An evaluation of disinfectants for the sanitation of porcine reproductive and respiratory syndrome virus-contaminated transport vehicles at cold temperatures.

The objective of this study was to evaluate the efficacy of commercially available disinfectants to sanitize porcine reproductive and respiratory syndrome virus (PRRSV) contaminated trailer models in cold climates (-20 degrees C and 4 degrees C). Disinfectants evaluated included Synergize, Aseptol 2000, Biophene, Sentramax, Virkon, Tek Trol, and DC&R. All products were applied to trailers via fumigation at 4 degrees C. Following experimental contamination of model trailers with PRRSV MN 30-100 (5 x 10(5) TCID50), models were tested for the presence or absence of PRRSV-RNA by polymerase chain reaction (PCR) on swabs collected 0, 30, and 60 min after treatment. Treatments included washing only, washing plus disinfectant fumigation, washing plus fumigation, and washing plus overnight drying. The PRRSV-RNA detected across trailers ranged from 0/12 replicates in trailers treated with Synergize or allowed to dry for 8 h. These trailers were also negative for the presence of infectious PRRSV, based on the lack of sentinel pig infection (0/4 replicates). In contrast, the detection of PRRSV-positive swabs by PCR ranged from 3/12 (Aseptol) to 10/12 (Biophene). Based on these results, the efficacy of Synergize was evaluated at -20 degrees C. In an attempt to reduce the impact of freezing on disinfectant activity, 30 mL of disinfectant was added to a 3840 mL of a 40% methanol solution, a 10% propylene glycol (PG) solution, or water alone. The PRRSV-contaminated trailers were treated with 1 of 3 disinfectant mixtures via fumigation, stored for 8 h at -20 degrees C, allowed to thaw, and sampled as described. Trailers treated with 40% methanol or 10% PG did not freeze and were negative for PRRSV-RNA and infectious virus following thawing. In contrast, trailers treated with disinfectant and water were frozen within 60 min at -20 degrees C, and decontamination was not successful.

An assessment of sanitation protocols for commercial transport vehicles contaminated with porcine reproductive and respiratory syndrome virus.

The objective of this study was to develop and test a rapid (< 2 h) sanitation protocol designed for porcine reproductive and respiratory syndrome virus (PRRSV) positive commercial transport vehicles involving cold water washing and disinfection via fumigation using scale models of weaned pig trailers. The study consisted of 2 phases. Following experimental contamination of model trailers with PRRSV MN 30-100 (5 x 10(5)TCID50), phase 1 evaluated the presence or absence of PRRSV RNA by polymerase chain reaction (PCR) on swabs collected from the trailer interiors 0, 60, and 90 min after treatment. Phase 2 consisted of evaluating the infectivity of trailers 90 min posttreatment by monitoring changes in the PRRSV-status of naive sentinel pigs housed for 2 h. Treatments included washing only (treatment 1), washing plus formaldehyde fumigation (treatment 2), washing plus fumigation with glutaraldehyde-quaternary ammonium chloride (treatment 3), and washing plus overnight drying (treatment 4). Porcine reproductive and respiratory syndrome virus RNA was detected in all trailers (20 out of 20 replicates) at 60 and 90 min following the application of treatments 1 and 2. These trailers also contained infectious PRRSV, as determined by the infection of naive pigs housed in treated trailers and the testing of organic debris collected from the interior of trailers by swine bioassay. At 90 min posttreatment, all trailers treated with glutaraldehyde-quaternary ammonium chloride were PCR-negative, non-infectious to sentinel pigs, and swine bioassay negative. Similar results were observed in trailers allowed to dry for 8 h. Under the conditions of this study, it appears certain disinfectants may possess different levels of efficacy against PRRSV and PRRSV-positive models may be effectively sanitized in the absence of overnight drying.