recommendation is to give the live, attenuated vaccine for the first three immunizations to prevent the child from acting as a reservoir, followed by boosters using the killed vaccine.
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A 70-year-old retired carpenter has signed up with a volunteer organization to build houses in a developing country where polio is still endemic. He plans to be there about 9 months. He thinks he has never been immunized against polio. Which one of the following is the most appropriate thing to do?
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(A) Give immune serum globulins (ISG).
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(B) Give the killed vaccine containing only type 3.
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(C) Give the killed vaccine containing types 1, 2, and 3.
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(D) Give the live vaccine containing only type 3.
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(E) Give the live vaccine containing types 1, 2, and 3.
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Regarding norovirus, which one of the following is most accurate?
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(A) The diarrhea is caused by an exotoxin that increases cyclic adenosine monophosphate (cAMP).
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(B) There are no neutrophils or red cells in the stool.
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(C) Ritonavir, a protease inhibitor, is the drug of choice for chronic diarrhea caused by norovirus.
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(D) Ingestion of undercooked hamburger is a common mode of acquisition of norovirus as cattle are a major reservoir of the virus.
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(E) The diagnosis of norovirus-induced diarrhea is typically made by the detection of a fourfold or greater rise in antibody titer to the virus.
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Regarding rotavirus, which one of the following is most accurate?
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(A) Rotavirus is a major cause of nosocomial diarrhea in intensive care units.
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(B) The vaccine against rotavirus contains live, attenuated virus as the immunogen.
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(C) Rotavirus has a nonsegmented, single-stranded RNA genome, and there is no polymerase in the virion.
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(D) The diagnosis of rotavirus diarrhea is typically made by the detection of a fourfold or greater rise in antibody titer to the virus.
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(E) Diarrhea caused by rotavirus is due to a viral protein that increases the release of IgA from many submucosal B lymphocytes.
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An outbreak of jaundice occurs in several young children who attend the same day care center. If the outbreak was caused by a virus, which one of the following is the most likely cause?
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Regarding hepatitis A virus (HAV), which one of the following statements is most accurate?
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(A) The HAV vaccine contains live, attenuated virus as the immunogen.
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(B) The screening of blood for transfusion has greatly reduced the spread of this virus.
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(C) The diagnosis is typically made by serologic tests rather than by culturing the virus.
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(D) Multiple episodes of hepatitis A are common because it has three serotypes.
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(E) It has a segmented, negative-polarity, single-stranded RNA genome and an RNA polymerase in the virion.
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A woman who is hepatitis B surface antigen (HBsAg) positive and hepatitis B surface antibody (HBsAb) negative has just given birth. Which one of the following is the most appropriate thing to do for the newborn?
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(A) Nothing. The child is protected against hepatitis B.
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(B) Immunize with the vaccine containing HBsAg (HBV vaccine).
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(C) Give hepatitis B hyperimmune globulin (HBIG).
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(D) Give both the HBV vaccine and HBIG.
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Regarding hepatitis B virus (HBV) and the disease hepatitis B, which one of the following is most accurate?
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(A) The most reliable indicator that a person can transmit HBV is the presence of HBsAg in the blood.
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(B) HBV has a circular, partially double-stranded DNA as its genome and has a DNA polymerase in the virion.
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(C) Healthcare personnel who sustain a needle-stick injury while taking blood from a person with hepatitis B should receive acyclovir.
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(D) HBV infection induces antibody to HBcAg (core antigen), which protects the person from a second attack by the same strain of HBV.
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(E) A person in the “window period” can be diagnosed as having been infected by HBV if antibody to the surface antigen (HBsAg) is present.
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Regarding hepatitis C virus (HCV), which one of the following is most accurate?
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(A) Chronic infection with HCV predisposes to hepatocellular carcinoma.
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(B) HCV is a defective virus that requires concurrent hepatitis B virus (HBV) infection in order to replicate.
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(C) Chronic infection with HCV occurs less frequently than chronic infection with HBV.
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(D) The killed vaccine against HCV is poorly immunogenic, so booster doses must be given at least every 5 years.
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(E) Proper sewage disposal has significantly decreased the incidence of hepatitis C.
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Regarding hepatitis D virus (HDV), which one of the following is most accurate?
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(A) Alpha interferon can eradicate the latent state established by HDV.
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(B) Immunization against hepatitis B virus (HBV) will reduce the incidence of hepatitis caused by HDV.
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(C) HDV has DNA as its genome and an RNA-dependent DNA polymerase in the virion.
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(D) The laboratory diagnosis of HDV infection is made by growing HDV in cells coinfected with HBV.
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(E) Many HDV infections occur in young children in the diaper stage in day care centers because the virus is transmitted primarily by the fecal-oral route.
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Your patient is a 35-year-old man who complains that the whites of his eyes have turned yellow. After taking a history and doing a physical, you order serologic tests to determine whether he has viral hepatitis. On the basis of the results, you tell him that he has a mild form of hepatitis that does not cause long-term damage to the liver. Your conclusion is based on a positive result on which one of the following tests?
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(A) Antibody to hepatitis C virus
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(B) Hepatitis B surface antigen
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(C) Hepatitis delta antigen
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(D) IgM antibody to hepatitis A virus
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Your patient is a 20-year-old woman with chronic hepatitis B that was diagnosed by detecting hepatitis B antigen in her blood more than 6 months after her acute infection. Which one of the following is the best choice of drug to treat her chronic hepatitis B?
