Objective: To select chemical substances with attractive effects on Aedes albopictus for on-field assessment, and to explore the preference of Ae. albopictus to six human odors. Methods: Under laboratory conditions, six chemical substances (1-octen-3-ol, lactic acid, myristic acid, ammonia, acetone, and ethyl acetate) were separately tested for their individual attracting effects on female Ae. albopictus at concentrations of 0.1, 1.0, and 10.0 mg/ml. The six substances were mixed in pairs (1∶1) at certain concentrations, and then the pairs were tested for attracting effects on female Ae. albopictus. The pair with good attractive effects was combined with lactic acid for testing. The attractant combination selected by laboratory experiments was tested for attractive action for Ae. albopictus in the field. The attracting effects of the substances or combinations on Ae. albopictus were compared using the t test and one-way analysis of variance. Results: Ae. albopictus mosquitoes were attracted to 1-octen-3-ol at 0.1, 1.0, and 10.0 mg/ml, myristic acid at 1.0 and 10.0 mg/ml, and ethyl acetate at 0.1 mg/ml, but not to the other three substances at any concentration. The pairs of 1-octen-3-ol+myristic acid, lactic acid+myristic acid, and lactic acid+1-octen-3-ol statistically attracted Ae. albopictus compared with the control group (t=8.102, P=0.001; t=4.696, P=0.009; t=5.127, P=0.007). The combination of lactic acid+1-octen-3-ol+myristic acid statistically attracted Ae. albopictus compared with the control group (F=86.841, P < 0.001). Field testing showed significant differences in the attracting effect between lactic acid+1-octen-3-ol+myristic acid and the control (day 1: t=7.462, P=0.014; day 2: t=20.500, P < 0.001; day3: t=9.383, P=0.001). Conclusion: The combination of lactic acid, 1-octen-3-ol, and myristic acid has attractive action for Ae. albopictus, which should be further researched in the field.

Objective: To investigate knockdown resistance (kdr) genotypes of Aedes albopictus which is the major vector of dengue in Nanning, so as to understand their insecticide resistance levels and provide evidence for scientific control of Ae. albopictus. Methods: Ae. albopictus larvae were collected using the dip method in Nanning and raised to adults in the laboratory. After morphological identification, Ae. albopictus mosquitoes were soaked in 75% ethanol and stored at -20 ℃. DNA was extracted from individual mosquitoes using the magnetic bead-based method. The partial fragments of the voltage-gated sodium channel (VGSC) gene were amplified by PCR and sequenced for alignment with the Basic Local Alignment Search Tool on the platform of National Center for Biotechnology Information. DNAStar 7.1 was used to analyze single-site and multiple-site mutations in the confirmed VGSC gene of Ae. albopictus mosquitoes. Results: A total of 175 Ae. albopictus mosquitoes were examined in 2022, obtaining 350 sequences (about 400 bp in length). Mutations were detected at the 1016 and 1534 loci but not at the 1532 locus of the VGSC gene. At the 1016 locus, there were two alleles (wild-type V [148, 78.28%] and mutant G [49, 21.72%]) and three genotypes (wild-type homozygote V/V [126, 72.00%], mutant homozygote G/G [27, 15.43%], and wild-type/mutant heterozygote V/G [22, 12.57%]). At the 1532 locus, there was one allele (wild-type I [175, 100%]) and one genotype (wild-type homozygote I/I [175, 100%]). At the 1534 locus, there were three alleles (wild-type F [51, 16.86%], mutant S [116, 36.29%], and mutant C [135, 46.85%]) and six genotypes (wild-type homozygote F/F [8, 4.57%], wild/mutant heterozygotes F/S [21, 12.00%] and F/C [22, 12.57%], mutant heterozygote S/C [64, 36.57%], and mutant homozygotes S/S [21, 12.00%] and C/C [39, 22.29%]). Conclusion: VGSC gene mutations are frequent in Ae. albopictus in Nanning. Attention should be paid to the insecticide resistance levels of Ae. albopictus for scientific, standardized, and efficient use of insecticides.

