Objective To investigate the seroprevalence of IgG antibodies among individuals with different characteristics 12 years after Dengue virus infection, so as to provide a scientific basis for the prevention of severe dengue fever. Methods In October 2021, serum samples were collected from symptomatic and asymptomatic cases in the 2009 dengue outbreak in Yiwu, Zhejiang Province, China. IgG antibodies to Dengue virus in the samples were measured using indirect enzyme-linked immunosorbent assay. The positive rates of IgG antibodies in populations with different characteristics were calculated and compared using the Chi-squared test. Multivariable logistic regression analysis was used to analyze the factors affecting the positive rate of the antibodies. R 4.2.1 was used for statistical analysis. Results A total of 123 samples were collected from individuals infected with Dengue virus in the outbreak, of which 101 samples were positive for dengue virus-specific IgG antibodies, with a positive rate of 82.11%. Among the investigated individuals, 57 were asymptomatic cases, with a positive rate of 64.91% (37/57), and 66 were symptomatic cases, with a positive rate of 96.97% (64/66). The positive rate of the symptomatic cases was significantly higher than that of the asymptomatic cases ( χ ²=21.401, P<0.001). There were 41 male and 82 female participants, with the positive rates being 85.37% (35/41) and 80.49% (66/82), respectively. Fourteen cases were ≤40 years old when they infected with Dengue virus in 2009, with 12 cases were positive; 58 cases were aged 41-60 years, with a positive rate of 81.03% (47/58); and 51 cases were ≥60 years old, with a positive rate of 82.35% (42/51). The logistic regression analysis showed a significant association between the type of infected individuals and the presence of the antibodies. The odds ratio of antibody positivity of symptomatic cases relative to asymptomatic cases was 17.30 (95% confidence interval: 3.83-78.21). Conclusions The positive rate of the IgG antibodies was still high 12 years after Dengue virus infection, which was significantly higher in symptomatic cases than in asymptomatic cases. Individuals with past Dengue virus infection have a high risk of being severe once they are re-infected.

Objective To investigate the epidemiological characteristics of dengue fever in Zhejiang province, China, from 2015 to 2019 and the different characteristics of imported cases and local cases, and to provide a scientific basis for accurate prevention and control of dengue fever in Zhejiang province. Methods The data of dengue fever cases in Zhejiang province from 2015 to 2019 were collected from the China Information System for Disease Control and Prevention, and SPSS 20.0 software was used to perform descriptive and statistical analyses of related data of imported cases and local cases, including sex, age, occupation, seasonal distribution, geographic distribution, and interval from disease onset to confirmed diagnosis. Results A total of 2 532 dengue fever cases were reported in Zhejiang province from 2015 to 2019, among which there were 961 imported cases and 1 571 local cases. Among the 2 532 patients, there were 1 424 male patients and 1 108 female patients, and the male/female ratio was 1.90:1 in imported cases and 1.02:1 in local cases; the composition ratio of male patients in imported cases was significantly higher than that in local cases ( χ ²=54.626, P<0.001). The median age of all cases was 44 years, with an inter-quartile range of 32-58 years; the median age was 37 years for imported cases and 50 years for local cases, and the imported cases had a significantly younger age than local cases ( Z=-15.681, P<0.001). The numbers of commercial service personnel, retired persons, workers, housekeeping and unemployed persons, farmers, and cadres were 474, 424, 352, 315, 287, and 214, respectively; commercial service personnel accounted for the highest proportion in imported cases, while retired persons accounted for the highest proportion in local cases; there was a significant difference in occupational distribution between imported cases and local cases ( χ ²=303.418, P<0.001). Imported cases were observed in each month, mainly June to October, and all local cases occurred in July to November. From 2015 to 2019, the number of counties (cities/districts) reporting dengue fever cases in Zhejiang province gradually increased year by year, and about 95.56% of the counties (cities/districts) reported dengue fever cases during the past 5 years, among which 48.89% reported local cases of dengue fever. Conclusion The epidemic situation of dengue fever in Zhejiang province becomes more severe year by year, and there are significant differences in sex, age, occupation, and disease onset between imported cases and local cases. Zhejiang province should adopt more precise and strict measures to reduce the epidemic risk of dengue fever according to epidemiological characteristics.

