Abstract We report a case of encephalitis associated with Zika virus infection and reactivation of varicella-zoster virus in the central nervous system of a Brazilian child. This case raises the possibility that reactivation of the latent varicella-zoster virus may be a mechanism of neurological impairment induced by acquired Zika virus infection.

This study showed that laboratory markers of recent infection by dengue, Zika or chikungunya arboviruses were detected in the biological samples of approximately one-third of patients with encephalitis, myelitis, encephalomyelitis or Guillain-Barré syndrome, in a surveillance programme in Piauí state, Brazil, between 2015-2016. Fever and myalgia had been associated with these cases. Since in non-tropical countries most infections or parainfectious diseases associated with the nervous system are attributed to herpesviruses, enteroviruses, and Campylobacter jejuni, the present findings indicate that in tropical countries, arboviruses may now play a more important role and reinforce the need for their surveillance and systematic investigation in the tropics.

o objetivo deste estudo foi mostrar, com base na literatura sobre o tema, o potencial de dispersão e estabelecimento do vírus chikungunya no brasil. O vírus chikungunya, um Togaviridae do gênero Alphavirus, atingiu as Américas em 2013 e, no ano seguinte, mais de um milhão de casos foram notificados. No Brasil, foi registrada transmissão autóctone no Amapá e Bahia, mesmo durante o período de baixo índice pluviométrico, expondo ao risco de propagação do vírus todo o território nacional. Historicamente, o Brasil é infestado por Ae. Aegypti e Ae. Albopictus, também vetores do dengue. É possível que o chikungunya se dissemine, sendo importante que medidas sejam tomadas para evitar que o vírus se torne endêmico no País. A adequada assistência a pacientes com febre de chikungunya requer treinamento de clínicos, reumatologistas, enfermeiros e especialistas em diagnóstico laboratorial. Até novembro de 2014 foram notificados no Brasil mais de 1.000 casos da virose. Estudos experimentais em modelos animais devem ser realizados para conhecer a dinâmica da infecção e a patogenia, bem como identificar mecanismos fisiopatológicos que possam contribuir para identificar drogas com efeito sobre o vírus. São necessários ensaios clínicos para identificar a relação causal do vírus com sérias lesões observadas em diferentes órgãos e nas articulações. Na ausência de vacinas ou drogas efetivas contra o vírus, a única forma de prevenir a doença é atualmente o controle vetorial, o que também reduzirá o número de casos de dengue.

This study aimed to show, based on the literature on the subject, the potential for dispersal and establishment of the chikungunya virus in Brazil. The chikungunya virus, a Togaviridae member of the genusAlphavirus, reached the Americas in 2013 and, the following year, more than a million cases were reported. In Brazil, indigenous transmission was registered in Amapa and Bahia States, even during the period of low rainfall, exposing the whole country to the risk of virus spreading. Brazil is historically infested by Ae. aegypti and Ae. albopictus, also dengue vectors. Chikungunya may spread, and it is important to take measures to prevent the virus from becoming endemic in the country. Adequate care for patients with chikungunya fever requires training general practitioners, rheumatologists, nurses, and experts in laboratory diagnosis. Up to November 2014, more than 1,000 cases of the virus were reported in Brazil. There is a need for experimental studies in animal models to understand the dynamics of infection and the pathogenesis as well as to identify pathophysiological mechanisms that may contribute to identifying effective drugs against the virus. Clinical trials are needed to identify the causal relationship between the virus and serious injuries observed in different organs and joints. In the absence of vaccines or effective drugs against the virus, currently the only way to prevent the disease is vector control, which will also reduce the number of cases of dengue fever.

