Researchers determined that Chapare virus likely spread from person to person during a deadly outbreak in Bolivia, according to findings presented at the American Society of Tropical Medicine and Hygiene Annual Meeting.
Chapare virus belongs to a family of viruses known as arenaviruses, which include pathogens such as Lassa and Machupo viruses. Arenaviruses are usually spread via contact with an infected rodent or its feces, according to the CDC.
However, researchers found that Chapare virus caused at least five infections near La Paz, Bolivia, in 2019 three of which were fatal and that infections occurred through encounters with infected patients.
It was only the second Chapare virus outbreak on record, according to a press release. The first occurred in 2004, 370 miles away from the more current outbreak, and consisted of a small cluster and only one confirmed case. Patients in the 2019 outbreak reported fevers, abdominal pain, vomiting, bleeding gums, rash and pain behind their eyes.
According to the release, the latest outbreak “surprised health authorities” because they initially only knew that it was a hemorrhagic fever presenting similarly to Ebola. This “sparked a rapid mobilization of infectious disease experts,” according to the release.
Outbreak data showed that a medical resident, who later died from Chapare, may have been infected while suctioning saliva from a patient, according to findings presented at the meeting. Another patient, an ambulance medic who survived infection, was likely infected while resuscitating the medical resident during transport. Additionally, researchers were able to detect viral RNA in the semen of another survivor more than 168 days after infection, raising the possibility of sexual transmission.
“Our work confirmed that a young medical resident, an ambulance medic and a gastroenterologist all contracted the virus after encounters with infected patients, and two of these health care workers later died," Caitlin Cossaboom, DVM, PhD, MPH, an epidemiologist with the CDC's Division of High-Consequence Pathogens and Pathology, said in the press release. "We now believe many bodily fluids can potentially carry the virus."
Cossaboom and colleagues think Chapare virus could have been circulating in Bolivia for several years, with some infected patients being wrongly diagnosed as suffering from dengue. Although the cause of the outbreak is still unknown, the researchers presented evidence that Chapare viral RNA was detected in pigmy rice rats and small-eared pigmy rice rats from areas near La Paz.
According to Cossaboom, the confirmation of human-to-human transmission demonstrates that anyone dealing with suspected cases “must take extreme care” to avoid contact with items contaminated with blood, urine, saliva or semen.