Résumé
Objective In order to offer scientific evidence for prevention and therapy of Lyme disease, we had investigated the natural infection of lyme disease Borrelia burgdorferi(Bb) of 4 ticks in Diebu and Huajian areas of Gansu province. MethodsEpidemiology detection of natural infection of lyme disease Bb was accomplished for four dominant tick ( Dermacetor silvarum , Dermacentor nuttalli , Haemaphysalis Japonica and Ixodes Crenulatus ) at Diebu, Diebu forest zone(Qin mountain), north of Min Mountains of Huajian region and Huajian forest zone, north of Qilian Mountains of Sunan region, Gansu, from March to June, 2010. The methods of dispersion of clamp every 10 m which was put in the morning and retrieved at night were used to capture rodent animal and gnawer retrorse hair inspection insect methods were used to collect parasitic tick. Flagging methods were used to collect free tick.Four kinds of live adult ticks were dissected after cleaning and disinfection. Intestinal contents were smeared, lyme disease Bb was observed under dark-field microscope. Etiological agent was cultivated and separated. Separated spirochete was confirmed by spirochete monoclonal and polyclonal antibody. Results The ticks collected were classified as 2 families, 8 genera, 36 species, i.e. Ixodidae 6 genera, 33 species and Argasidae 2 genera, 3 species. The method of dark-field microscope was used to detect the lyme disease spirochete in 201 ticks intestines after dissection of Dermacentor silvarum, Dermacentor nuttalli, Haemaphysalis Japonica and Ixodes Crenulatus, the lyme disease Bb-positive were 25 with positive rate of 12.44％(25/201). The lyme disease Bb was cultivated and separated from 12 ticks with the positive rate of 18.46％(12/65) after inoculation and cultivation of 3 species, 65 ticks of Dermacentor silvarum, Dermacentor nuttalli and Haemaphysalis Japonica. ConclusionsDermacentor silvarum,Dermacentor nuttalli and Haemaphysalis Japonica have different degrees of natural infection of lyme disease Bb.