Linked outbreaks and control of porcine reproductive and respiratory syndrome and postweaning multisystemic wasting syndrome in a pig farm in Poland

Abstract

In a newly established farrow-to-finish farm (porcine reproductive and respiratory virus [PRRSV]-free, porcine circovirus type 2 [PCV-2]-infected), reproductive failure was seen seven months after population. The conception rate dropped from 89 to 51 per cent, and the abortion rate increased from 0.5 to 11 per cent. The following month, characteristic lesions of postweaning multisystemic wasting syndrome (PMWS) and elevated mortality were observed in weaned pigs. Laboratory examinations confirmed reproductive failure due to PRRSV and PMWS associated with apparent activation of the PCV-2 circulating in the farm. The herd was closed for replacement and a number of measures to improve hygiene, environmental conditions and feeding were applied. The abortion rate returned to preoutbreak levels four months after the beginning of the PRRS outbreak and the conception rate returned to normal four months later. Slower improvement was observed regarding the PMWS outbreak, with PMWS-related losses disappearing nine months after the detection of PMWS. Analysis of seroconversion profiles to PCV-2 and PRRSV during the outbreak and after its control indicated that while PRRSV was eliminated from sows and weaners by the control measures, the time of PCV-2 infection was unchanged and occurred at seven weeks of age during the PMWS outbreak as well as after its elimination. However, the elimination of PMWS from the herd coincided with increased levels of maternally derived antibodies to PCV-2 in one- to five-week-old pigs and faster serological responses to infection with PCV-2.

Production Losses Five Months After Outbreak With A Recombinant Of Two Prrsv Vaccine Strains In 13 Danish Sow Herds

“…A reduction in liveborns per litter of between one and two pigs has been reported in several studies after infection with PRRSV [12,13,14,15,16,17]. Similarly, an increased pre-weaning mortality of 4 to 17% [12,13,14,16,17,18] and a decreased farrowing rate [19,20,21] have been reported from outbreaks in other countries. As a result of this decline in farrowings and increased piglet mortality, the number of weaned pigs per litter decreased by two to three pigs [12,15,20].…”

Síndrome Reproductivo Respiratorio Porcino: Presentación en el Tiempo y Efecto sobre los Parámetros Productivos y Reproductivos

“…El incremento de los NM en los meses de mayor calor estaría relacionado con la infección inicial de las marranas con el virus del PRRS, ocurrido meses antes de la presentación del clímax de la enfermedad, en la temporada de frío. Según Stadejek et al (2011), el clímax del PRRS se alcanza dos meses posteriores al inicio del brote, donde se observa una mayor proporción de NM. Después de este clímax, los NM disminuyeron gradualmente, en este caso por efecto de una mayor temperatura ambiental, que se registró en los meses de verano y que afectó la sobrevivencia del virus del PRRS.…”

Production losses five months after outbreak with a recombinant of two PRRSV vaccine strains in 13 Danish sow herds

“…A reduction in liveborns per litter of between one and two pigs has been reported in several studies after infection with PRRSV [12][13][14][15][16][17]. Similarly, an increased preweaning mortality of 4 to 17% [12][13][14][16][17][18] and a decreased farrowing rate [19][20][21] have been reported from outbreaks in other countries. As a result of this decline in farrowings and increased piglet mortality, the number of weaned pigs per litter decreased by two to three pigs [12,15,20].…”