ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Objective To develop a test strip for rapid detection of antibodies against Western equine encephalitis virus (WEEV). Methods Staphylococcal protein A was labeled with 25 nm colloidal gold via immune-chromatography; cellulose nitrate-coated WEEV antigens and goat anti-rabbit antibodies were used as the test zone and the control zone, respectively. The sensitivity, specificity and stability of the test strip were evaluated and semi-quantitative detection was conducted with a curve of best fit. The detection capability of the test strip was assessed using healthy human serum, rabbit serum and rat serum samples containing simulated WEEV antibodies. Results The qualitative and semi-quantitative detection was completed within 20 min, with a resulting sensitivity of 120 ng/ml in simulated samples. The linear range of sensitivity was 120-1200 ng/ml. No nonspecific reaction was observed when applied to other homologous viruses and those leading to similar symptoms. Storage at 37 ℃ over a month did not make a difference in the test result. Conclusion The test strip is a fast, simple, sensitive, specific and reliable tool for detection of WEEV and is suitable for field application.
Objective To evaluate the community composition and seasonal dynamics of small mammals after the earthquake in Yingxiu Wenchuan Sichuan area to inform post-quake rodent control efforts and prevent rodent-borne disease outbreaks. Methods The surveys were conducted in July 2009 (summer), October 2009 (autumn), January 2010 (winter), and April 2010 (spring). Small mammals were sampled by the night trapping method and analyzed statistically. Results A total of 1645 traps were deployed during the investigation period, resulting in a capture rate of 4.38%. The captured small mammals belonged to 2 families, 6 genera and 9 species, including Anourosorex squamipe, Rattus tanezumi, R. nitidus, Niviventer confucianus, Mus musculus, Apodemus chevrieri, R. norvegicus, Ap. draco and Crocidura attenuate. The predominant species were A. squamipe and N. confucianus. The diversity index, evenness and dominance indices were 2.574, 0.205 and 0.812, respectively. The density of small mammals increased from summer and declined in spring the next year. The overall species, diversity index and evenness index decreased at the same period while the overall dominance index increased. Each of the indices presented a bimodal pattern. Conclusion The composition and the density of small mammals differs across seasons in Yingxiu area after the earthquake. The seasonal factors should be taken into account for rodent control and prevention of rodent-borne diseases.
Objective To determine the presence and virulence genes of enterohemorrhagic Escherichia coli(EHEC) O157∶H7 in diarrhea patients and host animals in Henan province in order to identify the cause and related risk factors. Methods Suspicious samples collected at surveillance sites from 2005 to 2009 were subjected to serological detection and PCR, and tested for stx1, stx2, eaeA, hlyA virulence genes. Results Of the 10 732 serum samples, 255 (2.38%) were positive for O157∶H7 strains. The detection rate in animal stool samples was 6.31% (8.04% for sheep and 7.20% for cows). Different detection rates were observed in different years. Most EHEC O157∶H7 strains were from sheep, cattle and chicken feces. A combination of virulence genes stx2, eaeA, hlyA was predominant. Conclusion EHEC O157∶H7 existed in the population and various animals in Henan province. The most important animal hosts were sheep and cows. Contaminated food during processing was a possible cause and might lead to potential outbreaks.
Objective To study the activity of Glutathione S-transferase (GSTs) of German cockroaches (Blattella germanica) at different developmental stages (from nymph to adult) and different field strains in Beijing. Methods The specific activity of GSTs and resistance levels of B. germanica were determined by spectrophotometry and contact biossay. Results The specific activity of GSTs increased gradually during the nymph period and reached the highest by week 4, which then decreased to the lowest value during eclosion. The specific activity of GSTs in susceptible strains of B. germanica was 2.70 nmol/(min·mg) with Km of 2.26 mmol/L and Vmax of 0.33 nmol/(min·mg); the specific activity of GSTs in nine field strains ranged from 2.76-8.69 nmol/(min·mg) with Km of 0.65-2.37 mmol/L and Vmax of 0.33-0.54 nmol/(min·mg) Vmax. Compared with susceptible strains, field strains had higher specific activity and Vmax yet lower Km values. Field strains also demonstrated different degrees of resistance to two commonly used pesticides (cypermethrin 1.50-8.37 fold; propoxur 1.04-3.34 fold). Conclusion GST activity varied in the developmental stages from nymph to adult, which may be involved in the development of insecticide resistance in the field strains of B. germanica.
