Objective To investigate mutations in the voltage-gated sodium channel gene ( VGSC) responsible for knockdown resistance (kdr) in Aedes aegypti and analyze the prevalence characteristics of the VGSC gene in the key areas of Ae. aegypti distribution in Yunnan Province, China. Methods Wild adult or larval Ae. aegypti samples were collected from 7 counties/cities (Yingjiang County, Ruili City, Zhenkang County, Gengma Dai and Va Autonomous County, Menghai County, Jinghong Municipality, and Mengla County) in Yunnan Province. The gene VGSC was amplified by direct sequencing to analyze the point mutation rate and the composition of combined mutations. The Chi-square test was used to compare the differences in the kdr mutation rate of VGSC gene between different loci and between different sexes of Aedes albopictus. Results The DNA was successfully extracted and VGSC gene were sequenced for a total of 561 Ae. aegypti mosquitoes (276 females, 242 males, and 43 larvae) in 7 counties/cities. Four point mutations were found in the VGSC gene. S989P, V1016G, and F1534C mutations were present in every county/city. The S989P mutation rate ranged from 71.43% to 100%, with a mean of 92.51% (95% confidence interval [ CI]: 90.33%- 94.70%). The V1016G mutation rate was 100%. The F1534C mutation rate was 55.81%-100%, with a mean of 85.38% (95% CI: 82.45%-88.32%). The Y1527F mutation was first detected in Ruili Municipality, Gengma and Zhenkang County, and the mutation rate ranged from 0 to 35.45%, with a mean of 8.73% (95% CI: 6.39%-11.08%). There were 4 types of co-occurring mutations: S989P+V1016G, V1016G+F1534C, S989P+V1016G+F1534C, and S989P+V1016G+Y1527F+F1534C. Single point mutations were not found. There were no significant differences in the mutation rates of 989, 1016, 1527, and 1534 loci and the composition ratios of combined mutations in female and male mosquitoes in six counties/cities except Yingjiang County. Conclusions The kdr mutation in the VGSC gene of Ae. aegypti in Yunnan Province is mainly characterized by multiple-point joint mutations, and a new Y1527F mutation appears. Kdr mutations surveillance in Ae. aegypti should be carried out regularly to grasp the changes in its resistance to insecticide targets in time.

Objective To verify the field efficacy of 0.2% curcumol baits against farmland rodents and determine the optimal dose. Methods A field experiment with 0.2% curcumol baits at three doses 1 500, 3 000, and 4 500 g/hm ² was carried out in the plague foci of Lijiang, Yunnan Province, China. The changes in rodent density,uterine development status, pregnancy rate, and litter size were investigated at 30, 60, and 90 days after baiting. The bait efficacy and intake level were calculated with the use of Excel 2010 software. Results The control effects of curcumol baits at 1 500, 3 000, and 4 500 g/hm ² groups were 47.06%, 51.87%, and 57.65% at 30 days, respectively; 50.00%, 63.64%, and 60.00% at 60 days, respectively; and 54.55%, 62.81%, and 50.91% at 90 days, respectively. The number of subadults decreased substantially, and the pregnancy rate and average litter size of female adult rodents also decreased. The curcumol bait intake coefficient of rodents was 0.77. No dead rodents or non-target organisms were observed during 15 consecutive days of investigation since the first day after baiting. Conclusion 3 000 g/hm ² of 0.2% curcumol baits is recommended for controlling farmland rodents based on the control effects and the economic threshold.

