Objective To investigate the species compositions of rodents and the chigger mites on their body surface and the infection rate of Orientia tsutsugamushi in rodents in Yongcheng, Henan province, China, and to provide a scientific basis for the prevention and control of scrub typhus in Yongcheng. Methods Rat traps were used to capture rodents and to collect ectoparasites from the body surface of rodents in different survey sites and different habitats in Yongcheng in October 2017. Nested PCR was used to detect nucleic acid of O. tsutsugamushi. The rodent density, chigger infestation rate, chigger index, and pathogen infection rate were calculated. Results A total of 110 rodents were captured with a capture rate of 12.21%. Apodemus agrarius accounted for 90.00%. A total of 1 249 chigger mites were collected from rodents. The chigger infestation rate and chigger index were relatively high in the forest along the riverbank, wetland, and mountain forest. Leptotrombidium scutellare (96.86%) was the dominant chigger mite species, which was mainly parasitic on the body surface of A. agrarius. The O. tsutsugamushi positive rate of rodent was 10.48%. Apodemus agrarius, Rattus norvegicus, and Mus musculus were detected O. tsutsugamushi positive with nPCR. Orientia tsutsugamushi in Yongcheng belonged to Kawasaki molecular type. Conclusion This study confirms that there are some epidemic foci of scrub typhus with host rodents in Yongcheng, which have the same hosts and vectors as the surrounding epidemic foci of scrub typhus.

Objective To compare the effectiveness of 4 adult mosquito sampling methods. Methods All the experiments were carried out in sheepfolds during mosquito active season around-the-clock continuously for 2 circles rotating positions one by one in Yongcheng city, Henan province. The mosquitoes were collected and sorted separately in the daytime (09:00-18:00) and nighttime (18:00-09:00 the next day). Results The results in the daytime did not give us any specific indication except all the tools did not work well as surveillance tools during daytime. All the monitoring tools caught the main mosquito species in the residential areas at nighttime, but all of them had the unexpected other insects especially the most in Kung Fu Xiao Shuai. Kung Fu Xiao Shuai showed excellent results in trapping Culex tritaeniorhynchus and Anopheles sinensis; BGS-trap and WJ-C captured a small number of mosquitoes; Maisicui caught a variety of mosquito species with the appreciable density for surveillance work. Conclusion Kung Fu Xiao Shuai might be a good surveillance tool for Cx. tritaeniorhynchus and An. sinensis; Maisicui could work as a good mosquito surveillance tool in general; this study can be used to evaluate the mosquito monitoring tools partially and the selection and replacement of monitoring tools need further efficacy evaluation.

Objective To decide the predominant mosquito species in Yongcheng city, and their natural occurrence, density, seasonal fluctuation, and habitat distribution. The results will guide the vector management in this area. Methods Light-trapped method was used twice a month in three towns which lies in different direction in Yongcheng area. Dwellings, houses premises, and livestocks were selected as the surveillance sites in each town. Excel 2007 and SPSS 20.0 were used for data analysis. Results The total mosquito number obtained in 2010 were 20 684 with the average density 34.08/(trap·night). Culex tritaeniorhynchus took up to 54.12%, which was the predominent species. The mosquito density in livestocks was 50.58/(trap·night) which was the highest; the mosquito density around dwellings and their premises had no significant difference. Mosquito density showed statistical significance in 3 surveillance habitats (F=74.450, P<0.01). Mosquito density began to increase in July, reach a small peak activity in late July, and reached the highest peak activity in September, followed a decline in October. The mosquito density in Renhu and Mengzhuang villages reached the peak in early September, showed a unimodal peak activity. Renhu had the highest mosquito density. Three towns showed statistically significant differences in mosquito species and their density (χ²=2 033.097, P<0.01). Conclusion The distribution of mosquitoes in Yongcheng city varied according to habitat and village characteristics, then the mosquito prevention and control work should be based on the mosquito distribution in different habit, different village, and seasonal performance by species in this area.

Objective To understand the daily activity rhythm of Aedes albopictus in Yongcheng city, and the results would be used for vector surveillance and control. Methods Double nets method used continually during daily time from 06:00-19:00, with capturing and counting for one hour interval separately. Results The biting activity of Ae. albopictus concentrated in the later afternoon (15:00-19:00). Conclusion Based on the ecological characteristics of Ae. albopictus in Yongcheng city, the surveillance time for Ae. albopictus should be carried during the later afternoon time (15:00-19:00), and the adult control with foging should also be implemented during the same time period (15:00-19:00).

Objective To evaluate the efficacy of ultra?low?volume (ULV) spraying and residual spraying, and the combined application of the two, in control of mosquitoes. Methods We used ULV spraying and residual spraying, alone or combined, to control mosquitoes. Mosquito density was monitored using animal?baited net traps, light traps, and labor hour method before and after application of the controlling methods. Results Residual spraying reduced indoor mosquito density, but had no significant effect on outdoor mosquito density. ULV spraying reduced indoor mosquito density too. However, mosquito density monitoring using light traps showed increased density after ULV spraying, while monitoring using animal?baited net traps showed decreased density. Conclusion Combined use of residual spraying and ULV spraying can improve mosquito control efficacy. Mosquito density monitoring using goat?baited net trap is a reliable method in evaluating the mosquito control effect of ULV spraying.

Objective To discuss the feasibility of lipL32-PCR for detecting Leptospira interrogans. Methods The specificity and sensitivity of primers based on the lipL32 gene were compared with the recommended standard G1/G2 primers. Using these gene-based primers, a PCR assay was conducted for detection of L. interrogans in kidney samples from frogs and rats in Changshan county. PCR identification was performed on isolates taken from Zhejiang in 2008. Results The lipL32-PCR was specific and sensitive to L. interrogans. The PCR identification result for 2008 isolates was consistent with serological testing. A consistency of 95.0% was noted between lipL32-PCR and the assay based on the standard G1/G2 primer. The positive rate was 10.0% for lipL32-PCR and 5.0% for G1/G2-PCR. No significant difference between the two positive rates was shown by Fisher's exact probability test (P＝0.25). Conclusion The lipL32-PCR was specific and sensitive in the detection of L. interrogans and can effectively reflect the carrier rate in animals, thus, providing evidence for the control of leptospirosis.

【Abstract】 Objective To approach the feasibility of FlaB?PCR used for the detection of leptospira. Methods The proper  primer  was  synthesized  according  to  FlaB  gene and its sensitivity and specificity was evaluated compared to the primer G1/G2 recommended by public health industry standard. It was applied to leptospira detection of frog and rats which were from Longyou and Changshan. And it was identified by PCR. Results FlaB?PCR was highly sensitive and specific, and pathogenic leptospira DNA could be specifically amplified with the selected primer. The PCR results on leptospira isolated from Zhejiang province  in  2007 were in accordance with the serology results. The positive rate of the kidneys of rats and frogs was 20.94% by FlaB?PCR. Compared with the primer G1/G2 recommended by public health industry, the coincidence of two methods was 90.54%. Conclusion FlaB?PCR can detect the pathogenicity leptospira specifically and quickly, which can reflect the carrying rate of leptospira in wild animals accurately and efficiently and provide the evidence for leptospira control.