Objective: To investigate the density distribution of Aedes mosquitoes in different habitats and seasonal fluctuation in Hangzhou, Zhejiang Province, China from 2017 to 2021, so as to provide a scientific basis for effective prevention and control, risk assessment, and early warning of dengue fever. Methods: According to the National Vector Surveillance Implementation Plan and the Zhejiang Provincial Vector Surveillance Plan, Aedes mosquitoes were monitored in 15 districts (counties and cities) in Hangzhou. Adult mosquitoes were monitored using the double-layered mosquito net method, and larvae were monitored using the Breteau index (BI) method. The surveillance time was set during April to November. The mosquito surveillance data of the 15 districts (counties and cities) were collected. Excel 2019 software was used for data analysis. The net trap index, BI, and container index (CI) were calculated. Categorical data were compared using the Chi-squared test. One-way analysis of variance was used for quantitative data. Results: From 2017 to 2021, the density of Ae. albopictus in Hangzhou by the double-layered mosquito net method was 2.54 mosquitoes/net·h, and no Ae. aegypti mosquitoes were captured. The density of adult mosquitoes was lowest in 2017 and highest in 2020. There was a statistical difference in the net trap index between different years (F=5.117, P=0.017). The seasonal distribution generally presented a bimodal pattern, with the peaks of mosquito densities mainly in July and October. The average BI from 2017 to 2021 was 9.18, and the peak period of the BI was during May to October. The CI showed that Ae. albopictus larvae were distributed in all kinds of water bodies. The CI differed statistically between different water bodies in the same year (all P < 0.001) and between different years in the same water body (all P < 0.001). Conclusions: Ae. albopictus density was high in Hangzhou, indicating a risk of dengue fever outbreaks and regional epidemics. It is recommended that the counties (cities, districts) take timely mosquito control measures according to the density, distribution, and seasonal fluctuation of mosquitoes.

Objective: To analyze the species, composition, density, distribution, and seasonal fluctuation of flies in Fengxian District, Shanghai, China, so as to provide a basis for the prevention and control of flies in Fengxian District. Methods: The fly surveillance data in Fengxian District, Shanghai from 2011 to 2021 were collected, and Excel 2013 was used to summarize and analyze of the data. The Kolmogorov-Smirnov test was used to compare the density of flies in different habitats. Results: From 2011 to 2016, there was no significant change in the population density of flies in Fengxian District, ranging from 0.50 to 1.02 flies per cage of average annual density. In 2017 and 2018, the density of flies (1.76 and 5.25 flies per cage, respectively) increased significantly, by 70.87% and 409.71%, respectively, compared with 1.03 flies per cage in 2015. The fly density decreased year by year in 2019 and 2020, and increased in 2021, second only to the peak density in 2018. A total of 2 996 adult flies were captured, with an average density of 2.02 flies per cage. Muscina stabulans was the main species (accounting for 31.38%), followed by Boettcherisca peregrina (accounting for 28.64%). The flies density in large-scale green belts was highest with 2.32 flies per cage. The density of flies reached its peak in June, dropped sharply from July to August, and steadily decreased from September to November. Conclusions: There are more flies in large-scale green belts of Fengxian District, and the fly density peaks in June. The critical period to prevent fly-borne diseases is before June. Relevant departments in Fengxian District should raise and strengthen awareness of fly control. The environment management of large-scale green belt should be strengthened to reduce the breeding environment of flies.

