Leptospira interrogansinfection in domestic and wild animals in Fiji

Abstract

Clinical and serological evidence has indicated that human leptospirosis in Fiji is an important disease, and the prevalence of antibody is exceptionally high. A serological survey of the rural population showed that only 12% of the people studied did not have complement fixing (CF) leptospiral antibody. As the origin of this infection could not be explained by the known distribution of leptospiral infection in domestic and wild animals, a serological survey using the complement fixation test (CFT) was undertaken as the first stage of an epidemiological investigation into human and animal leptospirosis. Sera from domestic and wild animals were tested for CF antibody to 12 leptospiral serovars, namely: pomona, copenhageni, grippotyphosa, hardjo, ballum, tarassovi, canicola, australis, bratislava, autumnalis, pyrogenes and bataviae. Antibody was detected in 27.5% of 480 cattle, 17.1% of 70 sheep, 10.3% of 252 goats, 10.0% of 480 pigs, 57.0% of 100 dogs, 55.8% of 34 rats (Rattus rattus, R. frugivorus, R. exulans and R. norvegicus), 53.1% of 32 mongooses (Herpestes auropunctatus) and 40.0% of 10 mice (species unknown.) Cross-reactivity precluded the identification of infecting serogroups with the exception of pomona in pigs and icterohaemorrhagiae, ballum and australis in dogs. Infection of dogs with a serovar of the australis serogroup may explain the predominance of serological reactions to bratislava in man. The survey revealed a significant level of leptospiral antibody in the animal populations of Fiji and indicated that cattle, dogs, rats, mongooses and mice are probably the most important maintenance hosts. Consequently, further investigation will concentrate on the attempted isolation of leptospires from these species.