RESUMO
Bovine herpesvirus 1 (BoHV-1) is the most common viral pathogen found in bovine semen, causing numerous reproductive disorders leading to economic losses to the cattle industry. For rapid detection of BoHV-1 in bovine semen, in this study, we applied a loop-mediated isothermal amplification (LAMP) assay. The assay could be completed within 90 min, including total DNA isolation, target amplification, and visual interpretation of positive or negative results with the naked eye. The assay detected as little as 10 fg of BoHV-1 DNA per reaction. The analytical sensitivity of the assay was 0.2 TCID50 BoHV-1 per reaction, which was 100 times more sensitive than conventional PCR and comparable to TaqMan real-time PCR. The applicability of the assay was assessed by analysing 118 semen samples collected from breeding bulls. On comparison with TaqMan real-time PCR, the LAMP assay had a diagnostic sensitivity of 97 %, specificity of 100 %, and accuracy of 99.2 % for detection of BoHV-1 in bovine semen. The LAMP assay developed in this study is a rapid, sensitive, and cost-effective alternative for detection of BoHV-1 in bovine semen.
Assuntos
Doenças dos Bovinos/virologia , Infecções por Herpesviridae/veterinária , Herpesvirus Bovino 1/isolamento & purificação , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Sêmen/virologia , Medicina Veterinária/métodos , Animais , Bovinos , Infecções por Herpesviridae/virologia , Herpesvirus Bovino 1/genética , Sensibilidade e Especificidade , Fatores de TempoRESUMO
Equine influenza is a contagious viral disease that affects all members of the family Equidae, i.e., horses, donkeys and mules. The authors describe the pattern of equine influenza outbreaks in a number of states of India from July 2008 to June 2009. The disease was first reported in June 2008 in Katra (Jammu and Kashmir) and spread to ten other states within a year. All outbreaks of equine influenza in the various states were confirmed by laboratory investigations (virus isolation and/or serological confirmation based on haemagglutination inhibition [HI] assays of paired samples) before declaring them as equine influenza virus-affected state(s). The virus (H3N8) was reported from various locations in the country including Katra, Mysore (Karnataka), Ahmedabad (Gujarat), Gopeshwar and Uttarkashi (Uttarakhand) and was isolated in 9- to 11-day-old embryonated chicken eggs. The virus was confirmed as H3N8 by HI assays with standard serum and amplification of full-length haemagglutinin and neuraminidase genes by reverse transcriptase-polymerase chain reaction. Serum samples (n = 4 740) of equines from 13 states in India screened by HI revealed 1074 (22.65%) samples as being positive for antibodies to equine influenza virus (H3N8).