Objective By analyzing the surveillance data of host animals of hemorrhagic fever with renal syndrome (HFRS) in Guyuan, Ningxia Hui Autonomous Region (Ningxia), China from 2015 to 2021, to investigate the distribution of host animals of HFRS in Guyuan and their infection with viruses, so as to provide a basis for prevention and control, early warning and prediction of human epidemic in this region. Methods Small mammal trapping in field and residential areas in spring and autumn was carried out annually in accordance with the National Hemorrhagic Fever with Renal Syndrome Monitoring Program in the Jingyuan, Pengyang, Xiji, and Longde Counties and Yuanzhou District of Guyuan from 2015 to 2021. The density, distribution, and species composition were monitored by the night trapping method and analyzed, and the lung and blood specimens of small mammals were collected for antigen and antibody detection. The SPSS 23.0 software was used for statistical analysis, counting data were expressed as rates, and were compared with the Chi-square test ( P<0.05 indicates a statistically significant difference). Results From 2015 to 2021, a total of 5 515 small mammals were captured in Guyuan, with a mean density of 2.00%. The density of small mammals in the field areas (2.18%) was statistically higher than that in the residential areas (1.71%)( χ ²=55.920, P<0.001). The density of small mammals was statistically different across years and between different counties (districts) in the field areas ( χ ²=991.300, 1 202.179, both P<0.001); the dominant rodent species in Jingyuan County, Yuanzhou District, and Longde County were Apodemus agrarius, the dominant rodent species changed from A. agrarius to Rattus norvegicus in Longde county, and the dominant rodent species in Xiji County and Pengyang County were Cricetulus longicaudatus and Mus musculus, respectively. The density of small mammals was statistically different across years and between different counties (districts) in the residential areas ( χ ²=326.600, 430.500, both P<0.001), and the density of small mammals was generally below 5%. The dominant rodent species in Jingyuan, Xiji, Longde, and Pengyang were all M. musculus, and the dominant rodent species in Yuanzhou was R. norvegicus, with the proportion increased year by year. From 2018 to 2020, the density of small mammals showed a downward trend in the field and residential areas of Jingyuan and Longde, the field areas of Yuanzhou and Xiji, and the residential areas of Pengyang. The density of small animals increased statistically from 2020 to 2021 in the field and residential areas of Yuanzhou and Longde and in the field areas of Pengyang (all P<0.05). The infection rate (antibody positivity rate) of small mammals was 5.48 times the virus-carrying rate (antigen positivity rate) in the 7-year period; the virus-carrying rate of small animals was highest in Jingyuan County (1.05%), and the infection rate of small mammals was highest in Longde County (10.61%). The infection rate of small mammals in residential areas was statistically higher than that in field areas ( χ ²=12.675, P=0.008), while Hantavirus carrying of small mammals was only detected in the field areas. The virus-carrying rate of A. agrarius (2.94%) was higher than its infection rate (1.96%), and the infection rate of R. norvegicus (3.20%) was higher than its virus-carrying rate (0). Conclusions In recent years, the density of small mammals in Guyuan of Ningxia was generally low, but showed a slight increasing trend in the past two years; the density in the field areas was higher than that in the residential areas. The dominant rodent species were mostly A. agrarius in the field areas and M. musculus in the residential areas. The virus-carrying rate and infection rate of rodents increased significantly in 2021, suggesting that although the density, distribution, and composition of host animals of HFRS in Guyuan of Ningxia have not changed significantly, we still need to be vigilant for outbreaks of human epidemics.

Objective To investigate the species composition, population density distribution, and seasonal fluctuation of flies in Qingdao, China, and to provide a scientific basis for fly control. Methods Flies were monitored using the cage trap method. Fly species composition was analyzed using the chi-square test, and fly population density was analyzed using the Kruskal-Wallis H test. Results From 2017 to 2022, a total of 10 490 flies were caught, with a mean annual density of 12.14 flies/cage. The dominant fly populations were Sarcophagidae, Musca domestica, and Lucilia sericata, accounting for 22.73%, 17.58%, and 17.45%, respectively. The species composition of fly differed significantly in different years ( χ ²=4 863.573, P<0.001). The activity of flies spanned a long period from March to November. The seasonal peak of fly population density in different years all occurred in July, at 47.63, 32.13, 33.63, 23.00, 26.75, and 28.50 flies/cage, respectively, and there was a significant difference in the seasonal fluctuations of fly density between different years ( H=36.442, P<0.001). For different habitats, fly density was highest in farmers’ markets (15.27 flies/cage) and lowest in restaurant surroundings (7.26 flies/cage), with a significant difference in the density of each fly species between different habitats ( H=2.386, P=0.035). Among the dominant species, M. domestica had the highest density in residential areas (3.18 flies/cage), Sarcophagidae had higher densities in farmers’ markets (2.68 flies/cage), green belts (2.73 flies/cage), and residential areas (3.75 flies/cage), and L. sericata had the highest density in farmers’ markets (3.34 flies/cage). Conclusions Flies in Qingdao are mainly infested farmers’ markets and residential areas, peaking in July, and different fly species prefer different habitats. Fly seasonality, dominant species, and breeding characteristics should be considered in formulating targeted control measures to effectively reduce fly population density.