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Your patient is a 27-year-old man with a history of intravenous drug use who now is diagnosed with chronic hepatitis C. He is HIV antibody negative. Which one of the following is the best choice of drugs to treat his chronic hepatitis C?
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(C) Sofosbuvir and velpatasvir
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(E) Tenofovir and simiprevir
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An outbreak of dengue hemorrhagic fever (DHF) recently occurred in two Central American countries. Regarding dengue and DHF, which one of the following is the most accurate?
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(A) Humans are dead-end hosts for dengue virus.
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(B) DHF occurs primarily in individuals who are deficient in the late-acting complement components.
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(C) Dengue virus is transmitted by Aedes mosquitoes, and monkeys are an important natural reservoir.
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(D) The vaccine containing live, attenuated dengue virus is recommended for those living or traveling in endemic areas.
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(E) DHF occurs more often in people infected for the first time than when they are reinfected because antibody protects against reinfection.
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Yellow fever still exists in many tropical areas of the globe. Which one of the following is the best reason yellow fever still exists?
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(A) Sewage disposal is inadequate in many areas.
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(B) Both humans and monkeys are reservoirs for yellow fever virus.
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(C) The virus has mutated, so the existing vaccine is no longer effective.
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(D) The vaccine has been withdrawn because it was found to have unacceptable side effects.
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(E) The people in developing countries cannot afford to take amantadine when they enter endemic areas.
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Regarding West Nile virus (WNV), which one of the following is the most accurate?
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(A) Rodents are the main reservoir for WNV.
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(B) WNV does not cause disease in the United States.
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(C) WNV is transmitted primarily by Ixodes ticks.
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(D) Most infections are asymptomatic, but the elderly are at risk for encephalitis.
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(E) The live, attenuated vaccine should be administered to elderly adults in endemic areas.
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An outbreak of febrile disease involving severe joint pain and an erythematous macular rash has occurred on several Caribbean islands. Infection with chikungunya virus is suspected. Which one of the following is correct regarding this virus?
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(A) Its genome is composed of double-stranded DNA.
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(B) It is transmitted by Aedes mosquitoes.
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(C) Wild birds are the most important reservoir.
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(D) Laboratory diagnosis involves electron microscopy to observe the very long filamentous shape of the virus.
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(E) The killed vaccine should be administered to travelers to endemic regions.
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Regarding viruses that play a role in human carcinogenesis, which one of the following statements is the most accurate?
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(A) Epstein–Barr virus is implicated as the cause of nasopharyngeal carcinoma primarily in Asia, where it is transmitted by mosquitoes in rural areas.
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(B) Evidence for hepatitis C virus (HCV) as a cause of hepatocellular carcinoma includes finding a DNA copy of the HCV genome integrated into the DNA of hepatocytes.
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(C) Hepatitis B virus is implicated as the cause of hepatocellular carcinoma because countries with a high incidence of chronic hepatitis B also have a high incidence of hepatocellular carcinoma.
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(D) Human T-cell leukemia virus is a retrovirus that was found to be associated with leukemia in Japan but is not found in the United States.
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Regarding the oncogenes of DNA tumor viruses, which one of the following is most accurate?
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(A) They encode protein kinases that phosphorylate p53 protein.
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(B) They interact with cellular proto-oncogenes and activate them.
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(C) They encode cellular growth factors that activate S-phase DNA synthesis.
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(D) They encode proteins that bind to the proteins encoded by tumor suppressor genes.
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Regarding the main mechanism by which oncogenic retroviruses cause malignant transformation, which one of the following is most accurate?
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(A) They cause point mutations in cellular regulatory genes.
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(B) They carry the genes for proteins that act as cellular growth factors.
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(C) They synthesize a protein that inhibits the action of the cellular p53 protein.
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(D) They encode a recombinase that causes translocation of certain chromosomes.
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(E) They encode a DNA polymerase that increases the rate of cellular DNA synthesis.
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Human T-cell lymphotropic virus (HTLV) causes T-cell leukemia in adults. Regarding this virus, which one of the following statements is most accurate?
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(A) HTLV is transmitted primarily by the fecal–oral route.
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(B) Oseltamivir cures the latent state established by HTLV within T cells.
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(C) The genome of HTLV consists of double-stranded RNA; therefore, there is no polymerase in the virion.
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(D) Infection by HTLV is diagnosed in the clinical laboratory by observing cytoplasmic inclusion bodies.
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(E) Oncogenesis by HTLV is related to a viral transcription factor that activates the production of interleukin-2 and its receptor.
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Regarding “slow viruses” and their diseases, which one of the following is the most accurate?
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(A) The viruses that cause slow diseases, such as progressive multifocal leukoencephalopathy (PML), have a slow rate of replication that accounts for the long latent period and slow progression of the disease.
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(B) PML is caused by a virus that causes widespread inapparent infections early in life but causes the disease PML primarily in people with reduced cell-mediated immunity.
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(C) Creutzfeldt-Jakob disease (CJD) is caused by CJ virus, a retrovirus that integrates a DNA copy of its genome into the DNA of brain neurons.
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(D) CJD occurs primarily in immunocompromised people, but infection with the virus that causes CJD is common, as evidenced by the presence of antibodies.
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Regarding prions, which one of the following is the most accurate?
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(A) The genome of prions consists of a negative-polarity RNA that has a defective polymerase gene.
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(B) Prion proteins are characterized by having changes in conformation from the alpha-helical form to the beta-pleated sheet form.
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(C) Prions are very sensitive to ultraviolet (UV) light, which is why UV light is used in hospital operating rooms to prevent their transmission.
