LEPTOSPIRA SPP. DETECTION BY SEROLOGICAL AND MOLECULAR ASSAYS IN DOMESTIC ANIMALS IN NAN PROVINCE, THAILAND

Abstract

Nan province is an index area of leptospirosis study model in Thailand where provided the evidence linkage of infecting pathogenic Leptospira spp. between human and rodents but lack of prevalence and animal carriage data of leptospirosis in domestic animals such as cattle, pigs and dogs. This study aimed to identify the pathogenic Leptospira spp. by serological assay, Microscopic Agglutination Test (MAT), molecular assay, rrs nested polymerase chain reaction (PCR), and culture from domestic animals in Nan province during 2013 to 2015. A total of 210 blood samples were collected from cattle (n=160) and dogs (n=50) and 341 urine samples were collected from cattle (n=131), pigs (n=152) and dogs (n=58) in 20 villages from three districts; Muang Nan, Chiang Klang and Tha Wang Pha. Overall, the seroprevalence (titer > 1:80) to leptospiral detection by MAT was 8.09% (17/210). The seropositive MAT was found in cattle with a prevalence 10.62% (17/160) but all were negative in dogs. The major leptospiral serogroup was Shermani and the minor serogroup were Sejroe and Tarassovi, respectively. By rrs nested PCR 9.97% (34/341) of urine samples were positive to pathogenic Leptospira spp. from cattle 12.21% (16/131), pigs 7.89% (12/152) and dogs 10.34%(6/58). Phylogenetic analysis that confirmed the 34 positive samples were clustered in a branch of L. interrogans (n=9), L. weilii (n=22) and unidentified Leptospira spp. (n=3). L. interrogans were detected in cattle (n=2), pigs (n=3) and dogs (n=4), L. weilii were found in cattle (n=11), pigs (n=9) and dogs (n=2) and unidentified Leptospira spp. were found in cattle (n=3). L. weilii were the most common pathogenic leptospiral species in this study and being the first report of L. weilii in animal in Thailand. Moreover, we could successfully isolate four leptospires from dogs; L. interrogans (n=2) and L. weilii (n=2). Areas with the most prevalence of animal leptospirosis were Tha Wang Pha district. In conclusions, 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.