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Lambert MÈ, Arsenault J, Côté JC, D'Allaire S. Contacts posing risks of disease introduction in swine breeding herds in Quebec, Canada: Is the frequency of contacts associated with biosecurity measures? Prev Vet Med 2023; 217:105966. [PMID: 37423151 DOI: 10.1016/j.prevetmed.2023.105966] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 06/12/2023] [Accepted: 06/17/2023] [Indexed: 07/11/2023]
Abstract
The introduction of pathogens into swine breeding herds can occur through a variety of contacts involving people, animals, vehicle or various supplies. Appropriate biosecurity is critical to mitigate these risks. A retrospective study was conducted to describe contacts with swine breeding sites over a one-month period and to evaluate their association with biosecurity measures and site characteristics. As part of a larger project, sites which had a recent porcine reproductive and respiratory syndrome virus introduction were selected. A questionnaire, logbooks and pig traceability system were used for collecting data relative to persons or supplies entering the breeding unit, live pig transportation, service vehicles, other animal species, neighboring pig sites and manure spreading around the site. The 84 sites investigated had a median sow inventory of 675. A median of 4 farm staff and 2 visitors entered the breeding unit at least once over the one-month period. A total of 73 sites (87%) received visitor(s), mostly from maintenance and technical services. All sites received at least 3 supply deliveries (median of 8) including semen (99% of sites), small material and/or drugs (98% of sites), bags (87% of sites), and/or equipment (61% of sites). Live pig movements were observed in all sites, with a median number of 5 truck entries on the site or exits from the site. For feed mill, rendering and propane trucks, at least one entry was noted in ≥ 61% of sites. For all service vehicle categories except feed mill and manure vacuum trucks, a single service provider was involved in each site. Dogs and cats were banned from all sites, but wild birds were observed in 8% of sites. Manure spreading within a 100 m radius of pig units was noted in 10% of the sites. With a few exceptions, biosecurity measures were not associated with the frequency of contacts. A 100-sow increase in sow inventory was associated with an increase of 0.34 in the cumulated number of staff entering the breeding unit, of 0.30 in the number of visitors and of 0.19 in the number of live pig movements. Live pig movements were also positively associated with vertically integrated farrow-to-wean (vs. independent farrow-to-wean) production and time interval of 4 weeks or more between farrowing (vs. less than 4). Considering the variety and frequency of contacts observed, biosecurity should be meticulously applied in all breeding herds to prevent endemic and exotic disease introduction.
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Affiliation(s)
- M-È Lambert
- Laboratoire d'épidémiologie et de médecine porcine, Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada; Centre de recherche en infectiologie porcine et avicole - Fonds de recherche du Québec - Nature et technologies, Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada; Groupe de recherche sur les maladies infectieuses en production animale, Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada.
| | - J Arsenault
- Laboratoire d'épidémiologie et de médecine porcine, Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada; Centre de recherche en infectiologie porcine et avicole - Fonds de recherche du Québec - Nature et technologies, Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada
| | - J-C Côté
- Laboratoire d'épidémiologie et de médecine porcine, Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada
| | - S D'Allaire
- Laboratoire d'épidémiologie et de médecine porcine, Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada; Centre de recherche en infectiologie porcine et avicole - Fonds de recherche du Québec - Nature et technologies, Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada; Groupe de recherche sur les maladies infectieuses en production animale, Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada
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Galvis JA, Jones CM, Prada JM, Corzo CA, Machado G. The between-farm transmission dynamics of porcine epidemic diarrhoea virus: A short-term forecast modelling comparison and the effectiveness of control strategies. Transbound Emerg Dis 2021; 69:396-412. [PMID: 33475245 DOI: 10.1111/tbed.13997] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/11/2021] [Accepted: 01/18/2021] [Indexed: 01/10/2023]
Abstract
A limited understanding of the transmission dynamics of swine disease is a significant obstacle to prevent and control disease spread. Therefore, understanding between-farm transmission dynamics is crucial to developing disease forecasting systems to predict outbreaks that would allow the swine industry to tailor control strategies. Our objective was to forecast weekly porcine epidemic diarrhoea virus (PEDV) outbreaks by generating maps to identify current and future PEDV high-risk areas, and simulating the impact of control measures. Three epidemiological transmission models were developed and compared: a novel epidemiological modelling framework was developed specifically to model disease spread in swine populations, PigSpread, and two models built on previously developed ecosystems, SimInf (a stochastic disease spread simulations) and PoPS (Pest or Pathogen Spread). The models were calibrated on true weekly PEDV outbreaks from three spatially related swine production companies. Prediction accuracy across models was compared using the receiver operating characteristic area under the curve (AUC). Model outputs had a general agreement with observed outbreaks throughout the study period. PoPS had an AUC of 0.80, followed by PigSpread with 0.71, and SimInf had the lowest at 0.59. Our analysis estimates that the combined strategies of herd closure, controlled exposure of gilts to live viruses (feedback) and on-farm biosecurity reinforcement reduced the number of outbreaks. On average, 76% to 89% reduction was seen in sow farms, while in gilt development units (GDU) was between 33% to 61% when deployed to sow and GDU farms located in probabilistic high-risk areas. Our multi-model forecasting approach can be used to prioritize surveillance and intervention strategies for PEDV and other diseases potentially leading to more resilient and healthier pig production systems.