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(D) The main host defense against prions consists of an inflammatory response composed primarily of macrophages and CD4-positive T cells.
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Regarding progressive multifocal leukoencephalopathy (PML), which one of the following is the most accurate?
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(A) It is caused by a defective mutant of measles virus.
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(B) The virus remains latent in hepatocytes for many years.
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(C) Lesions occur in several areas of the brain, resulting in diverse symptoms.
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(D) Acyclovir is the drug of choice for patients in the early stages of PML.
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(E) It is characterized by an inflammatory reaction in the brain containing many neutrophils.
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Regarding prion-mediated diseases, which one of the following is the most accurate?
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(A) Prion-mediated diseases are characterized by vacuoles in the brain called “spongiform changes.”
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(B) Variant Creutzfeldt-Jakob disease is a disease of cattle caused by the ingestion of sheep brain mixed into cattle feed.
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(C) Kuru is a prion-mediated disease for which the diagnosis can be confirmed in the laboratory by a fourfold or greater rise in antibody titer.
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(D) In Creutzfeldt-Jakob disease, only neurons latently infected by JC virus produce the prion filaments that disrupt neuronal function.
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(E) Creutzfeldt-Jakob disease occurs primarily in children under the age of 2 years because they cannot mount an adequate immune response to the prion protein.
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Regarding the structure and replication of human immunodeficiency virus (HIV), which one of the following is most accurate?
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(A) Viral mRNA is the template for the synthesis of the genome RNA.
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(B) During entry of HIV into the cell, the viral p24 protein interacts with the CD4 protein on the cell surface.
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(C) HIV contains an integrase within the virion that integrates copies of the viral genome into the progeny virions.
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(D) HIV has an enzyme in the virion that synthesizes double-stranded DNA using the single-stranded genome RNA as the template.
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(E) The HIV genome encodes a protease that cleaves cellular ribosomal proteins, resulting in the inhibition of cell-specific protein synthesis.
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Regarding clinical aspects of human immunodeficiency virus (HIV), which one of the following is most accurate?
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(A) During the primary infection with HIV, Pneumocystis pneumonia commonly occurs.
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(B) During the long asymptomatic period that can last for years, no HIV is synthesized.
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++
(C) During the period when many opportunistic infections occur, HIV usually cannot be detected in the blood.
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(D) The antibody response to a primary HIV infection usually is detected within 7 to 10 days after infection.
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(E) People with a high level of viral RNA in their plasma are more likely to have symptomatic AIDS (i.e., opportunistic infections) than those with low levels.
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Regarding the laboratory diagnosis of human immunodeficiency virus (HIV), which one of the following is most accurate?
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(A) The initial screening of blood for antibodies to HIV is done by the complement fixation test.
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(B) Viral load is the term used to describe the amount of infectious virus produced by the patient’s CD4-positive T lymphocytes in cell culture.
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(C) After infection with HIV, antibodies to the virus can be detected before the polymerase chain reaction (PCR) test can detect nucleic acids specific to HIV.
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(D) Because false-positive results occur in the screening test for HIV, a confirmatory test called the Western blot assay should be performed for those with a positive result on the screening test.
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Regarding the mode of action of drugs used in the treatment of human immunodeficiency virus (HIV) infection, which one of the following is most accurate?
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(A) Maraviroc acts by inhibiting the reverse transcriptase in the virion.
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(B) Raltegravir inhibits the integration of HIV DNA into host cell DNA.
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++
(C) Zidovudine is a nucleoside analog that inhibits messenger RNA (mRNA) synthesis of HIV.
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++
(D) Ritonavir acts by binding to the Tat protein, which prevents budding and release of the HIV virion.
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++
(E) Lamivudine is a “chain-terminating” drug because it inhibits the growing polypeptide chain by causing misreading of the viral mRNA.
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Regarding the adverse effects of drugs used in the treatment of human immunodeficiency virus (HIV) infection, which one of the following is most likely to cause bone marrow suppression?
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Regarding the adverse effects of drugs used in the treatment of human immunodeficiency virus (HIV) infection, which one of the following is most likely to cause lipodystrophy (i.e., abnormal fat deposits)?
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Regarding the adverse effects of drugs used in the treatment of human immunodeficiency virus (HIV) infection, which one of the following is most likely to cause Stevens-Johnson syndrome?
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Which of the following modes of transmission of human immunodeficiency virus (HIV) occurs significantly MORE often than the others?
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Your patient is a 25-year-old man who was just found to be infected with HIV based on a positive enzyme-linked immunosorbent assay (ELISA) and a positive Western blot test. His CD4 count is 125, and his viral load is 7000. He has not received any antiretroviral medications. Which one of the following is the best regimen to treat his infection?
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Regarding Sin Nombre virus (a hantavirus), which one of the following is most accurate?
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++
++
(A) Its main clinical manifestation is encephalitis.
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++
(B) The main reservoir is domestic animals such as pigs.
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++
(C) Infection is acquired by inhalation of dried mouse feces and urine.
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++
(D) Oseltamivir is an effective prophylactic drug if given within 48 hours of exposure.
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++
(E) Immunization of children at the age of 15 months with the killed vaccine has greatly reduced the incidence of disease.
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++
++
Regarding Japanese encephalitis virus (JEV), which one of the following is most accurate?
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++
++
(A) The principal reservoir of JEV is bats.
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++
(B) It is transmitted by the bite of the dog tick, Dermacentor.
