Serological and bacteriological survey of leptospiral infection in pigs in southern England.

A total of 597 pigs were examined for serological and bacteriological evidence of leptospiral infection. The sample comprised 189 porkers, 205 baconers and 203 sows. Sera were tested against 17 antigens from 16 serogroups and the overall prevalence of titres was 15.7 per cent. The lowest prevalence of titres was found in porkers (10.0 per cent). The highest prevalence of titres to an individual antigen was recorded with bratislava, a member of the Australis serogroup, with 12.2 per cent of pigs positive. Copenhageni titres were present in 1.8 per cent of the sera and sporadic titres were recorded to various other antigens. Leptospires were isolated from five pigs. Four isolates were identified as belonging to the Icterohaemorrhagiae serogroup and one to the Hebdomadis serogroup. The serological to bacteriological ratio for the Icterohaemorrhagiae serogroup was 11:4. The virtual absence of titres to pomona and tarassovi, the two serovars most commonly maintained by porcine populations in other countries, confirms the results of earlier serological surveys.