Clinical features of fatal cases of Chapare virus hemorrhagic fever originating from rural La Paz, Bolivia, 2019: A cluster analysis.

Introduction: In 2003 an emerging mammarenavirus (formerly arenaviruses) was discovered in Bolivia and named Chapare (CHAPV). It was associated with severe and fatal hemorrhagic fever, being similar in clinical features to Machupo (MACV). In mid-2019, CHAPV was the cause of a cluster of five cases, two of them laboratory confirmed, three of them fatal. Here, we report the main clinical findings, epidemiological features and the potential ecological aspects, of that cluster of cases in rural La Paz, Bolivia.

Methods: For this observational, retrospective and cross-sectional study, information was obtained from the Hospitals and the Ministry of Health for the cases that were laboratory-diagnosed and related, during 2019. RT-PCR was used for the detection of the RNA of CHAPV in the blood samples.

Results: Two cases were RT-PCR + for CHAPV. The median age of patients was 42 y-old (IQR 25-45), four out of five were male. All patients were hospitalized, admitted to the ICU and had fever, upper digestive hemorrhage, with two of them, presenting ARDS, and requiring mechanical ventilation. Three patients died (case fatality rate, CFR 60%).

Conclusions: Mammarenaviruses led to a high fatality rate. These cases occurred in areas with suitable ecoepidemiological conditions for rodent-borne diseases, including CHAPV infection. Socioenvironmental and occupational factors in rural areas of Bolivia may contribute with the risk of zoonotic spillover and transmission to humans.