ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Under long?term insecticide selection pressure, mosquitoes have evolved in various physiological aspects to become resistant to chemical insecticides, bringing difficulties in the control of diseases transmitted by mosquitoes. In this study we demonstrate the main molecular mechanisms of insecticide resistance and the fitness cost of the relevant resistance genes, and review both Chinese and international strategies for control of mosquito?borne diseases for providing guidance of prevention and control of mosquitoes and vectors in China.
Disease vectors are basically organisms that transmit pathogens of various diseases. Shanghai World Expo is to be held during the peak period of disease vectors. Therefore, to reduce densities of disease vectors and lessen the threat of vector?borne diseases has become an important part of public health protection during the Expo. An expert consultation was convened to elaborate issues on the control of disease vectors throughout the Expo, and expert advice was adopted by relevant departments. In view of this, inspection of disease vectors in various industries of the city is further strengthened; technical documents of control measures applicable for the Expo are developed, and emergency response training and drills are improved for the professional and technical personnel of vector control. As a result, a solid foundation has been laid for public health protection, particularly the control of vectors, during the Expo.
Objective To monitor changes in population densities of disease vectors in the earthquake?stricken areas, providing evidence for the control and management of insect?borne diseases, natural?focus diseases and zoonoses. Methods Densities of mosquitoes, flies and rats were monitored on a weekly basis at the relocated settlements and their surroundings in the earthquake?stricken Beichuan county, Pingwu county, An county and Jiangyou city from June 13 to October 31, 2008. The densities of mosquitoes and flies were visually determined; populations of rats were monitored using the trace method. Questionnaire survey was conducted on the effectiveness of the control of disease vector. Results The average density of mosquitoes was 4.60/man?hour, an increase of 265.08% compared to that before the earthquake (1.26/man?hour). The average density of rats was 0.74 nests/2000 m, an increase of 131.25% compared that in history (0.32 nests/2000 m). The average density of flies was 0.35/m2, a decrease of 85.83% compared to that before the earthquake (2.47/m2). Conclusion Various measures for eliminating four pests in earthquake?stricken areas have been implemented. Elimination of breeding grounds and implementation of vector control programs are effective measures to control disease vectors.
Objective Microsatellite DNA molecular markers were used in the present study to identify the genetic diversity of Anopheles dirus sensu lato in China. Methods Molecularly identified, An. dirus (laboratory strains in Hainan province and wild population from Maoyang, Hainan) and species D of An. dirus (wild populations from Jiangcheng and Mengla, Yunnan province) constituted the samples, of which ten polymorphic microsatellite DNA loci were amplified and calculation of relevant index were performed using Arlequin software. Results The amplification of microsatellite loci for 89 samples of An. dirus s.l. revealed a range of alleles from 1 to 32, with an average of 3.60-25.20. Not all microsatellite loci in each populations demonstrated polymorphism. The average expected heterozygosity and the observed heterozygosity were 0.49-0.72 and 0.36-0.58, respectively, being the lowest in Hainan province. The FST value between paired populations was negative or very small, suggesting that genetic differentiation did not occur among the populations. Hierarchical AMOVA calculations showed that the intrapopulatim variation of An. dirus s.l. amounted to 103.29% of the total variation, the intraspecific variation negative (-3.97%), and the interspecific variation accounted for only 0.67% of the total variance. Conclusion The intra- and interspecific genetic differences of An. dirus s.s. and An. dirus species D were trivial, microsatellite DNA variations mostly present in individuals.