Objective To investigate the seasonal fluctuation and spatial distribution of cockroaches and rodents on naval vessels to inform vector control programs in those settings. Methods Glue traps and boards were used to collect cockroaches and rodents at three monitoring regions of north, east and south oceans to identify the spatial distribution. Density was measured every other month. Results Cockroaches were present on naval vessels throughout the year. Activity started to rise in March and peaked in July, followed a slow decline until November in all monitored regions, while the seasonal fluctuation was not significant in the ocean area 2. Rattus norvegicus rats were the most common rodents while Mus musculus were observed occasionally. The fluctuation of rodents was not significant. Kitchens, dining halls, food warehouses and living cabins were severely infested by cockroaches with a mean infestation rate of 90.0%, 75.5%, 72.5%, and 61.5%, respectively. Rodents were mostly captured at the dinning areas with a mean positive rate of 75.2%, followed by living areas (50.3%), and the lowest prevalence was found in working areas (44.5%). Conclusion This study provides vital information for timely and organized vector control in vessels of different ocean regions.
Objective To determine the optimal rodenticide bait for the farming areas in Guangdong province. Methods Different formulations were screened in terms of palatability and applied indoors to evaluate their effects on major rodent species detrimental to the farming industry in Guangdong. Results Compared to crops, the Basic Formulation C＋ Attractant Ⅱ and Basic Formation G＋Attractant Ⅰ, which topped the screening, had the acceptance coefficient of 2.97, 2.89 and 1.76 for Rattus losea, Bandicota indica and R. norvegicus respectively. The two formulations were well palatable. Conclusion The study provide information for the application of rodenticide bait in future.
Objective To identify the most attractive mice baits for preparation of toxic baits. Methods The attracting effects of six types of bait (peanut, rice, potato, bean cake, fish bait, and cat food) on mice were determined in terms of the respective feeding coefficients. Results Mice showed different preferences for the six baits, of which potatoes and peanuts had the strongest attracting effects with feeding coefficients of 5.90 and 2.49, respectively, and average feeding rates of 60.71% and 25.61%, respectively. Bean cakes and rice followed with feeding coefficients of 1.08 and 1.16 and feeding rates of 14.49% and 11.94%, respectively. The attractive efficiency of fish baits and cat food were the lowest, with the feeding rates of 8.74% and 3.00%, respectively. Conclusion Potatoes and peanuts are the baits of choice when preparing poison baits for mice. Their attracting effects deteriorate with time and become the lowest beyond 48 hours. Furthermore, the nutritional balance or mixing of baits may be considered to improve palatability.
Objective To determine the deratting and disinsecting effects of sulfuryl fluoride (≥99.8%) and their relationship with the dose and exposure time. Methods Rats and cockroaches were divided and fumigated with sulfuryl fluoride at 4, 8, 12, 16, 20 g/m3. The death time of SD rats and Periplaneta americana was recorded. Results were simulated and predicted using the response-surface model. Results All groups of subjects were killed at different concentrations of sulfuryl fluoride. The average time to death ranged from 43 to 381 minutes for SD rats and from 97 to 387 minutes for P. americana. The response-surface model for SD rats was established as:Y＝1.57－1.16X1－0.37X2＋0.05X12＋0.22X1X2＋0.01X22 and that for P. americana: Y＝6.92－2.15X1－0.89X2＋0.15X12＋0.18X1X2＋0.02X22. Conclusion Desired killing effect resulted from sulfuryl fluoride at 4 g/m3 to 20 g/m3, concentration was negatively correlated with the exposure time (i.e. the time to death increased as the concentration dropped). Time and decrease of concentration. P. americana demonstrated stronger resistance to the agent compared with SD rats.