Objective To investigate the distribution of mosquito vectors in Hainan Province, China from 2020 to 2022, so as to provide common mosquito ecological surveillance data for analyzing the risk of transmission of imported mosquito-borne diseases after the initiation of China (Hainan) Pilot Free Trade Zone operations. Methods In 18 cities (counties) across the province throughout the years, adult mosquitoes were monitored using the light trap method and the double-layered mosquito net method, and larval mosquitoes were monitored using the Breteau index (BI) method. With the use of R 4.3.1 software, one-way analysis of variance (ANOVA) was performed to compare the mean values of different mosquito populations in different years and regions, and if the difference was significant, the least significant difference method was used for further pairwise comparison. Results From 2020 to 2022, a total of 12 240 lamps were set across Hainan Province, and 41 087 female mosquitoes were captured. The density of mosquitoes was 3.36 mosquitoes/light·night. The annual density fluctuated between 1.59 and 4.55 mosquitoes/light·night, and was significantly different in different years ( F=4.810, P=0.015). The net trap index for Aedes was 0.90 mosquitoes/net·hour. The annual fluctuated between 0.06 and 1.74 mosquitoes/net·hour, and there was no significant difference in the mean net trap index of different years ( F=2.697, P=0.082); The BI for Aedes larvae was 4.13. The annual BI fluctuated between 2.13 and 6.60, and the mean BI showed no significant difference between different years ( F=2.969, P=0.065). The mosquito density by the light trap method showed an obvious seasonal pattern, which was higher in summer than in winter; the density of Ae. albopictus also showed obvious seasonality, which was lowest during December to next February, and then increased to high levels during June to August, followed by a downward trend after August. There were significant differences in the mean annual values of adult mosquito density ( F=7.758, P<0.001) and BI ( F=11.630, P<0.001) between different dry and wet climate zones, but the net trap index showed no significant difference ( F=1.977, P=0.113). Conclusions The annual mosquito density, net trap index and BI were all at a low level in Hainan Province from 2020 to 2022, but mosquito density were high in some areas. It is necessary to pay close attention to the mosquito vector density after the closure of the free trade port, and strengthen the surveillance of the vector mosquitoes.

Objective To investigate the rodent species composition, density, and seasonality in different habitats based on the rodent surveillance program in Nanchang, China, so as to provide a basis for scientifically formulating rodent control strategies in Nanchang. Methods Three types of surveillance habitats including urban residential area, rural natural village, and special industry were chosen from 2017 to 2022. Rodent density was investigated by the night snap-trapping method. Descriptive methods were used to perform a statistical analysis of rodent species composition and seasonal variation of rodent density in three different habitats in Nanchang. With SPSS 26.0 and Excel 2021 softwares, descriptive methods were used to perform a statistical analysis of surveillance data, and the Chi-square test was used for comparison of rodent density across different years and habitats. Results A total of 104 121 effective traps were placed in Nanchang from 2017 to 2022, and 548 rodents were captured, with an average rodent density of 0.53%. The overall rodent density in the six years was statistically significant ( χ ²=34.857, P<0.001). A bimodal distribution with seasonal variation was found in the overall rodent density, the annual density of three dominant rodent species ( Rattus norvegicus, Mus musculus, and R. tanezumi), and the rodent density in residential areas and special industry habitats, while the rodent density in rural natural village habitats showed a unimodal trend, with the peak in July. The rodent density in rural natural villages (1.56%) was significantly higher than that in special industries (0.45%) and than that in urban residential areas (0.30%) ( χ ²=304.340, P<0.001). The dominant rodent species in urban residential areas and rural natural village habitats were R. norvegicus and R. tanezumi, while M. musculus predominated in special industry habitats (47.47%). The composition ratio of R. norvegicus in special industry and rural natural village habitats was decreasing year by year; the composition ratio of R. tanezumi in urban residential areas showed a decrease after increasing, while it was generally increasing in special industry and rural natural village habitats; the composition ratio of M. musculus in three different habitats showed an overall increasing trend. Conclusions The rodent density varies greatly in Nanchang from 2017 to 2022. The rodent density showed a bimodal distribution with seasonal changes and was high in rural areas. Specific control measures should be taken according to the changes in rodent species in different habitats to reduce the rodent density and the risk of rodent-borne diseases.

Objective To understand the composition of main vector species in Zibo City in 2022, master its density and seasonal fluctuation, so as to provide scientific basis for vector biological control in Zibo City. Methods Four vectors of mosquitoes, flies, mice and cockroaches were monitored in Zibo City.Mosquito surveillance was carried out by the mosquito lamp trapping method and the Breteau index (BI) method. Cage trapping method was used to monitor flies. The night snap trapping method was used outdoors for rodent surveillance.The method of sticky trapping was used for cockroach surveillance. The difference of species composition in different habitats was determined by Chi-square test or Fisher’s exact probability method. Results In 2022, the average density of adult mosquitoes was 11.81 mosquitoes/light·night, and the highest density was 32.51 mosquitoes/light·night in August; the dominant species was Culex pipiens pallens; As for the larvae, BI were all>10.00 in July and August, and >20.00 in September. The average density of flies was 12.51 flies/cage, and the density reached the peak of 66.98 flies/cage in July; Musca sorbens was the dominant species. In 2022, the average density of rodents was 1.15%, with the peak of rodent activity in September, and the dominant rodent species was Rattus norvegicus. In 2022, the average density index of cockroaches in the city was 3.15 cockroaches/sheet, with the peak occurring in September, and Blattella germanica was the dominant species. The composition ratio of mosquitoes, flies and mice in different habitats was different, and the difference was statistically significant ( χ ²=3 160.149, 1 029.005, 33.394, all P<0.001). Conclusion The main disease vectors in Zibo city were Cx. pipiens pallens, M. sorbens, R. norvegicus and B. germanica. with high densities during July to September in summer. Appropriate measures should be taken to control the density of the vectors to prevent the spread of vector-borne diseases.