Objective To determine the oviposition responses of Anopheles sinensis to bacteria A4 (unidentified), Aeromonas sp. and Enterobacter sp. and whether or not the three strains attracted the mosquitoes, providing theoretical and experimental evidence for the application of the three bacteria in the intervention of malaria. Methods Blood?fed and held for 48-60 h, copulated female An. sinensis were placed into cages with filter?paper oviposition cups that contained different bacteria in darkness for 12 h egg laying. The numbers of eggs in the oviposition cups counted, the difference was analyzed using paired t?test. Results Gravid An. sinensis laid the most eggs in the oviposition cups containing Enterobacter sp. The numbers in those containing bacteria A4 and Aeromonas sp. were significantly lower than those in the control cups and those containing Enterobacter sp., with the P values of 0.026, 0.012, 0.048 and 0.016, respectively. Despite slightly greater number of eggs in the oviposition cups of Enterobacter sp. compared to the control group, there was no noticeable difference between the two (P＞0.05). Conclusion Gravid An. sinensis demonstrated significant negative taxis towards bacteria A4 and Aeromonas sp., as well as slight taxis to Enterobacter sp., implying that the three bacteria were not the dietary preference for An. sinensis. However, in light of the possibility of their stable colonization into mosquito’s guts, these strains may serve as the host cells of larvicide genes and transgenic anopheline antimalarial genes.
Objective To determine the composition of mosquito species in northern Burma and provide preliminary observations on the diversity of these species. Methods From August to September in 2008, CDC mosquito light traps were used in four settlements in the region close to the Chinese border, and captured mosquitoes were classified and counted and the data were analyzed. Results A total of 2268 mosquitoes of 45 species, 17 sub?genera, 8 genera, 2 sub?families were captured in human resident houses, as well as 1703 ones of 33 species, 12 sub?genera, 7 genera, 2 sub?families in cattle breeding rooms. The dominant species and corresponding dominance in human houses were Anopheles minimus (58.16), An. kochi (46.27), Culex pseudovishnui (45.68), Cx. tritaeniorhynchus (41.97) and An. jeyporiensis (40.18); and those in cattle shelters were An. kochi (34.37), Cx. tritaeniorhynchus (34.30), An. minimus (29.13) and An. splendidus (27.68). The diversity index and evenness indices were 2.61 and 1.58 versus 2.68 and 0.48 in human houses and cattle houses, respectively. Conclusion The dominant species, An. minimus, was the major vector in local human houses, with significantly higher in numbers than in cattle shelters.
【Abstract】 Objective To determine the lethal feeding period (LFP) of 0.0025% Chlorophacinone baits in Meriones unguiculatus. Methods A LFP?resistance?based detection method developed by the EPPO (European and Mediterranean Plant Protection Organization) was adopted. Results The minimum lethal dose was 6.3510 mg/kg for M. unguiculatus, the highest survival dose 13.0230 mg/kg. Statistically significant differences were observed in the feeding period and its corresponding mortalities between male and female groups (P＝0.036), the Probit model (feeding period versus mortality) being Probit (p)＝-2.651 95＋0.798 17x (P＝0.901), and Probit(p)＝-5.620 58＋2.160 45x (P＝0.999), respectively. The LFP50, LFP98, LFP99 and their 95% confidence limits(CI) were 3.322 53 d(2.740 04-3.952 39), 5.895 58 d(4.939 49-8.323 31), and 6.237 11 d (5.184 50-8.950 40) in the female M. unguiculatus; and 2.601 59 d (2.210 62-2.989 34), 3.552 20 d (3.115 84-5.024 47) and 3.678 38 d (3.204 01-5.326 58) in the male M. unguiculatus. Conclusion In LFP resistance detection using 0.0025% Chlorophacinone baits in M. unguiculatus, the 95%CI upper limit of LFP98, an integer number of days when applied as the drug?resistant testing standards, was 8 d for female rats and 5 d for males that survived in the feeding period; on the other hand, the 95%CI upper limit of LFP99, as an alternative, was 9 d for surviving female rats and 5 d for surviving males in the feeding period.