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Affiliation(s)
- Jason A Galvis
- Department of Population Health and Pathobiology, College of Veterinary Medicine, Raleigh, NC, USA
| | - Chris M Jones
- Center for Geospatial Analytics, North Carolina State University, Raleigh, NC, USA
| | - Joaquin M Prada
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Cesar A Corzo
- Veterinary Population Medicine Department, College of Veterinary Medicine, University of Minnesota, St Paul, MN, USA
| | - Gustavo Machado
- Department of Population Health and Pathobiology, College of Veterinary Medicine, Raleigh, NC, USA.,Center for Geospatial Analytics, North Carolina State University, Raleigh, NC, USA
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Yang D, Su M, Li C, Zhang B, Qi S, Sun D, Yin B. Isolation and characterization of a variant subgroup GII-a porcine epidemic diarrhea virus strain in China. Microb Pathog 2019; 140:103922. [PMID: 31838173 PMCID: PMC7126716 DOI: 10.1016/j.micpath.2019.103922] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/01/2019] [Accepted: 12/10/2019] [Indexed: 01/10/2023]
Abstract
Background Highly virulent variants of porcine epidemic diarrhea virus (PEDV) have been closely associated with recent outbreaks of porcine epidemic diarrhea (PED) in China, which have resulted in severe economic losses to the pork industry. Methods In the current study, the variant PEDV strain HM2017 was isolated and purified and a viral growth curve was constructed according to the median tissue culture infective dose (TCID50). HM2017 were amplify with RT-PCR and analyzed by phylogeny analysis. Animal pathogenicity experiment was carried to evaluate the HM2017 clinical assessment. Results Genome-based phylogenetic analysis revealed that PEDV strain HM2017 was clustered into the variant subgroup GII-a that is currently circulating in pig populations in China. The highest median tissue culture infectious dose of strain HM2017 after 15 passages in Vero cells was 1.33 × 107 viral particles/mL. Strain HM2017 was highly virulent to suckling piglets, which exhibited clinical symptoms at 12 h post-infection (hpi) (i.e., weight loss at 12–84 hpi, increased body temperatures at 24–48 hpi, high viral loads in the jejunum and ileum, and 100% mortality by 84 hpi). Conclusion The present study reports a variant subgroup GII-a PEDV HM2017 strain in China and characterize its pathogenicity. PEDV strain HM2017 of subgroup GII-a presents a promising vaccine candidate for the control of PED outbreaks in China. A variant subgroup GII-a PEDV strain HM2017 was successfully isolated in China. PEDV strain HM2017 appeared to be highly virulent in suckling piglets. PEDV strain HM2017 was well adapted to Vero cells, as evidenced by the rapid growth.
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Affiliation(s)
- Dan Yang
- Laboratory for the Prevention and Control of Swine Infectious Diseases, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Mingjun Su
- Laboratory for the Prevention and Control of Swine Infectious Diseases, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Chunqiu Li
- Laboratory for the Prevention and Control of Swine Infectious Diseases, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Bei Zhang
- Laboratory for the Prevention and Control of Swine Infectious Diseases, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Shanshan Qi
- Laboratory for the Prevention and Control of Swine Infectious Diseases, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Dongbo Sun
- Laboratory for the Prevention and Control of Swine Infectious Diseases, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, China; College of Animal Science and Technology, Jilin Agricultural Science and Technology University, Jilin, China.
| | - Baishuang Yin
- College of Animal Science and Technology, Jilin Agricultural Science and Technology University, Jilin, China.
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