Equine Viral Arteritis

Prevalência de anticorpos contra o vírus da arterite equina nas mesorregiões Noroeste, Centro Ocidental e Norte Central do Paraná

RESUMO: O objetivo deste estudo foi investigar a prevalência de anticorpos contra o vírus da arterite viral equina (EVAV) em equinos sadios criados nas mesorregiões Noroeste, Centro Ocidental e Norte Central do estado do Paraná. Após o cálculo do tamanho amostral, foram analisadas, utilizando a técnica de soroneutralização, amostras de soro sanguíneo de 653 equinos. Nenhum animal sororreagente foi encontrado nas mesorregiões Noroeste (0/236) e Centro Ocidental (0/99). Na mesorregião Norte Central a prevalência foi de 0,62% (2/318), totalizando 0,30%. Pode-se concluir que a arterite viral equina (AVE) ainda não representa um problema de importância epidemiológica nos equinos criados nas mesorregiões paranaenses estudadas.

Equine arteritis virus

Equine arteritis virus (EAV) is the causative agent of equine viral arteritis (EVA), a respiratory and reproductive disease of equids. There has been significant recent progress in understanding the molecular biology of EAV and the pathogenesis of its infection in horses. In particular, the use of contemporary genomic techniques, along with the development and reverse genetic manipulation of infectious cDNA clones of several strains of EAV, has generated significant novel information regarding the basic molecular biology of the virus. Therefore, the objective of this review is to summarize current understanding of EAV virion architecture, replication, evolution, molecular epidemiology and genetic variation, pathogenesis including the influence of host genetics on disease susceptibility, host immune response, and potential vaccination and treatment strategies.

Comparison of two real-time reverse transcription polymerase chain reaction assays for the detection of Equine arteritis virus nucleic acid in equine semen and tissue culture fluid

Two previously developed TaqMan fluorogenic probe-based 1-tube real-time reverse transcription polymerase chain reaction (real-time RT-PCR) assays (T1 and T2) were compared and validated for the detection of Equine arteritis virus (EAV) nucleic acid in equine semen and tissue culture fluid (TCF). The specificity and sensitivity of these 2 molecular-based assays were compared to traditional virus isolation (VI) in cell culture. The T1 real-time RT-PCR had a higher sensitivity (93.4%) than the T2 real-time RT-PCR (42.6%) for detection of EAV RNA in semen. However, the T1 real-time RT-PCR was less sensitive (93.4%) than the World Organization for Animal Health (OIE)-prescribed VI test (gold standard). The sensitivity of both PCR assays was high (100.0% [T1] and 95.2% [T2]) for detecting EAV RNA in TCF. In light of the discrepancy in sensitivity between either real-time RT-PCR assay and VI, semen that is negative for EAV nucleic acid by real-time RT-PCR that is from an EAV-seropositive stallion should be confirmed free of virus by VI. Similarly, the presence of EAV in TCF samples that are VI-positive but real-time RT-PCR-negative should be confirmed in a 1-way neutralization test using anti-EAV equine serum or by fluorescent antibody test using monoclonal antibodies to EAV. If the viral isolate is not identified as EAV, such samples should be tested for other equine viral pathogens. The results of this study underscore the importance of comparative evaluation and validation of real-time RT-PCR assays prior to their recommended use in a diagnostic setting for the detection and identification of specific infectious agents.