Brazil scientists find mutations in yellow fever virus
The variation does not compromise the effectiveness of the vaccine against the disease, researchers believe 
Scientists from the Oswaldo Cruz Foundation (IOC/FIOCRUZ) have identified eight genetic mutations in the yellow fever virus from the 2017 outbreak. The changes are associated with proteins involved in viral replication, and were detected after the first full genome sequencing of the samples from two howler monkeys. The animals were found in a wooded area in Espírito Santo state, late in February this year. The variation does not compromise the effectiveness of the vaccine against the disease, researchers believe, but studies will continue in order to identify possible changes in the level of aggressiveness in the virus.
The studies, released this week, show that the viruses belong to the so-called South American 1E lineage, which, according to the institute, has been predominant in Brazil since 2008.
Ricardo Lourenço, head of the IOC Laboratory for Hematozoa-bearing Mosquitoes and one of the research coordinators, believes that the condition in which the monkeys were taken for sampling was instrumental in the identification process. One of the monkeys had died not long before, and another was still alive, though in a grave state. “They were not deteriorating, which allowed the viral particles in their bodies to be detected,” he told Agência Brasil. The researcher also reported that the animals were found during a field study with the aid of traps for collecting mosquitoes.
Vaccine
Myrna Bonaldo, head of the IOC Laboratory for Flavivirus Molecular Biology and another research coordinator, dismissed any possibility that the mutation may compromise the effectiveness of the vaccine used against yellow fever. “It's not affected. It's a really effective vaccine that's been administered for 80 years,” she declared, adding that the variation is not taking place in the main viral proteins, located in the outer part of the virus, which is why the virus is not expected to become any less capable of causing an immune response.
The studies will now ascertain how the mutations can make the infection of monkeys, mosquitoes, and people more severe. Thus far, Bonaldo also pointed out, these mutations have not been registered in any yellow fever virus, either in Africa or South America.
Bonaldo also said that a possible link between the genetic variation and environmental disasters cannot be confirmed as yet. “Now is the time to study the several samples from the current epidemics, comparing them with old samples, so we can determine where these variations occurred and how it spread to different regions here in the Southeast,” she added.
In her opinion, studies will also contribute to the adoption of sanitary measures. “We'll learn more about how capable this virus is of circulating through Brazil. This may lead to invaluable tools for sanitary surveillance—prevention, in order to keep cases from growing even worse. It will also enable us to find out what areas in Brazil must be prioritized during vaccination campaigns,” she stated.
Translated by Fabrício Ferreira
Fonte: Brazil scientists find mutations in yellow fever virus
