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United States Department of Agriculture

Agricultural Research Service

Research Project: BITING ARTHROPODS: INTEGRATED PEST MANAGEMENT

Location: Mosquito and Fly Research Unit

Title: Development of life stages of Leptotrombidium imphalum and Leptotrombidium chiangraiensis (Acari: Trombiculidae) uninfected and infected with the scrub typhus rickettsia, Orientia tsustugamushi

Authors
item Phasomkusolsil, Siriporn -
item Tanskul, Panita -
item Ratanatham, Supaporn -
item Watcharapichat, Pochaman -
item Phulsuksombati, Duangporn -
item Frances, Stephen -
item Lerdthusnee, Kriangkrai -
item Linthicum, Kenneth

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 17, 2012
Publication Date: N/A

Interpretive Summary: Scrub typhus is a disease of humans that is caused by a rickettsial organism called Orientia tsutsugamushi. The disease causes significant illness if not treated with the proper antibiotics. Humans are infected by the bite of infected chigger mites. We examined the development times of 2 important species of chigger mites that were either infected or not infected. We found that infection of the mites with the agent that causes scrub typhus lengthened the developmental times from egg to adult stages.

Technical Abstract: Leptotrombidium chiangraiensis Tanskul and Linthicum and Leptotrombidium imphalum Vercammen-Grandjean are important vectors of scrub typhus in ricefield habitats in northern Thailand. The developmental biology of all stages of the life cycle of two generations of mites infected with Orientia tsutsugamushi and uninfected mites of both species is reported. Development times of infected lines of F1 L. imphalum and L. chiangraiensis were not significantly different. The development of the infected lines of both F1 and F2 L. chiangraiensis were significantly longer than their respective uninfected lines (p<0.05). The development times of uninfected and infected F1 lines of L. imphalum were not significantly different; however, F2 infected lines took significantly longer to develop (p<0.05).

Last Modified: 10/25/2014
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