Posters, talks & more from Surrey Diagnsotics
PCR False positives from Sentinal-Free Screening
This study discusses potential issues with "Sentinel Free" health monitoring via PCR on dust samples from IVC exhaust air filters. The authors present a case where these filters yielded false positives for an infectious agent not detected in live animal samples. They suggest that contaminating DNA, possibly from wild rodents in raw material storage, diet, and bedding, could lead to these false positives. The presence of mouse DNA in "clean" diet and bedding is confirmed through Real-Time PCR, raising concerns about the reliability of health monitoring via plenum filters. These false positives result in significant costs for research facilities due to additional testing to identify the source of the problem.
Comparision of PCR on faeces vs traditional sentinel methods for S. obvelata & P. pneumotropica
This study evaluates the use of Polymerase Chain Reaction (PCR) for routine health monitoring in animal colonies, specifically for detecting Pasteurella pneumotropica and Syphacia obvelata. The research compares PCR with traditional methods and finds that PCR is a suitable alternative to culture for detecting P. pneumotropica when animal stock is limited. However, for S. obvelata, PCR's correlation with anal imprint and direct examination of caecal contents is poor, suggesting that it may miss positive cases. Additionally, PCR cannot distinguish between DNA from live or dead organisms. Therefore, caution is advised when using PCR for S. obvelata detection, and microscopy may be needed in conjunction to reduce the risk of false negatives.
Combined screening strategy to reduce the numbers of sentinel animals used whilst maintaining confidence in results
This article addresses the common perception of PCR/RT-PCR as the "Gold Standard" for laboratory animal health monitoring and challenges this notion. It argues that relying solely on PCR for animal disease detection is inadequate, as it may not provide comprehensive information. The proposed approach advocates a combination of traditional methods such as serology, microbiological culture, and microscopy, alongside non-lethal serology and molecular techniques. This holistic approach aims to enhance result reliability and offer a more comprehensive view of a colony's health status while also reducing the need for sentinel animals in the process.
