Epidemiological study of bovine leukemia virus in dairy cows in six herds in the municipality of Pasto, Nariño
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Date
2013-09-24
Journal Title
Journal ISSN
Volume Title
Publisher
Corporación Universitaria Lasallista
Abstract
Introduction. Enzootic bovine leukosis is a highly
infectious disease caused by a deltaretrovirus of
the retroviridae family, which affects bovines of all
ages and that generates a high economic impact on
the dairy herds. This is caused by the high costs of
symptomatic treatments, premature deaths and replacement
of ill animals, the reduction of the milk
production and the restrictions of importation and exportation
imposed by some countries. Objective. To
determine the prevalence of bovine leukemia virus
(BLV) in its two different forms of disease presentations
(persistent lymphocytosis and lymphosarcoma)
and the factors associated with the seropositivity of
the virus in dairy herds from Pasto, (Nariño, Colombia).
Materials and methods. The study included six
specialized dairy herds from Pasto, Colombia. A total
of 242 blood samples were taken from 24 months of
age or older cows and were analyzed using the indirect
ELISA test to determine the seropositivity. The
management practices were evaluated in each herd
and an analysis binary logistic regression was used
to find associations with seropositivity. Results. A
seroprevalence of 19.8% was determined. Out of 48
positive animals, 13 had a total count over 10000
leukocytes/mm3, and 6 of these (12.5%) developed
persistent lymphocytosis (PL) according to their age.
No cases of lymphosarcoma or malignant lymphoma
were found in the study. Concerning the management
practices, the replacement of animals in different
herds or in livestock fairs is associated to farms
with a higher prevalence. Conclusions. Surveillance
programs for dairy herds should include diagnostic tests for BLV. Only a small number of animals
show consistent changes with lymphocytic or clinical
disease. In addition, early diagnosis allows efficient
control programs in the replacement of animals and
it also prevents the spread of the virus in dairy herds.
Description
Keywords
Corporación Universitaria Lasallista, Municipio de Pasto, Ganado - Enfermedades, Leucemia en animales, Linfocitosis persistente - Bovinos, Linfosarcoma, Ganado - Vacuno, Ganado de leche, Ganado lechero - Enfermedades