Tick-borne pathogens and associated co-infections in ticks collected from domestic animals in central China.

BACKGROUND: Ticks can transmit a number of pathogens to humans and domestic animals. Tick borne diseases (TBDs), which may lead to organ failure and death have been recently reported in China. 98.75% of the total cases (>1000) in Henan provinces have been reported in Xinyang city. Therefore, the aims of this study were to investigate the fauna of ticks and detect the potential pathogens in ticks in Xinyang, the region of central China. METHODS: Ticks were collected from 10 villages of Xinyang from April to December 2012, from domestic animals including sheep, cattle and dogs. Then identification of ticks and detection of tick-borne pathogens, including Babesia spp., Theileria spp., Anaplasma spp., Ehrlichia spp., Rickettsia spp., tick-borne encephalitis virus (TBEV), Borrelia burgdorferi sensu lato, Leishmania infantum, were undertaken by using polymerase chain reaction assay (PCR) and sequence analysis. Moreover, the co-infection patterns of various pathogens were compared among locations where ticks were collected. RESULTS: A total of 308 ticks were collected. Two species of Ixodidae were found, namely Haemaphysalis longicornis (96.75%) and Rhipicephalus microplus (3.25%). Five genera of pathogens, namely Theileria spp. (3.25%), Anaplasma spp. (2.92%), Babesia spp. (1.95%), Ehrlichia spp. (2.92%) and Rickettsia spp. (0.65%), were detected in 7 villages. Co-infections by two pathogens were diagnosed in 11.11% of all infected ticks. CONCLUSIONS: Both human and animal pathogens were abundant in ticks in the study areas. Humans and animals in these regions were at a high risk of exposure to piroplasmosis, since piroplasm had the highest rates of infection and co-infection in positive ticks.

[Resistance of Anopheles sinensis to insecticides in Huaibin County of Henan Province].

Anopheles sinensis adults were captured from Huaibin County and raised in laboratory. Larvae dipping method and the WHO tubes were used to determine the resistance of F1 IV-stage larvae and 3-5 day-old adult mosquitoes to dimethyl dichlorovinyl phosphate (DDVP), deltamethrin, and arprocarb. The activity of acetylcholine esterase (AChE) of larvae and adult mosquitoes was measured by colorimetric method before and after the respective addition of the 3 insecticides. The results showed that the mortality of adult mosquitoes in 0.05% deltamethrin testing tube (0.017 8 g/m2) was 51.2%, which was less than 80% and judged as resistant group. The LC50 of larvae to DDVP, deltamethrin, and arprocarb were 2.76, 320.85, 754.32 mg/L, respectively. The inhibition rates of 0.005 mmol/L DDVP, deltamethrin, and arprocarb to AChE activity were 77.8%, 62.8%, and 58.9% in larvae, while 76.1%, 62.2%, and 58.22% in adults, respectively, showing a significant inhibition on the AChE activity of An. sinensis (P < 0.01).