The breakout of this disease started in Bolivia, due to deforestation, agriculture, and the removal of predators. The jungle was cleared for corn cultivation in the 1950's which caused the field mouse (the local host of the Machupo virus) to feast on the corn. Its population exploded and overran the villages, fatally infecting up to 20% of the local inhabitants. Yet to endure the problem was the fact that the village cats had been killed off by massive DDT spraying to control malarial mosquitoes. Then the reintroduction of cats, which aren't affected by the virus, has slowed the epidemic.
Bolivian hemorrhagic fever (BHF), also known as black typhus or Machupo virus, is a hemorrhagic fever and zoonotic (animal to human transmitted) infectious disease occurring in Bolivia. It was first identified in 1959, black typhus is caused by infection with machupo virus, a negative single-stranded RNA virus of the Arenaviridae family. The infection is slow with fever, malaise, headache and muscular pains. Blood spots on the upper body and bleeding from the nose and gums happens when the disease progresses to the hemorrhagic phase, usually within seven days. The mortality rate is estimated at 5 to 30 percent. Due to its pathogenicity, Machupo virus requires Biosafety Level Four conditions, the highest level.
The main transmitter is the vesper mouse which is a rodent indigenous to northern Bolivia. Infected animals show no evidence of the disease but shed the virus in excretions, by which humans are infected. Evidence of person-to-person transmission of Machupo virus exists but it is very rare. In other words Machupo is excreted in mice urine and feces, which contaminate human food supplies and enter the body when eaten or inhaled. It kills by disrupting capillaries, causing victims to bleed to death.
Measures to reduce contact between the vesper 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 JunÃn virus which causes Argentine hemorrhagic fever has shown evidence of cross-reactivity with Machupo virus and may be an effective preventive or protective measure for people at high risk of infection. But there are no cures or immunizations for this disease, although those who have contracted it are immune.
Most of the people that are around these diseases are farmers and animal husbandry workers. They are directly working in these types of environments and don't take many precautions but there are new things being developed to help this. New techniques are being taught to these workers so that they can avoid getting this disease and transmitting it even though it is rare to transmit it. Candid #1 AHF vaccine is an alternative used for workers at high risk. Finally, agricultural workers in the disease-endemic region should be taught methods to reduce exposure to rodent reservoirs, especially around rural shelters in order to reduce their risk of exposure to Machupo virus in the environment.
