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Essentials of Diagnosis
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Transmitted by rodents and cause two clinical syndromes
Hemorrhagic fever with renal syndrome (HFRS): mild to severe illness
Hantavirus pulmonary syndrome (HPS): 40% mortality rate
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General Considerations
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Hantaviruses are enveloped RNA bunyaviruses; hosts are rodents, moles, and shrews
Hantavirus infection in humans can cause several disease syndromes
HFRS caused by Old World hantaviruses
Nephropathia epidemica (NE) is a milder form of HFRS. Puumala virus is the most prevalent pathogen and is present throughout Europe.
HPS, also known as hantavirus cardiopulmonary syndrome, is caused mainly by Sin Nombre virus and Andes virus, the New World Hantaviruses in Americas
A specific strain is not associated with a specific syndrome and overlap is seen between the syndromes
Aerosols of virus-contaminated rodent urine and feces are thought to be the main vehicle for transmission to humans
Person-to-person transmission is observed only with the Andes virus
Occupation at highest risk for transmission of all hantaviruses include
Animal trappers
Forestry workers
Laboratory personnel
Farmers
Military personnel
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A total of 728 cases of hantavirus infection have been reported in the United States since 1993
Average case fatality rate of 36%
Most of the cases were reported from states west of the Mississippi River
Outbreaks of HPS associated with other hantavirus types are also reported in Central and South America as well as the Caribbean
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Vascular leakage is the hallmark of the disease for both syndromes
HFRS manifests as mild, moderate, or severe illness depending on the causative strain
A 2- to 3-week incubation period is followed by a protracted clinical course, typically consisting of five distinct phases
Febrile period
Hypotension
Oliguria
Diuresis
Convalescence phase
Various degrees of renal involvement are usually seen
Puumala virus infection is often referred to as nephropathia epidemica
The kidney dysfunction component appears to correlate with levels of the plasma adipokine resistin that may by internalized or diffuse (as a capillary leak syndrome) and often confused with the complications of disseminated intravascular coagulation
Thromboembolic phenomena are also recognized complications
A secondary hemophagocytic lymphohistiocytosis can be seen with HFRS
Pulmonary edema is not typically seen but when present usually occurs in the final stages of disease (oliguric and diuretic phase)
Encephalitis and pituitary involvement are rare, although a few cases are reported with Puumala virus
Patients may have persistent hematuria, proteinuria, or hypertension up to 35 months after infection
Smoking appears to exacerbate the viremia with the Puumula virus infection, and bradycardia can ...