Plurality of Leptospira strains on slaughtered animals suggest a broader concept of adaptability of leptospires to cattle.Acta Trop 2017; 172:156-159AT
Leptospirosis in bovines is in majority determined by the host-adapted serovars, mainly Hardjo (types Hardjoprajitno and Hardjobovis), that belong to the serogroup Sejroe. Members of other serogroups as Pomona and Tarassovi have been eventually reported, mainly when outbreaks occurs. Nevertheless, the real role of other strains (non-Hardjo) on determining disease or being transmitted by cattle free of apparent clinical signs of acute infection remains to be elucidated. In that context, the aim of the present study was to investigate the hypothesis that strains of serovars/serogroups other than Hardjo may also be maintained and shed by cattle free of clinical signs. Samples of urine and/or vaginal fluid were collected from 697 bovines from a slaughterhouse located close to Rio de Janeiro, Brazil. Culturing yielded 19 isolates what represents the largest number ever obtained in Brazil on similar studies. These strains were serogrouped and genetically characterized. Fifteen of those were described in other papers and four are first described on the present study. Isolates belong to three different species (Leptospira santarosai, L. alstonii and L. interrogans) and five serogroups (Sarmin, Tarassovi, Shermani, Grippotyphosa and Sejroe). The majority (84.2%) of the isolates belongs to the species L. santarosai, the most prevalent species on cattle in the studied region. Non-Hardjo (non-Sejroe) strains represent 57.9% of the isolates, what indicates an unexpected high diversity of serogroups obtained from these cattle. This suggest that non-Hardjo (non-Sejroe) strains may also be maintained and shed by cattle and that finding must be considered in the epidemiology and control of the disease.