Vet. Res. 31 (2000) 74-75

Monitoring of PRRSV infection status in swine herds based on analysis of antibodies in meat sample drippings

S. Mortensen^a, B. Strandbygaard^b, A. Bøtner^b, N. Feld^c and P. Willeberg<sup>a

a</sup>  Danish Bacon and Meat Council, Veterinary and Food Advisory Service, Axeltorv, DK-1609 Copenhagen V, Denmark
^b  Danish Veterinary Institute for Virus Research, Lindholm, DK-4771 Kalvehave, Denmark
^c  Danish Veterinary Laboratory, DK-1790 Copenhagen V, Denmark

Abstract - An ELISA test was developed to analyse meat samples from pig carcasses for presence of antibodies against porcine reproductive and respiratory syndrome virus (PRRSV). A study of meat samples from herds with known PRRS status was undertaken. The PRRS status of the herds was evaluated based on analysis of blood samples by another serological test capable of differentiating between infection with PRRSV of American type and European type, respectively. The specificity of the test on meat samples was assessed to be 0.98. The sensitivity of the test depended on the type of PRRSV strain involved. The sensitivity of the test in herds infected with the American type of PRRSV was assessed to be 0.44 by assuming that all pigs from infected herds had truly been infected. The sensitivity of the test in herds infected with the European type of PRRSV was likewise assessed to be 0.64. Herd level sampling and herd level criteria for assessing the PRRS status of herds by the new test were developed. Herds were classified as PRRS negative or PRRS seropositive based on 10 samples collected randomly at slaughter throughout a 3-month-period. Herd PRRS status classification was validated in 47 herds by collection of blood samples from the herds. Eighteen herds were classified as PRRS negative by both test systems. Twenty-nine herds were classified as PRRS seropositive by both test systems. This study confirms that acceptable herd classification can be achieved using a test with sub-optimal sensitivity and specificity.

Corresponding author: S. Mortensen Tel.: (45) 33 73 25 94; fax: (45) 33 14 57 56;
    e-mail: sm@ds-data.dk

© INRA, EDP Sciences 2000