The current Ebola outbreak in Guinea-Conakry may have been triggered by a survivor of the disease epidemic in West Africa that killed more than 11,300 people in West Africa between 2013 and 2016. This scenario was suggested after three research teams sampled the virus from patients in the recent Guinea-Conakry outbreak. But we need to investigate further.
The latest outbreak in Guinea-Conakry has already reported at least 18 infected people and nine deaths. This outbreak was detected after a 51-year-old nurse diagnosed with malaria and typhoid died in late January. After his funeral, several people (including his family members) fell ill and four died. It is even believed that Ebola caused all of the deaths. In early February, the virus was discovered in the nurse’s husband’s blood, according to an article on Science magazine’s website. The outbreak was reported in mid-February and the nurse is likely patient zero.
Then Guinea’s Infectious Disease Research and Education Center and the country’s National Hemorrhagic Fever Laboratory sequenced the four genomes of each patient after the most recent outbreak. The Paskar Institute in Dakar has already sequenced two more. In three articles that have not yet been peer-reviewed and are available on the virology website, the groups report that the new genomes are very similar to those of the Makona variant of the virus collected from the same region in 2014 and were responsible for the previous epidemic. Or they even indicate that the samples now sequenced belong to this variant of the virus. A phylogenetic tree shows that the new virus “fits” into the samples from the epidemic five years ago. This is highlighted in the article in Science.
The Ebola vaccination started in Guinea-Conakry at the end of February
Based on these results, it is believed that the virus that triggered the most recent outbreak has been dormant with a survivor of the 2013-2016 epidemic all along and has now triggered a new outbreak. Eric Delaporte, a researcher at the University of Montpellier, is part of one of the teams and told Science that a new outbreak that started with a latent infection since the other epidemic was something “terrifying and new”. Michael Wiley, a virologist at the University of Nebraska Medical Center, who was also involved in the investigation, even described the new outbreak in the New York Times as a “continuation” of the previous one.
Stephan Günther, virologist at the Bernhard Nocht Institute for Tropical Medicine (in Germany) and member of one of the teams, points out that until recently it was assumed that an Ebola outbreak began when a virus “jumped” for a vet People, what could have happened in Guinea-Conakry. With the results achieved, however, it must be “incredibly unlikely,” he says.
Last week, Mike Ryan (Director of the World Health Organization’s Health Emergencies Program) stated at a news conference that the current Guinea-Conakry outbreak was likely caused by a latent infection of the human population since the last outbreak and its onset would not coincide with the transmission of the Virus from animal to human (a zoonosis). The WHO official said these words based on the results of genetic sequencing but said more research was needed.
“Very surprising” results
While all of this makes sense, scientists who did not take part in the study warn that it has not yet been proven that the virus has actually been sleeping in a person for five years. “From the tree [filogenética]It is concluded that it is a virus that somehow persisted in the region and, of course, likely a survivor, ”Daniel Bausch, a virologist at the London School of Hygiene and Tropical Medicine, told Science. It is not known that the nurse could have been a survivor of the previous epidemic, but she may have had contact with someone (even through her job) or she was even infected a few years ago and had few symptoms. “Finding out exactly what happened is one of the big questions,” says Daniel Bausch.
Angela Rasmussen, a virologist at Georgetown University (in the US), thinks these results are “very surprising”. “Ebola viruses are not herpes viruses [conhecidos por causarem infecções prolongadas] and usually RNA viruses [o seu material genético] You don’t stop here without replicating yourself. “It was already known that the Ebola virus can persist in the human body for a long time, but not that long. For example, a resurgence in Guinea-Conakry in 2016 came from a person who spread the virus more than 500 days after being infected by semen.
There’s also currently an outbreak in the Democratic Republic of the Congo that started transmitting someone who was infected in a previous outbreak, says Eric Delaporte. The researcher notes that all of this suggests that humans are likely the source of new Ebola outbreaks as well as wildlife. “This is clearly a new paradigm for outbreak onset.”
There are now important questions that need to be answered, such as: B. the therapies that can be developed for survivors or the consequences that may remain with them. It will also be crucial to face the stigma (and even violence) that they will face. Because there are survivors who may have few symptoms, there are also people who may have been infected without knowing it. Daniel Bausch therefore calls for new awareness-raising campaigns that explain, for example, that there is a risk to have unprotected sex with a survivor, but that there is no risk in working with them or shaking hands. It would also be important to continue to monitor survivors at the clinical level.
The Ebola vaccine was given to people at high risk in Guinea-Conakry on February 23. The vaccination campaign against this virus in the Democratic Republic of the Congo began on February 15.