Serologic Characterization of Leptospira among Rats Trapped in Selected Public Markets in Iloilo City, Philippines

Pia Regina Fatima C. Zamora1 and Nina G. Gloriani2

1College of Medicine, University of the Philippines Manila
2Department of Medical Microbiology, College of Public Health,
University of the Philippines Manila

 

Objective. Rats have been identified as primary sources of leptospires in the environment. This study aimed to characterize Leptospira species circulating among rats found in public markets in Iloilo City, Philippines.

Methods. Dark-field microscopy was used to determine leptospire presence in tissue cultures. Isolates from the cultures were characterized via serotyping with monoclonal and polyclonal antibodies. To characterize the antibodies present in rat sera, the microscopic agglutination test (MAT) was used.

Results. In this study, 19 rats were obtained from 7 markets in Iloilo City. Three (3) rats (15.8%) were found to harbor leptospires in the urinary bladder (2) and kidney (1). Serotyping of the isolates showed that they did not belong to previously reported common serovars in the Philippines such as Manilae, Losbanos, Javanica or Grippotyphosa. Using another panel of polyclonal antibodies, it was shown that the isolates belonged to serovar Icterohaemorrhagiae. The MAT results showed that 16 (84.2%) serum samples were positive for anti-Leptospira antibodies. The most common infecting serovars were Autumnalis (47.4%), Pomona (42.1%), Copenhageni (36.8%) and Hebdomadis (31.6%). Other infecting serovars identified were Icterohaemorrhagiae, Poi, Grippotyphosa, Patoc, and Pyrogenes.

Conclusion. The results of the present study provide baseline data on the circulating leptospiral serovars in Iloilo City. Results suggest the possible role of rats in disease transmission inf the study areas.

Key Words: Leptospirosis, Leptopsira, MAT, Iloilo, public markets