Objective To determine the population distribution and seasonal fluctuation of rats in Nanchang city. Methods Night trapping and powder trace were employed to survey the rat density in different settings over four years. Results The rodent densities were 1.24% and 5.96% by night-trapping and powder trace, respectively. Two peaks of rat density were found to begin from March and September. Rattus norvegicus, R. tanezumi and Mus musculus accounted for 35.62%, 23.84% and 33.38% in the captured rats. R. norvegicus in residential areas accounted for 56.99%. R. norvegicus and M. musculus in special industries accounted for 49.84% and 27.54%, respectively. M. musculus and R. tanezumi in rural villages accounted for 45.71% and 30.48%, respectively. Conclusion The rodent density in Nanchang was relatively high with obvious seasonal fluctuation. The dominant species had shifted from R. norvegicus to M. musculus, and different dominant species were found in varying environments.
Objective To evaluate the resistance in Culex pipiens pallens to commonly used insecticides in different areas of Shaanxi province. Methods Larval mortality for 4 insecticides and LC50 of 8 insecticides determined via the dosing method and median lethal dose method, respectively. Results The resistance level of Cx. pipiens pallens in all five areas was high except the population in Yulin city, which had elementary resistance to permethrin. The LC50 values for larvae to β - cypermethrin, permethrin, deltamethrin, cypermethrin, DDT, DDVP, parathion and propoxur were 0.001 82-0.012 24, 0.008 16-0.094 19, 0.000 58-0.005 59, 0.002 76-0.020 17, 0.100 96-1.296 86, 0.144 11-0.512 40, 0.001 47-0.007 06, and 0.234 60-1.182 37 mg/L, respectively. The highest resistance level to all pesticides was found in Baoji city, except for deltamethrin, cypermethrin and parathion, while the lowest level was found in Yulin city, except for parathion and propoxur. Conclusion The development of mosquito resistance was closely related with the use of insecticides. Therefore, it is important to ensure appropriate administration and regular resistance surveillance to defer and prevent the occurrence of resistance in mosquitoes.
Objective To determine the association between carboxylesterase (CarE) and beta - cyfluthrin resistance in Musca domestica in various habitats, and monitor this resistance at an early phase by using carboxylesterase. Methods Biological assessment was conducted using dripping titration and the activity of carboxylesterase was determined by the Asperen method. Results Except for the population in transfer stations, the three populations of M. domestica in residential areas, restaurants and farmer's market presented different resistance levels to beta-cyfluthrin with resistance ratios of 1.84, 15.31, 3.19 and 8.84, respectively. The CarE activities in the three populations were significantly elevated (P＜0.05), while 75%, 54% and 72% of them showed remarkably high activities, respectively. Overlapping susceptible strains were found in the three populations except for that in transfer stations. Conclusion Increased CarE activitiy was associated with beta-cyfluthrin resistance in M. domestica. The distribution of high CarE-activity strains showed that the populations in those areas were hybrid resistant strains, which was consistent with the bioassay Results. Based on this finding, it is advisable to restrict the use of beta-cyfluthrin in residential areas and use other pesticides as an alternative to avoid or defer the occurrence of resistance and apply this agent with caution in other habitats.
Objective To identify the presence of microorganisms and parasites in Microtus fortis and evaluate the purification techniques. Methods Microorganisms and parasites carried by wild M. fortis in Dongting Lake were measured before and after purification according to the monitoring index for clean grade susliks. The feeding environment was purified and mass drug prophylaxis administered for positive communities. Results Detected microorganisms and parasites in the wild animals included Trichophytion mentagrophytes (13.33%), Leptospira spp. (10.00%), Toxoplasma gondii (13.33%), mites (16.67%) and lice (6.67%), while only T. mentagrophytes (3.33%) and mites (3.33%) were detected upon purification. No virus was found either before or after purification. Conclusion A variety of pathogenic microorganisms and parasites were found to be carried by wild M. fortis; purification of the feeding environment and mass drug prophylaxis are effective control measures.
