Philippine Science Letters
vol. 5 | no. 1 | 2012
published online February 28, 2012


Binary (lipL32 and gyrB) gene marker analysis detects pathogenic Leptospira interrogans in a captured Rattus norvegicus in Marikina City, Philippines

by Vladimir Lennin A. Roque1, Karen Joy B. Adiao1, Marilen M. Parungao-Balolong1,2,
Ernesto C. Balolong Jr.2, and Francisco M. Heralde III3*

1Department of Biology, College of Arts and Sciences, University of the Philippines - Manila
2Institute of Molecular Biology and Biotechnology, National Institutes of Health,
  University of the Philippines - Manila
3Department of Biochemistry and Molecular Biology, College of Medicine,
  University of the Philippines - Manila



Leptospirosis is a major zoonotic disease endemic in the Philippines with an emerging pattern of post-typhoon increase of epidemiological cases. In 2009 after the typhoons Ondoy and Pepeng, a large number of cases were reported in Marikina City, Metro Manila, one of the major flood sites. The incidence pattern was in contrast with the absence of cases in prior years, suggesting the emergence of a vulnerable site with climatic change. The lack of information on infectious agent reservoirs like feral rats thriving in the site presents an opportunity for testing a biosurveillance protocol where gene-based detection methods could be explored. Thus, this study was aimed to test the utility of binary gene markers, lipL32 and gyrB in the detection and identification of leptospires in feral rats in Marikina City. Traps were installed in two selected sites: Barangay Malanday and the Marikina Public Market where twenty-seven rats were recovered. The rats were dissected on site for their kidneys; genomic DNAs were extracted and assayed for leptospires by PCR amplification of lipL32 and gyrB. Results showed one rat sample from Barangay Malanday to be positive for pathogenic Leptospira spp. and subsequent sequence analysis of the amplicons indicated that the DNA sequence belongs to Leptospira interrogans. The partial gyrB sequence obtained differed from the L. interrogans strain sequences deposited in the GenBank, suggesting a possible new strain. This study reports the utility of binary (lipL32 and gyrB) gene marker analysis in the detection of pathogenic Leptospira in a sample biosurveillance of emerging infection of feral rats in Marikina City.

* Corresponding author
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Submitted: November 19, 2011
Revised: January 4, 2012
Accepted: January 25, 2012
Published: February 28, 2012
Editor-in-charge:Cynthia T. Hedreyda
Esperanza C. Cabrera
Cynthia T. Hedreyda
Windell L. Rivera