Progress 10/01/06 to 09/30/08
Outputs
OUTPUTS: During this period, a third and last experiment was conducted and completed with the main objective of testing the hypothesis that BEV-1 Oklahoma isolate is virulent to cattle. In this experiment, 18, 8-12 week old calves were divided into 3 groups of 6 calves each. Calves were kept in separate pens. Blindly, in each group, 4 calves were inoculated intranasally with 1 ml of virus-infected media and 2 calves were inoculated with 1 ml of non-infected media (placebo). Calves were observed for clinical signs, and then euthanized at 4 hours, 5 days, and 10 days post inoculation. A complete necropsy was performed in each animal, and samples of blood, feces, and fresh tonsils, small intestine, large intestine, mesenteric lymph nodes, lung, liver, spleen, and kidney were subjected to laboratory analysis. PARTICIPANTS: Jeremiah T. Saliki - Virologist, developed virus isolation and serology assays Susan Sanchez - Molecular Microbiologist, developed molecular tests, PCR assay Corrie C. Brown - Pathologist, helped with evaluation of tissues; in-situ hybridization assay Amelia Woolums - Bovine Veterinarian, performed clinical evaluation of calves Jian Zhang - Laboratorian, developed and performed the in-situ hybridization Deborah Keys - Study Statistician, helped in the study design TARGET AUDIENCES: Veterinary Diagnosticians and Pathologists - These audiences are to be targeted through seminars and publications in major journals PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
None of the infected calves had clinical or postmortem evidence of disease. Microscopic lesions were few and mild and were limited to the spiral colon of the large intestine; these consisted of mild multifocal inflammation and hemorrhage and predominantly occurred in calves at 5 days post inoculation. Seroconversion to BEV-1 was noted in virus-infected calves at 5 and 10 days post inoculation. BEV-1 was isolated from feces and colon of most infected animals at 5 and 10 days post infection. Two placebo inoculated calves were positive for virus isolation from the colon and feces. PCR testing detected BEV-1 only in the large intestine; results were very strong in most virus inoculated calves at 5 and 10 days post inoculation. The same two placebo inoculated calves that tested positive for virus isolation from the colon and feces were also strongly positive through PCR testing. Findings indicate that the BEV-1 isolate tested is capable of infecting cattle; that under the tested conditions, the virus is able to infect cells of the large intestine, from which the virus replicates and is shed to the environment; and that the virus is infectious to other animals. The contribution of the current study is to add to current knowledge of the pathogenesis of viruses that can potentially affect the US and Georgia cattle populations. Currently, testing of formalin fixed, paraffin embedded tissue for the presence of virus through in-situ hybridization and immunohistochemistry, is underway. Results will be published.
Publications
- No publications reported this period
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: With the main objective of testing the hypothesis that the BEV-1 Oklahoma isolate is virulent to susceptible cattle, two initial experiments were conducted and completed. A thrid experiment was planned but not conducted.
PARTICIPANTS: Jeremiah T. Saliki, Corrie C. Brown, Susan Sanchez, Amelia Woolums, Deborah Keys, Jian Zhang
Impacts
Inital experiments allowed to describe clinical signs associated with acute BEV-1 infection in calves, to partially characterize the fecal shedding that occurs following challenge, to partially characterize the gross and microscopic tissue alterations associated with BEV-1 Oklahoma isolate infection, and to develop some techniques, such as serum neutralization and viral isolation in cell culture. Because an additional experiment has not been conducted yet, evaluation of laboratory clinical parameter alterations (if any) associated with acute BEV-1 infection and developmet of other techniques, such as real-time PCR, in situ hybridization, and other diagnostic tests for the detection and further characterization of BEV-1 have not been developed. Thus far, experimental results indicated that at the effective dose, experimental animals were infected with the virus; animals developed a detectable SN titers to the virus; and virus was recovered from the feces of infected
animals. Experimental findings suggest that bovine enterovirus isolate used is able to infect experimental animals and that such animals are able to, potentyially, transmit the virus to suceptible animals.
Publications
- No publications reported this period
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