Objective To investigate the biodiversity and fauna of Tachinidae in Songshan National Nature Reserve of Beijing. Methods Entomological taxonomy and zoogeography principles and Methods were used in this study. Results There were 76 species, belonging to 4 subfamilies, 18 tribes and 53 genera, including 16 endemic species for China, 50 new records for Beijing and 2 new records for China. The catalogue of Tachinidae in Songshan was provided. Conclusion The Palaearctic composition is the main characteristic of the Tachinidae fauna in Songshan National Nature Reserve of Beijing. This fauna is enriched by the findings in this region. All specimens are preserved in the Insect Collections, Beijing Forestry University, China.
Fleas are an important vector, and the Xenopsylla genus plays an important role in the spread of plague in China. This study describes the defining characteristics, geographical distribution, plague host and association of seven Xenopsylla species, providing the basis for the research and development of control strategies regarding the Xenopsylla genus.
Objective To design a computer program for risk analysis and assessment of import and export containers based on the statistical analysis system (SAS). Methods The feasibility of developing a container risk analysis system for inspection and quarantine (CRASIQ) based on SAS was analyzed by means of applicability assessment, analysis of procedures and software. Typical modules of the program were demonstrated. Results The SAS software was suitable for research and development of CRASIQ. The system included parallel data management and core application layers, as well as six sub-modules, which would provide fifteen functions. Conclusion The SAS - based CRASIQ may enhance the inspection, quarantine and supervision for import and export containers to support intellectual decision for prevention and control of exotic epidemic cases or toxic and harmful substances.
Objective To compare five Methods in screening Yersinia pestis carried by imported marmot skins based on their sensitivities calculated by the positive rates, and identify a rapid detection suitable to port environments and inform further quarantine practice. Methods Bacterial culture, reverse passive hemagglutination test (RIHA), colloidal gold rapid test, phosphorescent immunochromatography test (UPT) and polymerase chain reaction test (PCR) were applied and compared. Results The positive rate of Y. pestis was 0 for bacterial culture and the colloidal gold test, 0.74% for RIHA, 0.56% for UPT and 0.87% for PCR. The detection rate was higher in PCR and RIHA but lower in UPT. Conclusion In view of the Y. pestis antigens carried in some old marmot skins, the possibility of viable Y. pestis on the fresh marmot skins cannot be ruled out at present. Therefore, it is important to take quarantine measures, such as disinfection and fumigation, for each imported marmot skin.
Objective To investigate the population composition and seasonal dynamics of Calyptrate flies in Yangpu district, Shanghai. Methods The cage trap and butterfly nets Methods were used to capture the flies. Results Sixty-six species (4 families, 41 genus) were collected in the area from March, 2006 to December, 2009. The dominant species was Chrysomya megacephala, accounting for 76.67%. The flies first appeared in March and gradually disappeared in December. Two peaks of the population were observed in August and November and the highest density was in November. Conclusion The fly population was abundant in this district with Ch. megacephala as the dominant species that should be properly managed. Dichaetomyia corrugicerca and Phallosphaera gravelyi were newly recorded species. Specific control measures should be implemented in August and November when fly activities reached their peak.
Objective To analyze the species composition, seasonal variation and the diversity of fly at different habitants in Hongkou district, Shanghai from 2006 to 2010 to provide evidence for the prevention and control. Methods Cage traps with sugar and vinegar baits were used to capture flies. Quarterly analysis of biodiversity was performed from March to November each year. Results The flies in this district belonged to 10 species, 7 genera and 3 families. The highest density was noted in Musca domestica (0.62 flies per day for every cage). The density of M. domestica was increased, whereas the density of Lucilia sericata declined each year. The fly densities were 2.52, 1.91, 1.46, 1.12, and 0.70 flies per day for every cage from 2006 to 2010, respectively. The highest density was noted in late April, early May, late June and mid-July from 2006 to 2010. In July, eight species were collected at most. The species diversity index and evenness index were highest in May. Different habitats by fly density in descending in the last five years were: farm trade market ＞ residential area ＞ public green belt ＞ external environment of restaurants. The most abundant species were observed in residential areas (ten species), which had the highest species diversity index and evenness index. Conclusion The fly diversity declined year by year from 2006 to 2010, which had a peak from late April to mid-July each year. The dominant species were M. domestica and L. sericata. The population characteristics could be generally described by the species diversity index and evenness index.
