title: Emergence of highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) in medium-scale swine farms in southeastern Cambodia.
abstract: Since 2006, reports from China and Viet Nam have alerted of an emergent highly pathogenic variant of porcine reproductive and respiratory syndrome virus (HP-PRRSV) in that region. The frequent occurrence of outbreaks in these countries puts Cambodian pig farms at high risk of infection, but no study had been conducted to investigate the presence of HP-PRRS in Cambodian farms. We investigated the presence of HP-PRRS in medium-scale (semi-commercial) swine farms in the Cambodian southeastern region. Specifically, one province bordering Viet Nam (Takeo) was selected due to the concentration of most semi-commercial farms in that province. A cross-sectional study was carried out, between July and September 2010 to assess whether the prevalence of infection in these farms was indicative of recent spread of PPRSV and to identify risk factors for infection. The number of farms to be sampled was established using methods for Lot Quality Assurance Surveys (LQAS), in order to achieve a pre-established ability to discriminate between two different prevalence settings. The target population comprised all semi-commercial farms in Takeo province from which a random sample of 35 farms was selected. Selected farms were visited and questionnaires administered to gather information on farm characteristics and husbandry practices. Blood samples from individual pigs were collected in each of the study farms and tested for PRRSV, along with a number of other swine respiratory pathogens in order to investigate potential interactions. Our results showed that the virus was already present in Takeo semi-commercial pig population (LQAS herd prevalence ≥85%) at the time of sampling. The presence of sows in the farm and farm density were significantly associated (P<0.05) with the introduction and the presence of PRRS - but this was an unadjusted association as small sample size precluded multivariate analysis. Spatiotemporal description of the supposed pattern of infection revealed that the 1st farms infected were closely located to major national and provincial roads, connecting the Cambodian capital Phnom Penh to Viet Nam.
authors.affiliation: Department of Production and Population Health, Royal Veterinary College, Hatfield AL9 7TA, United Kingdom; Virology Department, Animal Health and Veterinary Laboratories Agency (AHVLA), Weybridge KT15 3NB, United Kingdom. Electronic address: btornimbene@rvc.ac.uk.
authors.forename: B
authors.initials: B
authors.lastname: Tornimbene
authors.affiliation: Virology Department, Animal Health and Veterinary Laboratories Agency (AHVLA), Weybridge KT15 3NB, United Kingdom.
authors.forename: J-P
authors.initials: JP
authors.lastname: Frossard
authors.affiliation: National Institute of Veterinary Research (NaVRI), Animal Health and Production Office, Ministry of Agriculture Food and Fishery, Phnom Penh, Cambodia.
authors.forename: V
authors.initials: V
authors.lastname: Chhim
authors.affiliation: National Institute of Veterinary Research (NaVRI), Animal Health and Production Office, Ministry of Agriculture Food and Fishery, Phnom Penh, Cambodia.
authors.forename: S
authors.initials: S
authors.lastname: Sorn
authors.affiliation: Department of Production and Population Health, Royal Veterinary College, Hatfield AL9 7TA, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Guitian
authors.affiliation: Virology Department, Animal Health and Veterinary Laboratories Agency (AHVLA), Weybridge KT15 3NB, United Kingdom.
authors.forename: T W
authors.initials: TW
authors.lastname: Drew
mesh_terms: D000383:Agriculture; D000822:Animal Husbandry; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002160:Cambodia / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004196:Disease Outbreaks / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D016015:Logistic Models; D055810:Lot Quality Assurance Sampling; D008297:Male; D019318:Porcine Reproductive and Respiratory Syndrome / Q000097:blood / Q000453:epidemiology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology; D015995:Prevalence; D011795:Surveys and Questionnaires; D013552:Swine
chemical_list: D000914:Antibodies, Viral
keywords: Cambodia; Lot Quality Assurance Survey (LQAS); Outbreak; Pigs; Porcine reproductive and respiratory syndrome (PRRS)