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++
(C) Acyclovir is the drug of choice for encephalitis caused by JEV.
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++
(D) The killed vaccine should be given to those living in an endemic area.
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++
(E) JEV is a nonenveloped virus with a circular double-stranded RNA genome.
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++
++
Which one of the following outcomes is MOST common following a primary herpes simplex virus infection?
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++
++
(A) Complete eradication of virus and virus-infected cells
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++
(B) Persistent asymptomatic viremia
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(C) Establishment of latent infection
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(D) Persistent cytopathic effect in infected cells
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Each of the following pathogens is likely to establish chronic or latent infection EXCEPT:
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++
Each of the following statements regarding poliovirus and its vaccine is correct EXCEPT:
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++
++
(A) Poliovirus is transmitted by the fecal–oral route.
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++
(B) Pathogenesis by poliovirus primarily involves the death of sensory neurons.
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++
(C) The live, attenuated vaccine contains all three serotypes of poliovirus.
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++
(D) An unimmunized adult traveling to countries where there is a known risk of being infected with poliovirus should receive the inactivated vaccine.
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++
++
Which one of the following strategies is MOST likely to induce lasting intestinal mucosal immunity to poliovirus?
++
++
++
(A) Parenteral (intramuscular) immunization with inactivated vaccine
++
++
(B) Oral administration of poliovirus immune globulin
++
++
(C) Parenteral immunization with live vaccine
++
++
(D) Oral immunization with live vaccine
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++
++
Each of the following clinical syndromes is associated with infection by picornaviruses EXCEPT:
++
++
++
(A) Myocarditis/pericarditis
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++
Each of the following statements concerning rubella vaccine is correct EXCEPT:
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++
++
(A) The vaccine prevents reinfection, thereby limiting the spread of virulent virus.
++
++
(B) The immunogen in the vaccine is killed rubella virus.
++
++
(C) The vaccine induces antibodies that prevent dissemination of the virus by neutralizing it during the viremic stage.
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++
(D) The incidence of both childhood rubella and congenital rubella syndrome has decreased significantly since the advent of the vaccine.
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++
++
Each of the following statements concerning the rabies vaccine for use in humans is correct EXCEPT:
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++
++
(A) The vaccine contains live, attenuated rabies virus.
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++
(B) If your patient is bitten by a wild animal (e.g., a skunk) the rabies vaccine should be given.
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++
(C) When the vaccine is used for postexposure prophylaxis, rabies immune globulin should also be given.
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++
(D) The virus in the vaccine is grown in human cell cultures, thus decreasing the risk of allergic encephalomyelitis.
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++
++
Each of the following statements concerning influenza is correct EXCEPT:
++
++
++
(A) Major epidemics of the disease are caused by influenza A viruses rather than influenza B and C viruses.
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(B) Likely sources of new antigens for influenza A viruses are the viruses that cause influenza in animals.
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(C) Major antigenic changes (shifts) of viral surface proteins are seen primarily in influenza A viruses rather than in influenza B and C viruses.
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++
(D) The antigenic changes that occur with antigenic drift are due to reassortment of the multiple pieces of the influenza virus genome.
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++
++
Each of the following statements concerning the prevention and treatment of influenza is correct EXCEPT:
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++
++
(A) The inactivated influenza vaccine contains H1N1 virus, whereas the live, attenuated influenza vaccine contains H3N2 virus.
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++
(B) The vaccine is recommended to be given each year because the antigenicity of the virus drifts.
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++
(C) Oseltamivir (Tamiflu) is effective against both influenza A and influenza B viruses.
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++
(D) The main antigen in the vaccine that induces protective antibody is the hemagglutinin.
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++
++
A 6-month-old child develops a persistent cough and a fever. Physical examination and chest X-ray suggest pneumonia. Which one of the following organisms is LEAST likely to cause this infection?
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++
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(A) Respiratory syncytial virus
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A 45-year-old man was attacked by a bobcat and bitten repeatedly about the face and neck. The animal was shot by a companion and brought back to the public health authorities. Once you decide to immunize against rabies virus, how would you proceed?
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++
++
(A) Use hyperimmune serum only
++
++
(B) Use active immunization only
++
++
(C) Use hyperimmune serum and active immunization
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++
(D) Use active immunization and follow this with hyperimmune serum if adequate antibody titers are not obtained in the patient’s serum
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++
++
Each of the following statements concerning mumps is correct EXCEPT:
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++
++
(A) Mumps virus is a paramyxovirus and hence has a single-stranded RNA genome.
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++
(B) Meningitis is a recognized complication of mumps.
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++
(C) Mumps orchitis in children prior to puberty often causes sterility.
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++
(D) During mumps, the virus spreads through the bloodstream (viremia) to various internal organs.
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++
Each of the following statements concerning respiratory syncytial virus (RSV) is correct EXCEPT:
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++
++
(A) RSV has a single-stranded RNA genome.
++
++
(B) RSV induces the formation of multinucleated giant cells.
++
++
(C) RSV causes pneumonia primarily in children.
++
++
(D) RSV infections can be effectively treated with acyclovir.
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++
++
The principal reservoir for the antigenic shift variants of influenza virus appears to be:
++
++
++
(A) People in isolated communities such as the Arctic
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++
(B) Animals, specifically pigs, horses, and fowl
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++
(C) Soil, especially in the tropics
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++
++
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++
The role of an infectious agent in the pathogenesis of kuru was BEST demonstrated by which one of the following observations?
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++
++
(A) A 16-fold rise in antibody titer to the agent was observed.
