Porcine reproductive and respiratory syndrome virus (PRRSV) surveillance using pre-weaning oral fluid samples detects circulation of wild-type PRRSV

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• 作者：Apisit Kittawornrat ; Yaowalak Panyasing ; Christa Goodell ; Chong Wang ; Phillip Gauger ; Karen Harmon ; Rolf Rauh ; Luc Desfresne ; Ian Levis ; Jeffrey Zimmerman
• 关键词：PRRSV ; Oral fluid antibody ; RT-qPCR ; Surveillance
• 刊名：Veterinary Microbiology
• 出版年：31 January, 2014
• 年：2014
• 卷：168
• 期：2-4
• 页码：331-339
• 全文大小：568 K

文摘

Oral fluid samples collected from litters of piglets (n = 600) one day prior to weaning were evaluated as a method to surveil for porcine reproductive and respiratory syndrome virus (PRRSV) infections in four sow herds of approximately 12,500 sow each. Serum samples from the litters鈥?dam (n = 600) were included for comparison. All four herds were endemically infected with PRRSV and all sows had been vaccinated 鈮? times with PRRSV modified-live virus vaccines. After all specimens had been collected, samples were randomized and assayed by PRRSV real-time reverse transcription polymerase chain reaction (RT-qPCR) and four PRRSV antibody ELISA assays (IgM, IgA, IgG, and Commercial Kit). All sow serum samples were negative by PRRSV RT-qPCR, but 9 of 600 oral fluid samples tested positive at two laboratories. Open reading frame 5 (ORF5) sequencing of 2 of the 9 positive oral fluid samples identified wild-type viruses as the source of the infection. A comparison of antibody responses in RT-qPCR positive vs. negative oral fluid samples showed significantly higher IgG S/P ratios in RT-qPCR-positive oral fluid samples (mean S/P 3.46 vs. 2.36; p = 0.02). Likewise, sow serum samples from RT-qPCR-positive litter oral fluid samples showed significantly higher serum IgG (mean S/P 1.73 vs. 0.98; p < 0.001) and Commercial Kit (mean S/P 1.97 vs. 0.98; p < 0.001) S/P ratios. Overall, the study showed that pre-weaning litter oral fluid samples could provide an efficient and sensitive approach to surveil for PRRSV in infected, vaccinated, or presumed-negative pig breeding herds.