Objective To determine the resistance of Musca domestica to commonly used insecticides to inform proper application of chemical killing agents. Methods The median lethal dose (LD50) for M. domestica was determined by the dripping method. Results The LD50 values of beta-cypermethrin, deltamethrin, and dichlorvos for M. domestica were 0.064, 0.010, and 0.037 μg/♀, respectively, and the corresponding resistance coefficients of M. domestica were 9.14, 50.00 and 61.67, respectively. M. domestica showed low resistance to beta - cypermethrin and high resistance to deltamethrin and dichlorvos. Conclusion For effective control of M. domestica, comprehensive control strategies shall be employed, such as eliminating breeding places and physical management, chemical control and regular resistance monitoring, along with appropriate application of pesticides.
Objective To determine the population constitution and density of mosquitoes in different habitats in the worst- hit areas of earthquake - stricken Wenchuan to inform risk evaluation, prevention and control of mosquito - borne disease. Methods Light traps were applied to collect adult mosquitoes, followed by classification and identification. Results The mosquito density was 1.64 per light per hour. The population consisted of Culex pipiens quinquefasciatus mostly, which accounted for 64.53% of the total number. Cx. tritaeniorhynchus and Anopheles sinensis accounted for 15.69% and 10.77%, respectively. The mosquito density in settlement residences and central city was higher than that in earthquake ruins. An upward trend from June to August was shown from the seasonal fluctuation. Conclusion The overall density of mosquitoes was low. However, integrated management is still needed for the settled communities and central city in combination with systematic monitoring to prevent potential outbreaks of related infectious diseases.
Objective To investigate the mosquito density in pooled water and containers in the mud-rock flow disaster areas of Zhouqu county and provide technical support for the control of mosquito and associated infectious diseases. Methods The density surveillance was conducted by the spoon method, and 10% beta-cypermethrin and 1% Abate larvicide were deployed on the spot for larval control. Results Upon investigation of thirteen water bodies and containers, including those in construction areas, the average density of mosquito larvae was 6.7, with the highest of 21.0 and lowest of 0.3 per spoon. After pesticide deployment, the average density declined by 87.30% and 90.14% at day 1, and down by 96.83% and 98.59% by day 2, with 10% beta-cypermethrin and Abate, respectively. Conclusion The two insecticides were effective in larval mosquito control in various water bodies. They would bring potential benefits in vector control of the public health emergency response system in Gansu province.
Objective To identify the dynamics and distribution of the dengue mosquito population in Kaijiang county, Sichuan province for effective dengue fever control and prevention. Methods The container index of Aedes albopictus mosquitoes was examined at different habitats of Kaijiang county from June to October, 2010. Adult mosquitoes were captured on human baits to calculate the adult mosquito density. Results The average container index of mosquito larvae was 6.25% after investigation of 2639 water containers and 165 positive habitats. This index ranged from 1.65% to 12.07% from June to October with difference between months (χ2＝71.50,P＜0.01). As for different habitats, the highest index was found in special habitats (38.83%), followed by mountainous woods (18.18%), and farmland (16.53%), while others ranged between 2.40% to 6.69% in other places, with statistically significant differences (χ2＝271.89,P＜0.01). As for containers, the highest index was found in waste tires (38.83%), while others ranged from 2.03% to 12.77% with statistical differences (χ2＝216.05,P＜0.01). The overall adult density was 4.47/man-hour, which ranged between 2.67 to 6.50/man-hour from June to October but, there was no statistical difference between months (t＝0.09-1.31,P＞0.05). The highest density was found in mountainous woods (9.60), followed by farmland (7.40) and special places (5.80), which were obviously higher than those in other environments (1.00-2.00) (t＝ 2.78-3.64,P＜0.05). Conclusion As dengue mosquitoes, Ae. albopictus, were widely distributed in the county, it is important to implement prevention and control measures against the disease.
