Variation in weight loss inMus musculus(Rodentia) fed upon byLeptotrombidium chiangraiensisandLeptotrombidium imphalum(Acari: Trombiculidae) infected with two strains ofOrientia tsutsugamushi(Rickettsia)

Laboratory mice fed upon by Leptotrombidium chiangraiensis and L. imphalum infected with Orientia tsutsugamushi lost a significantly higher percent of their weight than did control mice. A polymerase chain reaction and heteroduplex mobility assay were used to determine the strain of infection in the chiggers. Mice infected with TA 678 lost significantly more weight than mice infected with the new strain chiangraiensis; however, both strains were lethal within 10 days of post-feeding.