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Updated: Apr 25, 2026
Diagnosis of Ecto- and Endoparasites in Laboratory Rats and Mice
Published on: September 6, 2011
Identification of rickettsiae from wild rats and cat fleas in Malaysia
S T Tay1, A S Mokhtar, K C Low
1Department of Medical Microbiology, Tropical Infectious Diseases Research and Education Centre, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Abstract:
Rickettsioses are emerging zoonotic diseases reported worldwide. In spite of the serological evidence of spotted fever group rickettsioses in febrile patients in Malaysia, limited studies have been conducted to identify the animal reservoirs and vectors of rickettsioses. This study investigated the presence of rickettsiae in the tissue homogenates of 95 wild rats and 589 animal ectoparasites. Using PCR assays targeting the citrate synthase gene (gltA), rickettsial DNA was detected in the tissue homogenates of 13 (13.7%) wild rats. Sequence analysis of the gltA amplicons showed 98.6-100% similarity with those of Rickettsia honei/R. conorii/R. raoultii (Rickettsiales: Rickettsiaceae). Sequence analysis of outer membrane protein A gene (ompA) identified Rickettsia sp. TCM1 strain from two rats. No rickettsia was detected from Laelaps mites, Rhipicephalus sanguineus and Haemaphysalis bispinosa ticks, and Felicola subrostratus lice in this study. R. felis was identified from 32.2% of 177 Ctenocephalides felis fleas. Sequence analysis of the gltA amplicons revealed two genotypes of R. felis (Rf31 and RF2125) in the fleas. As wild rats and cat fleas play an important role in the enzoonotic maintenance of rickettsiae, control of rodent and flea populations may be able to reduce transmission of rickettsioses in the local setting.
Insights
Spotted fever group rickettsioses are emerging zoonotic diseases. This study found Rickettsia DNA in wild rats and cat fleas in Malaysia, highlighting their role in disease transmission.
Area of Science:
- Zoonotic diseases
- Vector-borne diseases
- Microbiology
Background:
- Rickettsioses are emerging global zoonotic diseases.
- Serological evidence of spotted fever group rickettsioses exists in Malaysia.
- Limited research has identified reservoirs and vectors in Malaysia.
Purpose of the Study:
- Investigate rickettsiae presence in Malaysian wild rats and ectoparasites.
- Identify potential animal reservoirs and vectors of rickettsioses.
- Determine the genetic diversity of detected rickettsiae.
Main Methods:
- PCR assays targeting citrate synthase gene (gltA) and outer membrane protein A gene (ompA).
- Analysis of rickettsial DNA in tissue homogenates of wild rats.
- Detection of rickettsiae in various ectoparasites including fleas, mites, ticks, and lice.
Main Results:
- Rickettsial DNA detected in 13.7% of wild rats, with sequences similar to Rickettsia honei/R. conorii/R. raoultii.
- Rickettsia sp. TCM1 strain identified in two rats.
- Rickettsia felis identified in 32.2% of cat fleas, with two genotypes (Rf31 and RF2125) found.
Conclusions:
- Wild rats and cat fleas are significant in the enzootic maintenance of rickettsiae.
- Controlling rodent and flea populations could reduce rickettsioses transmission.
- Further research is needed to fully understand the epidemiology of rickettsioses in Malaysia.
