Survivors of an outbreak of Ebola five years ago may have caused an ongoing outbreak in Guinea

The plastic sheet separates the 5-month-old gelation from the mother’s collet, a patient at the Ebola Treatment Center in Beni, North Kivu.Image Credit: UNICEF

The current outbreak of Ebola in Guinea has almost certainly survived the historic 2014-16 epidemic in West Africa, carrying the virus for at least five years, and then infecting sexual partners via semen. It has started, researchers reported on Friday. Gene-sequence-based discoveries of viral samples taken from patients with current outbreaks shocked researchers. To date, the longest known survival of the virus in survivors was 500 days. “It’s amazing,” Dr. William Schaffner, an infectious disease expert at Vanderbilt University, who wasn’t involved in the study, said in an interview. “This is an unusual phenomenon.”

The current outbreak in Guinea was first recognized in January, infecting at least 18 people and killing 9 people.

The finding that survivors are most likely to have started the outbreak has profound implications. A previous epidemic in West Africa infected more than 28,000 people, killed more than 11,000 and left thousands of survivors. Some of them were already repelled because of fear of illness. The prospect that the survivors may be infectious for years can exacerbate their plight.

New discoveries also increase the likelihood that other outbreaks in the region, which appear to have originated from infections from animals, have actually been initiated by survivors of unrecognized, protracted infections.

According to Schaffner, one possible solution is to “vaccinate most of Equatorial Africa” ​​against Ebola, even if it does not currently occur. Effective vaccines from Merck and Johnson & Johnson are available, but so far they have generally been used only to combat outbreaks.

When the immune system clears the virus, people recover from Ebola. However, certain parts of the body, such as the eyes, central nervous system, and testicles, are so-called privileged areas that go beyond the immune system. Viruses can hide in those places. But no one knew it could hide for a long time.

“We don’t know how often this is happening,” Schaffner said. “Several studies are underway. As you can imagine, it’s not easy to study viruses that are hidden in immune-privileged areas such as the testicles, eyes, and rarely the central nervous system. These are easy. Not an accessible place to study. “

The gene sequences of viral samples from current patients were compared to those from the 2014-16 outbreak and found to be so similar that they must be closely related, the researchers said. Stated. The report, posted online on Friday, was attended by researchers from the Ministry of Health of Guinea, other laboratories in the country, the Pastur Institute in Senegal, the University of Edinburgh, the University of Nebraska Medical Center, and Praesens Bio.

A member of the siege vaccination team will vaccinate a man in the village of Bosoro. Image credit: WHO / L.Mackenzie

Findings reported by early Friday Science And statistics..

“There are few changes in the genome, and the virus needs to multiply in order for them to occur,” Schaffner said. “I think the virus is almost dormant.”

“In particular, it provides great insights that molecular whole genome sequencing can provide,” he said. “Until this moment, we all believed that the current outbreak was the result of a natural, bat infection, but it probably came from a human reservoir.”

Michael Wily, a virologist at the University of Nebraska Medical Center and Chief Executive Officer of Praesens Bio, who provided the materials used to study the samples, described the outbreak as a “continuation” of the previous outbreak.

He said persistent and sexually transmitted infections were already recognized during outbreaks in West Africa and in the Democratic Republic of the Congo. Each new milestone in virus persistence is a shock, he said. The first 180 days, then 500 days, and now more than five years after the first infection.

The US Centers for Disease Control and Prevention said in a statement provided by its spokesman, Thomas Skinner: Although not 100% certain, the CDC agrees that the data support the conclusion that cases of current outbreaks are likely to be associated with cases in the region of West African Ebola hemorrhagic fever in 2014-2016. I will. “

He added: “This suggests that the outbreak is likely to have started with a persistent infection, a survivor, not a new introduction of the virus from an animal reservoir. The outbreak in the Democratic Republic of the Congo has given survivors. As we have seen related, the period from the end of the 2014-2016 outbreak to the emergence of this outbreak is surprising and requires further research to better understand complex epidemiology. It highlights the sex. The epidemiology of Ebola hemorrhagic fever. “

Dr. Ian Lipkin, a virologist at Columbia University, assumed that after having several semen samples in which male patients were tested negative for Ebola, they generally cleared the virus, but that is not always the case. He said it was not a correct assumption.

“People with Ebola probably need to be monitored regularly to make sure they are negative and remain negative,” he said.

Denise Grady. c.2021 The New York Times Company