title: An evaluation of thermo-assisted drying and decontamination for the elimination of porcine reproductive and respiratory syndrome virus from contaminated livestock transport vehicles.
abstract: The purpose of this report is to validate a new protocol, the thermo-assisted drying and decontamination (TADD) system, for eliminating porcine reproductive and respiratory syndrome virus (PRRSV) from contaminated transport vehicles. Scale models of weaned pig trailers were used. The principle of TADD is to raise the interior temperature of trailers to 71 degrees C for 30 min to promote drying and degradation of PRRSV. Trailer interiors were artificially contaminated with 5 x 10(5) TCID50 of PRRSV strain MN 30-100, then treated with 1 of 4 treatments: 1) TADD; 2) air only (no supplemental heat); 3) overnight (8 h) drying; and 4) washing only. Following treatment, swabs were collected from the trailer interiors at 0, 10, 20, and 30 min post-treatment and from the overnight group after 8 h. Swabs were tested for PRRSV-RNA by polymerase chain reaction (PCR). As a measure of the presence of infectious PRRSV, sentinel pigs were housed in treated trailers for 2 h post-treatment and supernatants from swabs were injected IM into naive pigs (bioassay), the recipient pigs were then tested for PRRSV infection. All trailers were PRRSV positive by PCR immediately after washing, prior to treatment (pt). At 10 min pt, 7/10 swabs were positive from the TADD trailers; however, all swabs collected at 20 and 30 min pt were PRRSV negative by PCR, and trailer interiors were visibly dry. In contrast, 9/19, 6/10, and 6/10 swabs collected at 10, 20, and 30 min, respectively, from trailers treated with air only were positive and visibly wet. All swabs (10/10) collected from trailers treated with washing only were PRRSV positive by PCR and all swabs collected at 8 h of drying were PRRSV negative by PCR. All tests for the presence of infectious PRRSV were negative for trailers treated with TADD and overnight drying, while infectious PRRSV was detected in sentinel pigs and bioassay pigs in the other groups. Under the conditions of this study, the efficacy of the TADD system was equal to that of the overnight drying treatment, and it required a shorter period of time to complete its objective.
authors.affiliation: Swine Disease Eradication Center, 385 C Animal Science/Veterinary Medicine Building, 1988 Fitch Avenue, University of Minnesota College of Veterinary Medicine, St. Paul, Minnesota 55108, USA. deexx004@umn.edu
authors.forename: Scott
authors.initials: S
authors.lastname: Dee
authors.forename: Montserrat
authors.initials: M
authors.lastname: Torremorell
authors.forename: Bob
authors.initials: B
authors.lastname: Thompson
authors.forename: John
authors.initials: J
authors.lastname: Deen
authors.forename: Carlos
authors.initials: C
authors.lastname: Pijoan
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000662:veterinary; D004197:Disease Reservoirs / Q000662:veterinary; D004203:Disinfection / Q000379:methods*; D006358:Hot Temperature; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D019318:Porcine Reproductive and Respiratory Syndrome / Q000517:prevention & control* / Q000635:transmission; D019316:Porcine respiratory and reproductive syndrome virus / Q000302:isolation & purification*; D012367:RNA, Viral / Q000032:analysis; D013552:Swine; D013997:Time Factors; D014186:Transportation
chemical_list: D012367:RNA, Viral
references.citation: Vet Rec. 2001 Jun 2;148(22):687-90
references.pmid: 11425255
references.citation: Arch Virol. 1997;142(3):629-33
references.pmid: 9349308
references.citation: Am J Vet Res. 1997 Aug;58(8):828-32
references.pmid: 9256964
references.citation: Vet Microbiol. 1997 Apr;55(1-4):329-36
references.pmid: 9220630
references.citation: J Vet Diagn Invest. 1995 Oct;7(4):456-64
references.pmid: 8580165
references.citation: J Vet Diagn Invest. 1992 Apr;4(2):127-33
references.pmid: 1616976
references.citation: Can J Vet Res. 2004 Apr;68(2):128-33
references.pmid: 15188957
references.citation: Can J Vet Res. 2004 Jan;68(1):19-26
references.pmid: 14979431
references.citation: Vet Rec. 2003 Jan 18;152(3):73-6
references.pmid: 12570309
references.citation: Can J Vet Res. 2003 Jan;67(1):12-9
references.pmid: 12528824
references.citation: Can J Vet Res. 2002 Oct;66(4):232-9
references.pmid: 12418778
references.citation: Can J Vet Res. 2002 Jul;66(3):191-5
references.pmid: 12146891
references.citation: Vet Rec. 2002 Jan 26;150(4):114-5
references.pmid: 11838995