Two days after returning from a short trip to Venezuala, an otherwise
healthy 48-year-old male arrives at your office complaining of fever,
chills, nausea, vomiting, malaise, and arthralgias. On exam he was
toxic appearing febrile, and you note abdominal tenderness, icterus,
and multiple erythematous papular lesions on his lower extremities.
Because of his recent tropical travel, you immediately send him
by ambulance to the ER. There, staff physicians suspect a case of
VHF and contact the local health department. During the course of
his deteriorating clinical course in the intensive care unit, the
patient developed severe coagulopathy and died. Autopsy revealed necrotic
portions of the liver and histologic findings consistent with yellow
fever. Yellow fever antigens were noted in blood samples, and the
diagnosis was confirmed by PCR. What infection control and decontamination
procedures should you have followed? In this case of a febrile individual
with a rash and with recent travel abroad, what is your DDX?
Extreme contagiousness, virulence, and mortality rates make VHFs
among the most feared diseases of humankind (Fig. 13–1).
Since the first documented case of a Marburg in 1967, VHFs have
been identified all over the world and have observable naturally
occurring outbreaks. No documented use of VHFs as bioweapons has
yet occurred; however, it is commonly accepted that the United States,
Russia, and probably other governments have successfully developed
weaponized versions of VHFs. What is known about the epidemiology,
transmission, clinical presentation, and prevention of VHFs is therefore
based on naturally occurring epidemics and bioweapons research.
Electron micrograph image of Lassa virus.
Courtesy of the CDC.
VHFs are caused by four distinct families of RNA viruses. Filoviridae,
which includes Ebola and Marburg viruses; Arenaviridae, which include
the etiologic agents of Argentine, Bolivian, and Venezuelan hemorrhagic
fevers, Machupo and Lassa fever; Bunyaviridae, which includes the Congo-Crimean
hemorrhagic fever virus (CCHFV) and the Rift Valley fever (RVF);
and finally, Flaviviridae, which includes dengue and yellow fever
viruses. With the important exception of filovirus, whose animal
reservoirs are speculative, VHFs are zoonotic.
Table 13–1 Timeline
of Ebola and Marburg |Favorite Table|Download (.pdf)
Table 13–1 Timeline
of Ebola and Marburg
|October 2000||The Ugandan Ministry of Health reports 176 cases of Ebola, including 64 deaths. |
|February 2001||A Canadian physician activates the national contingency plan for viral hemorrhagic fevers (VHFs) when VHF is diagnosed in a woman returning from the Congo.|
|December 2003||The Ministry of Health of the Republic of the Congo reported a total of 35 cases, including 29 deaths from Ebola.|
|March 2005||CDC confirms that VHF outbreak in Angola is Marburg. A total of 124 cases, with 117 fatalities, was reported.|
September 2004: A Case of Lassa Fever in New Jersey