Objective To evaluate the effect of ultra-low-volume spraying using unmanned aerial vehicle (UAV) in mosquito control in urban residential areas, and to provide a basis for the prevention and control of mosquitoes and mosquito-borne diseases. Methods Two comparable residential areas (villages) were selected in Pujiang county, Zhejiang province, China, from July 15 to 27, 2017. One area applied UAV-based ultra-low-volume spraying to kill mosquitoes for five rounds with an interval of three days, while the other area served as a control. Adult mosquito density surveillance by mosquito trap lamps for the two areas started three days before UAV spraying and continued till 15 days after five rounds of spraying. The changes in mosquito density were compared between the two areas for evaluating the mosquito-killing effect of UAV spraying. The decline rate of mosquito density was calculated based on the mean value of every three days. Results After the first round of UAV spraying, in the spraying area, the number of female mosquitoes decreased by 41.71%, male mosquitoes by 4.12%, and total mosquitoes by 27.10%. Fifteen days after five rounds of UAV spraying, the number of female mosquitoes, male mosquitoes, and total mosquitoes declined by 44.34%, 20.96%, and 35.69%, respectively. Conclusion Ultra-low-volume spraying by UAV is an effective method to kill mosquitoes in urban residential areas, and will be widely used control of mosquito-borne diseases as technology develops.

Objective To identify a newly recorded species discovered in tick surveillance in Zhejiang province, China, 2018. Methods Ticks were collected from grasses, shrubs, and the body surface of domestic animals in Jiaojiang district, Anji county, and Pujiang county of Zhejiang province, China. Morphological identification was conducted, followed by amplification of the mitochondrial 16S rRNA and cytochrome coxidase I (COⅠ) genes by PCR. After sequencing, homology analyses were performed. Results In 2018, 13 male ticks, a newly recorded species captured in Zhejiang province, were morphologically identified as Haemaphysalis flava Neumann (1897). The mitochondrial 16S rRNA gene of this tick displayed 100% identity to the known fragment of that gene of H. flava (Henan, KX450282.1); in comparison with other Haemaphysalis, the homology was 86.9%-92.2% and the divergence was 8.2%-14.7%. The mitochondrial COⅠgene of this tick showed 99.8% identity to the known COⅠ gene fragment of H. flava (Hunan, KJ195464.1); in comparison with other Haemaphysalis, the homology was 84.7%-90.7% and the divergence was 10.0%-17.2%. Conclusion The combination of morphological and molecular biological identification methods can accurately identify the species of ticks.

Objective To investigate the epidemic situation of hemorrhagic fever with renal syndrome (HFRS) and the surveillance data of host animals in Tiantai county of Zhejiang province, China, and to understand the epidemiological characteristics and changing trend of HFRS. Methods Case surveillance data were collected; the case data in 1984-2003 were collected from the epidemic data archives of Tiantai county, and the case data in 2004-2018 were collected from the China Information System for Disease Control and Prevention. As a national surveillance site, Tiantai county carried out host surveillance and data collection according to national requirements. Excel 2010 and SPSS 17.0 softwares were used to perform a descriptive epidemiological analysis of HFRS epidemic data and surveillance data of host animals, and ArcGIS 10.0 software was used to draw the disease map of townships. Results A total of 6 223 HFRS cases were reported in Tiantai county in 1984-2018, with a mean annual incidence rate of 32.36/100 000; the peak of HFRS epidemic was observed in 1986, with an incidence rate of 206.10/100 000, and then the incidence rate of HFRS decreased rapidly; the incidence rate of HFRS remained at a low level in 2001-2018, with a mean annual incidence rate of 7.01/100 000. The onset seasons of HFRS showed two peaks, with a peak in November to next January (44.08%, 2 743/6 223) and a small epidemic peak in April to June (1 369/6 223, 22.00%). Surveillance data showed that 90.92% (5 658/6 223) of the cases were distributed in 8 plain townships/streets at the Shifeng River Coast of Tiantai county. Most patients were male young adults, and the male/female ratio was 1.66:1 (3 884/2 339). Most patients were farmers (5 553/6 223, 89.23%). The mean density of rodents was 8.87% in 1984-2018, and the mean proportion of virus-carrying rodents was 4.49%. Conclusion The overall incidence rate of HFRS tends to decrease in Tiantai county and maintains at a low level in recent years, and the cases are widely but unevenly distributed and have obvious regional characteristics. Tiantai county is a mixed HFRS epidemic area with Apodemus as the main type of host animal, and there are still high rodent density and virus-carrying rate.

