Monitoraggio sierologico,virologico e produttivo per il controllo dell'infezione da PRRSV in un allevamento da riproduzione endemicamente infetto

The aim of this study was to monitor the epidemiologic situation of PRRSV in an endemically infected breeding herd which controls the infection through the replacement gilts acclimatization associated with a high biosecurity policy. From April 2007 to March 2009, 24 consecutive groups of gilts were tested when introduced into the breeding unit to verify their serological and virological status. Furthermore, five transversal monitorings were carried out regularly to investigate the viral circulation in the productive units of the herd involved in the acclimatization program and to analyze the virus stability over time. After an outbreak of 27 abortions in the period October-November 2008, it was possible to demonstrate the entry of a new viral strain comparing its ORF7 sequence with previous sequences obtained in the same herd. The analysis of the most relevant production parameters confirmed the breakdown of the productive performance during the outbreak, but it demonstrated that in a well managed acclimatization system the return to herd stability can be achieved rapidly.