Objective From May 2017 to November 2021, there was an increased number of cases of fever with rashes admitted to Huoshan County Hospital in Lu’an City, Anhui Province, China. The aim of the study is to find out the etiology of the patients through epidemiological and clinical characteristic analysis, so as to provide a scientific basis for the prevention and control of the febrile illness with rashes. Methods An epidemiological investigation was carried out on the cases of fever with rashes through inquiring their medical histories and reviewing their medical records. The acute sera at admission and convalescent sera were collected from the patients to examine IgG antibody titers to Anaplasma, Borrelia burgdorferi, Orientia, Ehrlichia, Rickettsia rickettsii, and R. typhi using indirect immunofluorescence assay. An infection of a pathogen was determined by a 4-fold increase of the serum IgG antibody titer to the pathogen between the acute serum and the convalescent serum. The etiologic agent causing the outbreak was further identified by PCR amplification and DNA sequences of the rickettsial genes from acute serum. Results The IgG antibodies to Anaplasma, B. burgdorferi, and R. typhi were all negative in the acute sera of the patients. The positive rate of serum IgG antibodies to R. rickettsii was 51.52% (68/132) in the acute sera and 89.19% (33/37) in the convalescent sera. In the paired sera, the IgG titer had more than four time increase in the acute sera than in the convalescent sera. Phylogenetic analysis with the Rickettsia ompA sequence indicated that the etiologic agent formed a monoclade with newly identified Candidatus R. jingxinensis in Yunnan, China. Conclusion The febrile cases with rashes in Lu’an were serologically diagnosed as spotted fever rickettsial infection.

Objective To compare the performance of three time series models in predicting the incidence of hemorrhagic fever with renal syndrome (HFRS),and to explore the predictive performance of a modified seasonal autoregressive integrated moving average (SARIMAX) model with independent variables introduced from a least absolute shrinkage and selection operator (LASSO) model. Methods The information on HFRS incidence, rodent density, meteorological and socio-economic data in Guangzhou,China from 2006 to 2022 were systematically collected. Exponential smoothing (ETS), SARIMAX, and LASSO-SARIMAX models were constructed to predict the incidence of HFRS. Autocorrelation function (ACF), mean percentage error (MPE), and mean absolute percentage error (MAPE) were used to evaluate the predictive effects of the models. MAPE was used to compare the prediction effects of the three models in different prediction times. Results The mean annual incidence rate of HFRS in Guangzhou from 2006 to 2022 was 0.06/100 000. The MAPE for the training set was 45.066 for the ETS model, 51.403 for the SARIMA model,and 39.466 for the LASSO-SARIMAX model. The LASSO-SARIMAX model had the lowest MAPE in the training data set at a prediction length of 12 months,with a lower MAPE compared with the ETS model at a length of 24 months. Conclusion The LASSO-SARIMAX model shows good performance in predicting the incidence of HFRS in Guangzhou in the short and medium term.

Objective To describe the epidemiological characteristics of dengue fever in the China-Myanmar border area, and to explore the spatial-temporal clustering characteristics of dengue fever at different spatial-temporal scales. Methods The data on dengue fever cases were collected in the China-Myanmar border area, Jinghong, China in 2019, and a spatial-temporal clustering analysis of dengue fever was performed using a Knox model. Results In this study, the average time interval and average spatial distance of dengue fever transmission in Jinghong were 23.49 d and 5.54 km, respectively. When the time interval was 1 day, the risk of dengue fever was highest ( RR≈2.00) at a spatial distance of 0.40-0.50 km, relatively high ( RR>1.60) at >0.50-1.00 km, and moderate ( RR≥1.40) at 1.00-2.00 km; and the RR was still >1.00 at a distance of 15.00 km. Among populations of different characteristics (sex, age, and occupation), the spatial-temporal transmission pattern of dengue fever was heterogeneous, and the strength of spatiotemporal clustering was strongest in people with long-time and short-distance contact. For occupations, worker-worker case pairs had the highest strength at a large scale (0-1.00 km), and farmer-farmer case pairs had the highest strength at a small scale (0-0.10 km). Conclusion The risk of dengue fever transmission in Jinghong decreases rapidly with an increasing time interval and spatial distance, and spatial-temporal clustering is markedly heterogeneous at different scales and in populations of different characteristics (sex, age, and occupation).