Objective To determine the attractiveness of different foods and identify an effective attractant that can act as a toxic bait for chemical control for Blattella germanica. Methods The four?arm olfactometer was used to sort out strongly attractive foods from a variety of edible materials for B. germanica. The candidate was then prepared with insecticides into toxic baits. Results The strongest attractants identified from four groups were fried soybean powder, cabbage juice, bananas and glucose, with attracting rates of 63.33%, 59.44%, 63.33% and 42.78%, respectively. The four best attractive ingredients were subject to the optimal luring test, which showed that fried soybean powder had the greatest attracting effect on B. germanica with the attracting rate of 45.66%, followed by bananas (25.83%). Combined with deltamethrin or Phoxim, bananas could act as the most efficiently attractive toxic bait. Conclusion The screening study showed that soybean powder and bananas had strong attractiveness for B. germanica. Bananas can be used to produce the most effective toxic bait.
Objective To analyze the morphological characteristics of the receptors on ovipositors and legs related to the selection of oviposition substrates in female houseflies. Methods Ultrastructural observation of ovipositors and legs of female houseflies was performed under a scanning electron microscopy. Results Six receptors of different morphologies were found on the ovipositors and legs of female houseflies, including bristle sensilla, styliform sensilla, trichoid sensilla, basiconic sensilla, cavity sensilla and coeloconic sensilla. Among them, they were mostly presented on bristle, styliform and trichoid sensilla, followed by basiconic, cavity and coeloconic ones. The bristle sensilla formed a large angle between its stretch direction and the surface. Segmentation of the surface junctional membrane of trichoid sensilla could be seen or not. The length of the styliform sensilla on the 5th abdominal segment was 300-700 μm, while those on the legs no more than 120 μm. The basiconic sensilla under the hypopygium were inserted in the cotyloid cavity, the ends slightly thin and blunt; and those on the hindtarsus did not have such basal cavity, suddenly tapering at the ends. In the tibial base of the mid legs there were cavity sensilla?intensive areas. At the end of the left cerci was a coeloconic sensillum. Conclusion It is implied that houseflies regulate their oviposition behaviors according to the mechanical and humidity information of oviposition substrates detected by the sensitization of these sensilla.
Objective To determine the niche breadth and overlap in eleven dominant species of gamasid mites parasitic on 39 species of small?mammal hosts around Biluoxueshan Mountain in Weixi, Yunnan. Methods The niche breadth was determine using the Levins model, the niche overlap the Colwell?Futuyma model, based on which the systematic grouping of niche overlap for all gamasid mites was completed by cluster analysis. Results （1） Eulaelaps huzhuensis and Hypoaspis pavlovskii had the widest niche breadth (0.1067 and 0.1044), while Laclaps traubi Domrow and Haemogamasus sanxiaensis had the narrowest (0.0390 and 0.0365). （2）L. traubi Domrow and L. turkestanicus shared a highly similar population distribution with L. chin, Ha. oliviformis and Hy. pavlovskii. Conclusion The niche breadth could be used as an index for evaluating the host specificity of gamasid mites, whose similarity in population distribution was largely related to that of their hosts, as well as their taxonomic distance.
Objective To evaluate the attractiveness of main components isolated and extracted from of Laminaria and applied them as the attractive baiting agents in molluscicides to enhance the killing effect of molluscicides. Methods A series of experiments using the attractant extracts of different main components of Laminaria were conducted at different temperatures and humidity conditions. Results The initially identified attractants in Laminaria were dietary fiber and fucoidan. At 25 ℃, the 48 h Oncomelania hupensis?attracting rates of dietary fibers and fucoidan were 79.33% and 56.33%, respectively, higher than those at 15 ℃ and 35 ℃; under 60% relative humidity, the 48 h O. hupensis?attracting rates of fucoidan and dietary fibers were 47.67% and 72.33%, respectively, higher than those under 30% relative humidity. Conclusion The dietary fibers in Laminaria, which had a favorably attracting effect on O. hupensis, were a valuable material worth exploitation and utilization.