Objective: To analyze the situation of vector control in the 7th Military World Games in 2019, so as to provide a scientific basis for vector control in similar major events in the future. Methods: The surveillance results of major vectors in different types of places (venues, hotels, designated hospitals, etc.) in urban areas of Wuhan, China from June to September 2019 were analyzed. Excel 2007 and SPSS 23.0 softwares were used for data processing. The Chi-squared test and Fisher's exact test were used for data analysis. Results: In June, the positive rate of fly breeding sites, the infestation rate of nymph and adult cockroaches, and the detection rate of cockroach eggs were highest, which were 3.88%, 1.69%, and 0.06%, respectively. In July, the positive rate of indoor rodent trace, mosquito larval route index and dip index, and indoor fly density were highest, which were 2.91%, 1.31 stagnant waters per km, 4.20%, and 4.81%, respectively; the qualified rates of rodent-proof and fly-proof facilities were lowest, which were 85.97% and 87.84%, respectively. In August, the outdoor rodent density route index and adult mosquito landing index were highest, which were 1.04 rodents and 1.63 mosquitoes per person, respectively. Conclusions: Authorities should continuously monitor vector infestation and control effects in key places of Wuhan Military World Games, scientifically and effectively evaluate the implementation of vector control, and timely detect relevant problems and adjust response strategies to prevent the occurrence of emergencies.

Objective To analyze the epidemiological characteristics of typhus fever in Jinzhai County, Anhui Province, China in recent ten years, so as to provide a basis for scientific control of typhus fever. Methods The descriptive epidemiological method was used to systematically analyze the characteristics of the surveillance data on cases of typhus fever in Jinzhai County from 2013 to 2022 collected from the China Information System for Disease Control and Prevention. Qualitative data were described as rates or constituent ratios, and analyzed using the Chi-squared test. Results From 2013 to 2022, 426 cases of typhus fever were reported in Jinzhai County, with a mean annual incidence of 8.23/100 000, and no deaths were reported. The incidence peak occurred between April and September (spring and summer), during which the number of cases accounted for 85.68% (365/426) of the total number of cases reported. The incidence of typhus fever was significantly higher among women than among men ( χ ²=30.878, P<0.001), and the male-to-female ratio was about 0.62:1. The incidence of typhus fever was highest in the age group of 60-<70 years (256.67/100 000). A vast majority of cases were farmers among occupations (93.90%). Cases were reported in 22 of 23 townships. Conclusions Cases of typhus fever were widely reported across Jinzhai County, predominantly affecting farmers and middle-aged and elderly people, with significant sex difference and seasonality. Therefore, typhus fever surveillance, prevention, and control should be strengthened for high-incidence areas and high-risk populations.

Objective: To investigate the rodents species, density, and pathogens they carry in Zunyi, Guizhou Province, China. Methods: A total of 70 sampling points were set in 14 counties/districts of Zunyi, with five points in the east, south, west, north, and center of each county/district. Small mammals were monitored through night trapping in Zunyi from October 2021 to October 2022, followed by species identification and pathogen detection. Excel 2021 was used for data organization. SPSS 26.0 was used to analyze the density, species, and pathogen-carrying status of small mammals through rate or constituent ratio comparison with the Chi-square test (P < 0.05 indicates a statistically significant difference). Results: A total of 9 969 effective traps were placed at all the surveillance points, capturing 549 small mammals in total, of which 522 were rodents. The total density of small mammals was 5.51%. The total density of rodents was 5.24%. The rodent density was highest in Honghuagang District (12.94%), followed by Fenggang County (12.34%), and lowest in Chishui City (1.80%). There was a statistical difference in rodent density between the counties/districts (χ²=195.619, P < 0.001). Rattus norvegicus was the dominant rodent species in urban residential areas, rural residential areas, and key industries, while Apodemus agrarius was the dominant species in farming areas. The composition of rodent species statistically differed in different regions (the center, north, east, and west) of Zunyi (χ²=117.357, P < 0.001). Each small mammal was examined for Leptospira interrogans and Orientia tsutsugamushi in the liver, spleen, and kidney; Dabie bandavirus in the liver, spleen, and lung; and Hantavirus in the lung. Among 343 samples tested, 27 were positive, all for L. interrogans, with a pathogen detection rate of 7.87%. Shrews had the highest detection rate (16.00%), followed by A. agrarius (12.35%), and R. norvegicus had the lowest detection rate (1.64%). There was a significant difference in the detection rates of different species of small mammals (χ²=14.372, P=0.002). The detection rate was 9.66% (26/269) in farming areas, which was highest, and 2.94% (1/34) in key industries, with negative detection results in urban and rural residential areas. There were no differences in detection rates between different habitats (χ²=5.171, P=0.160). The detection rate was 27.03% in Meitan County, followed by 25.00% in Suiyang County, and zero in Renhuai City, Fenggang County, and Yuqing County, with a statistical difference between different counties/cities/districts (χ²=35.409, P=0.001). Conclusions: The density of rodents was relatively high in Zunyi. The detection of L. interrogans should be a warning of the possibility of related diseases. Local authorities should strengthen rodent control in spring and autumn and take comprehensive control measures according to actual situation and dominant rodent species and pathogen detection status in different habitats, so as to reduce the density of rodents and prevent the occurrence of rodent-borne diseases.

