| Autor: |
Contreras-Luna MJ; Departamento de Microbiología e Inmunología (DMEI), FMVZ-UNAM, Ciudad de México, Mexico., Ramírez-Martínez LA; Departamento de Microbiología e Inmunología (DMEI), FMVZ-UNAM, Ciudad de México, Mexico., Sarmiento Silva RE; Departamento de Microbiología e Inmunología (DMEI), FMVZ-UNAM, Ciudad de México, Mexico., Cruz Lazo C; Centro de Enseñanza, Investigación y Extensión en Ganadería Tropical, Sección Ovinos, FMVZ-UNAM, Veracruz, Mexico., Pérez Torres A; Departamento de Biología Celular y Tisular, Facultad de Medicina, UNAM, Ciudad de México, Mexico., Sánchez-Betancourt JI; Departamento de Medicina y Zootecnia de Cerdos (DMZC), Facultad de Medicina Veterinaria y Zootecnia (FMVZ), Universidad Nacional Autónoma de México (UNAM), Av. Universidad 3000, Copilco, CP 04510 Ciudad de México, Mexico. |
| Abstrakt: |
This is a first report in Mexico of the presence of antibodies against respiratory syncytial virus (RSV) and parainfluenza-3 virus in Mexican sheep in different productive stages. We determine the association of serological positivity with age and production system, and obtain molecular evidence of infection by both virus. RSV prevalence in adult sheep was 47% (49/105) at the tropic and 64% (63/99) at the uplands. A significant difference in RSV seropositivity between animals from the tropic and the uplands was observed ( P < 0.05). Seropositivity correlated with production system ( P = 0.003, OR = 2.042), with a risk of showing antibodies was 2.042 times higher in sheep under an extensive production system. A significant difference in PI3V seropositivity between animals from either provenance ( P = 0.017, OR = 0.475) were also found, with a risk of showing antibodies 0.475 times higher in sheep under an extensive production system. Genetic material from RSV and PI3V was identified by RT-PCR in nasal swab samples from clinically healthy lambs and confirmed by sequencing and phylogenetic analysis. Serological results show that sheep are susceptible to infection by both viruses, and molecular results suggest that the identified antibodies are result of natural infections and reinfections. |
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