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++
(B) The viral genome was isolated from infected neurons.
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++
(C) Electron micrographs of the brains of infected individuals demonstrated intracellular structures resembling paramyxovirus nucleocapsids.
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++
(D) The disease was serially transmitted to experimental animals.
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++
++
A 64-year-old man with chronic lymphatic leukemia develops progressive deterioration of mental and neuromuscular function. At autopsy the brain shows enlarged oligodendrocytes whose nuclei contain naked, icosahedral virus particles. The MOST likely diagnosis is:
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++
++
++
++
(B) Creutzfeldt-Jakob disease
++
++
(C) Subacute sclerosing panencephalitis
++
++
(D) Progressive multifocal leukoencephalopathy
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++
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++
A 20-year-old man, who for many years had received daily injections of growth hormone prepared from human pituitary glands, develops ataxia, slurred speech, and dementia. At autopsy the brain shows widespread neuronal degeneration, a spongy appearance due to many vacuoles between the cells, no inflammation, and no evidence of virus particles. The MOST likely diagnosis is:
++
++
++
++
++
(B) Creutzfeldt-Jakob disease
++
++
(C) Subacute sclerosing panencephalitis
++
++
(D) Progressive multifocal leukoencephalopathy
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++
++
++
++
A 24-year-old woman has had fever and a sore throat for the past week. Moderately severe pharyngitis and bilateral cervical lymphadenopathy are seen on physical examination. Which one of the following viruses is LEAST likely to cause this picture?
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++
Scrapie and kuru possess all of the following characteristics EXCEPT:
++
++
++
(A) A histologic picture of spongiform encephalopathy
++
++
(B) Transmissibility to animals associated with a long incubation period
++
++
(C) Slowly progressive deterioration of brain function
++
++
(D) Prominent intranuclear inclusions in oligodendrocytes
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++
++
Each of the following statements concerning subacute sclerosing panencephalitis is correct EXCEPT:
++
++
++
(A) Immunosuppression is a frequent predisposing factor.
++
++
(B) Aggregates of helical nucleocapsids are found in infected cells.
++
++
(C) High titers of measles antibody are found in cerebrospinal fluid.
++
++
(D) Gradual progressive deterioration of brain function occurs.
++
++
++
The slow virus disease that MOST clearly has immunosuppression as an important factor in its pathogenesis is:
++
++
++
(A) Progressive multifocal leukoencephalopathy
++
++
(B) Subacute sclerosing panencephalitis
++
++
(C) Creutzfeldt-Jakob disease
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++
++
++
++
You think your patient may be in the “window period” of hepatitis B virus (HBV) infection because his blood tests for HBs antigen and anti-HBs antibody are negative. Which one of the following additional tests is MOST useful to establish that he has been infected with HBV and is in the “window period”?
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++
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++
++
++
++
++
Which one of the following is the MOST reasonable explanation for the ability of hepatitis B virus to cause chronic infection?
++
++
++
(A) Infection does not elicit the production of antibody.
++
++
(B) The liver is an “immunologically sheltered” site.
++
++
(C) Viral DNA can persist within the host cell.
++
++
(D) Many humans are immunologically tolerant to HBs antigen.
++
++
++
The routine screening of transfused blood has greatly reduced the problem of post-transfusion hepatitis. For which one of the following viruses has screening eliminated a large number of cases of post-transfusion hepatitis?
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++
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++
A 35-year-old man addicted to intravenous drugs has been a carrier of HBs antigen for 10 years. He suddenly develops acute fulminant hepatitis and dies within 10 days. Which one of the following laboratory tests would contribute MOST to a diagnosis?
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++
++
++
++
++
++
++
++
(D) Anti-delta virus antibody
++
++
++
Which one of the following is the BEST evidence on which to base a decisive diagnosis of acute mumps disease?
++
++
++
++
++
(B) A fourfold rise in antibody titer to mumps antigen
++
++
(C) A history of exposure to a child with mumps
++
++
(D) Orchitis in young adult male
++
++
++
Varicella-zoster virus and herpes simplex virus share many characteristics. Which one of the following characteristics is NOT shared?
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++
++
(A) Inapparent disease, manifested only by virus shedding, is common
++
++
(B) Persistence of latent virus after recovery from acute disease
++
++
++
++
(D) Linear, double-stranded DNA genome
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++
++
Herpes simplex virus and cytomegalovirus share many features. Which one of the following features is LEAST likely to be shared?
++
++
++
(A) Important cause of morbidity and mortality in the newborn
++
++
(B) Congenital abnormalities due to transplacental passage
++
++
(C) Important cause of serious disease in immunosuppressed individuals
++
++
(D) Mild or inapparent infection
++
++
++
The eradication of smallpox was facilitated by several features of the virus. Which one of the following contributed LEAST to eradication?
++
++
++
(A) It has one antigenic type.
++
++
(B) Inapparent infection is rare.
++
++
(C) Administration of live vaccine reliably induces immunity.
++
++
(D) It multiplies in the cytoplasm of infected cells.
++
++
++
Which one of the following statements concerning infectious mononucleosis is the MOST accurate?
++
++
++
(A) Multinucleated giant cells are found in the skin lesions.
++
++
(B) Infected T lymphocytes are abundant in peripheral blood.
++
++
(C) Isolation of virus is necessary to confirm the diagnosis.
++
++
(D) Infectious mononucleosis is transmitted by virus in saliva.
++
++
++
Which one of the following statements about genital herpes is LEAST accurate?
