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Hantaviruses
Hantaviruses are part of the viral family Bunyaviridae. They represent one of the groups
of zoonotic viruses, which can be transmitted from animals to humans. Hantaviruses are
spherical, about 100 nm in diameter. Interestingly, unlike humans, their genetic material
is not composed of double-stranded DNA. Instead, it is composed of a single strand of RNA
in three segments. These viruses are surrounded by a lipid (fatty) envelope, so they are
somewhat fragile. The lipid envelope can be destroyed and the virus killed by fat solvents
like alcohol, ordinary disinfectants and household bleach. That is why one of the most
important ways to prevent transmitting HPS is to carefully wet down dead rodents and areas
where rodents have been with disinfectant and/or bleach. When you do this, you are
reducing the chance that any virus will get into the air, as well as killing virus
particles themselves.
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Thin-section electron micrograph of Sin Nombre virus
isolate, a causative agent of hantavirus pulmonary syndrome (HPS). From the 1994
outbreak of HPS in the southwestern United States.
High-resolution view |
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As far as human disease is concerned, hantaviruses are divided into two major groups.
The Hantaan, Puumala, and Seoul viruses are found mostly in the Asia and Europe. They
cause a group of illnesses called hemorrhagic fever with renal syndrome (HFRS). In people
with HRFS, the kidneys may not function properly, so the body is not as able to produce
urine. People with severe cases of HFRS may have circulatory problems, including shock,
bleeding, and fluid buildup in the lungs, and abnormal liver function is sometimes seen.
In general, these hantaviruses cause death in less than 10% of the people who become
infected with these viruses.
So far, the second group of hantaviruses has been found only in the Americas. In the
United States, this group includes the Sin Nombre virus (SNV), carried by the deer mouse,
which caused the well-publicized "Four Corners" outbreak. Three other
hantaviruses have been recently discovered that have caused several cases with the same
pulmonary symptoms. The Black Creek Canal virus, carried by the cotton rat, was found in
Florida, while the Bayou Virus, carried by the rice rat, was found in Louisiana. In New
York, the New York-1 virus was linked to the white-footed mouse. Several other
hantaviruses, Prospect Hill, Rio Segundo, Rio Mamore, and El Moro Canyon, have also been
discovered, but they have not yet been associated with any disease in humans.
HPS cases have also been confirmed elsewhere in the Americas, in Argentina,
Bolivia, Brazil, Canada, Chile, Panama, Paraguay and Uraguay. In addition,
rodents carrying viruses similar to Sin Nombre have also been found in
Costa Rica and Mexico, but these hantaviruses have not been associated
with disease in humans.
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National
Center for Infectious Diseases
