BIV was discovered in the late 1960s in the search for the infectious agent causing bovine
lymphosarcoma. This search led to the isolation and identification of three distinct classes of bovine retroviruses. BIV was specifically identified by Dr. Cameron Seger, a veterinarian of the Louisiana State University Agricultural Center, while he was studying dairy cattle at the Southeast Louisiana Experiment Station at Franklinton, Louisiana. The cows presented with high white blood cell counts, referred to as persistent lymphocytosis (PL) which is associated with the development of bovine leukemia/lymphosarcoma.[citation needed
]
The first animal studied was an eight-year-old
necropsy was performed. The diagnosis was lymphosarcoma, however, none of the tumors usually associated with the diseases were present in the postmortem gross examination. Tissue samples were sent to Dr. Van Der Maaten at the National Animal Disease Center; Dr. Van Der Maaten was able to isolate the BIV.[citation needed
]
When the isolated BIV was inoculated into
acquired immunodeficiency syndrome (AIDS) was caused by HIV.[2]
Replication
One of the identifying characteristics of lentiviruses is being able to infect non-dividing cells. BIV, being a lentivirus has this characteristic.
plasma membrane and form a complex with the viral RNA as the virus buds and is released from the cell. The virus matures after proteolytic processing by the viral protease (PR). The virus is then ready to infect another cell and repeat the process.[2]
Structure
The mature virus is about 110–130 nm in size, with the
polyproteins. These polyproteins are cleaved in the mature virus to their functional forms.[4]
Pathogenesis
As mentioned before, leukocytosis and lymphadenopathy are associated with early infection. Researchers do now know how long cow R-29 was infected with BIV so some of the
Like other retroviruses, BIV is spread through exchange of
bodily fluids. When looking at prevalence of BIV infection, it was found that BIV is more prevalent in the southern United States and most prevalent in South America.[5] When an animal tests positive, many of the animals within the herd are also positive. Some of the spread is attributed to reuse of contaminated needles used in vaccinations, communal sharing of colostrum by calves, and failure to completely sterilize instruments after invasive treatments.[2]
