Circovírus suíno 2: viremia, eliminação e perfil sorológico em granjas com e sem sinais clínicos da Síndrome da Refugagem Multissistêmica (SRM)

Abstract

PCV-2 serology, viremia and shedding were studied in pigs from herds with and without postweaning multisystemic wasting syndrome (PMWS) in three different experiments. In the first study, a comparative PCV-2 serology, viremia and shedding was evaluated in two herds using swabs, serum and blood samples from 40 pigs at different ages. In the second study, PCV-2 viremia, nasal and fecal shedding and seroprofile were evaluated in 35 animals at 8 to 19, 30 to 35, 56 to 70, 85 to 100 and 150 days of age. In the third, study, the presence of PCV-2 DNA was tested in boar semen and PCV-2 shedding was demonstrated in naturally infected boars. Swabs, blood, tissues and semen were evaluated for the presence of nucleic acid of PCV2 by polymerase chain reaction (PCR). The presence of serum antibodies specific to PCV-2 was tested by immunoperoxidase monolayer assay (IPMA). PCV-2 DNA was more frequently detected in swabs samples from pigs of herd with PMWS, which may indicate a high PCV-2 circulation. There are differences in the serologic profile of herds with and without PMWS, especially concerning maternal antibodies duration. In the second study, it was demonstrated that the decrease of antibodies was concomitanted with increase of the number of viremic animals and more shedding. The results of the third study indicated that PCV-2 virus may be shed intermittently in semen of naturally infected boars from two different herds for a period of two months. In conclusion, PCV-2 was wildly distributed in pigs of different ages from herds with and without PMWS. It seems that low antibodies levels influence the occurrence of disease, viremia and PCV-2 shedding.