Post by kng6876 on Jul 17, 2011 8:17:59 GMT -5
I found this article and wanted to share it with ya'll
Bovine Leukosis Virus Update II: Impact on Immunity & Disease Resistance
Lorraine Sordillo & Ron Erskine
Dept. of Large Animal Clinical Sciences
Bovine Leukosis Virus (BLV) causes leukemia and alters the normal immune defenses of cattle. This article describes how the virus infects cattle and the potential impact BLV may have on susceptibility to other infectious diseases.
Introduction
Bovine Leukosis Virus (BLV) is a retroviral infection that causes leukemia in cattle by targeting white blood cells and causing them to grow uncontrollably. Most BLV-infected cattle seldom present with outward clinical signs. Approximately 30% of infected animals, however, will have abnormally high white blood cell counts and up to 5% will develop malignant tumors or lymphosarcomas. The most severe cases of BLV will exhibit enlarged lymph nodes, weight loss, loss of appetite, infertility and decreased milk production [1, 2]. The virus is transferred from cow to cow by BLV-laden white blood cells found in blood, saliva, semen and milk.
Certain management practices that expose uninfected animals to contaminated blood, such as the use of common needles, contaminated surgical instruments and multiuse rectal sleeves, can dramatically increase the prevalence of BLV within a herd. There is also evidence to suggest that BLV-infected dams may transmit the virus to offspring via colostrum or placental transfer.
Once infected with BLV, cattle become lifetime carriers since there are no vaccines or treatments that can eliminate the infection. Indeed, a recent survey of the US dairy cattle farms suggest that over 80% of all dairy farms have cows that have BLV infection (http://nahms.aphis.usda.gov/dairy/dairy07/Dairy2007_BLV.pdf). Economic losses associated with BLV and management practices that can reduce or eliminate transmission of BLV from infected carriers to future replacement animals was covered in a previous article (https://www.msu.edu/user/mdr/vol14no1/erskine.html). This article will focus on how the virus attacks important host defense mechanisms and the potential impact on susceptibility to other infectious diseases
Bovine Leukosis Virus Update II: Impact on Immunity & Disease Resistance
Lorraine Sordillo & Ron Erskine
Dept. of Large Animal Clinical Sciences
Bovine Leukosis Virus (BLV) causes leukemia and alters the normal immune defenses of cattle. This article describes how the virus infects cattle and the potential impact BLV may have on susceptibility to other infectious diseases.
Introduction
Bovine Leukosis Virus (BLV) is a retroviral infection that causes leukemia in cattle by targeting white blood cells and causing them to grow uncontrollably. Most BLV-infected cattle seldom present with outward clinical signs. Approximately 30% of infected animals, however, will have abnormally high white blood cell counts and up to 5% will develop malignant tumors or lymphosarcomas. The most severe cases of BLV will exhibit enlarged lymph nodes, weight loss, loss of appetite, infertility and decreased milk production [1, 2]. The virus is transferred from cow to cow by BLV-laden white blood cells found in blood, saliva, semen and milk.
Certain management practices that expose uninfected animals to contaminated blood, such as the use of common needles, contaminated surgical instruments and multiuse rectal sleeves, can dramatically increase the prevalence of BLV within a herd. There is also evidence to suggest that BLV-infected dams may transmit the virus to offspring via colostrum or placental transfer.
Once infected with BLV, cattle become lifetime carriers since there are no vaccines or treatments that can eliminate the infection. Indeed, a recent survey of the US dairy cattle farms suggest that over 80% of all dairy farms have cows that have BLV infection (http://nahms.aphis.usda.gov/dairy/dairy07/Dairy2007_BLV.pdf). Economic losses associated with BLV and management practices that can reduce or eliminate transmission of BLV from infected carriers to future replacement animals was covered in a previous article (https://www.msu.edu/user/mdr/vol14no1/erskine.html). This article will focus on how the virus attacks important host defense mechanisms and the potential impact on susceptibility to other infectious diseases