Rickettsial seropositivity in the indigenous community and animal farm workers, and vector surveillance in Peninsular Malaysia

Rickettsioses are emerging zoonotic diseases that are often neglected in many countries in Southeast Asia. Rickettsial agents are transmitted to humans through exposure to infected arthropods. Limited data are available on the exposure of indigenous community and animal farm workers to the aetiological agents and arthropod vectors of rickettsioses in Peninsular Malaysia. Serological analysis of Rickettsia conorii and Rickettsia felis was performed for 102 individuals from the indigenous community at six rural villages and 87 workers from eight animal farms in Peninsular Malaysia in a cross-sectional study. The indigenous community had significantly higher seropositivity rates for R. conorii (P<0.001) and R. felis (P<0.001), as compared to blood donors from urban (n=61). Similarly, higher seropositivity rates for R. conorii (P=0.046) and R. felis (P<0.001) were noted for animal farm workers, as compared to urban blood donors. On the basis of the sequence analysis of gltA, ompA and ompB, various spotted fever group rickettsiae closely related to R. raoultii, R. heilongjiangensis, R. felis-like organisms, R. tamurae, Rickettsia sp. TCM1, R. felis, Rickettsia sp. LON13 and R. hulinensis were identified from tick/flea samples in animal farms, indigenous villages and urban areas. This study describes rickettsial seropositivity of the Malaysian indigenous community and animal farm workers, and provides molecular evidence regarding the presence of rickettsial agents in ticks/fleas infesting domestic animals in Peninsular Malaysia.