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.


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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    ABSTRACT: Influenza A virus (FLUAV) infections are endemic in pork producing countries worldwide but in Brazil it was not considered an important pathogen in pigs. Since the emergence of 2009 pandemic H1N1 (H1N1pdm) FLUAV, many outbreaks of respiratory disease were observed in pig herds. The aim of this study was to evaluate FLUAV infection in swine in 48 pig farms located in seven Brazilian states with previous reports of influenza-like signs by clinical, serological and virological cross-sectional studies. Serological results showed that pigs from all farms had anti-influenza antibodies by NP-ELISA. Antibodies to H3N2, H1N2 and H1N1pdm were detected by HI in pigs from 24 farms. Co-infection with two or more FLUAV subtypes was detected in pigs in seven of those 24 farms. Detection of FLUAV in nasal swabs and oral fluids by RT-qPCR indicated a global concordance >81% for the two biological samples. Moreover, our results show that H1N1pdm, H1N2 and H3N2 viruses are widespread in Brazilian pig herds. The monitoring of FLUAV emergence and evolution in pigs is urgent, as well the study of the pathogenesis of Brazilian isolates, aiming to control influenza in pigs.
    Veterinary Microbiology 09/2015; 180(1). DOI:10.1016/j.vetmic.2015.08.021 · 2.51 Impact Factor
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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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    ABSTRACT: Background Oral fluid collected by means of ropes has the potential to replace serum for monitoring and surveillance of important swine pathogens. Until now, the most commonly used method to collect oral fluid is by hanging a cotton rope in a pen. However, concerns about the influence of rope material on subsequent immunological assays have been raised. In this study, we evaluated six different rope materials for the collection of oral fluid and the subsequent detection of total and PRRSV-specific antibodies of different isotypes in oral fluid collected from PRRSV-vaccinated and infected pigs. Results An initial experiment showed that IgA is the predominant antibody isotype in porcine saliva. Moreover, it was found that synthetic ropes may yield higher amounts of IgA, whereas all rope types seemed to be equally suitable for IgG collection. Although IgA is the predominant antibody isotype in porcine oral fluid, the PRRSV-specific IgA-based IPMA and ELISA tests were clearly not ideal for sensitive detection of PRRSV-specific IgA antibodies. In contrast, PRRSV-specific IgG in oral fluids was readily detected in PRRSV-specific IgG-based IPMA and ELISA tests, indicating that IgG is a more reliable isotype for monitoring PRRSV-specific antibody immunity in vaccinated/infected animals via oral fluids with the currently available tests. Conclusions Since PRRSV-specific IgG detection seems more reliable than PRRSV-specific IgA detection for monitoring PRRSV-specific antibody immunity via oral fluids, and since all rope types yield equal amounts of IgG, it seems that the currently used cotton ropes are an appropriate choice for sample collection in PRRSV monitoring.
    BMC Veterinary Research 06/2014; 10(1):134. DOI:10.1186/1746-6148-10-134 · 1.78 Impact Factor
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    • "The possible disadvantage associated with the use of serum is the fact that a skilled veterinarian is needed to obtain the samples. Because of this, the use of additional matrices for antibody testing, such as meat-juice or saliva, which have already proven to be useful for other tests (Vercruysse et al. 2006; Wilhelm et al. 2007; Prickett et al. 2008 "
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    Parasitology 04/2014; 141(14):1-8. DOI:10.1017/S0031182014000328 · 2.56 Impact Factor
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