Objective To investigate the seroprevalence of immunoglobulin G (IgG) antibodies in dengue cases nine years after being infected with dengue virus and associated factors, and to provide a scientific basis for dengue prevention and control. Methods A seroprevalence survey was conducted on dengue cases from a dengue outbreak (dengue virus-3) in Yiwu, Zhejiang province, China, 2009. Serum samples were collected from them from May to August, 2018 for dengue virus IgG antibody detection by ELISA. The distribution of dengue virus IgG antibodies in the serum samples was calculated, and associated factors for positive dengue virus IgG antibodies were analyzed. Results A total of 126 serum samples from dengue cases were collected and the mean seroprevalence of dengue virus IgG antibodies was 79.37% (100/126). The seroprevalence of males and females was 75.00% (30/40) and 81.40% (70/86), respectively, showing no significant difference ( χ ²=0.682, P=0.409). The seroprevalence in the groups aged 1-, 21-, 41-, and ≥ 61 years were 100%, 94.12%, 85.42%, and 67.86%, respectively; there was a significant difference in the seroprevalence of dengue virus IgG antibodies between the four groups ( χ ²=9.161, P=0.027). The seroprevalence of dengue virus IgG antibodies in apparent infection cases was significantly higher than that in inapparent infection cases (89.11% vs 40.00%, χ ²=29.511, P=0.000). Conclusion Dengue virus IgG antibodies are detectable in dengue cases nine years after infection. The seroprevalence of dengue virus IgG antibodies in apparent cases is significantly higher than that in inapparent cases.

Objective To compare the epidemiological characteristics of indigenous dengue cases in the high-risk areas of Guangdong and Yunnan provinces, China. Methods The data of dengue cases from 2005 to 2017 were collected, which included the present address, sex, age, occupation, time of onset, time of diagnosis, and whether the cases were imported or not. Statistical analysis was performed using SPSS 20.0 and R 3.5.0. Results From 2005 to 2017, there were 44 676 and 3 676 indigenous dengue cases in the high-risk areas of Guangdong and Yunnan provinces, respectively. The two study regions were significantly different in the occupation, age, sex, and interval from onset to diagnosis for indigenous dengue cases ( χ ²=989.647, P=0.000; χ ²=98.666, P=0.000; χ ²=7.429, P=0.006; U=5.360, P=0.000). Besides, the indigenous dengue cases were mainly household and unemployed workers in the high-risk areas of Guangdong province and commercial service workers in Yunnan province. The indigenous dengue cases were widely distributed in all ages in the high-risk areas of Guangdong province, but concentrated in young adults in Yunnan province. The male proportion of dengue cases in the high-risk areas of Guangdong province was lower than that in Yunnan province. Conclusion The numbers of indigenous dengue cases in Guangdong and Yunnan provinces rose from 2005 to 2017, and there was a significant difference in their epidemiological characteristics between the two provinces.

Objective To investigate and evaluate the constructive process and effect of vector control which based on the construction of "mosquito-free village" in Xuexiazhuang village, Pujiang, Zhejiang province, and then to provide experience for mosquito control in rural areas. Methods The adult and larval densities were monitored with lamp traps and 100-household index respectively from April to October in each year from 2016 to 2017. A random sampling method was adopted to select 50 households in pilot and control villages from which one family member was surveyed. The face-to-face questionnaire was about the anti-mosquito related knowledge, attitude and behaviors. Examination and evaluation of construction mode of "mosquito-free village" was deeply explored via the method of interview, data review, on-site observation. Results Monitoring results of Xuexiazhuang village from April to October 2017 showed that the adult mosquito density was 0.50, 0.50, 0, 0, 0.75, 0, 0 individual per lamp trap per night, respectively, and the 100-household index was 18.00, 4.00, 4.00, 2.00, 0, 2.00, 2.00. The awareness rates of anti-mosquito and correct behavior formation reached 82.80%, higher than that in the control village (67.80%). The construction of "mosquito-free village" is much more institutionalized and standardized than before, and the long-term mechanism has been formed. Conclusion The mode of rural mosquito control based on "mosquito-free village" can effectively reduce the density of mosquitoes. Formation of institutionalized, standardized long-term mechanism of "mosquito-free village" construction work may provide reference for a much more scientific, effective, low cost and sustainable development of vector control in rural areas in the future.

