For the first time, a group of Brazilian researchers discovered the presence of West Nile virus in Minas Gerais. The study analyzed a series of samples collected from horses suspected of being infected between 2018 and 2020. In addition, circulation of the infectious agent was confirmed in two other states: São Paulo and Piauí.
West Nile virus was detected by researchers from the Oswaldo Cruz Institute (IOC / Fiocruz), from the Veterinary School of the Federal University of Minas Gerais (UFMG) and from the Federal University of Piauí (UFPI). The disease has been identified in horses, and it can also affect humans and, in extreme cases, can be fatal. However, both humans and horses are only hosts and cannot transmit disease.
We also explored the dynamics of suspected human cases of WNV [vírus do Nilo Ocidental] In the three Brazilian states [MG, SP e PI] For which we have the sequence data. Between the end of 2015 and the beginning of 2020, all countries had suspicious cases, indicating the continued circulation or recent importation from other regions of the country or anywhere else, “as the authors point out in Pre-print Peer-reviewed study – published on bioRxiv.
What is West Nile virus?
Similar to yellow fever virus, West Nile virus is transmitted to wild birds through the bite of an infected mosquito. However, the transmission of the infectious agent mainly occurs through Culex mosquitoes, commonly known as mosquitoes or mosquitoes. Among them, the main types are Coolex Babies. However, midway through, other animals may get sick by mistake.
“The horse is the main epidemic and acts as a guard for the disease. Clarifying suspected cases is important to detect the presence of the virus in the area and prevent its transmission to herds of horses and humans,” said study coordinator Louise Alcantara. Researcher at IOC’s Flavivirus Laboratory, for UOL.
In other words, it looks as if the cases identified in animals were a warning. It is important now to expand genetic surveillance for West Nile fever and prevent a possible exacerbation of transmission. “From the data currently available, we do not know whether the disease is endemic in Brazil or whether its transmission occurs intermittently, from introductions from other countries. Active surveillance, with analysis of horse and bird samples, is important to understanding the local epidemiology of the virus,” commented Alcantara.
What are the symptoms of the disease?
According to the World Health Organization (WHO), about 80% of people infected with West Nile virus do not have symptoms. When the disease becomes symptomatic, the manifestations are usually mild, such as fever, headache, fatigue, and vomiting. Now, in severe cases, the disease can lead to cases of meningitis and encephalitis. In these cases, a person may experience a high temperature and stiff neck to convulsions, paralysis, and coma.
However, this is not a new disease and science has been researching its consequences for years. “West Nile virus (WNV), which is a member of the Flaviviridae family, was first recognized in the West Nile region of Uganda in 1937, but is presently found commonly in Africa, Europe, North America, the Middle East and Asia.” Research authors.
Has the infectious agent been identified in Brazil?
In South America, West Nile virus was found, for the first time, in horses in Argentina, during 2006. Six years later, in 2012, captive flamingos were identified with the disease in Colombia. The researchers say: “The first genome sequence in Brazil was in 2019, when the virus was isolated from a horse with acute neurological disease in the state of Espirito Santo.”
“Despite numerous studies citing serological evidence suggesting the circulation of WNV in Brazil and the reporting of confirmed cases of human disease by WNV in the state of Piauí, little is known about the genetic diversity, evolution and transmission dynamics across the country,” notes the team of scientists. For example, evidence of the presence of the infectious agent was already found in 2019, from horse samples from the Pantanal. In humans, 10 cases have already been diagnosed from 2014 to 2020 in Piawi.
To verify a study that identified West Nile virus in horses in three Brazilian states, it was published as Pre-print On the bioRxiv platform, click Here.
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