Skip to main content
ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Food Safety and Enteric Pathogens Research » Research » Publications at this Location » Publication #111051
Title: OUTBREAKS OF PORCINE REPRODUCTIVE FAILURE: REPORT ON A COLLABORATIVE FIELD INVESTIGATION

Author
item Hurd, Howard
item BUSH, E - USDA:APHIS:VS:CEAH
item LOSINGER, W - USDA:APHIS:VS:CEAH
item CORSO, B - USDA:APHIS:VS:CEAH
item ZIMMERMAN, J - IOWA STATE UNIVERSITY
item WILLS, B - UNIVERSITY OF NEBRASKA
item SWENSON, S - USDA:APHIA:VS:NVSL
item PYBURN, D - NATL PORK PROD COUNCIL
item YESKE, P - AM ASSOC SWINE PRACT
item BURKGREN, T - AM ASSOC SWINE PRACT

Submitted to: Swine Health and Production
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/3/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: During the latter half of 1996, a series of abortion outbreaks occurred primarily in Southeast Iowa. These outbreaks were similar to the Swine Mystery disease or Porcine Reproductive and Respiratory Syndrome (PRRS) outbreak of 1989. In response, a collaborative case- control study was designed. Collaborators included veterinary practitioners, laboratory diagnosticians, allied industry, the National Pork Producers Council (NPPC), the USDA Agricultural Research Service, and the USDA Animal and Plant Health Inspection Service (APHIS). The study's objectives were to: 1) describe these cases of intense reproductive failure; 2) attempt isolation of an associated infectious agent; and 3) identify potential management risk factors. Case herds were identified from submissions to the cooperating veterinary diagnostic labs. Control herds were selected from the submitting practitioner's list of qualifying swine producers. Seventeen case and 34 control herds were enrolled between June 25, 1997, and November 10, 1998. PRRS virus was isolated from seven case and one control operation. On case and control premises, 87% and 55.7% of sows were PRRS serologically positive, respectively. The 1996-97 outbreak of reproductive failure was likely due to a strain of PRRS virus for which there was minimal herd immunity. The U.S. pork industry is vulnerable to emerging diseases and needs to develop rapid capabilities for recognition of new infections and novel pathogens, and need to develop strategies to detect and control new emerging diseases.

Technical Abstract: During the latter half of 1996, a series of abortion outbreaks, with a clinical picture similar to porcine reproductive and respiratory syndrome (PRRS) in a naive herd, occurred, primarily in Southeast Iowa. A collaborative case-control study was designed. Its objectives were to: 1) describe these cases of intense reproductive failure; 2) attempt isolation of an associated infectious agent; and 3) identify potential management risk factors. Eligible case operations were those experiencing a current outbreak of abortion and submitting samples to one of the seven participating diagnostic laboratories. Control herds were randomly selected, by the investigating veterinary medical officer, from a list of candidate herds generated by the practitioner who referred the case herd. During a farm visit, management data, sow blood samples, and fetal tissues were collected for PRRS serology and virus isolation. Management data were statistically analyzed to identify potential risk factors. Seventeen case and 34 control herds were enrolled between June 25, 1997, and November 10, 1998. PRRS virus was isolated from seven cases and one control operation. On case and control premises, 87% and 55.7% of sows were PRRS serologically positive, respectively. The 1996-97 outbreak of reproductive failure was likely due to a strain of PRRS virus for which there was minimal herd immunity. The U.S. pork industry is vulnerable to emerging diseases and needs to develop rapid capabilities for recognition of new infections and novel pathogens, and needs to develop strategies to detect and control new emerging diseases.