Objective: To analyze the species, density, distribution, and variation of flies in Shanghai, China, to carry out risk assessment, prediction, and early warning of fly-borne diseases in a timely manner, so as to provide scientific reference for fly control. Methods: Using the cage trap method, fly traps were placed in farmers' markets, residential areas, external environment of restaurants, and large green belts. Fly surveillance data were collected every ten days from March to November in 2016-2021 in Shanghai. The data were processed and analyzed using Excel 2019 and SPSS 20.0. Results: From 2016 to 2021, 18 052 flies were caught with an average density of 1.52 flies/cage. The identified fly species belonged to 5 families, 9 genera, and 14 species. The dominant species were Muscina stabulans, Boettcherisca peregrina, Chrysomya megacephala, Lucilia sericata, and Musca domestica. M. stabulans showed the highest density of 0.28 flies/cage, followed by B. peregrina (0.24 flies/cage). In large green belts, the density of B. peregrina was higher than that of M. stabulans, and in all other habitats, the density of M. stabulans was the highest. There was a significant difference in density between B. peregrina and M. stabulans in the farmers' market (t=-2.674, P=0.023). The proportion of Mu. domestica decreased year by year, and the proportion of M. stabulans increased. The fly density was the highest in 2018 (1.82 flies/cage) and the lowest in 2016 (1.04 flies/cage). Fly density peaked from June to August, with the monthly average densities of 2.65, 2.49, and 2.28 flies/cage, respectively. In 2016-2021, the fly density in different habitats was in the order of farmers' markets > large green belts > residential areas > external environment of restaurants. Conclusions: The fly species are diverse in Shanghai. M. stabulans has the highest density. Fly density peaks from June to August, and farmer's market is a key place for targeted fly control. Fly density rose again after decline in 2019, suggesting that comprehensive control of flies should be continuously strengthened.

Objective To optimize the conditions for the induction expression and purification of recombinant Hq012 (rHq012) inclusion bodies of Haemaphysalis qinghaiensis. Methods The novel gene Hq012 with no homogenous sequences in the GenBank database was cloned from the cDNA expression library of H. qinghaiensis to be transfected into Escherichia coli Rosetta (DE3) using the prokaryotic expression plasmid pET-30a-Hq012. Isopropyl-β-D-thiogalactoside (IPTG) was used to induce the expression of rHq012 protein. After homogenizing the bacteria under high pressure, the inclusion bodies were dissolved in 6 mol/L guanidine hydrochloride solution. We compared the yield of the target protein obtained by first renaturation and then purification (refolding by dilution followed by purification with nickel ion affinity chromatography) and by first purification and then renaturation (purification with nickel ion affinity chromatography followed by refolding by dialysis). The obtained protein was identified by 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis. Results The nucleotide sequence length of the Hq012 gene was 759 bp, containing an open reading frame of 486 bp, encoding a protein with a relative molecular mass of 18 500. The protein expression was the highest at 8-hour induction with IPTG at 0.1 mmol/L. The inclusion bodies were dissolved with 6 mol/L guanidine hydrochloride. The yield of rHq012 harvested by first renaturation and then purification was higher compared with that by first purification and then renaturation. The relative molecular mass of the protein purified by nickel ion affinity chromatography was about 17 000, which was consistent with expected results. Conclusions Induction at an concentration of 0.1 mol/L IPTG for 8 hours was the best induction condition, and the method of first refolding followed by purification was an optimal purification method for the tick-derived recombinant protein rHq012. The study provides a reference for the purification of inclusion body protein.

