Epidemiologia e controle da infecção por Haemophilus parasuis

Abstract

ln the present study the epidemiological aspects of the infection byHaemophilus parasuis isolated from swine with or without clinicalsymptoms from 204 herds with more than 50 sows using thetraditional management in the States of Minas Gerais, Sao Paulo,Rio de Janeiro, Espirito Santo, Parana, Goias, Mato Grosso andBahia, were considered. The highest frequency of infection by H.pamsuis was observed between July and September. Animals from70 to 100 days old were more affected. Samples from lung, tracheaand nose were used for laboratory analysis. The frequency of H. 'pamsuis serovars were studied in the 321 samples isolated from the204 herds. lt was observed, for the first time in Brazil and SouthAmerica, the presence of all the 15 serovars, however the mostfrequent were l, 4, 5 and l2 which represented 47,4% of all `analyzed samples. In 59 (28,9%) of the herds there were more than ono serovars with predominance of 1, 4, 9 and l2. A monovalentbacterin of H. parasuis serovar 5 was produced and tested against65 days old animals. This bacterin protect all 32 pigs challengedagainst 4 ml of homologous bacteria containing 2.5x10° UFC/mL,however 31 of the 32 nonvaccinated pigs died. A trivalent bacterincontaining l, 4 e 5 serovars of H. parasuis was also produced andevaluated against 3 groups (C, D and E) of 17 piglets in each one.¤ Fourteen piglets were vaccinated and the other 3 were lefi without .vaccination as controls. The 73 days old animals of each group were. challenged with intratracheal 4 mL of 109 UFC/mL of the 1, 5 or 6serovars, respectively. All the 14 vaccinated animals of each groupsurvived to the challenge but all 3 non-vaccinated animals of each.