Detection of Porcine Reproductive and Respiratory Syndrome virus infection in porcine oral fluid samples: a longitudinal study under experimental conditions

Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011-1250, USA.
Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc (Impact Factor: 1.35). 04/2008; 20(2):156-63. DOI: 10.1177/104063870802000203
Source: PubMed


Isolation of Porcine reproductive and respiratory syndrome virus (PRRSV) from oral fluids was first reported in 1997. The objective of the present study was to determine whether PRRSV and/or anti-PRRSV antibodies were present in oral fluids at diagnostic levels. The level and duration of PRRSV and anti-PRRSV antibodies in serum and oral fluids was evaluated in 3 age groups of pigs (4, 8, or 12 weeks of age) inoculated with a type 2 (North American) PRRSV isolate. Serum, buccal swabs, and pen-based oral fluid samples were collected for 63 days following inoculation. Specimens were assayed for PRRSV by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), and for anti-PRRSV antibodies by enzyme-linked immunosorbent assay (ELISA) and indirect fluorescent antibody test (IFAT). Porcine reproductive and respiratory syndrome virus was detected by real-time qRT-PCR in serum for approximately 5 weeks and in oral fluids for approximately 4 weeks postinoculation. Pig age at the time of inoculation had no effect on the quantity or duration of virus in oral fluid samples. Low levels of anti-PRRSV antibody were detected in oral fluid samples by ELISA and IFAT. Although the approach remains to be validated in the field, the results of this experiment suggest that pen-based oral fluid sampling could be an efficient, cost-effective approach to PRRSV surveillance in swine populations.

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Available from: Kyoung-Jin Yoon
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    • "Nasal swabs were individually taken and placed into 2 mL MEM (Gibco 1 ) supplemented with bovine serum albumin and immediately stored at À80 C. Individual blood samples were collected by jugular venipuncture and sera were stored at À20 C. A pen-based OF was collected using a cotton rope hanging from the ceiling. Each cotton rope contained OF from 10 pigs, totalizing three samples per farm, which were pooled after collection and stored at À80 C (Prickett et al., 2008). "
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    • "In the vaccination experiment, “stimulated” oral fluids (oral fluids collected by masticatory or gustatory stimulation such as chewing [20]) were collected 1 day before the first vaccination and 14 days after each vaccination with four different rope materials according to procedures described by Prickett et al. [17]. In brief, one rope (length 1 m; diameter 14 mm) was suspended in each pen and was left in place for 30 min, during which the animal could chew on it and moisten it with oral fluid. "
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