Objective To determine the flea fauna and distribution in Three Rivers’ Headwaters region of Qinghai province. Methods Based on the results of the investigation and surveillance on plague foci, fleas were collected in vitro from the captured small mammals in the regions, and taxonomic identification was conducted. Results A total of 104 species of fleas had been found in Three Rivers’ Headwaters region in Qinghai (including sub?species), belonging to 33 genera, 6 families, the dominant species being Ceratophyllidae, Leptopsyllidae and Ctenophthalmidae, accounting for 33.65% (35/104), 27.88% (29/104) and 24.04% (25/104), respectively. Thirty four species, 16 genera and 33 families in the Qiangtang Plateau sub?region, 100 species, 16 genera and 6 families in South Tibet sub?region were also found, including 28 unique species in Three Rivers’ Headwaters region. Conclusion Further biological investigation on fleas should be strengthened along with vector control research in order to provide data for the prevention and control of plague.
Objective To provide a preliminary evaluation of the self?made horseradish peroxidase (HRP) marked Hantavirus (HV) recombinant N protein (rNP) rNP?IgM direct capture ELISA diagnostic kit. Methods Assessment of the specificity and stability of the kit and comparison of clinical results with similar products were performed to evaluate the sensitivity of the kit in the detection of serum anti?HV?IgM. Results (1) The kit was only responsive to anti?HV?IgM positive serum, and irresponsive to anti?varicella?zoster virus?IgM (anti?VZV?IgM), anti?Japanese encephalitis virus?IgM (anti?JEV?IgM), anti?dengue virus?IgM (anti?DV?IgM), anti?hand, foot and mouth EV71 virus?IgM (anti?EV71?IgM) positive sera. No obvious reduction in serum anti?HV?IgM detecting capability was noticed after placement at 37 ℃ for 3 d. (2) In 144 sera samples in 120 patients with suspected hemorrhagic fever with renal syndrome, inconsistency was observed only in the anti?HV?IgM test results in 12 sera of 12 patients between the two kinds of kits, in which 8 primary sera samples were detected positive by the kit and negative by commercial ones (the secondary sera samples were positive for both kits); 3 primary samples (the secondary samples unavailable) were at the critical value for the kit and negative for commercial kits. Meanwhile, one other primary serum sample was positive for the kit and negative for the commercial ones (the secondary and tertiary ones positive for both). Conclusion The laboratory developed capture ELISA anti?HV?IgM diagnostic kits had favorable specificity, stability and sensitivity, suitable for the clinical diagnosis and epidemiological surveillance of HV infections.
Objective To determine the current situation of Bartonella infection in and types of Bartonella carrying small mammals in Hainan province, providing evidence for prevention and control of Bartonella infection. Methods The rat?cage method was employed to capture small mammals, of which heart blood was collected and treated with anticoagulants. A 1∶4 dilution of 100 μl anti?coagulation blood and trypsin soy broth was inoculated onto the trypsin soybean agar culture media containing 5% de?fiber sheep blood and cultured in a 5% CO2 incubator at 37 ℃ for 45 d. Suspected colonies were smeared, Gram- and Gimanez?stained and screened under microscopy. The polymerase chain reaction (PCR) was performed for the Gram?negative bacilli with Bartonella genus?specific primers, followed by sequencing of the PCR products. The nucleic acid sequences were submitted to GenBank for similarity comparison and sequence analysis. Results A total of 6 suspected colonies were isolated from 65 samples, all being Gram?negative small bacilli, and red for Gimanez staining. The PCR results confirmed that the six strains were all Bartonella, two isolated from Rattus losea and Rattus brunneusculue each, and one from Niniventer fulvescens and Suncus murinus each. The sequence analysis suggests that the isolated Bartonella had the highest similarity with Bartonella rattimassiliensis, B. tribocorum and B. queenslandensis. Conclusion Bartonella infection was found among small mammals in Hainan province, indicating risks of infection among human beings.