Objective To analyze epidemiological characteristics and outbreak of dengue fever in Yunnan Province, China, so as to provide a scientific basis for formulating effective prevention and control measures. Methods Relevant data on dengue fever cases and outbreaks reported in Yunnan Province during 2013-2022 were collected from the “Infectious Disease Surveillance System” and “Public Health Emergency Management Information System” of “China Disease Control and Prevention Information System”. The concentration method was used to analyze seasonal characteristics. Excel 2007 software was used to sort out the data. MapInfo 7.8 software was used to draw the map. SPSS 26.0 was used to analyze the correlation, and the Chi-square test was used to compare the rate or composition ratio. The descriptive epidemiological method was used to analyze the epidemiological characteristics and outbreak response to dengue fever. Results A total of 16 774 cases of dengue fever were reported in Yunnan Province from 2013 to 2022, including 11 944 local cases, 4 521 overseas imported cases, and 309 domestic imported cases, with an average annual reported incidence of 3.53/100 000. The disease showed a high incidence every other year. The concentration ( M) was 0.84, showing strong seasonality. Imported cases mainly occurred from June to October, and local cases mostly from August to November. The male-to-female ratio of imported cases was slightly higher than that of local cases ( χ ²=37.596, P<0.001). The majority of local cases were 30～<40 years old (20.14%), and the majority of imported cases were 20～<30 years old (27.58%). The local cases were found in 5 border prefectures (cities). The overseas imported cases were mainly from southeast Asian countries and African countries, and Myanmar, Cambodia, and Laos were the main source countries (96.81%). The domestic imported cases were mainly from Xishuangbanna Dai Autonomous Prefecture (85.76%). The majority of cases were farmers, commercial service personnel, cadres/retirees, housekeepers, job-waiting people, and students. Commercial service personnel accounted for the highest proportion in local cases (21.89%), while farmers accounted for the highest proportion in imported cases (39.90%). There was a significant difference in occupational distribution between imported cases and local cases ( χ ²=1 535.415, P<0.001). A total of 28 dengue fever outbreaks were reported from 2013 to 2022, including 1 major event and 27 general events. The number of reported cases accounted for 83.41% of the total number of cases, and each event involved an average of 499.71 cases. The median time from the onset of the first case to the verification of event occurrence was 7 (5, 9) days, and the median duration of the outbreak was 110 (27, 140) days. Twenty-five outbreaks occurred in villages/communities. Conclusions Dengue fever in Yunnan has obvious seasonal, aggregated, and regional distribution patterns. We need to further strengthen imported case management, disease vector surveillance and control, and the prevention and control of dengue fever in key areas.

Objective To investigate the general situation of human plague in Inner Mongolia Autonomous Region (Inner Mongolia) and to grasp the dynamics and trend of the epidemic, so as to provide a basis for the prevention and control of the plague. Methods The descriptive epidemiological method was applied for the analysis of the data of human plague cases in Inner Mongolia from 1950 to 2021. Chi-square test was used for comparison of counting data. Results From 1950 to 2021, 271 cases of plague were reported in Inner Mongolia, with 130 deaths (case fatality rate: 47.97%). The cases were mainly distributed in 88 epidemic foci in 26 banners (counties and districts) of 8 leagues (cities), i.e., Tongliao, Chifeng, Xing’an League, Xilin Gol League, Ordos, Bayannur, Ulanqab, and Baotou. The plague peaked from July to August, during which 20 outbreaks were observed. The case fatality rates of plague in the natural plague foci of Spermophilus dauricus and Meriones unguiculatus were 51.84% and 32.00%, respectively, with no significant differences between the two ( χ²=3.571, P=0.059). Conclusion Human plague in Inner Mongolia has a wide range of transmission and a high case fatality rate, mainly occures in the S. dauricus plague foci and M. unguiculatus plague foci. In the prevention and control of plague in Inner Mongolia, should strengthen innovative research, monitoring and early warning, and timely disposal and control of animal plague to avoid human infection.

Objective To establish a multiplex real-time fluorescent quantitative reverse transcription polymerase chain reaction (multiplex real-time qRT-PCR) method for rapid detection of nucleic acids of Alongshan virus (ALSV) and Songling virus (SGLV). Methods Specific primers and TaqMan probes were designed for the conserved regions of the NS 3 gene of ALSV and the S gene of SGLV. A multiplex real-time qRT-PCR method was established for the two viruses, and the specificity, sensitivity, and repeatability of the method were evaluated. Tick specimens were used to verify the method. Results The detection method had no cross-reactivity with six other arboviruses, such as tick-borne encephalitis virus, with a sensitivity up to 1×10 ¹ copies/μl, and the coefficient of variation of cycle threshold for repeatability testing was less than 2.00%. Through this method, two groups of ALSV-positive specimens and one group of SGLV-positive specimens were detected from 30 groups of tick specimens collected from Heilongjiang, China in 2019. This method was verified to be 100% consistent with the general PCR method in terms of test results. Conclusion In this study, a highly sensitive and highly specific multiplex real-time qRT-PCR method for rapid detection of ALSV and SGLV has been successfully established.