Objective To explore the establishment of a set of construction standard and evaluation index for "mosquito-free village" in rural areas. Methods Mosquito control technology and management were applied to pilot village from the principles of green, economic, sustainable, and long-term management mechanism, and a set of "mosquito-free village" construction standard and evaluation index were summarized from this practice. Results "Mosquito-free village" construction standard contains technical requirements mainly on environmental renovation and management, the evaluation is based on organization and management, the density of mosquitoes and the villagers-health education effect, which limits the sampling principle. Conclusion The standard is feasible in rural practice, and provides reference basis for the integrated mosquito control in rural areas.

Objective To analyze intervals between illness onset and confirmation of severe fever with thrombocytopenia syndrome (SFTS) cases and related factors which will provide scientific information for its precise control and prevention. Methods Data on SFTS cases from 2011 to 2016 were obtained from China Information System for Diseases Control and Prevention. The intervals from illness onset to confirmation of SFTS cases in different genders, age groups, occupations, seasons, and provinces were summarized and compared using SPSS 20.0 software. Results A total of 5 360 SFTS cases were reported in China from 2011 to 2016 and the median interval from illness onset to confirmation of these cases was 9 d. Intervals from illness onset to confirmation of SFTS cases were significantly different from year to year and the maximum median of the interval of SFTS in 2014. Intervals between illness onset and confirmation of SFTS cases from different provinces were also significantly different, the intervals of Hubei province were the longest and the intervals of Zhejiang province were the shortest. Conclusion Although there were differences in the intervals of SFTS cases from different years, provinces and individual cases, the intervals were nevertheless very long. Appropriate interventions should be implemented to shorten the intervals for the control and prevention of SFTS.

Hematophagous arthropods are important vectors for vector-borne diseases. The identification of hematophagous arthropods'hosts is critical to exploration of vector-borne disease ecology and further control measures. The strategy of bloodmeal identification is effective to ascertain arthropod hosts. With the development of molecular biology technology, DNA-based methods, which include PCR, DNA sequencing, restriction fragment length polymorphism, reverse line blot hybridization, and DNA fingerprinting, enhanced the specificity and sensitivity of hematophagous arthropod bloodmeal identification greatly. This paper reviewed the principles, advantages and disadvantages of molecular protocols for detection of host DNA, which might help to provide reference for the prevention and control of related vector-borne diseases.

Objective To investigate the brucellosis infection and risk factors among occupational populations in Zhejiang province, and to provide scientific basis for preventive measures. Methods Occupational populations engaged in cultivation, transportation, trading, veterinarian services, fur making, marine fishing from October 2015 to March 2016 were selected for study. Rose bengal plate test (RBPT) and Serum agglutination test (SAT) were used for serological test. A case-control study was conducted to analyze the risk factors through logistic regression analysis. Results Among all 3 410 respondents, 105 were infected with brucellosis, with the infection rate of 3.08%. The difference of infection rate between male (3.10%) and female (3.02%) had no statistical significance ( χ ²=0.010, P=0.970). Multivariate logistic regression analysis showed that no wearing gloves and hand wound were found to be associated with the incidence of brucellosis. Conclusion Risk factors for the incidence of brucellosis in Zhejiang province were no wearing gloves and hand wound. Health education and intervention should be strengthened to improve the protection and awareness of brucellosis in occupational populations.

Objective To retrospectively analyze the hemorrhagic fever with renal syndrome (HFRS) epidemics using SaTScan software in Zhejiang province, 2010-2014, providing a scientific evidences for establishing further prevention and control measures. Methods The cases of HFRS and county boundary map were collected from the Chinese Center for Disease Control and Prevention. The descriptive epidemiological method was used to conduct the three dimensional statistical analysis by SPSS 17.0 software, and the SaTScan 9.1.1 software was used to complete space-time scan. The results of exhibition were visualized using ArcMap 10.2 software. Results The pure spatial scan detected one primary cluster(Lishui), the log likelihood ratio was 85.16 ( P<0.01); and 8 secondary clusters (Quzhou) ( P<0.01). The pure time scan cluster was in 2014 (November-December). The space-time scan detected one primary cluster (Lishui) and one secondary cluster (Quzhou). Conclusion The epidemic of HFRS of Zhejiang province in 2010-2014 was relatively stable, but in some areas still had risk of outbreak. Prevention measures should be taken to control the epidemic situation.