Objective To determine the current situation and dynamics of rats around Alataw pass areas, providing evidence for early warning, prediction, prevention and control. Methods Fifteen monitoring sites, including different habitats such as downtown, outskirts and natural fields around the Pass, were established using cages, traps and cave detectors. Exoparasites were classified and identified. Blood and organ samples were collected from captured rats for micro determination of F1 antibodies and antigens. Positive results were retested using test tubes. Results A total of 599 small mammals of 13 species belonging to 10 genera, 6 families and 4 orders were captured around the Alataw pass in 2008, the annual average capture rate being 2.8% (0.5% in urban areas, 2.1% in suburban areas and 4.6% in fields). The dominant species was Mus musculus in urban areas, Rhombomys opimus in outskirts and fields. A total of 6050 fleas of 17 species from 12 genera and 6 families were collected, dominated by Xenopsylla minax. 238 ticks and 23 mites were also collected. Serological assays revealed 873 positive samples of F1 antibody and 548 of F1 antigens. Four batches of rodents, one of canine bodies and three of mites were found in the aboard?passing vehicles, amounting to 338. Conclusion The rat density had reduced to the lowest level around the urban areas of Alataw pass in 2008. R. opimus were the dominant species in the suburbs and fields, mostly mediated by X. minax, indicating that epidemics among R. opimus were still present. A variety of vectors were found entrained in the aboard?passing vehicles, increasing the risk of epidemic transmission.
Objective To investigate and determine the composition, distribution and biological characteristics of rodent populations in Baoshan. Methods Multi?year survey and monitoring were conducted. Results A total of 46 species, 21 genus and 6 families of rodents were found in Baoshan district. Rattus tanezumi a key storage reservoir of Yersinia pestis, was the dominant species, accounting for 58.73% of the total captured rodents. Density peaks appeared in the indoor environment in April, August and October, whilst they presented in May and September in the fields. This kind of rats could breed throughout the year with an average annual pregnancy rate of 5.48%, maximizing in April and May (8.62% and 9.01%), followed by the period from August to October (6.31%-7.38%), and reaching the bottom in January (2.81%). The bimodal pattern of pregnancy rates was featured by a noticeable initial peak in spring and early summer that was significantly higher than the autumn peak (t＝7.345, P＜0.01). The sex ratio of R. tanezumi revealed a higher proportion of females than of males. Conclusion Large?scale rodent control has not only significantly reduced the number of R. tanezumi, but also altered the seasonal pattern in the population dynamics, which may play an inhibitory role in the long?term dynamics of Y. pestis.
Objective To determine species composition and densities of rodents, mosquitoes, flies, cockroaches and other vectors at three monitoring sites in Heilongjiang province from 2006 to 2008, providing scientific evidence for the development of vector control. Methods Night traps and sticky traps were used to monitor rats and cockroaches throughout the years; lamp traps and cage traps were used for mosquitoes and flies from May to October each year. Results The rat densities reached 2.02%, 2.17% and 2.36% from 2006 to 2008, respectively, the highest found in rural villages, and the dominant species being Rattus norvegicus. The densities of adult mosquitoes reached 18.03, 7.36 and 2.58 per lamp hour in the three years, respectively, the highest density found in livestock sheds, with Anopheles sinensis, Culex tritaeniorhynchus and Cx. pipiens pallens as the dominant species. The fly densities were 24.90, 14.91 and 8.69 per cage day, respectively, the highest found in farmers’ markets, the dominant species being Muscidae and Calliphoridae. The densities of Blattella germanica reached 3.05, 3.71 and 1.91 per sticky sheet, the encroachment rates being 23.35%, 26.05% and 23.75%, respectively, with the highest density found in farmers’ markets. Conclusion The 3?year monitoring program revealed the species composition and population dynamics of major biological vectors in Heilongjiang. Further surveillance and monitoring would be necessary.