Objective: To explore the factors affecting Aedes surveillance by the mosquito ovitrap method in a grid mode, so as to provide a scientific basis for the surveillance and control of Aedes mosquitoes and related mosquito-borne infectious diseases. Methods: Three adjacent residential areas with similar areas, building ages, and greenery ratios were selected as surveillance points in Jing'an District, Shanghai, China. Each residential area was divided into secondary surveillance blocks (about 90 m × 60 m) in a 3×3-grid mode. On-site monitoring was conducted in each surveillance block using the mosquito ovitrap method and the human landing catch method, three times one month from July to September 2021. By comparing the surveillance results of different residential areas, different surveillance blocks, and different environmental characteristics, the factors influencing the positive rate of the mosquito ovitrap method were determined. Excel 2016 and SPSS 16.0 were used to process the data. The Kruskal-Wallis rank sum test, tow-way analysis of variance, and Spearman correlation analysis were performed. Results: A total of 30 secondary surveillance blocks were designated. Eight times of surveillance were completed, and 131 mosquito ovitraps were set each time. The mosquito ovitrap index (MOI) in residential areas 1, 2, and 3 were 8.71, 12.38, and 11.97, respectively, with no significant difference (χ²=2.750, P=0.253). There were significant differences in the MOI among different blocks of residential areas 1 and 2 (F=2.135, P=0.047; F=2.168, P=0.044). In residential areas, the positive rate was 12.24 in living areas and 5.76 in community school areas, with a significant difference (χ²=6.657, P=0.010). The MOI was 14.10 for green areas on the house side, 8.87 for concentrated green areas, and 7.98 for green areas on the road side, with a significant difference (χ²=8.372, P=0.015). During the surveillance period, the MOI was 13.28 when the days of rainfall was < 2 d, and 8.79 when the days of rainfall was ≥2 d, with a significant difference (χ²=4.218, P=0.047). In residential area 1, the average MOI was 8.69, and the average landing index was 3.33 mosquitoes/person·h. In residential area 2, the average MOI was 12.45, and the average landing index was 8.58 mosquitoes/person·h. In residential area 3, the average MOI was 11.88, and the average landing index was 6.50 mosquitoes/person·h. The ratio of the MOI to the landing index was distributed between 1∶1 and 3∶1. Pearson correlation analysis showed that the MOI was highly correlated with the human landing index in each block (r=0.549, P=0.005). Conclusions: The density of Aedes mosquitoes may differ greatly in different areas of large residential areas due to differences in greening types, functional zoning, and other factors. The mosquito ovitrap method has the advantages of simple operation and high specificity compared with other surveillance methods for Aedes mosquitoes, and it is highly consistent with the human landing catch method. The mosquito ovitrap method with grid-based surveillance point distribution can be used in actual practice, which can effectively avoid deviations caused by point selection and fully reflect the density of Aedes mosquitoes.

Objective: To analyze cockroach infestation and its intestinal pathogen infection status in catering places in Pudong New Area, Shanghai, China, so as to provide scientific suggestions for cockroach control and the prevention and control of infectious diarrhea in catering places. Methods: From April 2021 to March 2022, cockroach infestation survey and sampling were conducted using cockroach traps in five types of catering places in 12 subdistricts and towns of Pudong New Area in the middle of each month. The captured cockroaches were examined for intestinal pathogens. Excel 2019 and SPSS 22.0 were used for data collation and statistical analysis. Results: In the catering places of Pudong New Area, the cockroach infestation rate was 20.83%, and the cockroach density was 0.74 cockroaches/trap. Blattella germanica (65.79%) and Periplaneta fuliginosa (34.21%) were captured, with a statistical difference in the constituent ratio in various types of places (χ²=126.509, P < 0.001). The cafeterias of enterprises and public institutions had the highest cockroach infestation rate and density, which were 29.03% and 1.32 cockroaches/trap, respectively. The pathogen detection rate of the cockroach samples was 28.13%. A total of 53 groups of 7 categories of pathogens were detected, including Sapovirus, Norovirus, Astrovirus, Shiga toxin-producing Escherichia coli (STEC), Aeromonas hydrophila, Blastocystis hominis, and Cryptosporidium. The dominant pathogens carried by B. germanica were Sapovirus, B. hominis, and STEC, and those carried by P. fuliginosa were Sapovirus, STEC, and A. hydrophila. Conclusion: Cockroaches in catering places in Pudong New Area carried various human intestinal pathogens, so attention should be paid to targeted cockroach control strategies in catering places.

