Like all arenaviruses, Chapare virus has a rodent host as its reservoir. Humans can contract CHHF through contact with an infected rodent. Contact can be direct or through inhalation of aerosolized Chapare virus from the urine or feces of infected rodents.
Although arenaviruses have been isolated from insects, neither they nor any other intermediary host appear to spread CHHF.
Person-to-person transmission of arenaviruses through aerosolization, although possible, is rare. From the only observed cluster of cases of CHHF, there was no evidence of person-to-person transmission.
Transmission, if it can occur with CHHF, is most likely the result of direct contact with an infected person.