Objective To evaluate deratization effects for controlling rat populations in regions for resettlement after the reservoir was formed at the Longtan hydropower station and preventing occurrence and prevalence of rodent?borne diseases. Methods 0.005% bromadiolone baits of wheat grain were intermittently applied to the residential and farming areas. Powder trace and night trap methods were employed to measure the rat density before and after deratization. Results The powder?block positive rate in residential areas averaged 9.90% before deratization and 2.04% after bait deployment, with the reduction of 79.39%. The average rat density in farming areas was 6.54% and 1.08% before and after deratization, respectively, with the reduction rate of 83.49%. Statistically significant difference was observed in the rat densities before and after rodent control (χ2 values were 64.33 and 32.15, P＜0.01). Conclusion The results of rodent control showed that the applied control measures were effective with well organized procedures and choice of drugs, formulations of toxic baits and timing based on rodent characteristics of local populations.
Objective To determine the susceptibility of Aedes aegypti and Ae. albopictus to commonly used insecticides in the previously Dengue fever?prevalent areas in Hainan province. Methods The larvae dipping method was used to measure the susceptibility of mosquitoes to commonly used insecticides. Results The resistance ratio of Ae. aegypti to deltamethrin was 2.04-2.82, and 3.76 to Beta cypermethrin in Sanya. The resistance ratio of Ae. albopictus to deltamethrin was 2.40-3.60, and 2.63 and 2.07 to fenobucarb and propoxur, respectively, in Haikou. Conclusion Decreased susceptibility of Ae. aegypti and Ae. albopictus to the sample insecticides was observed in the previously Dengue fever?prevalent areas in Hainan.
Objective The study summarizes and analyzes the data of plague surveillance along the Qinghai?Tibet railway since its construction in Qinghai province, and provides scientific assessment of the plague epidemic dynamics in the region to support the establishment of prevention and treatment of plague along the Qinghai?Tibet railway. Methods Monitoring was conducted at the designated sites in accordance with the Technological Solutions for Prevention and Control of Plague along the Qinghai?Tibet railway and the Prevention and Control Program of Plague along the Qinghai?Tibet railway, national?level surveillance sites deployed along the railway line in accordance with the National Plague Surveillance Program. Meta?analysis was performed based on the plague monitoring data from 2001 to 2008 along the Qinghai?Tibet railway in Qinghai province. Results An area of 224 190 km2 had been monitored, a total of 5822 specimen of rodent materials, 2617 samples of vector materials, 4966 samples of animal sera, 93 isolates of Yersinia pestis strains were collected from 2001 to 2008, including 249 cases of positive sera. Conclusion In recent years, increased plague transmission in animal populations had been observed along the Qinghai?Tibet railway, with high plague?endemic in Wulan county and Tianjun county along the railway. Therefore, relevant departments should attach great importance to preventing plague from long?distance spread along the Qinghai?Tibet railway line.
Objective To investigate temporal and spatial distribution patterns of hemorrhagic fever with renal syndrome (HFRS) in Ju’nan county. Methods A probabilistic model was used for temporal and spatial distribution analysis of HFRS in Ju’nan. Results Neither the temporal nor spatial distribution of HFRS cases in Ju’nan was consistent with the Poisson distribution (χ2＝38.44, P＜0.05; χ2＝138.58, P＜0.05). Both of them were consistent with a negative binomial distribution (χ2＝2.81, P＞0.05; χ2＝2.96, P＞0.05), suggesting spatial and temporal aggregation of HFRS cases. The incidence was high from February 10 to June 25 with the peak on April 21. The cases of HFRS mainly clustered in the county’s western plains. Conclusion Prevention and control of HFRS should be spatially and temporally targeted to crucial areas and seasons.
