Early and late neuropathological features of meningoencephalitis associated with Maraba virus infection

Maraba virus is a member of the genus Vesiculovirus of the Rhabdoviridae family that was isolated in 1983 from sandflies captured in the municipality of Maraba, state of Pará, Amazônia, Brazil. Despite 30 years having passed since its isolation, little is known about the neuropathology induced by the Maraba virus. Accordingly, in this study the histopathological features, inflammatory glial changes, cytokine concentrations, and nitric oxide activity in the encephalon of adult mice subjected to Maraba virus nostril infection were evaluated. The results showed that 6 days after intranasal inoculation, severe neuropathological-associated disease signs appeared, including edema, necrosis and pyknosis of neurons, generalized congestion of encephalic vessels, and intra- and perivascular meningeal lymphocytic infiltrates in several brain regions. Immunolabeling of viral antigens was observed in almost all central nervous system (CNS) areas and this was associated with intense microglial activation and astrogliosis. Compared to control animals, infected mice showed significant increases in interleukin (IL)-6, tumor necrosis factor (TNF)-α, interferon (INF)-γ, MCP-1, nitric oxide, and encephalic cytokine levels. We suggest that an exacerbated inflammatory response in several regions of the CNS of adult BALB/c mice might be responsible for their deaths.

Vesicular stomatitis due to Indiana III (Alagoas/VSIV-3) is endemic in Brazilian state of Ceará / Estomatite vesicular causada pelo subtipo Indiana III (Alagoas/VVI-3) é endêmica no estado do Ceará, Brasil

ABSTRACT: Although Northeast Brazil is considered free of foot and mouth disease (FMD) with vaccination, several economic and health damages are still recorded due to the occurrence of vesicular syndromes that can be evaluated, such as Vesicular Stomatitis (VS). Therefore, this study aimed to confirm the occurrence of this disease and to determine the predominant viral serotype in suspected cases notified to the Official Veterinary Service of Ceará in 2013 performing official diagnostic protocols recommended by the World Organization for Animal Health. After clinical and epidemiological investigation in 46 farms, 32 probable cases of VS were considered with 78 sampled animals, 65 bovines and 13 equines. Serum (54) and epithelium (24) samples were collected. Six (14.6%) of 41 bovines and 8 (61.5%) of 13 equines described seroconversion to Indiana Vesiculovirus (IVV) by viral neutralization. The IVV was detected in 15 (62.5%) of 24 bovines epithelia using the indirect sandwich ELISA. Finally, positive epithelium underwent complement fixation test viral subtyping that identified the occurrence of Indiana III serotype (Alagoas/IVV-3) in 11 (73.3%) of 15 previous positives cattle. These were the first confirmed cases of VS in Ceará with an official diagnosis of IVV-3, confirming the endemic character attributed to the state through previous unofficial serological surveys. The presence of VS is a continuing diagnostic challenge, given the risk of possible incursions of FMD. Vesicular stomatitis is recurrent and is a worrying in this area free of foot and mouth disease with vaccination that bring damage to producers and a maximum alert to the Sanitary Defense Organs in the face of a probable case of vesicular syndrome.

RESUMO: Embora o Nordeste do Brasil seja considerado livre de Febre Aftosa (FA) com a vacinação, ainda são registrados vários prejuízos econômicos e sanitários devido à ocorrência de síndromes vesiculares que precisam ser adequadamente avaliadas, como Estomatite Vesicular (EV). Portanto, este estudo teve como objetivo confirmar a ocorrência desta doença e determinar o sorotipo viral predominante em casos suspeitos notificados ao Serviço Veterinário Oficial do Ceará no ano de 2013 realizando protocolos oficiais de diagnóstico recomendados pela Organização Mundial de Saúde Animal. Após investigação clínica e epidemiológica em 46 propriedades rurais, foram considerados 32 casos prováveis de propriedade foco de EV com 78 animais amostrados, sendo 65 bovinos e 13 equídeos. Amostras de soro (54) e epitélio (24) foram coletadas. Análises sorológicas de 6 (14,6%) de 41 bovinos e 8 (61,5%) de 13 equídeos apresentaram soroconversão ao Vesiculovírus Indiana (VVI) por neutralização viral. O VVI foi detectado em 15 (62,5%) de 24 epitélios bovinos usando ELISA indireto sanduíche. Por fim, amostras de epitélio positivas foram submetidas a subtipagem viral por fixação do complemento que identificou a ocorrência do sorotipo Indiana III (Alagoas/VVI-3) em 11 (73,3%) de bovinos. Estes foram os primeiros casos confirmados de EV no estado do Ceará com diagnóstico oficial de VVI-3 confirmando o caráter endêmico atribuído ao Estado por meio de levantamentos sorológicos não oficiais anteriores. A presença de EV é um desafio diagnóstico contínuo, dado o risco de possíveis incursões de FA. A Estomatite Vesicular é recorrente e preocupante nesta área livre de FA com vacinação pois, além de prejuízos aos produtores, traz um alerta máximo aos Órgãos de Defesa Sanitária diante de um caso provável de síndrome vesicular.

