POLYARTHRITIS OF PIGS IN WESTERN AUSTRALIA: THE ROLE OF ERYSIPELOTHRIX RHUSIOPATHIAE

Abstract

A 3-month survey of polyarthritis in pigs was carried out at 3 metropolitan abattoirs in Western Australia. The incidence of total carcass condemnations for polyarthritis was 0.46% and partial condemnation for "arthritis" 1.66% of 15,919 pigs. It was demonstrated that the majority of joint lesions found in either total or partial condemnations were identical pathological conditions, usually differing only in the number of joints involved. Erysipelothrix rhusiopathiae was isolated from the joints of 63% of pigs condemned for polyarthritis; it appears that this organism is the most significant aetiological agent of polyarthritis in Western Australia. The role of mycoplasmas has not been determined. The groww and microscopic lesions seen in affected joints were those of a non-suppurative proliferative polysynovitis. The stifle and elbow joints showed the highest incidence of the most severe lesions. Pigs condemned for polyarthritis over a 6-month period were traced back to 125 farms. Eighty per cent of pigs that had been condemned for polyarthritis had not been vaccinated against erysipelas or were of doubtful vaccination status. Only 3% of pigs had been vaccinated as recommended. The results would suggest that erysipelas vaccine is not directly implicated in the pathogenesis of polyarthritis. The majority of pigs condemned for polyarthritis originated from poorly managed small piggeries run as sideline enterprises. There was no significant pattern to the geographical distribution of polyarthritis cases in Western Australia. Likewise, no significant realtionship was established between polyarthritis condemnations and either breed, sex or bodyweight of thepigs involved.