Prevelence of Porcine Reproductive and Respiratory Syndrome Virus in Chiba Prefecture

Abstract

In 1993 46.4% of test sera from Chiba Prefecture had antibody against porcine reproductive and respiratory syndrome (PRRS) virus and serological survey was retrospectively done with sera collected in 1988 when similar clinical signs were recorded in North-Eastern Chiba Prefecture. Antibody to PRRS virus was detected in sera collected in June 1988 from fattening pigs by indirect immunofluorescence. The decreases in the number of piglets weaned per sow were from 2.35 to 2.59 per year at the first outbreak in 1988.