Objective Analyze and evaluate the economic burden of rabies exposure population in Zhejiang province, so as to provide a quantitative basis for health administrative departments to develop disease prevention strategies. Methods Literature retrieval and questionnaire collection were used to get the general features of the 1 471 cases of dog hurt exposure in dog hurt outpatient service from February to May, 2012. The direct medical costs, the direct medical costs and delays indirect economic burden were analyzed. Through DALY and human resources to estimate the dog hurt exposed economic burden. Results Median direct medical costs was RMB 220.42 Yuan, and the direct non-medical costs was RMB 16.24 Yuan, which transportation costs accounted 76.10% was the highest. The indirect economic burden due to the loss caused by per capita was RMB 135.96 Yuan, and particularly 72.73% of all was the families delay loss. In Zhejiang province total population, the indirect economic burden of post-exposure of rabies was RMB 77 487 000 Yuan (Delay work loss). According to the weight of different age groups, calculated the Zhejiang rabies death all the population average indirect economic burden for RMB 15 767 614.70 Yuan, which 45-60 years (46.51%) and 15-45 years (46.43%) old group were the highest percentage. Economic burden of post-exposure of rabies in Zhejiang province was RMB 400.34 Yuan per capita, of which the direct medical cost of total economic burden ratio of 59.12%, followed by the indirect economic burden caused by delays, accounted for 33.97%. If the grade Ⅲ exposures to accept human rabies immunoglobulin, so will the economic burden for the 4%-20%. Economic burden was overwhelmed. Conclusion Transportation accounts for direct and has the highest percentage of medical costs, should be reasonable to layout dog injury outpatient services, which location and quantity should satisfy a range of services. The family cost (direct economic costs and delays indirect economic burden) was higher than the social cost (death indirect economic burden). Direct economic burden, especially direct medical costs was the main source of the economic burden of post-exposure of rabies. The government should formulate relevant policies to help low-income people in cost, improve the clinic proportion, improve grade Ⅲ exposure rate of immunoglobulin injections.

Objective To analyze the impact of rodent density on the incidence of hemorrhagic fever with renal syndrome (HFRS) in Zhejiang province, and to provide background for the prevention and control of the rodent-borne diseases. Methods The monitoring data of rodent density and the incidence of HFRS were collected from January 2005 to December 2014 in Zhejiang province. Spearman correlation analysis and linear regression method were applied for data analysis. Results The average density of rodents in the last decade was 0.88% in Zhejiang province, and the Rattus norvegicus was the predominant species which accounting for 51.16% of the total number. There was correlation with the rodent density and the incidence of HFRS lagging one month to four months, and the correlation coefficients were 0.247, 0.369, 0.328, and 0.213 respectively (P < 0.05). The linear regression found that the rodent density was significantly associated with the incidence of HFRS lagging one month to four months (R²=0.106, 0.167, 0.134, and 0.067, P < 0.05). Every 1% increase in the rodent density, followed by 0.326, 0.409, 0.367 and 0.258 (/100 000) increase in the HFRS incidence lagging one month to four months respectively. Conclusion Rodent density has certain influence on the incidence of HFRS in Zhejiang province. The density monitoring and rodent control should be carried out on a routine basis.

Objective To understand the epidemic characteristics of endemic typhus nearly 10 years in Zhejiang province, and provide a scientific basis for prevention and control. Methods Through the National Disease Reporting Information system, typhus cases data were collected in Zhejiang province from 2005 to 2014, analyzed by descriptive epidemiological methods. Results In total 39 typhus cases were reported in Zhejiang province from 2005 to 2014, the average annual incidence rate was 0.0086/100000. The incidence of the high risk season was June to September, and the cases were distributed in 6 cities, 18 counties (districts), and mainly in rural areas (87.18%). The male to female ratio was (1.05:1), the median age was 47 years old. The average time of clinical diagnosis and laboratory diagnosis were 10.0 d and 14.5 d, two diagnosis regimens of occupational distribution had statistically significant difference (χ²=7.257, P=0.006); gender constitute no statistical difference (χ²=1.293, P=0.256). Conclusion The key area of prevention and control typhus were rural and rural-urban fringe zone of Zhejiang province, health education in tourists and enhanced detection are warranted and improve the ability to detect.

