Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 17, 2013
Publication Date: N/A
Interpretive Summary: Determining the cause of abortions in cattle helps producers design better ways of managing herds. One of the groups of viruses that can cause abortions in cattle is bovine viral diarrhea viruses (BVDV). The purpose of this study was to determine if diagnosis is more reliable using some fetal tissues compared to others and to determine if storage conditions of materials before testing affected detection. The test method used was based on detection of viral genetic material and is referred to as a polymerase chain reaction amplification test or PCR test. It was found that testing of brain tissue and storage of tissues at - 80° C resulted in the most reliable results. Frequently tissues, submitted to diagnostic laboratories or collected by research laboratories, are placed in freezers for long term storage (archiving). It was also shown that contamination of tissues with fecal material did not reduce test accuracy if samples were tested within 7 days of collection but did affect accuracy in archived samples. These results indicate that there are modifications that diagnostic laboratories can institute that will increase their accuracy in diagnosing BVDV as a cause of abortions in cattle
Technical Abstract: Infection of pregnant cattle with bovine viral diarrhea viruses can result in reproductive disease that includes fetal reabsorption, mummification, abortion, still births, congenital defects affecting structural, neural, reproductive and immune systems and the birth of calves persistently infected with BVDV. Accurate diagnosis of BVDV-associated reproductive disease is important to control of BVDV at the production unit level and assessment of the cost of BVDV infections in support of BVDV control programs. The purpose of this study was to examine the stability of viral nucleic acid in fetal tissues exposed to different conditions, as measured by detection by PCR. Five different types of fetal tissue, including brain, skin and muscle, ear, and two different pooled organ samples, were subjected to conditions that mimicked those that might exist for samples collected after abortions in production settings or possible storage conditions after collection and prior to testing. In addition, tissues were archived for 36 months at – 20° C and then retested, to mimic conditions that might occur in the case of retrospective surveillance studies. Based on the results of this study, brain would be the tissue of choice for BVDV detection in persistently infected fetal tissues. The impact of fecal contamination was increased following archiving in all tissue types suggesting that, for long-term storage, effort should be made to reduce environmental contaminants before archiving.