CLINICAL INCIDENCE AND FREQUENCY OF LESIONS ASSOCIATED TO PORCINE CIRCOVIRUS TYPE 2 IN PIGS OF A FARM IN THE STATE OF YUCATAN, MEXICO.

Abstract

The objectives of this study were to determine the incidence rate, the cumulative incidence of Postweaning multisystemic wasting syndrome (PMWS) and porcine dermatitis nephropathy syndrome (PDNS), and the frequency of macroscopic and microscopic lesions of PMWS and PDNS in pigs in a farm in the state of Yucatan, Mexico. A group of production consisting of 235 pigs was observed from 4 to 22 weeks of life to determine the number of new cases compatible with the PMWS and PDNS. In addition pigs necropsied on the farm that were discarded and with signs consistent with syndromes studied. 80 pigs were studied, the organs inspected during the necropsy were the lungs, lymphonodes, spleen, liver, tonsils, ileum, kidneys and skin, samples of all organs were obtained for histopathological studies. The results were: 14 pigs with signs consistent with syndromes mentioned, 7 with the PMWS and 7 with the PDNS. The cumulate incidence and incidence rate for both syndromes was 0.06 and 0.0034 respectively. 5 pigs died, the lethality rate calculated for PMWS y PDNS was 0.4 and 0.3 respectively. The average time elapsed since the start of the observation period until the pigs sick with the PMWS and PDNS were 13.8 and 16.8 weeks respectively. The principal organ affected were the lymphonodes (100%) where the main macroscopic injury was a lymphadenomegaly with diffuse edema (56%) and the microscopic was a histiocytic lymphadenitis with lymphoid atrophy (64%)