An investigation of the role of wild rats in transmitting <i>Leptospira</i> spp. to stray cats and dogs in Malaysia

Stray cats and dogs have been reported to shed <i>Leptospira</i> spp., and wild rats are speculated to be involved. We aimed to elucidate the role of wild rats in transmitting <i>Leptospira</i> to stray cats and dogs in Malaysia. We tested sera from 124 wild rats with the microscopic agglutination test (MAT): 88 of 122 (72%) sera were positive (titer ≥1:100), with the predominant serovars Icterohaemorrhagiae, Bataviae, Ballum, Javanica, Lai, and Pomona. With a <i>Leptospira</i>-specific PCR assay, we detected pathogenic <i>Leptospira</i> spp. in 33 of 124 (27%) kidney samples and 13 of 79 (16%) urine samples. Isolates obtained by culture of rat kidney and urine were identified to the species level with MAT using hyperimmune sera and the PCR assay. From 29 isolates, 2 pathogenic species were identified: <i>L. interrogans</i> serovar Bataviae and <i>L. borgpetersenii</i> serovar Javanica. Phylogenetic analysis using partial 16S rDNA sequences of the <i>Leptospira</i> spp. from the wild rats indicated that the species were similar to isolates from stray cats and dogs in previous studies. We confirmed that wild rats carried pathogenic <i>Leptospira</i> spp. and were a potential source of leptospiral infection of stray cats and dogs in Malaysia.