Serological and virological surveillance for porcine reproductive and respiratory syndrome virus, porcine circovirus type 2, and influenza A viruses among smallholder swine farms of the Mekong Delta, Vietnam
Nguyen Van Cuong, MSc; Juan Carrique-Mas, DVM, PhD; Ho Thi Viet Thu, PhD; Nguyen Duc Hien, MSc; Ngo Thi Hoa, PhD; Lam Anh Nguyet, BSc; Pham Hong Anh, MSc; Juliet E Bryant, PhD
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Objectives: To evaluate the feasibility and utility of oral-fluids collection for surveillance of porcine viruses in the Mekong Delta, Vietnam, and to establish baseline serological and virological prevalence estimates for porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), and influenza A virus (IAV) among smallholder farms.
Materials and methods: Paired serum and oral-fluids samples from 68 farms (sows, boars, weaners, and growers) were tested during 2011 by reverse transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay for PRRSV, PCV2, and IAV.
Results: Low numbers of PRRSV-positive and IAV-positive pigs were detected (1.6% PRRSV viremic, two of 124; 0.8% IAV in oral fluids, one of 124). However, PCV2 detection rates were high in both serum and oral fluids (54.8% and 61.3%, respectively). Overall proportions of pigs seropositive for IAV and PRRSV were 37.9% and 33.9%, respectively. Proportions of pigs seropositive for PRRSV were 48.6% (17 of 35) and 12.1% (four of 33) on vaccinated and unvaccinated farms, respectively. Oral fluids and serum samples yielded comparable prevalence estimates for molecular detection of PCV2, and detected one sample PCR-positive for hemagglutinin of influenza A/H1N1/pdm09. There was no evidence of PRRSV shedding in oral fluids.
Implications: Antibody prevalence estimates based on testing oral fluids may provide an acceptable and useful surrogate for testing serum in future field studies if optimized assays are employed.
Keywords: oral fluids, influenza, porcine reproductive and respiratory syndrome virus, PRRSV, Vietnam
Cite as: Cuong NV, Carrique-Mas J, Thu HTV, et al. Serological and virological surveillance for porcine reproductive and respiratory syndrome virus, porcine circovirus type 2, and influenza A viruses among smallholder swine farms of the Mekong Delta, Vietnam. J Swine Health Prod 2014;22(5):224-231.
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