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- Bundibugio from the high road: the Ebola virus has mutated and got to humans from animals
Bundibugio from the high road: the Ebola virus has mutated and got to humans from animals
The genome of the Ebola Bundibugio strain circulating in Africa differs markedly from the variants of the virus in previous outbreaks due to mutations, a study by African scientists has shown. The changes may indicate that the pathogen has been transmitted between animals for a long time, and then got to humans. This led to the development of a deadly epidemic. Despite the fact that the mutations affected proteins important for cell penetration, it is premature to draw conclusions about the increased contagiousness of the virus and the severity of fever caused by it. However, it is already clear that other test systems and new vaccines are needed for Bundibugio, as the old ones are not effective enough, experts noted.
The other Bundibugio
Scientists from the Democratic Republic of the Congo (DRC) and Uganda conducted a genetic study of the Ebola virus strain Bundibugio (BDBV), which caused the current outbreak of the disease in Africa. The researchers compared its genome with samples obtained during previous epidemics of this pathogen in 2007 and 2012. Some of the work was done in a laboratory in the DRC, and the other in Uganda.
Scientists have found a noticeable difference in the genes, which suggests that Bundibugio is mutating. Given the degree of differences, experts are inclined to conclude that the virus has been in the body of animals for a long time, and then got to humans, which triggered the outbreak.
"Phylogenetic analysis has shown that the 2026 viruses form a cluster, but are genetically different from those identified during previous outbreaks in 2007 and 2012. This confirms the hypothesis that the current situation is related to a new case of transmission from an animal carrier, and not to the persistence in the human population of the virus that circulated during earlier outbreaks," the staff of the Ministry of Health, Hygiene and Social Welfare of the DRC interpreted the research data in an article in the Lancet journal.
According to the Ministry of Health of the DRC, as of June 1, the number of confirmed cases of Ebola infection in the Democratic Republic of the Congo (DRC) reached 282, 42 people died, 238 more patients are being treated, two recovered. Uganda, where nine infected people were identified and one death was recorded, closed the border with the DRC. Anti-epidemic measures are being introduced in other African countries. The media also reported two suspected cases of Ebola in Brazil. Rospotrebnadzor considers the risk of importing the disease into our country to be minimal.
How did the mutations affect the virus?
The results of the genomic analysis do not indicate the appearance of some kind of "super mutant", but that the outbreak of Bundibugio in 2026 is apparently associated with a new introduction of the virus from a natural reservoir into the human population, says Albert Rizvanov, head of the Center for Excellence "Personalized Medicine" at Kazan (Volga Region) Federal University.
— The genomes of the current outbreak form a separate branch and differ from the variants of 2007 and 2012 by hundreds of point substitutions in a genome about 19 thousand nucleotides long. At the same time, within the current outbreak, the samples are close to each other, which makes it possible to use these differences as molecular markers to restore transmission chains and estimate the time of the onset of infection," the specialist said.
There are no grounds to claim that the mutations found have made the virus more contagious, more lethal, or changed the way it was transmitted. Some of the substitutions affect proteins, including a glycoprotein, which is important for infection to enter cells, but the mere fact of a mutation does not mean a change in the properties of the virus. For such conclusions, separate laboratory and epidemiological studies are needed. It evolves in the usual mode for RNA viruses, accumulating point changes, but so far we see no signs of targeted adaptation to a greater danger to humans, the scientist emphasized.
Such changes are typical for all viruses that have been circulating among animals for a long time, says immunologist Mikhail Bolkov.
— So far, no proven reservoir of the virus has been found in nature. But everyone suspects fruit-eating bats. They revealed previous versions of the infection and antibodies to it. These animals can carry the infection asymptomatically due to their special immune system," Mikhail Bolkov said.
Similar mechanisms are observed, for example, in the influenza virus, which periodically enters the reservoir among animals and then returns to our population in a modified form. The study also showed that traditional specific PCR tests for the Ebola virus are ineffective in detecting the new Bundibugio strain. In this regard, the use of more universal diagnostic methods is required. In addition, it was found that antibodies against the widespread Zaire strain (against which existing vaccines have been developed) do not provide protection against the Bundibugio variant. The expert stressed the need for further mutation monitoring.
The article is about changing the structure of the virus, Andrey Pozdnyakov, an infectious disease specialist at INVITRO, agreed with the conclusions of his colleagues. According to him, due to mutations, the pathogen has ceased to be identified by part of the test systems originally developed for early versions of the pathogen. At the same time, other diagnostic methods — PCR and sequencing — still make it possible to identify the current strain. In other words, the virus has slightly mutated, and specialists are currently adapting the diagnosis to the modern version. How exactly this mutation will affect the pathogenicity and contagiousness of the pathogen remains unknown.
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