Emerging Ebola-like virus in Bolivia may spread between humans, scientists say

Madre de Dios river in Bolivia

Madre de Dios river in Bolivia
Photo: LIDIA PEDRO / AFP (Getty Images)

Scientists are calling for caution in the face of a mysterious Ebola-like viral disease that appears to have spread from person to person during a small outbreak in Bolivia last year. The disease, caused by the Chapare virus, has killed three people and is believed to have sickened at least five during the outbreak, including three health workers who came into contact with patients. Its symptoms include internal bleeding, fever, and generalized organ damage.

The virus is appointed after the place where the first known outbreak of the disease occurred at the end of 2003, near the Chapare River in Bolivia. Although several people were suspected of having the disease in 2003 and 2004, detailed information and blood samples were collected from only one patient at the time: a living 22-year-old tailor and farmer. in the rural village of Samuzabeti.

The man first developed a headache and fever, which progressed to joint pain, vomiting, and internal bleeding, also called hemorrhages. This collection of symptoms is known as hemorrhagic fever and is a familiar, often fatal, outcome of other very dangerous but generally rare viral diseases like Ebola. In less than two weeks, the man died.

Doctors were able to study his blood and isolate a virus never before documented, while ruling out other potential diseases common to the region such as dengue. The mystery virus was discovered to be a member of the arenavirus family, a group of viruses which commonly infect rodents and sometimes humans. Its parents include the more well-known Lassa virus and other viruses first found in South America, such as the Machupo virus in Bolivia and the Junin virus in Argentina. Many of these viruses can cause hemorrhagic fever in humans.

In 2019, the Chapare virus reappeared in Bolivia, first found in a farm worker who developed a hemorrhagic fever and ultimately died from it. After it became apparent that the patient’s alarming symptoms were not caused by dengue or more mundane illnesses, health officials began a detailed investigation, ultimately seeking help from the Centers for Disease Control and Prevention. in the USA. down with the Chapare virus.

More arenaviruses that make people sick are known to spread from rodents to humans. Usually this happens when people breathe in aerosols from dried rodent urine or virus-contaminated feces or come into direct contact with rodents. In this latest outbreak, health officials found traces of Chapare virus in rodents near where the farmer was working, according to research presented this week at the Virtual Annual Meeting of the American Society of Tropical Medicine and Hygiene.

But at least three healthcare workers who interacted with infected patients – a resident doctor, paramedic, and gastroenterologist – also developed illness, two of whom ultimately died. Health officials firmly believe that the virus has spread from person to person in these other cases. Another disturbing finding was that viral traces could be found in the semen of a survivor more than 160 days after infection, which has also been documented for hemorrhagic fever viruses like Ebola.

“We now believe that there are many bodily fluids that can potentially carry the virus,” said Caitlin Cossaboom, epidemiologist in the CDC’s Division of High-Risk Pathogens and Pathologies, declaration published by the American Society of Tropical Medicine and Hygiene.

Given the current pandemic and how it has begun, it’s understandable to be concerned about this news. But while this isn’t totally unwarranted, it’s worth noting that most human outbreaks of arenavirus tend to be limited, like this one. And their main route of transmission is still mainly rodents to humans. Even though this virus can be spread from person to person, it appears to be through direct contact with bodily fluids like blood or saliva, which limits its potential for spread, as does its lethality. Compare that to something like covid-19, which is a respiratory disease that spreads easily through the respiratory system – you only need to breathe the same air as an infected person – and can be transmitted even before someone else. is visibly ill.

That said, it is absolutely important for epidemiologists and other scientists to keep a close eye on potential threats such as the Chapare virus, especially in areas of the world where health care resources are limited, increasing the potential risk. transmission to health workers. Even viruses that are only truly spread by direct contact with bodily fluids can burst. major outbreaks under the right conditions, such as when an Ebola outbreak in West Africa in 2014 nearly infected 30,000 people and killed over 11,000 people. Lassa virus, linked to Chapare, also infects regularly up to 300,000 people per year in parts of Africa where it is found, killing around 5,000 per year.

For now, scientists plan to learn as much as possible about the Chapare virus from these latter cases, including its likely rodent hosts, where it may have originated, and whether it has circulated in the countries without the knowledge of doctors. In the wake of the 2019 outbreak, doctors have since documented three more possible cases, although all of the patients survived.

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