A Bolivian rice farmer arrived at a local rural clinic with a fever, muscle and joint pain, vomiting, rash, abdominal pain, and an ache behind the eyes. Those caring for him suspected dengue fever, caused by mosquito-borne dengue virus.
But a dengue test came back negative.
Before the 2019 outbreak was over, five people were infected and three died, including the farmer. When researchers in Bolivia and the U.S. retraced the chain of transmission and infectious agent behind the mysterious disease, they found that the culprit, was a hemorrhagic fever-causing arenavirus called Chapare virus, not seen for nearly two decades.
Viral sequences in samples from several infected individuals helped the team place Chapare within the “New World” arenavirus collection — evolutionary cousins to hemorrhagic fever-related arenaviruses such as Lassa virus in Sierra Leone, Liberia, and other parts of West Africa — and highlighted rodents as possible carriers responsible for passing the virus to humans in Bolivia.
As importantly, the new molecular clues made it possible to come up with a reliable diagnostic test for finding and curbing Chapare virus outbreaks in the future.
“They now have the ability to test in-country. That marked huge gains for Bolivia to improve its surveillance and diagnostic capacity for this virus and also other infectious diseases in general,” explained Caitlin Cossaboom, an epidemiologist and Epidemic Intelligence Service officer at the U.S. Centers for Disease Control and Prevention, who shared details from the outbreak investigation at the American Society of Tropical Medicine and Hygiene virtual annual meeting last week.…