Objective To investigate the current situation of vector control capacities of municipal and county-level centers for disease control and prevention (CDCs) in Shandong Province, China, so as to provide a basis for actively responding to the new situation of the prevention and control of vector-borne infectious diseases and improving vector control capacities of Shandong Province. Methods Through on-site interviews and questionnaire surveys, the information was collected on the vector control professionals and laboratory equipment of CDCs at the municipal and county levels in Shandong Province. Data were analyzed using WPS 2010 and SPSS 19.0 softwares. The t test or Wilcoxon’s rank-sum test was used for comparison of continuous data between groups, and the χ ² test was used for comparison of count data between groups. Results In Shandong Province, the average numbers of full-time personnel engaging in vector surveillance and control at municipal and county-level CDCs were 4.10 and 1.94, respectively. Among the professionals, junior and intermediate titles were more common, accounting for 34.43% and 36.79%, respectively; 46.70%(99/212) majored in preventive medicine (public health); and the majority had 1-5 years of work experience, accounting for 58.49%. The work mainly focused on carrying out ecological surveillance of disease vectors, and the vast vector laboratories were only able to carry out classification and identification disease vectors; The county-level CDCs undertook 59.38% of the training, and the average annual number of academic papers and scientific research achievements was 5.2 and 0.8, respectively. Conclusions In order to cope with the new challenges facing vector biological control, it is necessary to increase financial investment, strengthen talent and technical reserves, and strengthen scientific research and training. Professional and technical personnel should be based on the existing surveillance projects to strengthen data analysis and utilization, take more action in publicizing the knowledge of vector biological control, and continuously improve the level of social services.

Objective To investigate the prevalence of key human intestinal helminth infections in Yongxing County, Hunan Province, China, so as to provide a scientific basis for parasitic disease prevention and control. Methods An administrative village each from five townships (located in the eastern, western, southern, northern, and central regions, respectively) was randomly selected in Yongxing County, Hunan Province from 2016 to 2020. At least 200 permanent residents ≥3 years old were surveyed at each surveillance point every year. The intestinal worm eggs were examined by using the Kato-Katz technique. The hookworm species was identified by using filter paper culture. The pinworm eggs were examined by using the anal swab method with a transparent tape for children aged 3 to 9 years. WPS Excel 2021 software was used to establish the database, and SPSS 20.0 software was used to conduct statistical analysis. The infection rate was compared using the Chi-squared test. Results A total of 5 066 persons were examined for worms in feces, with a rate of key intestinal worm infections of 2.68% (136 cases). The infection rates for roundworms, hookworms, pinworms, whipworms, and liver flukes were 1.99%, 0.24%, 0.20%, 0.18%, and 0.08%, respectively. No co-infection was detected. The results of 12 hookworm larvae culture samples were all Necator americanus. The anal swab test detected a pinworm infection rate of 0.33% among a total of 1 500 children aged 3 to 9 years. The overall key intestinal worm infection rates from 2016 to 2020 were 4.08%, 1.97%, 3.24%, 1.10%, and 3.00%, respectively. Conclusion The key human intestinal worm infection rate is at a low epidemic level in Yongxing County, Hunan Province, but the infection factors still exist. It is necessary to strengthen categorical surveillance and promotion and education of parasitic disease prevention and control knowledge.

Objective To investigate the impact of quarantine management measures for inbound passengers on dengue fever during the prevention and control of novel coronavirus infection in Hangzhou, China. Methods The information on dengue fever cases from January 1, 2017 to December 31, 2022 and the mosquito surveillance data and the number of inbound passengers from 2017 to 2022 in Hangzhou were collected. Excel 2019 software was used to aggregate the data, and R 4.2.0 software was used for statistical analysis. The epidemiological characteristics of dengue fever before and after the implementation of quarantine management measures were compared using the Chi-squared test. The mosquito density surveillance data were compared using repeated-measures analysis of variance. The correlation between the number of inbound passengers and dengue fever cases was investigated using Spearman rank correlation analysis. Results After the implementation of quarantine management measures for inbound passengers from March 26, 2020 to December 31, 2022, a total of 5 imported cases of dengue fever were reported in Hangzhou, and the intensity of the risk of imported transmission was 0, which were significantly lower than those (250 cases, with 4.82 of risk intensity) before the implementation. There were no significant differences in the population characteristics, the season of importation, and the distribution of the source areas of imported dengue fever cases before and after the implementation of quarantine management measures (all P>0.05). After the implementation of quarantine management measures, four imported cases were found at isolation sites and one at a port, while 98.40% (246/250) of cases were found in hospitals before the implementation of quarantine management measures. The time interval between disease onset and diagnosis was significantly shorter than before the implementation of quarantine management measures ( t=2.053, P=0.041). The mean monthly Breteau index and mean monthly net trap index of Aedes mosquitoes during 2017 to 2019 were not significantly different from those during 2020 to 2022 (all P>0.05). The annual number of inbound passengers was positively correlated with the annual numbers of imported cases of dengue fever from 2017 to 2022 ( r=1.000, P=0.003). Conclusions The number of imported cases of dengue fever has decreased significantly after the implementation of quarantine management measures for inbound passengers in Hangzhou. However, there is still a risk of outbreak after lifting the management of inbound passengers.

