Orientia tsutsugamushi is the causative agent of scrub typhus vectored by larval stages of trombiculid mites (chiggers) that occur in most tropical regions of Southeast Asia. A total of 242 chiggers extracted from eight small mammals captured from a positive scrub typhus locality in Kelantan, Malaysia, were screened for the presence of O. tsutsugamushi. The chiggers were grouped in 16 pools for extraction of DNA prior to screening of O. tsutsugamushi based on the nucleotide sequence of 56-kDa type specific antigen (TSA) gene using nested polymerase chain reaction. Two species of on-host chiggers were identified, the one, Leptotrombidium deliense, much more dominant (94.8%) than the other, Ascoshoengastia sp. (5.2%). The pathogen was detected in two pools (12.5%) of L. deliense recovered from Rattus rattus and Tupaia sp. The 56-kDa TSA gene sequence analysis revealed the O. tsutsugamushi harboured in those chiggers were Karp prototype strain with high similarity (99.3%). Findings of this study strongly supported the existence of scrub typhus infections in certain parts of Malaysia which agrees with previous local reports. Moreover, this study highlighted the pressing need of a large-scale close observation of O. tsutsugamushi DNA sequences from chiggers that can probably be collected from other positive scrub typhus localities to precisely provide the distribution and prevalence of this zoonotic pathogen.
Two new nematodes belonging to the subfamily Nippostrongylinae (Nematoda: Trichostrongyloidea: Heligmonellidae) are described based on specimens from endemic murines of Sulawesi, Indonesia: Hasanuddinia maxomyos n. gen., n. sp. from Maxomys musschenbroekii and Eropeplus canus, and Heligmonoides musseri n. sp. from M. musschenbroekii, E. canus, and Margaretamys elegans. Hasanuddinia is closest to Rattusstrongylus of Malaysian rats in lacking a carene and in having a lateromedian gradient in the size of the synlophe ridges in the ventral side of the midbody but is distinguished in that the dorsal ray is divided in the distal half. Heligmonoides musseri most resembles H. bulbosus of Maxomys whiteheadi of Malaysia in having a carene supported by slender ridges of which the proximal portion is not thickened but is distinguished in having longer externodorsal rays and longer spicules. The ancestors of the present Sulawesi nematodes seem to have originated on the southeast Asian continent, were introduced to Sulawesi with the dispersal of some murines, and subsequently speciated.