Bolivian haemorrhagic fever

Machupo virus

Bolivian Haemorrhagic Fever (Machupo), more commonly known as Black Typhus, was first identified in 1959. BHF is a zoonotic infectious disease occurring in Bolivia. It is caused by infection with Machupo virus, a negative single-stranded RNA virus of the Arenaviridae family. The infection has a slow onset with fever, malaise, headache and muscular pains. Petechiae (blood spots) on the upper body and bleeding from the nose and gums are observed when the disease progresses to the hemorrhagic phase, usually within seven days of onset. The mortality rate is estimated at 5-30%. Due to its pathogenicity, Machupo virus requires biosafety level 4 conditions (the highest level of biosafety).

The reservoir is the vesper mouse (Calomys callosus), a rodent indigenous to northern Bolivia. Infected animals are asymptomatic and shed virus in excretions, by which humans are infected. Evidence of person-to-person transmission of Machupo virus exists but is believed to be rare (Kilgore et al, 1995).

Measures to reduce contact between the vespers mouse and humans have effectively limited the number of outbreaks, with no cases identified between 1973 and 1994. A vaccine being developed for the genetically related Junin virus which causes Argentine haemorrhagic fever has shown evidence of cross-reactivity with Machupo virus and may be an effective prophylactic measure for people at high risk of infection.

References

Kilgore, Paul E., Peters, Clarence J., Mills, James N., Rollin, Pierre E., Armstrong, Lori, Khan, Ali S. and Ksiazek, Thomas G. (1995). Prospects for control of Bolivian Hemorrhagic Fever. Emerging Infectious Diseases 1(3).