Abstract
Nan province is an index area of leptospirosis study model in Thailand where provided the evidence linkage between human and rodents but lack of a data in domestic animals such as cattle, pigs and dogs. This study aimed to detect and isolate the pathogenic Leptospira spp. from domestic animals by serological assay, Microscopic Agglutination Test (MAT), molecular assay, rrs nested polymerase chain reaction (PCR), and culture. Identification Leptospira species by near-full length 16S rRNA sequencing, determination Leptospira genetic relationship and clonality by constructed phylogenetic tree and MLST and PFGE from a total of 525 sample of bloods and urine from animal in Nan province during 2013 to 2015. Overall, the seroprevalence to leptospiral detection by MAT was 8.09% (95% confident interval (CI) 4.38-11.74). The major leptospiral serogroup was Shermani and the minor serogroup were Sejroe and Tarassovi, respectively. By rrs nested PCR, 7.42% (95% confident interval (CI) 5.18-9.66) of samples were positive to pathogenic Leptospira spp.. DNA sequencing and phylogenetic analysis found the positive samples were clustered in a branch of L. interrogans, L. weilii and unidentified Leptospira spp.. We could successfully isolate four leptospires from dogs and identification Leptospira species by near-full length 16S rRNA sequencing revealed L. interrogans (n=2) and L. weilii (n=2). In molecular epidemiological study by MLST, we found novel sequence type (STs) of Leptospira; ST26 and ST33 for L. interrogans and ST94 for L. weilii. ST26 and ST33 was a singleton without clonality to Leptospira species in database. ST94, however, was a putative founder of ST193 and ST183 isolated from human leptospirosis in China and Laos. Our study provides an important epidemiological information of animal leptospirosis in an endemic area that may be continually useful for disease control and prevention strategies.
