Definition: Chapare hemorrhagic fever (CHHF) is caused by Chapare virus, a single-strand RNA virus of the Arenaviridae family. Chapare virus is certainly zoonotic, or animal-borne. The limited clinical information about CHHF comes from a small, poorly described cluster of hemorrhagic fever cases in rural Bolivia. A single fatal case yielded the only clinical description and blood specimen to date.
Symptoms and Treatment: The symptoms of CHHF, as reported in the only described patient, resemble those of other South American hemorrhagic fevers, such as Argentine HF or Bolivian HF. The incubation period is unknown, but for Argentine hemorrhagic fever (AHF) is 6 to 16 days. The CHHF clinical course included: Fever, headache, articulation and muscle pain, vomiting. These symptoms were followed by deterioration with multiple hemorrhagic signs. The only described CHHF patient died 14 days after onset of symptoms. Supportive therapy is important in CHHF. This includes: maintenance of hydration, management of shock, sedation, pain relief, usual precautions for patients with bleeding disorders, transfusions. Use of convalescent plasma therapy for treatment of AHF reduces mortality significantly and anecdotal evidence shows that the antiviral drug ribavirin may also hold promise for treating AHF. Ribavirin has also been considered for preventing development of disease in people exposed to other arenaviruses.
Statistics: A second report utilizing young (2.5–4kg) and adult (5–8kg) rhesus macaques resulted in mortality rates of 85% and 50% following infection with 103 pfu. The MTD was similar as with the first study. Survivors developed late neurological disease 26 to 41 days after infection in which 66% of the surviving young macaques and all of the adult macaques succumbed to disease. Histopathological examination of infected macaques identified moderate to severe encephalitis with vasculitis and internal hemorrhage.