A real-time reverse transcriptase polymerase chain reaction for detection and quantification of Vesiculovirus

Vesiculoviruses (VSV) are zoonotic viruses that cause vesicular stomatitis disease in cattle, horses and pigs, as well as sporadic human cases of acute febrile illness. Therefore, diagnosis of VSV infections by reliable laboratory techniques is important to allow a proper case management and implementation of strategies for the containment of virus spread. We show here a sensitive and reproducible real-time reverse transcriptase polymerase chain reaction (RT-PCR) for detection and quantification of VSV. The assay was evaluated with arthropods and serum samples obtained from horses, cattle and patients with acute febrile disease. The real-time RT-PCR amplified the Piry, Carajas, Alagoas and Indiana Vesiculovirus at a melting temperature 81.02 ± 0.8ºC, and the sensitivity of assay was estimated in 10 RNA copies/mL to the Piry Vesiculovirus. The viral genome has been detected in samples of horses and cattle, but not detected in human sera or arthropods. Thus, this assay allows a preliminary differential diagnosis of VSV infections.

Investigação epidemiológica de estomatite vesicular por achados clínicos em bovinos e equinos no Estado do Maranhão / Stomatitis vesicular in cattle and horse in the Maranhão state

A Estomatite Vesicular (EV) é uma doença infecciosa que acomete equinos, bovinos, suínos, mamíferos silvestres e humanos. Por apresentar sinais clínicos semelhantes a outras doenças vesiculares, principalmente, febre aftosa, sua presença em determinadas regiões pode interferir no intercâmbio comercial internacional dos animais, seus produtos e subprodutos. Apesar de sua importância, a epidemiologia e a manutenção do vírus no ambiente não estão totalmente esclarecidas dificultando a aplicação de medidas de controle efetivas. A doença já foi diagnosticada em todas as regiões brasileiras. Bovinos com sialorréia, perda do epitélio lingual, lesões abertas com bordas amareladas nas gengivas, lábios, língua e mucosa oral e equinos com sialorréia e lesões abertas na mucosa oral e lábios foram observados e notificados ao Serviço Veterinário Oficial do Estado do Maranhão, Agência Estadual de Defesa Agropecuária do Maranhão (AGRD/MA). Amostras de soro de equinos e bovinos com sintomas de EV foram coletadas para investigação por ELISA e por neutralização viral, além do diagnóstico diferencial para Febre Aftosa (FA). Fragmentos epiteliais de bovinos com lesões na língua foram coletados para identificação molecular do agente. Todos os animais foram negativos para FA. Todos os bovinos e equinos foram reativos para EV nos testes sorológicos. A partir dos fragmentos epiteliais de bovinos enviados ao Instituto Biológico de São Paulo para PCR, foi possível caracterizar o agente como VesiculovirusIndiana III (Alagoas/VSAV).

Vesicular stomatitis (VS) is an infectious viral disease that affects bovines, equines, swine, wild animals and humans. As it is indistinguishable from other vesicular diseases, mainly Foot and Mouth Disease (FMD), it causes restrictions in commercial livestock trade at national and international levels and also significant economic losses. As the epidemiology and maintenance of VS virus in nature are not clearly understood it is difficult to take effective control measures. VS was diagnosed in some regions of Brazil, such as Minas Gerais, Santa Catarina, São Paulo and Alagoas. Cattle and horses with clinical symptoms of drooling, shedding of the lingual epithelium, presence of vesicles on the oral mucosa were observed and reported to the National Animal Health Office health of Maranhão State, Brazil. Samples of serum of these animals were collected and sent to Laboratório Nacional de Agropecuaria for ELISA and virus neutralization and differential diagnosis for Foot and Mouth Disease (FMD). The results of ELISA confirmed the VS. In the differential diagnosis, the results were negative for FMD. Samples of bovine epithelial tissue for VS by PCR confirmation of diagnosis were collected and sent to Biological Institute of São Paulo. Molecular results confirmed the VesiculovirusIndiana III (Alagoas/VSAV) infection.