Postweaning multisystemic wasting syndrome: Epidemiology and clinical presentation

John C. S. Harding, Edward (Ted) G. Clark, John H. Strokappe, Phil I. Willson, John A. Ellis

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Objective: To describe the characteristics of postweaning multisystemic wasting syndrome (PMWS).

Methods: A retrospective analysis of the production records of a 600-sow herd with clincial signs consistent with endemic PMWS was conducted.Also, data elicited by a descriptive epidemiologic survey that was completed by 15 producers with herds that had confirmed PMWS was analyzed.

Results: In the case herd, postweaning mortality rate peaked at 7.67% on month 9 of the epidemic, then returned within 16 months to pre-outbreak levels of 2.1%-2.5%. The most common causes of death reported by the farm were unthriftiness (weight loss, emaciation), jaundice (liver disease), and dyspnea (respiratory disease). In the surveyed herds, PMWS was found to be a slow and progressive disease with a high case fatality rate (81.4% +/-23.4%). Clinical disease was observed most commonly in pregrower barns (90%), followed by nursery (62%) and grower barns (39%). The syndrome was first noted in pigs 42 +/-13.5 days of age. The most frequent clinical signs of PMWS included unthriftiness, dyspnea, pallor, rough hair coat, diarrhea, and jaundice. Postweaning mortality averaged 6.7% +/-5.1% (SD) in affected herds, and was reported as 18.3% in the most severely affected herd. Poor response to various modes of antimicrobial therapy was reported.

Implications: Control of PMWS is difficult and may depend largely on pig flow, improved sanitation, and early recognition and segregation of sick pigs.

Keywords: porcine circovirus, postweaning multisystemic wasting syndrome

RIS citationCite as: Harding JCS, Clark EG, Strokappe JH, et al. Postweaning multisystemic wasting syndrome: Epidemiology and clinical presentation. J Swine Health Prod 1998;6(6):249-254.

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