Synonyms and introduction
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Synonyms
Introduction
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It is a lymphoproliferative disease of cattle where there is extensive proliferation of leukocyte forming tissues.
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Bovine leukemia virus (BLV) belongs to the family Retroviridae. Only one antigenic type has been found.
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Most infected animals develop a persistent lymphocytosis without any apparent clinical features.
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The virus produces syncytia in cell cultures. This is used as an assay for virus or antibody detection.
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The bovine leukemia virus (BLV) is distributed worldwide and occurs particularly frequently in dairy cattle.
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Cattle and buffaloes are the most susceptible hosts. Although non-immune cattle of all breeds can be infected at any age with bovine leukemia virus (BLV), most infections occur in dairy cattle more than two years of age.
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The fact that disease is seldom seen in younger animals is related to the presence of protective maternal antibody (for 5 - 6 months) and the separation of younger animals from the remaining herd until they reach sexual maturity. Most infections are inapparent and as many as 80% of a dairy herd may be infected.
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Cattle are infected by direct contact with blood from an infected animal during blood sampling, clinical examinations, castration and dehorning.
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Mechanical transmission by biting insects may play a role, particularly in tropical regions.
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This disease also transmitted through vertical transmission routes such as transovarian, transplacental and through colostrum. Approximately 10 to 15% of calves born to infected cows are infected.
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Last modified: Sunday, 3 June 2012, 8:10 AM