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- To win at once: hundreds of deaths from Ebola in Africa caused by a new variant of Bundibugio
To win at once: hundreds of deaths from Ebola in Africa caused by a new variant of Bundibugio
The outbreak of deadly Ebola in Africa is caused by a new variant of the Bundibugio strain. It is genetically different from earlier viruses that caused the epidemics of previous years, a study by African scientists has shown. According to experts, the changes found may affect the rate of reproduction and the ability of the pathogen to evade immunity. However, animal experiments and patient observations are necessary for an accurate assessment. As the Gamaleya Center told Izvestia, the vaccine created there was developed specifically against the Bundibugio variant currently circulating in Africa. But she needs further testing. The death toll from Congo fever is approaching a thousand. The countries of the region are extremely interested in the Russian drug, the Russian Foreign Ministry stressed.
A new variant of Ebola
An international team of scientists from Congo, Uganda and several other countries conducted a study of the Ebola virus that is currently circulating in Africa. It turned out that the current version of Bundibugio is markedly different from the pathogens of this strain that caused the epidemics in 2007 and 2012. At the genetic level, the difference between related viruses exceeded 1.1%. This discrepancy is enough to consider the pathogen, which has already led to almost a thousand deaths, as a separate variant or subtype.
"At the genomic level, the new sequence from Uganda contained a total of 219 single-nucleotide genetic variations (i.e. changes in the genetic code. — Ed.)," the researchers noted in an article in the Lancet journal.
We are not talking about a fundamentally new Ebola virus, but about a new evolutionary line of the Bundibugio virus, Albert Rizvanov, head of the Personalized Medicine Center of Excellence at Kazan (Volga Region) Federal University, explained to Izvestia.
— Substitutions have been found in the genes of glycoprotein, polymerase, and proteins involved in viral reproduction and suppression of the immune response. Theoretically, they can affect the ability of the virus to enter cells, multiply, or evade immunity. However, based on the genome sequence alone, it cannot be said that the new variant has become more contagious or dangerous: experiments on cellular and animal models, as well as clinical and epidemiological data, must confirm this," the specialist said.
The number of people infected with Ebola during the outbreak in Congo has reached 2,344, 930 have died. The mortality rate from the disease caused by the Bundibugio virus, for which there is still no specific treatment, is 39.7%.
The obtained sequences are of great practical importance, since they can be used to check how accurately diagnostic tests recognize a new variant, whether antiviral antibodies retain the ability to bind its glycoprotein and whether vaccine antigens correspond to the circulating virus, Albert Rizvanov added.
— A licensed vaccine against the Zaire variant (the more common Ebola strain. — Ed.) has no proven effectiveness against Bundibugio, so now priority is being given to special vaccines against this virus. At the same time, the differences found do not mean that existing vaccine candidates will have to be completely redesigned: it is necessary to check whether mutations have affected key regions of the glycoprotein and whether they reduce the neutralization of the virus," he said.
Vaccine effectiveness
A specific vaccine against Bundibugio has already been developed at the Gamalea Center. It is currently in the testing stage.
— The vaccine was made based on the genetic sequence of the current strain from Africa, which was published. But further tests in the laboratory with this variant on monkeys will be required to make sure that the vaccine protects against this pathogen," Alexander Gintsburg, scientific director of the N.F. Gamalei Center, told Izvestia.
African states are interested in a Russian vaccine against a new strain of Ebola, the director of the Department of Sub-Saharan Africa told the media Russian Foreign Ministry Anatoly Bashkin.
— Now there is a certain competition, whose vaccine is more effective. All of them are being tested in specific countries and conditions. I think the demand for our vaccine will be quite high, because Ebola outbreaks occur regularly in Africa and the virus is constantly being modified," he said.
Different parts of the virus genome may have different meanings for its properties. For example, in SARS-CoV-2 (the causative agent of COVID-19), a shift in some proteins by even a hundredth of a percent could greatly affect it. However, to understand the role of changes in the Bundibugio virus, you need to know how the clinical picture and the ability to evade immunity have changed, says immunologist Mikhail Bolkov.
— Such assessments require observations "on the ground" in the epidemic zone. However, the genetic changes that we see are enough to consider the current pathogen as a new variant," the specialist said.
It is impossible to predict the further direction of evolution. Most likely, the virus will continue to gradually accumulate point mutations, most of which will not give it advantages. But with long-term transmission between humans, theoretically, changes can be fixed that increase the efficiency of reproduction or evade the immune response, Albert Rizvanov explained. According to him, it is especially important to constantly sequence new samples and compare mutations with the contagiousness, severity of the disease and effectiveness of treatment, without making premature conclusions about the appearance of a "super-dangerous" variant.
Переведено сервисом «Яндекс Переводчик»