Objective To get epidemiological data on plague hosts and vectors in the history of plague epidemic in Zhejiang province, and providing scientific basis for the prevention and control in the province. Methods The rodents were captured in the 20 surveillance sites in the province by trapping, then calculated the rodent density, flea index, flea infected rates, SPSS 17.0 software was applied for statistical analysis of the data; The animal livers and spleens were collected for Yersinia pestis culture and used for indirect hemagglutination assay (IHA) detection F1 antibody of Y. pestis. Results The average indoor and outdoor rodent was 4.19% and 4.47%, there is a considerable difference between the rat density in different regions. The capture was 50 680 rodents, belong to 3 orders, 5 families, 9 genera and 16 species (Subfamily). There were 32 482 rodents and 1062 that were processed. Average flea infected rate was 3.27%, the flea infected rate were different among species, with statistical significance (χ²=3723.567, P=0.000). The fleas are 7 species from 3 genera and 3 families, among different areas there were significant differences (F=5.659, P=0.000). No plague were cultured or detected in 46 881 rodent samples and 49 327 serum samples. Conclusion The composition of plague hosts and vectors is stable, no mouse and human plague epidemic, however plague surveillance standardize should strengthen to be prepared for emergency and plague resurgence.

Objective To investigate the distribution, species, and seasonality of ticks and rodents and detection of severe fever with thrombocytopenia syndrome virus (SFTSV) in vectors and hosts. Methods In seven counties of Zhejiang province, the free ranging ticks were collected by flagging and the parasitic ticks were collected from the host skin by hand searching on a 3-month basis of 2013. Rodents were captured by squirrelcage method. The specimens of liver and spleen were collected with sterile operations. The SFTSV nucleic acid in the viscera of rodents and in the ticks were detected by fluorescence quantitative RT-PCR. Results A total of 751 ticks were collected, consisting of 2 families, 5 geniuses and 6 species, including 439(58.5%) Haemaphysalis longicornis, which were the predominant species in Zhejiang province. The ticks species distribution varied in different counties in Zhejiang province (χ²=1198.409, P < 0.05). Ticks were active from March to October and the peak was in the second 3-month of the year. The total number of captured rodents was 1078, the rodentia belonged to 13 species in 7 genera in 3 families. The insectivora belonged to 2 species in 2 genera of 2 families. The predominant captures were 355(32.9% ) of Apodemus agrarius and 326(30.2% ) of Eothenomys melanogaster. The distribution of the rodent species also varied in different counties in Zhejiang province (χ²=1623.480, P < 0.05). The results were negative in RNA detection of SFTSV in the specimens of ticks and rodents by RT-PCR. Conclusion The vectors and the host animals of SFTSV were found in Zhejiang province. But the vectors and the possible hosts need further studies.

Severe fever with thrombocytopenia syndrome (SFTS) is caused by a newly discovered bunyavirus, which is an emerging infectious disease often leading high mortality. New cases have been reported from more than 10 provinces across China since 2010. This article reviews the most recent advances on the epidemiological characteristics, the hosts and vectors, transmission route, and risk factors for the disease.

Objective To analyze the epidemiologic characteristics and disposal of the events of multi-victim bitted by one dog in Zhejiang province, and provide the basis for the control and prevention of rabies. Methods The investigation report of the event of multi-victim bitted by one dog in Zhejiang province during 2011-2013 were collected for statistical analysis. Results Fifty-five events of multi-victim bitted by one dog had been reported in Zhejiang province during 2011-2013, and most occurred on the midwest of the province. The positive rate of rabies virus in dog of those events was 85.00%. 352 persons were exposed in those events and farmers were the most frequently reported victim. The inoculation rates of rabies vaccine and rabies immune globulin were 95.73% and 80.63%, respectively. Two victims died from rabies as none post-exposure prophylaxis was received, and the incidence rate was 0.57%. Conclusion The exposed people in the events of multi-victim bitted by one dog are in high risk of rabies, and surveillance, health education and post-exposure prophylaxis should be strengthened.

Objective To analyze the epidemic situation of hemorrhagic fever with renal syndrome (HFRS) and the population distribution and virus-carrying status of the hosts in Zhejiang province, China, in 2013, and to provide scientific evidences for establishing further prevention and control measures. Methods The descriptive epidemiological method was used to analyze the three-dimensional (time, region, and population) distribution of HFRS. Rodents were captured by night trapping in five HFRS monitoring points in Zhejiang province. Lung and serum samples were collected followed by detection of hantavirus antigen and antibody using an immunofluorescence assay, and the rodent population distribution and virus-carrying status in Zhejiang province were analyzed. Results A total of 527 HFRS cases were reported in 2013 in Zhejiang province. The incidence rate was 0.9622/100 000, resulting in a 3.89% increase compared with 2012, and no death was reported. The cases were mostly seen in five cities (Ningbo, Taizhou, Shaoxing, Quzhou and Lishui), and all the prefectural level cities had cases reported except Zhoushan. There were two peaks of incidence, one in spring (May-June) and the other in winter (around December). The high-risk age group of HFRS was between 20 and 65 years, accounting for 93.17% of the overall incidence rate (491/527). A total of 13 785 effective traps were set in the five monitoring points, and 546 rodents were captured, so the average density of rodents was 3.96%. A total of 678 rodent serum samples were collected and 80 were positive (positive rate: 11.80%). A total of 669 lung samples were collected and 44 were positive (positive rate: 6.58%). There were significant differences in the positive rate of HFRS antibody and the virus-carrying rate between the five HFRS monitoring points (χ²=30.962, P<0.05 and χ²=9.83, P<0.05, respectively). Conclusion The incidence of HFRS in Zhejiang province in 2013 is on a rising trend compared with that in 2012, and the density of host animals and virus-carrying rate are both higher. Preventive measures should be taken into consideration to control the epidemic situation.

