Horizontal Maedi-Visna virus (MVV) infection in adult dairy-sheep raised under varying MVV-infection pressures investigated by ELISA and PCR.
Res Vet Sci
; 80(2): 235-41, 2006 Apr.
Article
em En
| MEDLINE
| ID: mdl-16005917
A three year long experimental study was carried out to investigate horizontal MVV-infection by PCR and ELISA, in 191 one year-old latxa dairy-sheep raised in two separate groups under low and high MVV-infection pressure, respectively. Sheep originated from a previous MVV-transmission study in lambs and seroprevalence among one year-old sheep in both groups was 15% approximately. The high infection-pressure group (H-group) consisted of 147 replacement ewes that joined a milk-producing, housed dairy-flock with 42-66% MVV-seroprevalence and the low infection-pressure group (L-group) were castrated males raised in a separate shed. In contrast to results obtained when infection was investigated in lambs, the overall degree of agreement between ELISA and PCR results was very good and there was some indication that it increased further as sheep became older. MVV-prevalence did not change in the L-group and increased to 57% in three year-old sheep in the H-group (p<0.001). Random effects logistic regression confirmed seroconversion was significantly higher in the H-group compared to the L-group and was highest during the year after the sheep were introduced in the dairy flock and did not increase with age as in previous studies using less sensitive antibody assays. The evidence that horizontal transmission can be very low in spite of prolonged close contact between infected and non-infected sheep is valuable for MVV-control purposes. Furthermore it highlights the need to investigate virus excretion dynamics in infected animals and animal to animal transmission to improve our overall understanding of horizontal MVV transmission in MVV endemic populations.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vírus Visna-Maedi
/
Pneumonia Intersticial Progressiva dos Ovinos
/
Transmissão de Doença Infecciosa
Tipo de estudo:
Etiology_studies
/
Risk_factors_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2006
Tipo de documento:
Article