Detection and Identification of Leptospira spp. in Captured Rats in Marikina City via Amplification and Sequence Analyses of LipL32 and GYRB

Abstract

Leptospirosis has been a major zoonotic disease worldwide. In the Philippines, its most recent outbreak occurred after the typhoons Ondoy and Pepeng wherein Marikina City has been most affected. Although having a high number of cases during the outbreak, no case has been reported in the city prior to the outbreak. There has also been no data regarding the status of infection in carrier animals such as rats within the area. Thus, the status of leptospirosis within the area still remains unclear. To increase the knowledge regarding Leptospira spp. infection in carrier rats, this preliminary study detected and identified Leptospira spp. in feral rats within Marikina City using PCR amplification and sequence analysis of two gene markers: UpL32 which is specific only for pathogenic strains and gyrB which has been known to differentiate closely related strains. In the study, twenty-seven feral rats were captured in Barangay Malanday and Marikina Public Market and tested for leptospire infection through PCR using HpL32 and gyrB as gene markers. This was followed by DNA sequence analyses of both genes to identify the species of the detected leptospire. Results showed that one out of the 27 samples was positive for the presence of pathogenic leptospires under the species Leptospira interrogans. The limits of detection of the PCR protocols used for UpL32 and gyrB gene markers were also determined to be 1.425 x 106 DNA copies per PCR and 1.14 x 107 DNA copies per PCR respectively.