Objective To investigate the status of infection with Bartonella in domestic and feral cats in Beijing, China. Methods EDTA-anticoagulated blood and serum samples were collected from cats, and the relevant epidemiological information was recorded. The anticoagulated blood was diluted 1:4 in sterilized tryptic soy broth and a 100 μl aliquot was inoculated onto the brain-heart infusion agar supplemented with 5% defibrinated sheep blood followed by culturing in a 5% CO₂ incubator at 37 ℃ for 45 days. Bartonella-like isolates from the culture were examined by PCR analysis using the primers for gltA, ftsZ, and ribC. The PCR products were sequenced, and homologous comparison and phylogenetic analysis were performed to identify the species of Bartonella. Indirect immunofluorescence assay was carried out to measure the titer of anti-Bartonella henselae IIFT (IgG) in the serum samples. Data obtained from the experiments and the epidemiological information collected in the field were analyzed by the SPSS 13.0 software. Results The positive rate for Bartonella culture isolates was 13.8% in the cats tested in Beijing, and all the 22 strains obtained were B. henselae. The seropositivity rate for anti-B. henselae IgG was 39.4%. The feral cats, flea-infested cats, and kittens had significantly higher positive rates for Bartonella isolates (30.4%, 36.6%, and 27.9%, respectively). The seropositivity rate for anti-B. henselae IgG in flea-infested cats (61.0%) was also significantly higher than that in uninfested cats (31.9%). Conclusion Bartonella infection is common in both domestic and feral cats in Beijing, and the species is identified to be human pathogen B. henselae. Bartonella infection in humans could be avoided by flea control and preventing flea infestation in domestic cats, and strengthening the control of feral cats.

Objective To assess the progress and issues of the development of dog bite injury clinics since the Zhejiang Accreditation Standards for Dog Bite Injury Clinics (Tentative) (Zhejiang provincial Department of Public Health [2010] No. 50) was inaugurated, and to further improve the relevant standards for the development of dog bite injury clinics. Methods The assessment plan and questionnaire were developed, and trained staff conducted field survey of all dog bite injury clinics in Zhejiang province. A database was established using EpiData 3.0, and data analysis was performed using Excel. Results In 2011, there were 703 dog bite injury clinics in Zhejiang province; of these dog bite injury clinics, 79.23% were located in township health centers, 26.46% were operated independently, 68.71% provided full services, 9.39% had a facility smaller than 15 m², 39.12% had no cold and hot water supplies, 8.96% had no wound irrigation devices, and 3.27% had no availability of first-aid supplies. There were 7 medical workers on average in each dog bite injury clinic, and 5.85% of all clinics had no medical staff on holidays and during night. Conclusion Compared with the situation in 2008, the standardized development of dog bite injury clinics in Zhejiang province was improved overall in 2011, but with great variations among different regions. Further study is warranted to improve the access to health services after dog bite injury, and the location, number, and configuration of dog bite injury facilities should be reconsidered.

Objective To investigate the current situation of surveillance and study on the tick-borne diseases in Zhejiang province, China. Methods By literature research and surveillance data analysis, brief descriptive statistic analysis was performed on the literature and annual surveillance data on the tick-borne diseases in Zhejiang that have been published since 2000. Results Through ten years surveillance and study involving serological and molecular biological methods, more than 10 tick-borne diseases or pathogens, including Lyme disease, Anaplasma phagocytophilum, Ehrlichia chaffeensis, spotted fever, Bartonella, Rickettsia mooseri, and Boehner kirk austenite, were confirmed to exist in Zhejiang. Besides, the various tick species and tick-borne diseases were found in as many as 23 counties (county-level cities, districts) in Hangzhou, Jinhua, Lishui, Taizhou, Huzhou, Wenzhou, Quzhou, and Shaoxing in Zhejiang. Conclusion The ticks and tick-borne diseases diversified and widespread in Zhejiang province. Although some achievements have been made in the surveillance and study on tick-borne diseases, the surveillance is neither sufficient nor systematic since lack of proper planning. The related information cannot be fully integrated and utilized for risk assessment and early-warning. It is necessary to establish a platform for tick-borne disease surveillance.

