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Matsumoto N, Douangngeun B, Theppangna W, Khounsy S, Phommachanh P, Toribio JA, Bush RD, Selleck PW, Gleeson LJ, Siengsanan-Lamont J, Blacksell SD. Utilising abattoir sero-surveillance for high-impact and zoonotic pig diseases in Lao PDR. Epidemiol Infect 2023; 151:e40. [PMID: 36750223 PMCID: PMC10028928 DOI: 10.1017/s095026882300016x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 01/17/2023] [Accepted: 01/29/2023] [Indexed: 02/09/2023] Open
Abstract
National disease surveillance systems are essential to a healthy pig industry but can be costly and logistically complex. In 2019, Lao People's Democratic Republic (Lao PDR) piloted an abattoir disease surveillance system to assess for the presence of high impact pig diseases (HIPDs) using serological methods. The Lao Department of Livestock and Fisheries (DLF) identified Classical Swine Fever (CSF), Porcine Respiratory and Reproductive Syndrome (PRRS) and Brucella suis as HIPDs of interest for sero-surveillance purposes. Porcine serum samples (n = 597) were collected from six Lao abattoirs in March to December of 2019. Serological enzyme-linked immunosorbent assay (ELISA) methods were chosen for their high-throughput and relatively low-costs. The true seroprevalence for CSF and PRRS seropositivity were 68.7%, 95% CI (64.8-72.3) and 39.5%, 95% CI (35.7-43.5), respectively. The results demonstrated no evidence of Brucella spp. seroconversion. Lao breed pigs were less likely to be CSF seropositive (P < 0.05), whilst pigs slaughtered at <1 year of age were less likely to be PRRS seropositive (P < 0.01). The testing methods could not differentiate between seropositivity gained from vaccine or natural infection, and investigators were unable to obtain the vaccine status of the slaughtered pigs from the abattoirs. These results demonstrate that adequate sample sizes are possible from abattoir sero-surveillance and lifetime health traceability is necessary to understand HIPDs in Lao PDR.
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Affiliation(s)
- Nina Matsumoto
- Sydney School of Veterinary Science, The University of Sydney, 425 Werombi Road, Camden, NSW, Australia
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Bangkok 10400, Thailand
| | - Bounlom Douangngeun
- National Animal Health Laboratory, Department of Livestock and Fisheries, Ministry of Agriculture and Forestry, Souphanouvong Avenue, Sikhottabong District, PO. Box 6644, Vientiane, Lao People's Democratic Republic
| | - Watthana Theppangna
- National Animal Health Laboratory, Department of Livestock and Fisheries, Ministry of Agriculture and Forestry, Souphanouvong Avenue, Sikhottabong District, PO. Box 6644, Vientiane, Lao People's Democratic Republic
| | - Syseng Khounsy
- National Animal Health Laboratory, Department of Livestock and Fisheries, Ministry of Agriculture and Forestry, Souphanouvong Avenue, Sikhottabong District, PO. Box 6644, Vientiane, Lao People's Democratic Republic
| | - Phouvong Phommachanh
- National Animal Health Laboratory, Department of Livestock and Fisheries, Ministry of Agriculture and Forestry, Souphanouvong Avenue, Sikhottabong District, PO. Box 6644, Vientiane, Lao People's Democratic Republic
| | - Jenny-Ann Toribio
- Sydney School of Veterinary Science, The University of Sydney, 425 Werombi Road, Camden, NSW, Australia
| | - Russell D. Bush
- Sydney School of Veterinary Science, The University of Sydney, 425 Werombi Road, Camden, NSW, Australia
| | - Paul W. Selleck
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Bangkok 10400, Thailand
| | - Laurence J. Gleeson
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Bangkok 10400, Thailand
| | - Jarunee Siengsanan-Lamont
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Bangkok 10400, Thailand
| | - Stuart D. Blacksell
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd, Bangkok 10400, Thailand
- Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Mahosot Hospital, Vientiane, Lao People's Democratic Republic
