[Study on the coinfection of three tick-borne infectious diseases in China using polymerase chain reaction method].

Objective: To study the existence of Ehrluichiosis, lyme disease and tick-borne spotted fever coinfection in some areas in China.

Methods: Using polymerase chain reaction (PCR), B. burgdorferi sensu lato, spotted fever group (SFG) Rickettsiae and human granulocytic ehrlichia (HGE), Ehrlichia chaffeensis (EC) were detected in ticks and mouse samples collected from Inner Mogolia autonomous region, Heilongjiang province, Beijing and Fujian province.

Results: 408 Ixodes persulcatus collected from Inner Mogolia autonomous region, HGE and B. burgdorferi sensu lato and SFG Rickettsiae were detected positive, with rates as 6.8%, 7.8%, 45.6%, respectively. 5 (5/408) were coinfection with HGE and B. burgdorferi sensu lato while 1 (1/408) was coinfection with HGE and SFG Rickettsiae. 46 Ixodes persulcatus collected from Helongjiang province were determined positive, with rates as 6.5%, 10.8% and 34.8%, respectively including 1 (1/46) coinfected with HGE and B. burgdorferi sensu lato. 2 of 922 ticks collected from Beijing were detected positive with B. burgdorferi sensu lato. Among 283 groups of Haemaphysalis yeni ticks (3/group) and from 38 rodent samples collected from Ninghua county of Fujian province HCE and B. burgdorferi sensu lato and SFG Rickettsiae were detected. Out of them, 25 groups were positive with EC and the minimal positive rate was 3.8% while 21 rodent samples were positive with EC with a positive rate of 56.4%. 2 ticks and 1 rodent sample were detected positive with EC and spotted fever group.

Conclusion: Coinfection of HGE and B. burgdorferi sensu lato or spotted fever group Richi did exist in Ixodes persulcatus collected from Inner Mogolia autonomous region and Heilongjiang province. Coinfection of EC and spotted fever group Richi was found in the ticks and rodents collected from Fujian province.