OBJECTIVETo investigate whether Leptotrombidium scutellare could be naturally infected by both Hantaan virus (HV) and Orientia tsutsugamushi (OT) and transmission status by stinging.

METHODS3459 Leptotrombidium scutellares from mice bodies and 3265 which were free were collected in the epidemic area of hemorrhagic fever with renal syndrome (HFRS) and tsutsugamushi disease.15 days later, the suspensions of lung and spleen of mice with 6 in a group stung by 1, 5 or 10 infected mites were injected intra-cerebrally into other mice for the detection of HV and OT in the next 6 generations of the mice, with immunofluorescent antibody technique (IFAT) and Giemsa staining technique. The passages of Vero-E6 cells inoculated on the aseptic filtrations from different number of infected mites were used to detect HV and OT pathogens. HV-RNA and OT-DNA were detected by PCR.

RESULTSAfter passage, HV positive mouse body mite group out of both 5 and 10 mites in the sixth generation, OT positive mouse body mite group out of the 10 mites in the sixth generation, both HV and OT positive mouse body mite group out of 1 mite in the fifth and sixth generation, both HV and OT positive mouse body mite group out of 5 and 10 mites in the sixth generation, and free mites group out of 1, 5 and 10 mites in the sixth generation, were found one mouse infected by both HV and OT, respectively. Out of the fourth generation of Vero-E6 cells, one sample was found both HV and OT positive out of 5 and 10 HV and OT mouse body mite group, respectively. In the sixth generation, both HV and OT positive cells were detected in one mouse mite group and the 1, 5, 10 free mite groups, respectively. HV-RNA and OT-DNA were all detected by PCR.

CONCLUSIONBoth HV and OT could be coexisted in wild Leptotrombidium scutellare and transmitted by stinging.