Objective To establish the sensitive baseline of houseflies to six commonly used insecticides, so as to provide a basis for the monitoring and control of the insecticide resistance of houseflies. Methods The topical application method was used to test the sensitivity of laboratory susceptible housefly strains to six insecticides (deltamethrin, beta-cypermethrin, permethrin, dichlorvos, propoxur, and dinotefuran) of four categories. Data from previous literature were collected for comparison. The statistical significance of sensitivity differences was determined according to whether the 95% confidence interval of the median lethal dose (LD ₅₀) overlapped. Based on the above steps, the baseline sensitivity of houseflies to the six insecticides was established. Results The baseline sensitivity of the six test insecticides against houseflies were as follows: deltamethrin (LD ₅₀=0.002 236 μg/♀, y=13.76+5.19 x), beta-cypermethrin (LD ₅₀=0.003 692 μg/♀, y=9.34+3.84 x), permethrin (LD ₅₀=0.007 152 μg/♀, y=10.03+4.67 x), dichlorvos (LD ₅₀=0.074 20 μg/♀, y=5.02+4.44 x), propoxur (LD ₅₀=0.415 9 μg/♀, y=0.93+2.43 x), and dinotefuran (LD ₅₀=0.103 6 μg/♀, y=6.31+6.41 x). Conclusion This study established the baseline sensitivity of houseflies through testing the sensitivity of laboratory susceptible strains to six commonly used insecticides, providing a reference for monitoring and assessing the resistance level of houseflies in China.

This paper describes a new species collected from Cangyuan Wa Autonomus County, Yunnan Province, China, in July 2020: Heizmannia (Heizmannia) cangyuanensis sp. nov.. The main distinguishing features of the new species are as follows: white scales on the ventral side of the basal proboscis; anterior pronotums with all white scales; ventral plates Ⅲ-Ⅵ are all white; the middle lobe of the ventral plate of segment Ⅸ has no scales, with numerous and large the ventral middle teeth in the aedeagus, as well as a finger-like protrusion on the lateral apex of gonostylus. There was no significant difference between the morphology of its larvae and that of Hz. menglianensis larvae. All specimens were preserved in the Mosquito Collection of Yunnan Institute of Parasitic Diseases.