++
++
++
(A) Acyclovir reduces the number of recurrent disease episodes by eradicating latently infected cells.
++
++
(B) Genital herpes can be transmitted in the absence of apparent lesions.
++
++
(C) Multinucleated giant cells with intranuclear inclusions are found in the lesions.
++
++
(D) Initial disease episodes are generally more severe than recurrent episodes.
++
++
++
There are several influenza vaccines administered in the United States. Regarding these vaccines, which one of the following statements is LEAST accurate?
++
++
++
(A) One of the vaccines contains purified peptide subunits of neuraminidase produced in yeast.
++
++
(B) One of the vaccines is an inactivated vaccine consisting of formaldehyde-treated influenza virions.
++
++
(C) One of the vaccines contains a temperature-sensitive mutant of influenza virus that replicates in the nose but not in the lungs.
++
++
(D) Influenza vaccines contain influenza A and B strains but not C strains.
++
++
++
Which of the following is the MOST common lower respiratory pathogen in infants?
++
++
++
(A) Respiratory syncytial virus
++
++
++
++
++
++
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++
++
Which of the following conditions is LEAST likely to be caused by adenoviruses?
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++
++
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++
++
Regarding the serologic diagnosis of infectious mononucleosis, which one of the following is CORRECT?
++
++
++
(A) A heterophil antibody is formed that reacts with a capsid protein of Epstein–Barr virus.
++
++
(B) A heterophil antibody is formed that agglutinates sheep or horse red blood cells.
++
++
(C) A heterophil antigen occurs that cross-reacts with Proteus OX19 strains.
++
++
(D) A heterophil antigen occurs following infection with cytomegalovirus.
++
++
++
Herpes simplex virus type 1 (HSV-1) is distinct from HSV-2 in several different ways. Which one of the following is the LEAST accurate statement?
++
++
++
(A) HSV-1 causes lesions above the umbilicus more frequently than HSV-2 does.
++
++
(B) Infection by HSV-1 is not associated with any tumors in humans.
++
++
(C) Antiserum to HSV-1 neutralizes HSV-1 much more effectively than HSV-2.
++
++
(D) HSV-1 causes frequent recurrences, whereas HSV-2 infection rarely recurs.
++
++
++
Which one of the following statements about the src gene and src protein of Rous sarcoma virus is INCORRECT?
++
++
++
(A) The src protein inactivates a protein encoded by p53, a tumor suppressor gene.
++
++
(B) The src protein is a protein kinase that preferentially phosphorylates tyrosine in cellular proteins.
++
++
(C) The src protein is required to maintain neoplastic transformation of infected cells.
++
++
(D) The viral src gene is derived from a cellular gene found in many vertebrate species.
++
++
++
Each of the following statements supports the idea that cellular proto-oncogenes participate in human carcinogenesis EXCEPT:
++
++
++
(A) The c-abl gene is rearranged on the Philadelphia chromosome in myeloid leukemias and encodes a protein with increased tyrosine kinase activity.
++
++
(B) The N-myc gene is amplified as much as 100-fold in many advanced cases of neuroblastoma.
++
++
(C) The receptor for platelet-derived growth factor is a transmembrane protein that exhibits tyrosine kinase activity.
++
++
(D) The c-Ha-ras gene is mutated at specific codons in several types of human cancer.
++
++
++
Each of the following statements concerning human immunodeficiency virus (HIV) is correct EXCEPT:
++
++
++
(A) Screening tests for antibodies are useful to prevent transmission of HIV through transfused blood.
++
++
(B) The opportunistic infections seen in AIDS are primarily the result of a loss of cell-mediated immunity.
++
++
(C) Zidovudine (azidothymidine) inhibits the RNA-dependent DNA polymerase.
++
++
(D) The presence of circulating antibodies that neutralize HIV is evidence that an individual is protected against HIV-induced disease.
++
++
++
Which one of the following statements concerning viral meningitis and viral encephalitis is CORRECT?
++
++
++
(A) Herpes simplex virus type 2 is the leading cause of viral meningitis.
++
++
(B) Herpes simplex virus type 1 is an important cause of viral encephalitis.
++
++
(C) The spinal fluid protein is usually decreased in viral meningitis.
++
++
(D) The diagnosis of viral meningitis can be made by using the India ink stain on a sample of spinal fluid.
++
++
++
Each of the following statements is correct EXCEPT:
++
++
++
(A) Coxsackie viruses are enteroviruses and can replicate in both the respiratory and gastrointestinal tracts.
++
++
(B) Influenza viruses have multiple serotypes based on hemagglutinin and neuraminidase proteins located on the envelope surface.
++
++
(C) Flaviviruses are RNA enveloped viruses that replicate in animals as well as humans.
++
++
(D) Adenoviruses are RNA enveloped viruses that are an important cause of sexually transmitted disease.
++
++
++
Which one of the following statements concerning the prevention of viral disease is CORRECT?
++
++
++
(A) Adenovirus vaccine contains purified penton fibers and is usually given to children in conjunction with polio vaccine.
++
++
(B) Coxsackie virus vaccine contains live virus that induces IgA, which prevents reinfection by homologous serotypes.
++
++
(C) Flavivirus immunization consists of hyperimmune serum plus a vaccine consisting of subunits containing the surface glycoprotein.
++
++
(D) One of the influenza virus vaccines contains killed virus that induces neutralizing antibody directed against the hemagglutinin.
++
++
++
Each of the following statements concerning hepatitis C virus (HCV) and hepatitis D virus (HDV) is correct EXCEPT:
++
++
++
(A) HCV is an RNA virus that causes post-transfusion hepatitis.
