Apoptosis in the late replication phase of Bovine alphaherpesvirus 1 in experimentally infected calves.

Bovine alphaherpesvirus 1 (BoHV-1) is a pathogen causing respiratory and reproductive clinical signs in cattle. Infected animals may develop rhinotracheitis, vulvovaginitis, balanoposthitis, and abortion. Viral latency is generally established in neuronal ganglia simultaneously to a decrease in both genes or genome expression and viral replication. Under stressful conditions, infection is reactivated leading to viral replication and the manifestation of clinical signs. In this study, we evaluated both viral reactivation and apoptosis in trigeminal ganglia cells as BoHV-1 progressed from the latent to the acute phase of infection after dexamethasone administration in experimentally infected calves. To test ganglia cell death as a consequence of BoHV-1 infection, we stained the BoHV-1 samples with TUNEL after the viral shedding by the calves. RT-qPCR of apoptotic genes was also performed, showing the upregulation of the caspase 8 gene in the trigeminal ganglia from cattle experimentally infected with BoHV-1. These results showed the occurrence of apoptosis in ganglion cells of calves infected by BoHV-1.

Latent bovine herpesvirus 1 and 5 in milk from naturally infected dairy cattle.

Bovine herpesvirus 1 and 5 (BoHV-1 and -5) are antigenically and genetically related and can establish latent infection. We aimed to analyze the applicability of the milk sample to detect latently BoHV-infected cattle. BoHV-1 non-vaccinated clinically healthy cows from five dairy cattle herds (herd 1, n=24; herd 2, n=39; herd 3, n=39; herd 4, n=36; herd 5, n=70) were studied. We confirmed the presence of BoHV-1, and for the first time, BoHV-5 in the milk of naturally infected dairy cattle.

Surveillance of neutralizing antibodies against Bovine Herpesvirus 1 in cattle herds from different farming property systems / Distribuição de anticorpos neutralizantes contra o Herpesvirus bovino 1 em propriedades bovinas de diferentes sistemas de criação

The aim of this study was to investigate the presence of neutralizing antibodies against bovine herpesvirus 1 (BoHV-1) in 722 non-vaccinated animals from eight properties that use different farming systems (extensive, semi-confinement and confinement). Serum samples were subjected to neutralization tests in order to search for anti-BoHV-1 antibodies. Serological results were categorized as negative, low titer, intermediate titer or high titer. One property showed no positive samples; while other properties presented frequency of positive samples ranging from 17.95% to 86.96%. For animals raised under confinement, the number of positive samples and neutralizing antibody titers were lower compared to others, possibly due to good sanitary practices adopted by this type of system. Altogether, our results can contribute towards the understanding of the endemic infection in Brazil.

Este trabalho teve por objetivo avaliar a distribuição de anticorpos neutralizantes contra o herpesvirus bovino 1 (BoHV-1) em 722 animais não vacinados pertencentes a oito propriedades que utilizam diferentes sistemas de criação (extensivo, semi-confinamento e confinamento). As amostras sorológicas foram submetidas ao teste de soroneutralização para pesquisa de anticorpos anti-BoHV-1. Os resultados foram classificados em títulos negativo, baixo, médio e alto. Uma propriedade não apresentou amostras positivas, enquanto que nas demais propriedades a frequência de amostras positivas variou de 17,95% a 86,96%. Os animais do sistema de criação por confinamento apresentaram menor número de amostras positivas quando comparado aos animais do outros sistemas de criação, possivelmente devido às boas práticas sanitárias adotadas por esse sistema. Dessa forma, nossos resultados podem contribuir para o entendimento dessa infecção endêmica no Brasil.

Detecção de peptídeos importantes para o diagnóstico da cisticercose bovina no immunoblot / Detection of important peptides for bovine cysticercosis diagnosis in immunoblot

A dificuldade de se localizar cisticercos em bovinos com infecção discreta torna o diagnóstico tradicional da cisticercose bovina em matadouros um recurso de baixa sensibilidade, o que gera uma demanda de diagnóstico por métodos alternativos como o immunoblot. Para tanto, neste trabalho, foram realizados ensaios de immunoblot a fim de analisar os peptídeos responsáveis pela reação do antígeno vesicular de Taenia crassiceps. Foram utilizadas 28 amostras de soro de bovinos comprovadamente negativos e 28 amostras coletadas de bovinos infectados experimentalmente com ovos de Taenia saginata. Os resultados dos ensaios de immunoblot com as amostras de soros-controle mencionadas indicaram que os peptídeos de 4-6, 14 e 18kDa destacaram-se entre os demais, mostrando altas taxas de desempenho no diagnóstico da cisticercose bovina e uma aparência diferenciada, com área e largura maiores, ao contrário dos peptídeos de média e alta massa molecular, que se apresentaram sob a forma de linha e com reações inespecíficas. O immunoblot mostrou ter um potencial como uma alternativa de diagnóstico da cisticercose bovina, incluindo sua aplicação em animais vivos, como método auxiliar de diagnóstico em estudos epidemiológicos da doença.

The diagnosis of cysticercosis in bovines that presents discreet infection is committed by the conventional methodology of detection employed in slaughterhouses. This deficiency leads to the development of alternative methods, such as immunoblot, in order to improve the detection of this disease. An immunoblot assay was developed to detect peptides from Taenia crassiceps antigenand it was used to test 56 samples of bovine serum (28 confirmed as negative and 28 from experimentally infected animals with Taenia saginata eggs). The peptides 4-6, 14 and 18 kDa showed better performance in bovine cysticercosis diagnosis due to an enhanced appearance, once they showed higher area and wide, contrasting with medium and high molecular weight peptides, that showed unspecific reactions and discreet appearance. The obtained results indicated that immunoblot can represent a potential alternative in bovine cysticercosis diagnosis, including its use in live animals, improving the detection of this disease even in epidemiological studies.