Detection of Orientia Tsutsugamushi in Chiggers and Tissues of Small Mammals Using Polymerase Chain Reactions

This study is to detect the presence of Orientia tsutsugamushi in chiggers and host target organs of scrub typhus such as liver, spleen as well as blood. Nine locations of Peninsular Malaysia were chosen; Slim River, Perak; Janda Baik, Pahang; Seremban, Negeri Sembilan; Hulu Langat, Selangor; Raub, Pahang; Bukit Panchor, Pulau Pinang; Gunung Inas, and Ulu Sedim, Kedah and Setiu, Terengganu. Collection sites included oil palm plantations, rubber estates, secondary forests, housing estates and coastal areas. All samples were processed by a standard method for extraction of DNA, followed by amplification of DNA using nested polymerase chain reactions (PCR) and then visualized by gel electrophoresis. A total of 465 chiggers, Leptotrombidium deliense extracted from 11 species of hosts Callosciurus spp, Leopoldamys sabanus, Maxomys rajah, Maxomys whiteheadi, Niviventor cremoriventori, Rattus rattus, Rattus tanezumi, Rattus tiomanicus, Rhinosciurus laticaudatus, Sundamys muelleri, Tupaia glis and Tupaia minor. All chiggers and animal tissues were found negative with scrub typhus except for a blood sample from a rodent, L. sabanus from Sungai Sedim, Kedah. The finding showed that the prevalence of scrub typhus in Peninsular Malaysia was very low. More study and survey need to be done.