++
++
(B) HDV is a defective virus that can replicate only in a cell that is also infected with hepatitis B virus.
++
++
(C) HDV is transmitted primarily by the fecal–oral route.
++
++
(D) People infected with HCV commonly become chronic carriers of HCV and are predisposed to hepatocellular carcinoma.
++
++
++
Each of the following statements concerning measles virus is correct EXCEPT:
++
++
++
(A) Measles virus is an enveloped virus with a single-stranded RNA genome.
++
++
(B) One of the important complications of measles is encephalitis.
++
++
(C) The initial site of measles virus replication is the upper respiratory tract, from which it spreads via the blood to the skin.
++
++
(D) Latent infection by measles virus can be explained by the integration of provirus into the host cell DNA.
++
++
++
Each of the following statements concerning measles vaccine is correct EXCEPT:
++
++
++
(A) The vaccine contains live, attenuated virus.
++
++
(B) The vaccine should not be given at the same time as the mumps vaccine because the immune system cannot respond to two viral antigens given at the same time.
++
++
(C) Virus in the vaccine contains only one serotype.
++
++
(D) The vaccine should not be given prior to 15 months of age because maternal antibodies can prevent an immune response.
++
++
++
Each of the following statements concerning rubella is correct EXCEPT:
++
++
++
(A) Congenital abnormalities occur primarily when a pregnant woman is infected during the first trimester.
++
++
(B) Women who say that they have never had rubella can, nevertheless, have neutralizing antibody in their serum.
++
++
(C) In a 6-year-old child, rubella is a mild, self-limited disease with few complications.
++
++
(D) Acyclovir is effective in the treatment of congenital rubella syndrome.
++
++
++
Each of the following statements concerning rabies and rabies virus is correct EXCEPT:
++
++
++
(A) The virus has a lipoprotein envelope and single-stranded RNA as its genome.
++
++
(B) The virus has a single antigenic type (serotype).
++
++
(C) In the United States, dogs are the most common reservoir.
++
++
(D) The incubation period is usually long (several weeks) rather than short (several days).
++
++
++
Each of the following statements concerning arboviruses is correct EXCEPT:
++
++
++
(A) The pathogenesis of dengue hemorrhagic shock syndrome is associated with the heterotypic anamnestic response.
++
++
(B) Wild birds are the reservoir for encephalitis viruses but not for yellow fever virus.
++
++
(C) Ticks are the main mode of transmission for both encephalitis viruses and yellow fever virus.
++
++
(D) There is a live, attenuated vaccine that effectively prevents yellow fever.
++
++
++
Each of the following statements concerning rhinoviruses is correct EXCEPT:
++
++
++
(A) Rhinoviruses are picornaviruses (i.e., small, nonenveloped viruses with an RNA genome).
++
++
(B) Rhinoviruses are an important cause of lower respiratory tract infections, especially in patients with chronic obstructive pulmonary disease.
++
++
(C) Rhinoviruses do not infect the gastrointestinal tract because they are inactivated by the acid pH in the stomach.
++
++
(D) There is no vaccine against rhinoviruses because they have too many antigenic types.
++
++
++
Each of the following statements concerning herpes simplex virus type 2 (HSV-2) is correct EXCEPT:
++
++
++
(A) Primary infection with HSV-2 does not confer immunity to primary infection with HSV-1.
++
++
(B) HSV-2 causes vesicular lesions, typically in the genital area.
++
++
(C) HSV-2 can cause alterations of the cell membrane, leading to cell fusion and the formation of multinucleated giant cells.
++
++
(D) Recurrent disease episodes due to reactivation of latent HSV-2 are usually more severe than the primary episode.
++
++
++
Each of the following statements concerning Epstein–Barr virus is correct EXCEPT:
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(A) Many infections are mild or inapparent.
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(B) The earlier in life primary infection is acquired, the more likely the typical picture of infectious mononucleosis will be manifest.
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(C) Latently infected lymphocytes regularly persist following an acute episode of infection.
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(D) Infection confers immunity against second episodes of infectious mononucleosis.
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Each of the following statements regarding rotaviruses is correct EXCEPT:
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(A) The rotavirus vaccine contains recombinant RNA polymerase as the immunogen.
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(B) Rotaviruses are a leading cause of diarrhea in young children.
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(C) Rotaviruses are transmitted primarily by the fecal–oral route.
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(D) Rotaviruses have a double-stranded, segmented RNA genome.
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Each of the following statements concerning the antigenicity of influenza A virus is correct EXCEPT:
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(A) Antigenic shifts, which represent major changes in antigenicity, occur infrequently and are due to the reassortment of segments of the viral genome.
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(B) Antigenic shifts affect both the hemagglutinin and the neuraminidase.
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(C) The worldwide epidemics caused by influenza A virus are due to antigenic shifts.
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(D) The protein involved in antigenic drift is primarily the internal ribonucleoprotein.
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Each of the following statements concerning adenoviruses is correct EXCEPT:
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(A) Adenoviruses are composed of a double-stranded DNA genome and a capsid without an envelope.
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(B) Adenoviruses cause both sore throat and pneumonia.
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(C) Adenoviruses have only one serologic type.
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(D) Adenoviruses are implicated as a cause of tumors in animals but not humans.
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Each of the following statements concerning the prevention of viral respiratory tract disease is correct EXCEPT:
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(A) To prevent disease caused by adenoviruses, a live enteric-coated vaccine that causes asymptomatic enteric infection is used in the military.
