The Ebola-like disease that sparked alarm in Bolivia over its human-to-human transmission

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He has been asleep for more than 15 years, until a few months ago he killed three people. A hemorrhagic virus similar to Ebola raised the alarm in Bolivia after killing a farmer and two toilets near the capital. It is called chapare, after the region in which it was first detected, in 2004, and in 2019 it resurfaced in its most lethal form. A group of researchers has concluded that it can be transmitted between humans and that this increases the risk of possible outbreaks in the future.

“We were in Colombia in the middle of fieldwork on hemorrhagic fevers when the news of these three suspicious deaths in Bolivia reached us,” María Morales-Betoulle, of the United States Center for Disease Control and Prevention, recounted in a telephone conversation. The deployment was immediate. The coroner at the hospital where the deaths occurred collected samples from the deceased and sent them to the Ministry of Health. These were analyzed in La Paz and Atlanta (United States) and in just a few weeks they obtained their sequencing. They designed a molecular test to detect other possible cases (similar to coronavirus PCRs but with blood samples). Another team traveled to the village of the deceased farmer to investigate the origin of the virus.

What they found was mice. The researchers took samples from several rodents in the area and found the virus (of the arenavirus type) in them. By approaching the farmers’ rice fields, they had infected patient zero. Doctors of the Pan American Health Organization Jairo Méndez and Sylvain Aldighieri were part of the device. “The human is an accidental host, so it is usually fatal, because it is not natural. As man extends his crops, the interaction with rodents begins and this is how the infection occurs ”, explains Aldighieri by phone. “For example, there is a risk when the corn grains are inside the houses and the animal enters to eat them and leaves their excrement”, he completes.

Now that there is a specific molecular test for this virus, it is foreseeable that more cases will be found. In fact, since the outbreak and thanks to the tests designed in those days, three other infected have been identified, one of them a child. They all survived. “The fact that there are periods of silence does not mean that the virus is not there, but that it is still in the animal but with little population explosion or far from human beings”, adds Méndez.

The symptoms of this disease are confused with others present in the region, such as dengue. The patients suffered from fever, abdominal pain, vomiting, skin rash, and pain behind the eyes. “But what alerted us the most was the blood on the gums,” emphasizes Betoulle, who is now in the Democratic Republic of the Congo working on Ebola issues. “Human-to-human transmission is by fluids. One of the patients had very important digestive bleeding, which increased the risk factors for contagion from the doctor who treated him, ”says the specialist. The doctor who lost her life was a young resident, and the other was the emergency doctor who took her in the ambulance. The experts also found 168 days after the contagion that the virus was still present in the semen of the son-in-law of patient zero, who was the one who accompanied him to the hospital, which also opens the door to sexually transmitted infection.

Can it cross borders? “There is no need to generate panic. The normal thing is that this type of virus cannot replicate itself, so it arrives and dies in the same host. But it is also true that as humans have more contact with viruses, they adapt in a slow but safe process, ”points out Méndez, the specialist at the Pan American Health Organization.

By being transmitted by direct contact with fluids, rather than by aerosols such as COVID, the spread of this disease is complicated. In similar cases, such as Ebola, the 2014 epidemic, the deadliest, hit mainly three countries: Guinea, Liberia and Sierra Leone. But experts like Méndez warn that we must learn the lessons that the covid has left us: “If a year ago they had asked me if a pandemic due to a coronavirus was possible, I would not have been able to answer. 2020 has shown us humility and that nothing can be taken for granted ”.

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