chapare hemorrhagic

fever (CHHF) is a viral hemorrhagic fever caused by infection with Chapare virus. The Chapare virus is in the arenavirus family. Arenaviruses are usually spread to people through direct contact with infected rodents or indirectly through the urine or feces (droppings) of an infected rodent.

There have been two documented outbreaks of CHHF to date. The first occurred in 2003 in Chapare Province, Bolivia, which resulted in one fatal case. The second outbreak occurred in 2019 in Caranavi Province, Bolivia and resulted in five confirmed cases— three of which were fatal.

Transmission

Though the rodent reservoir of Chapare virus is unknown, similar arenaviruses are typically transmitted either through direct or indirect contact with the saliva, urine, and droppings of infected rodents. Examples of direct contact include bites and scratches by infected rodents. Examples of indirect contact include breathing in the virus when it is stirred into the air or ingestion of food contaminated with the urine, salvia, or droppings of infected rodents.

An infected person can then spread the illness to other people through contact with the patient’s body fluids, or during procedures in healthcare settings that can aerosolize (spray particles of) the infected person’s body fluids—such as during chest compressions, CPR, and intubation. Because there are very few documented cases of Chapare in humans, more research is needed to understand how the virus spreads and causes illness.

Diagnosis

Because infection with Chapare virus infection can produce hemorrhagic symptoms in humans, often with a fatal outcome, work with suspected samples should be conducted using the highest biosecurity standards available (CDC advises a Biosafety Level 4 laboratory), strictly following all protocols for personal protection, sample inactivation and waste disposal. In the United States, Chapare virus is classified as a Select Agent.

CHHF virus was successfully isolated from both blood and serum during the acute febrile phase of illness in the first confirmed case in Bolivia in 2003. Subsequent complete genomic analysis of Chapare virus facilitated the development of specific molecular detection assays, including real-time reverse transcription polymerase chain reaction (rRT-PCR). Like other related arenaviruses, Chapare virus may be detectable in body fluids (serum, blood, semen, urine, respiratory secretions) of survivors following resolution of symptoms. These should be monitored prior to patient release.

Individuals from endemic areas and/or with compatible symptoms should be considered suspected cases and tested for Chapare virus using specific molecular detection assays that identify the virus. Depending on the region and clinical epidemiological picture of the patient, differential diagnoses may include Bolivian hemorrhagic fever (Machupo virus) or other South American New World arenaviruses, dengue, leptospirosis, yellow fever, hantavirus, and others. Serological assays specific for Chapare are not yet available.