Successful treatment with streptomycin of genital leptospirosis in naturally infected cows under field conditions.

The single-dose protocol of streptomycin treatment has been recommended to treat renal leptospirosis in bovines. However, treating genital infection remains a challenge. Recently, a protocol using three doses of streptomycin demonstrated effectiveness in the genital clearance of experimentally infected ewes. Therefore, the present study aimed to apply this three-dose protocol for genital infection treatment in naturally infected cows under field conditions. Thirty beef cows were diagnosed as positive by lipL32-PCR in their genital samples. Nucleotide sequences (n = 10) characterized them as Leptospira interrogans sg Sejroe, genetically related to Hardjoprajitno strains. After molecular diagnosis, 13 cows received a single dose of 25 mg/kg streptomycin. The other 17 cows were submitted to the three-dose protocol. The successful treatment rate of genital infection on the single streptomycin dose was 7/13 (53.8%), while the cows that received the three doses 16/17 were negative (94.1% of efficacy). Based on those results, we conclude that the standard treatment preconized for renal infection is not adequate for genital infection, and the three-dose protocol was successful in eliminating the carrier status of genital leptospirosis.