Objective The study was conducted to analyze the molecular mechanisms of deltamethrin resistance in house flies (Musca domestica). Methods The deltamethrin?resistant strains of housefly were analyzed using primers properly designed based on the conservative sequence of P450 gene CYP6D1 in the laboratory. Specific fragments were amplified in both sensitive and resistant strains by PCR. Results A specific fragment of 210 bp was obtained from both sensitive and resistant strains, demonstrating no difference in the fragment size and band brightness between the two. It was thus indicated that no noticeable mutation was present in P450 gene in resistant house flies at the DNA level. RT?PCR results revealed that amplified bands in resistant strains were brighter than those in sensitive ones, suggesting a different volume of RNA as the reverse transcription activity of P450 gene might be enhanced in resistant strains. Conclusion Deltamethrin resistance in house flies was probably correlated with the elevated reverse transcription activity of P450 in the resistant strains.
Objective To observe and evaluate the palatability and efficacy of α-chlorohydrin rodenticides that causes sterility in male rats in laboratory and the field. Methods （1） Male adult rats without offspring were fed with 1% α-chlorohydrin wheat baits as the experimental group whilst the control group was fed with normal rat feed. Male and female rats were caged for two weeks in prior to dissection of the females to determine the number of fetuses. （2） The powder trace method was applied to measure the rat density for evaluating the field efficacy of rodent control. Results With an average coefficient of intake of 0.221, this male sterility?inducing 1% α-chlorohydrin baits caused an averagely 70.7% to 100% reductions of rat fetuses. The on?site rodent control rate reached 84.09%. Conclusion In addition to remarkable efficacy of rodent control in a laboratory setting, this rodenticide had obvious on?site rodent control effects. However, further improvements of the palatability of wheat?based male?sterilization 1% α-chlorohydrin baits are desired.
Objective To determine the species composition, seasonal patterns of mosquitoes in Yichun city for providing data for the development of anti?mosquito measures and meet of the requirements of the “Model?Hygienic” city. Methods Hand?held electric mosquito apparatuses were applied in residential areas and livestock sheds to capture adult mosquitoes. Results The average density of mosquitoes was 20.82 per man?hour. Adult mosquitoes were observed in urban areas throughout the year, with the lowest density in January and February, followed by a gradual increment in March, and the highest in May and June in addition to another peak from September to November. Conclusion Drastic seasonal fluctuations in mosquito densities in Yichun city necessitates strengthening of control of breeding grounds for mosquitoes, anti?mosquito measures and vaccination in order to prevent and control vector?borne diseases.
Objective To determine species composition and distribution patterns and seasonal dynamics of fly populations in Haidian district, providing data for the formulation of scientific prevention and control measures. Methods The cage trap method was employed to monitor densities and population distributions of flies at five monitoring sites at Haidian district. Results The average density of flies was 22.52/cage in Haidian district in 2008, the dominant species being Sarcophagidae. Significant seasonal fluctuations of the fly populations were observed, the highest density, 59.60/cage in late July. Most flies were captured at the monitoring sites in Taizhouwu Dock Trade Market with a density of 59.19/cage. Conclusion Urban areas should be the key areas for prevention and control of flies for the successful proceeding of 2008 Olympic Games.
Objective To investigate the level of public awareness of cockroach control at Shunyi district, providing evidence for cockroach control in this region. Methods An on?site investigation was conducted using self?designed questionnaires concerning the knowledge of cockroach prevention and control. Results More than 90% of the investigated people had knowledge of cockroaches and a high level of understanding of cockroach habits. As for the prevention and control of cockroaches, most people preferred to handle the task by themselves, accounting for 59.98%. Those who tended to consult the Neighborhood Committee, the Patriotic Health Campaign Committee, and the Center for Disease Control and Prevention accounted for 17.34%, 12.92% and 5.42%, respectively. Cockroach?killer agents had been the most common control measure, accounting for 32.13%. Conclusion The general awareness of cockroaches was relatively high among the surveyed population, in spite of a deficiency of the knowledge related to the prevention and control of cockroaches. Therefore, it is necessary to enhance the development of a market?oriented operational mode of cockroach control, and promote the technical guidance and training of cockroach prevention and control for all industries in the region.