Objective To analyze the surveillance data of intercepted medical vectors at Zhongshan Port from 2017 to 2022, and to summarize the law of intercepted medical vectors at Zhongshan Port, so as to provide the reference for the formulation of vector surveillance strategies at the port and prevention of the infectious diseases transmission. Methods Descriptive statistical method was used to analyze the species composition, number, origin, and transportation route of vectors intercepted from inbound cargoes at Zhongshan Port from 2017 to 2022. Results From 2017 to 2022, the vectors intercepted at Zhongshan Port involved 51 species of 5 categories: cockroaches, flies, mosquitoes, rodents, and midges. Among the intercepted cockroaches, Periplaneta americana, P. australasiae, Panchlora nivea, and Blattella germanica accounted for 36.48%, 28.36%, 17.64%, and 13.37% of the total number, respectively. Megaselia scalaris, Musca domestica, Mu. sorbens, and Calliphora vicina accounted for 26.14%, 25.00%, 12.50%, and 11.36% of the total number of intercepted flies, respectively. Culex pipiens quinquefasciatus, Aedes togoi, and Ae. albopictus accounted for 85.11%, 7.98%, and 3.72% of the total number of mosquitoes, respectively. Rattus tanezumi was the main rodent species. Culicoides peregrinus was the predominant midge species. The cockroaches were mainly from Guyana, and the flies and mosquitoes were mainly from Hong Kong, China. The vectors were mainly carried into China through raw wood logs, containers, and inbound ships for maintenance. Wood logs carried various organisms, among which cockroaches were most common, with a percentage of 48.41%. Conclusions The intercepted vectors were diverse in species and in the source of origin, and six species were intercepted for the first time across domestic ports, with no domestic distribution, indicating high risks of vector invasion and associated potential public health problem. It is of great significance to further strengthen the detection, identification, surveillance, and control of vectors at ports.

Objective To investigate a cluster epidemic of severe fever with thrombocytopenia syndrome (SFTS) in a county in western Hubei Province, China, so as to provide a basis for formulating prevention and control measures for SFTS. Methods Descriptive epidemiological methods were used to analyze the epidemiological characteristics of the epidemic combined with clinical and laboratory tests, and Fisher’s exact probability method was applied to compare differences in rates of first-episode cases, with a focus on the risk factors for possible transmission. Results There was 1 index case and 4 subsequent cases, with 2 males and 3 females and ages ranging from 54 to 86 years (median: 64 years). The latency period of subsequent cases was 5 to 13 days,with a mean latency period of 7.75 days. Four of the 7 close contacts who swabbed the body of the index case (exposed to the blood) developed the disease,with a significant difference in the prevalence rate between people with different ways of exposure ( P=0.003). Conclusions This is the first cluster epidemic of SFTS that is transmissible from human to human in the area. Relevant regulatory authorities should disseminate the knowledge of prevention and control of SFTS among the public and strengthen SFTS diagnosis and treatment training among the medical staff. Thus,disease transmission can be effectively controlled and the case fatality rate can be reduced.

