Infection by Rocio and Saint Louis viruses may become emerging in Brazil

For researcher and USP professor in Ribeirão Preto, Luiz Tadeu Figueiredo, and the epidemic could already be happening and cases mistaken by dengue


Professor at the Ribeirão Preto Medical School from USP, Luiz Tadeu Figueiredo believes the Saint Louis encephalitis virus and probably the Rocio have Always been in Brazil producing sporadic or small outbreaks that are often mistaken with dengue

Arboviral diseases are a severe public health issue in the Country. The risk for new arboviral diseases in Brazil is related to the existence of large, populous cities infested by the Culex mosquito, the common mosquito, as well as the Aedes aegypti. Among the Brazilian arboviruses, the Mayaro, Dengue, Yellow Fever, Rocio and Oropouche (OROV) account for over 95% of the human arboviral diseases.

Among the encephalitis in Brazil, Rocio and Saint Louis perform an important role. Both viruses are flaviviruses (related to dengue and yellow fever viruses) that cause encephalitis. The Saint Louis encephalitis virus (brain infection transmitted by the Culex mosquito bite) has caused outbreaks in North America and most recently in Argentina. In Brazil, the cases were confirmed in the Amazon, especially in Pará and São Paulo states, where the cases were febrile pictures dengue simile and meningitis.

Flavivirus expert, infectious diseases physician Luiz Tadeu Figueiredo, from the Virology Research Center at the USP Medical School in Ribeirão Preto (SP), identified in a study a Saint Louis virus epidemic in São José do Rio Preto. Regarding the Rocio (causes meningoencephalitis), the physician has no doubts it will return. I believe the Saint Louis encephalitis virus and probably the Rocio have always been in Brazil resulting in uncommon or small outbreaks, many times mistaken as dengue, he warns while observing that certainly, the acute febrile symptoms caused by these viruses must have been mistaken as dengue and eventually even laboratory methods could result in cross-reactions with dengue.

According to the professor, we must diagnose the virus causing most of the viral infections in the central nervous system. He explains that people with the immunity suppressed by other disease or, even by age or people with previous central nervous diseases are more susceptible to meningoencephalitis by these viruses. In his opinion, the way to avoid these diseases from spreading is remembering that these viruses and the diseases they cause exist, as well as disseminating diagnostic methods in laboratories to detect cases. Surveillance is also very important, since the trigger for infection is the human, he points while warning that health professionals are not well informed about these viral diseases and that currently there are no prospects for vaccines in a short or medium terms.

The first Rocio cases in human victims in Brazil were reported during a viral encephalitis outbreak that lasted for around two years, during the 1970s, in the Southeast region. The first reported infections took place in Vale do Ribeira and Baixada Santista around 1974. Over 1,021 cases of arbovirus encephalitis have been detected, with a greater incidence among young men, 100 deaths and over 200 surviving patients with severe consequences. The diseases epidemiology remains a mystery, as well as the reasons Rocio appears and disappears; however, the possibility of a new epidemic has driven researchers to look after the infection and invasions mechanisms by flaviviruses. We have experimental studies in mice showing how the infection in the central nervous system by Rocio behaves, finished the infectologist.…