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Fahrion AS, Beilage EG, Nathues H, Dürr S, Doherr MG. Evaluating perspectives for PRRS virus elimination from pig dense areas with a risk factor based herd index. Prev Vet Med 2014; 114:247-58. [PMID: 24674019 DOI: 10.1016/j.prevetmed.2014.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 02/03/2014] [Accepted: 03/01/2014] [Indexed: 11/30/2022]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is wide-spread in pig populations globally. In many regions of Europe with intensive pig production and high herd densities, the virus is endemic and can cause disease and production losses. This fuels discussion about the feasibility and sustainability of virus elimination from larger geographic regions. The implementation of a program aiming at virus elimination for areas with high pig density is unprecedented and its potential success is unknown. The objective of this work was to approach pig population data with a simple method that could support assessing the feasibility of a sustainable regional PRRSV elimination. Based on known risk factors such as pig herd structure and neighborhood conditions, an index characterizing individual herds' potential for endemic virus circulation and reinfection was designed. This index was subsequently used to compare data of all pig herds in two regions with different pig- and herd-densities in Lower Saxony (North-West Germany) where PRRSV is endemic. Distribution of the indexed herds was displayed using GIS. Clusters of high herd index densities forming potential risk hot spots were identified which could represent key target areas for surveillance and biosecurity measures under a control program aimed at virus elimination. In an additional step, for the study region with the higher pig density (2463 pigs/km(2) farmland), the potential distribution of PRRSV-free and non-free herds during the implementation of a national control program aiming at national virus elimination was modeled. Complex herd and trade network structures suggest that PRRSV elimination in regions with intensive pig farming like that of middle Europe would have to involve legal regulation and be accompanied by important trade and animal movement restrictions. The proposed methodology of risk index mapping could be adapted to areas varying in size, herd structure and density. Interpreted in the regional context, this could help to classify the density of risk and to accordingly target resources and measures for elimination.
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Affiliation(s)
- A S Fahrion
- Veterinary Public Health Institute, Vetsuisse Faculty, University of Bern, Switzerland.
| | - E grosse Beilage
- Field Station for Epidemiology, University of Veterinary Medicine Hannover, Foundation, Büscheler Strasse 9, 49456 Bakum, Germany.
| | - H Nathues
- Clinic for Swine, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109A, 3012 Bern, Switzerland.
| | - S Dürr
- Veterinary Public Health Institute, Vetsuisse Faculty, University of Bern, Switzerland.
| | - M G Doherr
- Institute for Veterinary Epidemiology and Biostatistics, Department of Veterinary Medicine at the Freie Universität, Berlin, Germany.
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Nathues C, Zimmerli U, Hauser R, Nathues H, Grosse Beilage E, Schüpbach-Regula G. Risk assessment of the introduction of porcine reproductive and respiratory syndrome virus via boar semen into Switzerland as an example of a PRRSV-free country. Transbound Emerg Dis 2013; 61:546-54. [PMID: 23356485 DOI: 10.1111/tbed.12059] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Indexed: 12/27/2022]
Abstract
Switzerland is currently porcine reproductive and respiratory syndrome virus (PRRSV) free, but semen imports from PRRSV-infected European countries are increasing. As the virus can be transmitted via semen, for example, when a free boar stud becomes infected, and the risk of its import in terms of PRRSV introduction is unknown, the annual probability to accidentally import the virus into Switzerland was estimated in a risk assessment. A quantitative stochastic model was set up with data comprised by import figures of 2010, interviews with boar stud owners and expert opinion. It resulted in an annual median number of 0.18 imported ejaculates (= imported semen doses from one collection from one donor) from PRRSV-infected boars. Hence, one infected ejaculate would be imported every 6 years and infect a mean of 10 sows. These results suggest that under current circumstances, there is a substantial risk of PRRSV introduction into Switzerland via imported boar semen and that measures to enhance safety of imports should be taken. The time from infection of a previously negative boar stud to its detection had the highest impact on the number of imported 'positive' ejaculates. Therefore, emphasis should be placed on PRRSV monitoring protocols in boar studs. Results indicated that a substantial increase in safety could only be achieved with much tighter sampling protocols than currently performed. Generally, the model could easily be customized for other applications like other countries or regions or even sow farms that want to estimate their risk when purchasing semen from a particular boar stud.