Objective To investigate common pathogen infections in small mammals in Ningbo, Zhejiang Province, China, so as to provide a basis for the prevention and control of rodent-borne diseases. Methods From 2020 to 2022, small mammals were captured using the night cage-trapping method in Zhenhai District, Ninghai County, Cixi and Yuyao cities of Ningbo. The small mammals were identified by morphological method, and their livers, spleens, lungs, and kidneys samples were collected. Real-time fluorescent quantitative PCR (qPCR) or reverse transcription-qPCR (RT-qPCR) was used to detect four pathogens: Hantavirus, Dabie bandavirus (i.e., Severe fever with thrombocytopenia syndrome virus), Leptospira, and Orientia tsutsugamushi. The differences in pathogen positive rates in the small mammals between different species, sexes, habitats, districts (counties, cities), and years were compared using the χ ² test or Fisher’s exact test. Results A total of 668 small mammals were captured, of which Rattus norvegicus (24.70%) and Niviventer confucianus (23.65%) were dominant species. The overall positive rate of the four pathogens in the small mammals was 9.43%, of which Hantavirus (all Seoul virus) and Leptospira accounted for 2.84% and 6.89%, respectively. Coinfections with two viruses were found, with a coinfection rate of 0.30%. Neither Dabie bandavirus nor O. tsutsugamushi was detected. There were significant differences in the overall positive rate of pathogens in the small mammals between different species and between different habitats (all P<0.001), but not between different sexes, different years, and different districts (counties, cities) (all P>0.05). Among various small mammal species, the positive rate of Hantavirus was the highest in Mus musculus and in R. norvegicus (10.00% and 8.48%, respectively); the positive rate of Leptospira was the highest in R. losea (15.38%). In different habitats, the positive rate of Hantavirus in small mammals was the highest in key industries (10.84%); the positive rate of Leptospira was the highest in urban residential areas (11.76%). In different districts (counties, cities), the positive rate of Hantavirus in small mammals was the highest in Cixi (9.90%). The positive rates of Leptospira in small mammals in Yuyao and Ninghai were higher, at 10.00% and 9.12%, respectively. Conclusions Infections with pathogens such as Hantavirus and Leptospira in small mammals are found in Ningbo, which pose a potential threat to the health of the local population. Targeted prevention and control measures should be taken to reduce the risk of human infections.

Objective To identify whether the Aedes mosquitoes collected in Tumed Left Banner, Hohhot, the Inner Mongolia Autonomous Region, China in 2022 were Ae. albopictus. Methods Six suspected Ae. albopictus mosquitoes were captured in adult mosquito surveillance in August 2022. Their morphological features were characterized. Genomic DNA was extracted from three mosquitoes for amplification and sequencing of the mitochondrial cytochrome c oxidase subunitⅠ (COⅠ) gene and internal transcribed spacer 2 (ITS2) gene fragments. The sequencing results were aligned with those in GenBank, and a phylogenetic tree was constructed using the neighbor-joining method. Results The body color and foot characteristics of the collected Aedes mosquitoes were consistent with those of Ae. albopictus. The COⅠ and ITS2 alignment results showed the similarities to the sequences of Ae. albopictus were >99.00% and >90.00%, respectively. The phylogenetic tree based on the COⅠ and ITS2 sequences showed that they were all in the same branch as the known Ae. albopictus. Conclusions The Aedes mosquitoes captured in Hohhot in 2022 were morphologically and molecularly identified as Ae. albopictus, and this was the first time that Ae. albopictus was detected in the Inner Mongolia Autonomous Region.

Objective To explore the field efficacy of single application of S-methoprene against the dengue vector mosquitoes through a systematic literature search, and to put forward relevant suggestions. Methods The Web of Science, Embase, PubMed, CNKI, Wanfang Data, and VIP Chinese Science Journals Database were searched using keywords including dengue fever and S-methoprene for relevant literature between January, 1974 and January 1, 2023. Results Ten studies were finally included, of which eight were classified as efficacy studies and the remaining two investigated the effectiveness of S-methoprene in semi-field conditions. Screening studies showed that S-methoprene can provide excellent eclosion inhibition, when applied to larvae in target containers, but when used in urban or dengue endemic areas, there was limited evidence to suggest the effectiveness of S-methoprene alone. Conclusions S-methoprene can effectively reduce the number of immature Aedes mosquitoes in containers in a short term, but evidence is not enough to demonstrate that S-methoprene alone can control the dengue vector in a long term. It is necessary to further study the effectiveness of S-methoprene combined with other dengue vector control measures.

Marmota himalayana is an endemic species of the Qinghai-Tibet Plateau and an important part of its ecosystem, which plays a significant role in maintaining the ecological balance of the natural foci of plague. The distribution of marmots is influenced by environmental factors such as climate, soil, and vegetation, thereby determining the distribution and changes of natural plague foci and the risk of associated plague epizootics. In other words, the distribution of geographical landscape elements and the main host animals of plague play a decisive role in the distribution area of natural plague foci. Ecological research on M. himalayana has been widely reported. This paper reviews the research status in China and globally from the aspects of ecological, burrow, and habitat characteristics of M. himalayana, with the aim to improve the understanding of M. himalayana ecology and promote the application of ecology in plague prevention and control.

Japanese spotted fever (JSF) is a commonly neglected infectious disease,and misdiagnosis and treatment delay are pivotal determinants of adverse outcomes among JSF patients. This paper reviews the genetic and evolutionary characteristics, transmission routes, and hosts of the pathogen Rickettsia japonica as well as the epidemiology, clinical manifestations, laboratory examination, and response strategy of JSF. Although progress has been made in the epidemiological study of this deadly infectious disease in China,information on the nationwide distribution of JSF and tick vectors is lacking. It is necessary to strengthen epidemiological investigation of JSF and surveillance of the hosts and vectors across the country, so as to provide a basis for the prevention and control and clinical diagnosis of the disease.