o objetivo deste estudo foi mostrar, com base na literatura sobre o tema, o potencial de dispersão e estabelecimento do vírus chikungunya no brasil. O vírus chikungunya, um Togaviridae do gênero Alphavirus, atingiu as Américas em 2013 e, no ano seguinte, mais de um milhão de casos foram notificados. No Brasil, foi registrada transmissão autóctone no Amapá e Bahia, mesmo durante o período de baixo índice pluviométrico, expondo ao risco de propagação do vírus todo o território nacional. Historicamente, o Brasil é infestado por Ae. Aegypti e Ae. Albopictus, também vetores do dengue. É possível que o chikungunya se dissemine, sendo importante que medidas sejam tomadas para evitar que o vírus se torne endêmico no País. A adequada assistência a pacientes com febre de chikungunya requer treinamento de clínicos, reumatologistas, enfermeiros e especialistas em diagnóstico laboratorial. Até novembro de 2014 foram notificados no Brasil mais de 1.000 casos da virose. Estudos experimentais em modelos animais devem ser realizados para conhecer a dinâmica da infecção e a patogenia, bem como identificar mecanismos fisiopatológicos que possam contribuir para identificar drogas com efeito sobre o vírus. São necessários ensaios clínicos para identificar a relação causal do vírus com sérias lesões observadas em diferentes órgãos e nas articulações. Na ausência de vacinas ou drogas efetivas contra o vírus, a única forma de prevenir a doença é atualmente o controle vetorial, o que também reduzirá o número de casos de dengue.

This study aimed to show, based on the literature on the subject, the potential for dispersal and establishment of the chikungunya virus in Brazil. The chikungunya virus, a Togaviridae member of the genusAlphavirus, reached the Americas in 2013 and, the following year, more than a million cases were reported. In Brazil, indigenous transmission was registered in Amapa and Bahia States, even during the period of low rainfall, exposing the whole country to the risk of virus spreading. Brazil is historically infested by Ae. aegypti and Ae. albopictus, also dengue vectors. Chikungunya may spread, and it is important to take measures to prevent the virus from becoming endemic in the country. Adequate care for patients with chikungunya fever requires training general practitioners, rheumatologists, nurses, and experts in laboratory diagnosis. Up to November 2014, more than 1,000 cases of the virus were reported in Brazil. There is a need for experimental studies in animal models to understand the dynamics of infection and the pathogenesis as well as to identify pathophysiological mechanisms that may contribute to identifying effective drugs against the virus. Clinical trials are needed to identify the causal relationship between the virus and serious injuries observed in different organs and joints. In the absence of vaccines or effective drugs against the virus, currently the only way to prevent the disease is vector control, which will also reduce the number of cases of dengue fever.

Visando investigar a possível patogenicidade do vírus isolado (GOI 4191) de um evento adverso fatal pela vacinação antiamarílica, realizou-se um ensaio experimental em Syrian hamsters (Mesocricetus auratus), usando-se a cepa vacinal 17DD como parâmetro. As amostras virais foram inoculadas por via intracerebral, intra-hepática e subcutânea. Nos soros foram determinados níveis de viremia, resposta imune e aminotransferases, e nas vísceras a presença de vírus, antígeno e lesões teciduais. Não se detectou viremia para as duas amostras, a resposta imune foi maior para GOI 4191, e as aminotransferases não apresentaram alterações compatíveis com danos hepáticos. Nos animais inoculados por via intracerebral o vírus foi recuperado somente a partir do cérebro, sendo o antígeno viral detectado, por imuno-histoquímica, no cérebro e fígado. Infiltrado inflamatório e corpúsculos acidófilos foram observados no fígado e lesões tipo encefalite viral no sistema nervoso central. Alterações histológicas e antígeno viral foram observados, também, no fígado dos animais infectados por via intra-hepática, e ausentes naqueles inoculados por via subcutânea. Os resultados foram similares para as duas amostras testadas, entretanto distintos daqueles relatados na literatura para cepas silvestres do vírus amarílico.

In order to investigate the pathogenicity of the virus strain GOI 4191 that was isolated from a fatal adverse event after yellow fever virus (YFV) vaccination, an experimental assay using hamsters (Mesocricetus auratus) as animal model and YFV 17DD vaccine strain as virus reference was accomplished. The two virus strains were inoculated by intracerebral, intrahepatic and subcutaneous routes. The levels of viremia, antibody response, and aminotransferases were determined in sera; while virus, antigen and histopathological changes were determined in the viscera. No viremia was detected for either strain following infection; the immune response was demonstrated to be more effective to strain GOI 4191; and no significant aminotransferase levels alterations were detected. Strain GOI 4191 was recovered only from the brain of animals inoculated by the IC route. Viral antigens were detected in liver and brain by immunohistochemical assay. Histothological changes in the viscera were characterized by inflammatory infiltrate, hepatocellular necrosis, and viral encephalitis. Histological alterations and detection of viral antigen were observed in the liver of animals inoculated by the intrahepatic route. These findings were similar for both strains used in the experiment; however, significant differences were observed from those results previously reported for wild type YFV strains.