An analysis of Bovine immunodeficiency virus and Jembrana disease virus infections in Bos javanicus
McNab, Tegan Josephine (2010) An analysis of Bovine immunodeficiency virus and Jembrana disease virus infections in Bos javanicus. PhD thesis, Murdoch University.
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Two closely related bovine lentiviruses have been described, Jembrana disease virus (JDV) and Bovine immunodeficiency virus (BIV), that produce very different clinical manifestations in infected cattle. JDV causes an acute disease with a case fatality rate of about 21% in Bos javanicus (Bali cattle) and is endemic in the cattle population of parts of Indonesia. BIV produces a subclinical infection in Bos taurus and buffalo and serological evidence has shown that this virus has a worldwide distribution, possibly including Indonesia.
Attempts were made to confirm a previous report that BIV was present in the B. javanicus population in Indonesia. BIV proviral DNA was not detected in any of the animals although JDV proviral DNA was detected in 12 of 171 animals, only one of which was seropositive.
To define the kinetics of BIV infection in B. javanicus and determine the optimal time for sampling to detect BIV infection, 13 animals were experimentally infected with the R29 strain of BIV. No clinical effects were detected but proviral DNA was detected from 4-60 days post-infection (dpi) with peak titres 20 days dpi, and a transient viraemia from 4 to 14 dpi. An antibody response to TM was detected 12 dpi but an anti-capsid (CA) antibody response was detected in one animal only and not until 34 dpi. The results indicated that detection of BIV in infected Bali cattle using PCR would have a greater chance of success soon after infection and prior to the onset of a CA antibody response.
To determine the effect of BIV infection on subsequent JDV infection in B. javanicus, 15 cattle were infected with BIV-R29 and 9 of these were subsequently infected 42 days later with JDV. The response to BIV was typical of that observed previously but BIV infection did not markedly modify the response to subsequent infection with JDV. In response to JDV infection, all cattle previously infected with BIV still developed an acute disease process typical of Jembrana disease. The results suggested that despite the close genetic and antigenic relationship between BIV and JDV, BIV infection does not confer protection against subsequent JDV infection. The close antigenic relationship between BIV and JDV is a problem in the development of specific serological tests and immunosurveillance of JDV infection. To develop reagents capable of differentiating between antibody to BIV and JDV infections, peptide mapping was used to define linear B cell epitopes on the matrix (MA), CA and surface unit (SU) proteins of JDV. Short overlapping peptides that spanned these regions were synthesised and used in an ELISA format to screen their reactivity with a panel of bovine sera from animals experimentally infected with JDVTab87, JDVPul01 or BIV-R29. Peptides representing potential immunoreactive epitopes were identified that appeared to offer promise in the development of JDVspecific serological tests and need to be tested further with a panel of sera taken from naturally infected cattle.
|Publication Type:||Thesis (PhD)|
|Murdoch Affiliation:||School of Veterinary and Biomedical Sciences|
|Supervisor:||Wilcox, Graham and Desport, Moira|
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