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(B) To prevent disease caused by influenza A virus, an inactivated vaccine is available for the civilian population.
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(C) There is no vaccine available against respiratory syncytial virus.
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(D) To prevent disease caused by rhinoviruses, a vaccine containing purified capsid proteins is used.
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Each of the following statements concerning herpesvirus latency is correct EXCEPT:
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(A) Exogenous stimuli can cause reactivation of herpesvirus replication in latently infected cells.
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(B) During latency, antiviral antibody is not demonstrable in the sera of infected individuals.
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(C) Reactivation of latent herpesviruses is more common in patients with impaired cell-mediated immunity than in immunocompetent patients.
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(D) Herpesvirus genome DNA persists in latently infected cells.
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Each of the following statements concerning rhinoviruses is correct EXCEPT:
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(A) Rhinoviruses are the most common cause of the common cold.
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(B) Rhinoviruses grow better at 33°C than at 37°C; hence, they tend to cause disease in the upper respiratory tract rather than the lower respiratory tract.
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(C) Rhinoviruses are members of the picornaviruses family and hence resemble poliovirus in their structure and replication.
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(D) The immunity provided by the rhinovirus vaccine is excellent because there is only one serotype.
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Which one of the following statements concerning poliovirus infection is CORRECT?
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(A) Congenital infection of the fetus is an important complication.
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(B) The virus replicates extensively in the gastrointestinal tract.
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(C) A skin test is available to determine prior exposure to the virus.
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(D) Oseltamivir is an effective preventive agent.
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Each of the following statements concerning yellow fever is correct EXCEPT:
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(A) Yellow fever virus is transmitted by the Aedes aegypti mosquito in the urban form of yellow fever.
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(B) Infection by yellow fever virus causes significant damage to hepatocytes.
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(C) Nonhuman primates in the jungle are a major reservoir of yellow fever virus.
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(D) Acyclovir is an effective treatment for yellow fever.
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Which one of the following statements concerning mumps is CORRECT?
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(A) Although the salivary glands are the most obvious sites of infection, the testes, ovaries, and pancreas can be involved as well.
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(B) Because there is no vaccine against mumps, passive immunization is the only means of preventing the disease.
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(C) The diagnosis of mumps is made on clinical grounds because the virus cannot be grown in cell culture and serologic tests are inaccurate.
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(D) Second episodes of mumps can occur because there are two serotypes of the virus and protection is type-specific.
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Many of the oncogenic retroviruses carry oncogenes closely related to normal cellular genes, called proto-oncogenes. Which one of the following statements concerning proto-oncogenes is INCORRECT?
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(A) Several proto-oncogenes have been found in mutant form in human cancers that lack evidence for viral etiology.
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(B) Several viral oncogenes and their progenitor proto-oncogenes encode protein kinases specific for tyrosine.
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(C) Some proto-oncogenes encode cellular growth factors and receptors for growth factors.
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(D) Proto-oncogenes are closely related to transposons found in bacteria.
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Each of the following statements concerning human immunodeficiency virus is correct EXCEPT:
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(A) The CD4 protein on the T-cell surface is one of the receptors for the virus.
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(B) There is appreciable antigenic diversity in the envelope glycoprotein of the virus.
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(C) One of the viral genes codes for a protein that augments the activity of the viral transcriptional promoter.
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(D) A major problem with testing for antibody to the virus is its cross-reactivity with human T-cell leukemia virus type I.
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Each of the following statements concerning human immunodeficiency virus (HIV) is correct EXCEPT:
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(A) Patients infected with HIV typically form antibodies against both the envelope glycoproteins (gp120 and gp41) and the internal group-specific antigen (p24).
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(B) HIV probably arose as an endogenous virus of humans because HIV proviral DNA is found in the DNA of certain normal human cells.
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(C) Transmission of HIV occurs primarily by the transfer of blood or semen in adults, and neonates can be infected at the time of delivery.
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(D) The diagnosis of early HIV infection is made by testing the patient’s serum for antibodies against HIV and for p24 antigen.
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Each of the following statements concerning hepatitis A virus (HAV) is correct EXCEPT:
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(A) The hepatitis A vaccine contains inactivated HAV as the immunogen.
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(B) HAV commonly causes asymptomatic infection in children.
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(C) The diagnosis of hepatitis A is usually made by isolating HAV in cell culture.
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(D) Gamma globulin is used to prevent hepatitis A in exposed persons.
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Causes congenital abnormalities
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(E) Subacute sclerosing panencephalitis
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(E) Subacute sclerosing panencephalitis
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Respiratory syncytial virus causes
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(E) Subacute sclerosing panencephalitis
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(E) Subacute sclerosing panencephalitis
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Varicella-zoster virus causes
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(E) Subacute sclerosing panencephalitis
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Causes myocarditis and pleurodynia
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Grows better at 33°C than 37°C
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Causes tumors in laboratory rodents
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Causes croup in young children
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Causes infectious mononucleosis
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It is implicated as the cause of carcinoma of the cervix.
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(E) St. Louis encephalitis virus
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Wild birds are an important reservoir.
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(E) St. Louis encephalitis virus
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It is an important cause of pneumonia in immunocompromised patients.
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(E) St. Louis encephalitis virus
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Donated blood containing antibody to this RNA virus should not be used for transfusion.
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(E) St. Louis encephalitis virus
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It causes a hemorrhagic fever that can be life-threatening.
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(E) St. Louis encephalitis virus