title: Efficient surveillance of pig populations using oral fluids.
abstract: Currently virus surveillance in swine herds is constrained by the cost-effectiveness and efficiency of sampling methods. The objective of this study was to assess the value of using oral fluids collected by barn personnel as a method of surveillance based on PCR testing. Approximately 12,150 pigs in 10 wean-to-finish barns on 10 farms were monitored for the presence of porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus (IAV), and Torque teno virus genogroups 1 (TTV1) and 2 (TTV2) by sampling oral fluid specimens. Oral fluid samples were collected from 6 pens at each site starting at the time of pig placement (∼3 weeks of age) and continuing thereafter at 2-week intervals for a period of 18 weeks. Data were analyzed both on a pen basis and barn basis. Overall, 508 (85%) samples were positive for PCV2, 73 (12%) for PRRSV, 46 (8%) for IAV, 483 (81%) for TTV2, and 155 (26%) for TTV1 during the study period. The estimated arithmetic means of the quantitative PCR-positive oral fluids for PCV2, PRRSV, and IAV were 1×10(4.62), 1×10(4.97), and 1×10(5.49)per ml. With a single exception, all barns were positive for PCV2 and TTV2 at every sampling point in the study. Virus detection varied among barns, particularly for IAV and PRRSV. The pen level, cumulative distribution of agent combinations between all 10 barns were statistically different. The most commonly observed patterns were PCV2+TTV2 (239 pen samples, 40%), PCV2+TTV1+TTV2 (88 pen samples, 15%), and PCV2 alone (66 pen samples, 11%). This "proof-of-concept" project showed that a variety of viruses could be detected either intermittently or continuously in pig populations and demonstrated that barn herd virus status is highly variable, even among barns in the same production system. Oral fluid sampling is a promising approach for increasing the efficiency and cost effectiveness of virus surveillance in swine herds.
authors.affiliation: Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA. ramireza@iastate.edu
authors.forename: Alejandro
authors.initials: A
authors.lastname: Ramirez
authors.forename: Chong
authors.initials: C
authors.lastname: Wang
authors.forename: John R
authors.initials: JR
authors.lastname: Prickett
authors.forename: Roman
authors.initials: R
authors.lastname: Pogranichniy
authors.forename: Kyoung-Jin
authors.initials: KJ
authors.lastname: Yoon
authors.forename: Rodger
authors.initials: R
authors.lastname: Main
authors.forename: John K
authors.initials: JK
authors.lastname: Johnson
authors.forename: Chris
authors.initials: C
authors.lastname: Rademacher
authors.forename: Marlin
authors.initials: M
authors.lastname: Hoogland
authors.forename: Patrick
authors.initials: P
authors.lastname: Hoffmann
authors.forename: Anne
authors.initials: A
authors.lastname: Kurtz
authors.forename: Ernest
authors.initials: E
authors.lastname: Kurtz
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Zimmerman
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D018173:Circoviridae Infections / Q000453:epidemiology / Q000662:veterinary; D017925:Circovirus / Q000276:immunology / Q000302:isolation & purification*; D004266:DNA Virus Infections / Q000453:epidemiology / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D009980:Influenza A virus / Q000276:immunology / Q000302:isolation & purification*; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000662:veterinary; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011159:Population Surveillance / Q000379:methods*; D019318:Porcine Reproductive and Respiratory Syndrome / Q000453:epidemiology; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology / Q000302:isolation & purification*; D012463:Saliva / Q000821:virology; D016019:Survival Analysis; D013552:Swine / Q000097:blood; D013553:Swine Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology*; D022783:Torque teno virus / Q000276:immunology / Q000302:isolation & purification*; D014481:United States / Q000453:epidemiology
chemical_list: D000914:Antibodies, Viral