Objective To investigate the distribution of the vector mosquito of Dengue, Aedes albopictus, in Sichuan province, providing data for the prevention and control of dengue fever. Methods The larval index and adult densities of Ae. albopictus in its breeding grounds were monitored at ten representative observation spots by specified technicians. Results The container index was 27.50% at the ten monitoring spots, the overall adult mosquito density 8.08 per man?hour. The highest container index, 60.28%, was observed in discarded tires. Relatively higher densities of mosquitoes were found at special places and breeding and farming areas, being 18.17 and 10.08 per man?hour, respectively. The density was also high in summer, reaching a peak of 9.79 per man?hour. Regional variations in population densities of Ae. albopictus were observed, yet without geographic variations. The larval and adult density were correlated to a certain extent at various monitoring spots. Conclusion Ae. albopictus is widely distributed in Sichuan province, and may result in outbreaks of Dengue in case of imported cases. Therefore, we should strengthen surveillance of mosquito vectors.
Objective To assess the distribution, function settings and medical staffing of dog?bite injury clinics in Zhejiang province, providing evidence for the standardization and construction of dog?bite injury clinics. Methods The survey programs and questionnaires were properly designed, and trained investigators were designated to carry out on?spot investigations for all dog bite injury clinics in the province. A database was established using EpiData 3.0, and data analysis was done by SPSS 16.0. Results Of the 781 dog bite clinics in the province, 81.3% were located in rural health institutes, 52.0% had a fully functional partition, 21.5% served as an independent out?patient institute, and 89.9% had wound washing facilities in the consulting rooms or nearby. However, only 170(24.2%) clinics had two?phase hot and cold water supply; 98.0% were equipped with alcohol, iodine and other wound disinfectants. 58.5% were open for 24 h admissions. The minimal number of health care workers in these out?patient services was only one, with a maximum of 22. Conclusion The conditions and settings of dog bite injury clinics varied in Zhejiang and lacked standardization. Therefore, appropriate standards for dog?bite injury out?patient services should be established in order to improve service of dog?bite injury clinics in the province.
Objective To evaluate the situation of rats infected with Capillaria hepatica and Trichinella spiralis for providing evidence for the development of prevention and control of C. hepatica infections. Methods Rats captured from the old quarter of urban areas and peripheral rural areas were numbered and brought to the laboratory for identification of species and physiological age, followed by dissection for the entire liver and partial hind leg muscles to produce microscopic sections for examining C. hepatica and T. spiralis. Results The autopsy revealed 29 out of 199 rodents that had been infected with C. hepatica with the infection rate of 14.57%; of these Rattus norvegicus had the highest infection rate, 20.83%, followed by Mus musculus, 17.05%, and R. tanezumi the lowest, 4.65%. No infection was found in three shrews examined. The eighteen M. musculus captured in urban areas were all negative for T. spiralis infection, and the same was the leg muscle samples from the 199 animals.Conclusion Suburban and rural areas are prevalent with C. hepatica infection. Though epidemiological investigations of houses with infected rodents revealed no evidence of human infections, there is a potential risk of C. hepatica human infection. In contrast, no evidence of T. spiralis infection among rats was found in the old quarter of urban areas and peri?urban rural areas.
Increased attention is being paid to the effects of global warming on human health. Climate warming can not only expand the distribution of mosquitoes, shorten their generation period and enhance their survival, but also accelerate the proliferation of pathogens and increase their virulence, thus increase the virulence and scope of mosquito?borne diseases. Global warming contributes to the expansion or relapse of outbreak of many mosquito?borne diseases, making effective prevention and control of these diseases an urgent challenge. This article reviews the impact of climate warming on mosquitoes and pathogenic organisms, and its influence on the occurrence of mosquito?borne diseases, and proposes recommendations for mosquito?borne diseases control under global warming.
This study presents an overview of the current situation of the natural foci of plague in China and the research progress of genotyping of Yersinia pestis, as well as the impact on plague epidemiology by the present socio?economic development and changes in the ecological environment in China. Corresponding prevention and control measures are proposed.