Objective To investigate the species composition, population density, and seasonal fluctuation of flies in Hangzhou, Zhejiang Province, China from 2017 to 2021, and explore the impact of meteorological factors on fly density, so as to provide a scientific basis for fly control. Methods From April to November of 2017-2021, fly density was monitored by cage trapping method in four types of habitats in Hangzhou, including residential areas, catering-related outdoor environments, green belts, and farmers’ markets. The obtained data were analyzed using Excel 2019 and SPSS 20.0 softwares. The Chi-squared test and one-way analysis of variance were used to compare the data of different years and habitats. Correlation and regression analyses were performed on fly density and meteorological factors. Results From 2017 to 2021, a total of 4 967 fly traps were deployed in Hangzhou, collecting a total of 10 267 flies, with an overall density of 2.07 flies/cage. The dominant fly species were species of Sarcophagidae, Musca domestica, Lucilia sericata, and Chrysomya megacephala, together accounting for 74.00% of the total number of catches, with the density of Sarcophagidae flies being the highest at 0.32 flies/cage. In different habitats, the density of flies was highest in farmer’s markets at 2.79 flies/cage and lowest in catering-related outdoor environments at 1.44 flies/cage, with a statistical difference in fly density between different habitats ( F=8.493, P=0.001). Among different regions of Hangzhou, Yuhang District had the highest fly density, while Jiande had the lowest fly density, with no statistical difference in fly density between regions ( F=1.433, P=0.140). The overall seasonal fluctuations of fly density showed a double-peak pattern, with the peaks appearing in June and August, respectively. There was no statistical difference in the seasonality of fly density between different years ( F=0.865, P=0.495). The density of flies in Hangzhou showed positive linear correlations with the average temperature, average maximum temperature, extreme maximum temperature, days of average temperature ≥18 ℃, average dew point temperature, precipitation, maximum daily precipitation, average minimum temperature, and extreme minimum temperature. Multiple stepwise regression analysis shows that the mean maximum temperature can enter the regression equation y=-1.707+0.430 x ( F=79.701, P<0.001). Conclusions In Hangzhou, the density of flies is the highest in the farmers' market, the peak period of activity is mainly summer, and the density of flies is affected by a variety of meteorological factors. It is recommended that comprehensive control measures should be taken as early as possible before the peak period of fly activity to control the fly density at insufficient levels.

Objective To investigate the distribution of ticks and the carrying status of (SFTSV) in Dongyang, Zhejiang Province, China, so as to provide a basis for the prevention and control of severe fever with thrombocytopenia syndrome. Methods In 2019-2020, two towns (subdistrict) were set as monitoring sites in each of the mountainous, hilly, and basin areas of Dongyang. The artificial drag-flag method was used to collect free-living ticks in the wild. Parasitic ticks on the body surface of host animals, such as domestic animals (sheep, cattle, and dog) and field mice, were collected by tick inspection on the body surface of animals. Tick specimens were identified. Real-time quantitative reverse transcription polymerase chain reaction was used to detect SFTSV. The difference in rates was analyzed by the Chi-square test. The difference in the number of captured ticks was analyzed by the Fisher’s exact test. Results There were 10 species of ticks belonging to 4 genera and 1 family in Dongyang. There was statistically difference in the number of free-living ticks caught in different seasons in mountainous, hilly and basin areas ( P<0.001 by Fisher’s exact test), which was significantly higher in mountainous areas than in basin areas, and the tick density in the first and second quarters was significantly higher than that in the third and fourth quarters. The average density of free-living ticks was 30.83 ticks/flag·100 m. The average tick infection rate of domestic animals was 18.72%, with a tick index of 0.94, and the average tick infection rate of rodents was 8.59%, with a tick index of 0.22. The dominant populations of free-living ticks and parasitic ticks on the body surface of domestic animals and rodents were Haemaphysalis longicornis, Rhipicephalus haemaphysaloides, and Ixodes granulatus, respectively. No SFTSV was detected in 771 tick specimens from 251 groups. Conclusions Ticks are commonly found in the wild and on the body surface of animals in Dongyang, and the species are relatively rich. The density of ticks is high in spring and summer, suggesting that spring is the best time to kill ticks.