Objective To establish an effective model for monitoring and predicting the incidence trend of hemorrhagic fever with renal syndrome(HFRS)in Zhejiang province. Methods HFRS data from 2001 to 2009 in Zhejiang province were used to establish the GM(1,1)-Generalized regression neural network［GM(1,1)-GRNN］model. The GM(1,1)-GRNN model was used to predict the incidence trend of HFRS of the years 2010 to 2011. Results The predicted HFRS incidence with the GM(1,1)-GRNN model for the years 2001 to 2010 closely followed the observe value of the same years, with a relative error of 2.47%, more precise than that of GM(1,1) (11.19%). The forecast values for 2011 was 0.8591 per 10 ⁵ population. Conclusion The GM(1,1)-GRNN model is highly precise in the prediction of the incidence of HFRS. It provides reliable accurate predicative data, contributing to decision-making regarding the control and prevention of the disease.

Objective To summarize the epidemiological characteristics of human rabies according to the surveillance data on rabies in Zhejiang province from 2008 to 2010, and explore the existing problems and the countermeasures. Methods The surveillance data on human rabies from the clinics and the epidemiological characteristics of individual cases in Zhejiang from 2008 to 2010 were collected for descriptive analysis. Results It was found that the incidence of rabies decreased from 2008 to 2010 year by year. The epidemic was spread to the central and western regions of Zhejiang, with the incidence rising in Quzhou and Jinhua. The peak incidence of rabies was seen in summer and autumn, with a second peak in early winter in some areas. Farmer, migrant workers and students were frequently affected. The sex ratio of the cases in the 3 years was 3.2∶1, 2.1∶1 and 2.1∶1, respectively. The number was highest in the age group of 55-70 years, accounting for 39.7%. Dogs were the principal reservoir of the 94 cases from 2008 to 2010. The incubation period was 85 d, with the period for the majority of the cases (35.11%) being between 2 months and half a year. The vast majority of cases after exposure did not receive any treatment (62.77%). Some of the cases after exposure were managed only with simple disinfection or flushing (25.53%). There were only 8.5% of the cases who received vaccination after exposure, of which only 1 case (1.06%) got full immunization with rabies vaccine. 67.02% of all the cases were classified as grade Ⅲ exposure and only one of them (1.06%) was administrated rabies immunoglobulin (RIG) or anti-serum. Conclusion It needs to change the target population of health education about rabies and the focus of control. Training of primary care staff should be strengthened in terms of knowledge related to rabies control, especially the interventions of wound management and infiltration of passive immunity preparations.

Objective To establish a mce gene-based PCR detection method for the analysis of mce gene conservation of Leptospira interrogans and its bioinformatics. Methods The NCBI/Blast and NCBI/Cds online database was used for the search of the conserved functional domain in the mce gene and its specificity, with TMHMM Server-2.0 employed for the prediction of the transmernbrane regions of the encoded protein. The segments of entire mce gene from L. interrogans strain lai were amplified by PCR and then sequenced, with the sequence of cloned mce gene compared with the reported sequence of mce gene (GenBank accession No.: NP_712236) by DNAStar. The genome DNAs from the 13 prevalent strains of L. interrogans in China were used as the templates for the validation of the mce gene-based PCR detection method. A comparative analysis of the amplified mce gene products from different strains was also accomplished based on their sequences and a phylogenetic tree was generated from the presumed sequences of amino acids. Results The results of bioinformatic analysis showed that there was a mce super family conservation functional domain that was associated with adhesion and invasion of pathogens in the mce gene from L. interrogans. It was clear that there was a L. interrogans transmembrane structure in mce. High homology sequences of mce gene were present in L. interrogans, with the similarities of nucleotide sequences of mce gene from different L. interrogans strains more than 95%. Conclusion The mce gene with conservation specifically exists in different pathogenic L. interrogans strains, and it has a transmembrane structure and a super family functional domain that is associated with L. interrogans adhering to and invading their host cells.