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Affiliation(s)
- C Nathues
- Veterinary Public Health Institute, University of Berne, Liebefeld, Switzerland
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Nathues H, Chang YM, Wieland B, Rechter G, Spergser J, Rosengarten R, Kreienbrock L, grosse Beilage E. Herd-Level Risk Factors for the Seropositivity toMycoplasma hyopneumoniaeand the Occurrence of Enzootic Pneumonia Among Fattening Pigs in Areas of Endemic Infection and High Pig Density. Transbound Emerg Dis 2012. [DOI: 10.1111/tbed.12033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- H. Nathues
- Field Station for Epidemiology; University of Veterinary Medicine Hannover, Foundation; Bakum Germany
- Veterinary Epidemiology and Public Health Group; The Royal Veterinary College; Hatfield Hertfordshire UK
| | - Y. M. Chang
- Veterinary Epidemiology and Public Health Group; The Royal Veterinary College; Hatfield Hertfordshire UK
| | - B. Wieland
- Veterinary Epidemiology and Public Health Group; The Royal Veterinary College; Hatfield Hertfordshire UK
| | - G. Rechter
- Institute for Biometry, Epidemiology & Information Processing; WHO Collaborating Centre for Research and Training in Veterinary Public Health; University of Veterinary Medicine Hannover, Foundation; Hannover Germany
| | - J. Spergser
- Department of Pathobiology; Institute of Bacteriology, Mycology and Hygiene; University of Veterinary Medicine; Vienna Austria
| | - R. Rosengarten
- Department of Pathobiology; Institute of Bacteriology, Mycology and Hygiene; University of Veterinary Medicine; Vienna Austria
| | - L. Kreienbrock
- Institute for Biometry, Epidemiology & Information Processing; WHO Collaborating Centre for Research and Training in Veterinary Public Health; University of Veterinary Medicine Hannover, Foundation; Hannover Germany
| | - E. grosse Beilage
- Field Station for Epidemiology; University of Veterinary Medicine Hannover, Foundation; Bakum Germany
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grosse Beilage E, Nathues H, Meemken D, Harder TC, Doherr MG, Grotha I, Greiser-Wilke I. Frequency of PRRS live vaccine virus (European and North American genotype) in vaccinated and non-vaccinated pigs submitted for respiratory tract diagnostics in North-Western Germany. Prev Vet Med 2009; 92:31-7. [PMID: 19700211 PMCID: PMC7114236 DOI: 10.1016/j.prevetmed.2009.07.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 06/18/2009] [Accepted: 07/23/2009] [Indexed: 10/27/2022]
Abstract
The frequency of PRRSV corresponding to live vaccines and wild-type was determined in 902 pigs from North-Western Germany submitted for post-mortem examination. Overall, 18.5% of the samples were positive for the EU wild-type virus. EU genotype vaccine virus was detected in 1.3% and the NA genotype vaccine virus in 8.9% of all samples. The detection of the EU vaccine was significantly higher in pigs vaccinated with the corresponding vaccine (OR=9.4). Pigs vaccinated with NA genotype had significantly higher detection chances for the corresponding vaccine virus when compared to non-vaccinated animals (OR=3.34) animals, however, NA vaccine was also frequently detected in non-vaccinated pigs. Concluding, the dynamics of NA genotype vaccine and EU wild-type virus corresponds with studies on PRRSV spread in endemically infected herds. The potential of spontaneous spread of the NA genotype vaccine should be considered in the planning of eradication programs.
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Affiliation(s)
- Elisabeth grosse Beilage
- Field Station for Epidemiology, University of Veterinary Medicine Hannover, Buescheler Str. 9, D-49456 Bakum, Germany.
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