Objective To analyze the epidemiological characteristics (temporal, spatial, and demographic distributions) of indigenous and imported cases of dengue fever reported in Chinese mainland from 2005 to 2020. Methods The seasonal characteristics of dengue fever were analyzed using Excel 2010. Trend analysis was performed on the annual median age of disease onset using the Mann-Kendall test with the use of R 4.0.2. The map visualization and spatial analysis of cases were conducted using ArcGIS 10.3 software. Results A total of 81 648 indigenous cases of dengue fever were reported in 14 provinces (autonomous regions or municipalities) of Chinese mainland from 2005 to 2020. The indigenous cases were reported between May and December, concentrated between August and November (98.26%), and were distributed south from 35°36?N, mainly in Guangdong (74.01%) and Yunnan (13.74%) provinces, indicating seasonal and regional characteristics. Two major outbreaks of dengue fever occurred in 2014 and 2019, with 46 033 and 15 376 indigenous cases, respectively, adding up to 75.21% of the total indigenous cases. Among the local cases from 2005 to 2020, the male-to-female ratio was 0.99∶1; 54.93% were aged between 25 and <55 years; the top three frequent occupations were engagement in housework or unemployment (21.40%), service workers (12.46%), and retirees (11.71%). The median age of the total indigenous cases was 40 years (interquartile range [IQR]: 27-54). The difference of overall trend of the median age of indigenous cases since 2005 was not statistically significant ( Z=1.510, P=0.131). There were a total of 12 701 imported cases in 30 provinces (autonomous regions or municipalities) except the Tibet Autonomous Region in Chinese mainland from 2005 to 2020. The imported cases were reported throughout a year, frequently between June and November (81.81%), and were mainly distributed in Yunnan, Guangdong, Fujian, and Zhejiang provinces, suggesting seasonal and regional characteristics. The imported cases were mainly from Southeast Asian countries including Myanmar and Cambodia. In 2019, the number of imported cases reached a peak of 5 813, accounting for 45.77% of the total imported cases. Among the imported cases from 2005 to 2020, the male-to-female ratio was 2.05∶1; 73.29% were aged between 25 and 54 years; the top three frequent occupations were farmers (24.13%), service workers (19.34%), and engagement in housework or unemployment (13.91%). The median age of the total imported cases was 33 years (IQR: 26-44). The overall trend of the median age of imported cases since 2005 was not statistically different ( Z=0.413, P=0.679). A total of 15 376 indigenous cases and 5 813 imported cases reported in 2019, and the number of indigenous and imported cases reported were dramatically decreased to 616 and 158 in 2020, respectively. Conclusions Dengue fever outbreaks in Chinese mainland are still caused by imported cases, with significant seasonal and regional characteristics. The indigenous cases were mainly distributed in Guangdong and Yunnan provinces, while the imported cases were mainly from Southeast Asian countries including Myanmar and Cambodia. There was no significant change in the median age of dengue fever cases from 2005 to 2021.

Objective: To investigate the species composition, population density, and seasonal fluctuation of mosquitoes in Huai'an, Jiangsu Province, China from 2018 to 2022, so as to provide a scientific basis for the control of mosquitoes and mosquito-borne infectious diseases. Methods: The adult mosquito density data monitored by lamp trapping method in Huai'an from 2018 to 2022 were collected, and the species composition, population density, and seasonal fluctuation of mosquitoes were analyzed. The mosquito species composition ratio was compared using the Chi-squared test. The mosquito density in different habitats was analyzed using Welch's analysis of variance. Results: Culex pipiens pallens was the dominant mosquito species in Huai'an from 2018 to 2022. The species composition ratio was statistically different between different years (all P < 0.001). Cx. tritaeniorhynchus was the dominant mosquito species in livestock sheds, while Cx. pipiens pallens was the dominant mosquito species in the other habitats, with a statistical difference in the species composition ratio between different habitats (χ²=22 424.835, P < 0.001). Among different habitats, the highest density was in livestock sheds with 3.62 mosquitoes/lamp·h, and the lowest density was in residential areas with 0.92 mosquitoes/lamp·h. Welch's analysis of variance showed that the mosquito density differed statistically between different habitats (F=5.843, P=0.013). The seasonal fluctuation of mosquito density in Huai'an showed a unimodal curve in each year of 2018 to 2022, with the peaks occurring in July for 2019, 2020, and 2022, in August for 2018, and in June for 2021. The seasonal fluctuation of mosquito density showed a single-peak pattern in different habitats and for different species, with the highest densities in July. Conclusions: The species composition and density of mosquitoes differed in different habitats of Huai'an. The highest mosquito density was in livestock sheds, which should be the key area for mosquito control. Mosquitoes were most active during June to September, and mosquito control should be strengthened based on mosquito activity patterns in this period.