Objective To evaluate the vector control effect in a chikungunya epidemic in Zhongtang town, Dongguan city. Methods Mosquito breeding places were eliminated and the vectors killed at the epidemic sites. The mosquito density and related indicators were monitored. Results The breteau index (BI) reduced to 6.56 after 3 days of control, and decreased by 94.15% beyond 7 days (from 53.33 to 3.12). On day 7, the house index (HI) decreased by 92.51% (from 41.67 to 3.12) and the container index (CI) by 71.19% (from 14.75 to 4.25). The mosqito-ovitrap index was 0.75% in the first surveillance (on October 26) and reduced to 0 on November 4. Conclusion The vector control measures in Zhongtang town effectively reduced the Aedes density and prevented the spread of chikungunya epidemic.
Objective To determine the efficacy and feasibility of synthetic amorphous silica against Dermanyssus gallinae. Methods Forced contact tests were used in accordance with GB/T 13917.1-2009. Results The 3% synthetic amorphous silica was painted on three types of board at 6 g a.i/m2. For cement boards, the 24 h mortality was 100% and the residual efficacy lasted about 45 days; for silicate glass cotton board, the 24 h mortality was 100% and the residual efficacy lasted about 90 days; and for alkyd resin varnish boards, the 48 h mortality was 100% and the residual efficacy lasted about 60 days. Conclusion Synthetic amorphous silica was effective in the control of D. gallinae.
Objective To investigate the population composition of bloodsucking midges in Hulin city, Raohe county and Fuyuan county along the Wusulijiang River in Heilongjiang province. Methods Human-baited net traps, light traps, animal-baited traps and insect nets were used to capture bloodsucking midges. Results A total of 131 393 bloodsucking midges were collected, which belonged to 2 genera and 38 species. Seven newly recorded species were found and described. The predominant species was Culicoides punctatus (56.7%). The species composition varied in different habitats, places, months and collecting Methods. C. punctatus presented obvious phototaxis. Conclusion The investigation provided the basis for further studies on the population composition of bloodsucking midges in this area.
Objective To confirm whether one-time deployment of bromadiolone is effective in seaport rodent control. Methods Indoor and outdoor rodent density was investigated both indoor using powder tracking and night-trap Methods after saturated deployment of bromadiolone baits. Results The killing rates were 37.26% and 95.10%, in Mawei port, Fujian and in Dongjiang port, respectively. Conclusion One-time saturated deployment of a rodenticide in a sufficiently large area may yield satisfying killing effect.
Objective To investigate the dynamic structure and distribution of plague hosts and vector communities in various regions of Zhejiang province to understand the epidemiological characteristics of plague. Methods The gray mathematical theory was adopted to measure the maximum effect indices based on relevant data of different regions, hosts, and flea populations. Results Fifteen types of animal host (25 588) as well as eight types of body flea (1944) were subject to quality measurement, resulting in differences between each pair of groups, indicating a dominant species among host animals of each region and a vector population in each dominant community. Given adequate privilege of each dominant group, early warning, prevention and investigation shall be implemented. Conclusion A typical mathematical matrix can be formed based on the number of rodents and species of fleas. The quality measurement indicated that the larger vector and flea numbers resulted in high measurement Results, suggestive of high risk of plague in the region.
Dengue virus is a positive-sense RNA virus belonging to the Flavivirus genus of the family Flaviviridae. The virus is classified into four different serotypes based on the antigenicity of its envelope protein E. Mainly transmitted by Aedes aegypti or Aedes albopictus, it causes dengue fever, dengue hemorrhagic fever and dengue shock syndrome, mostly in tropical and subtropical areas. Dengue virus is distributed in more than 100 countries, a threat to the health of 2.5 billion people. This review provides a summary of recent studies on viral culture and detection techniques of the antigen, antibody, nonstructural proteins and nucleic acid. Evidence shows that marker detection, particularly rapid diagnosis, should include nucleic acid and/or nonstructural protein 1 test in combination with specific antibody assay.
Mosquitoes are an important, widely distributed vector of malaria dengue and Japanese encephalitis. An enormous number of studies have been conducted on this member from the insect family. This paper reviews the taxonomic characteristics of its fauna in China.
The detection of insecticide resistance in cockroaches is mostly done by a traditional biological test. However, recent studies have indicated that changes in a range of biochemical indicators and resistance genes are highly associated with the occurrence of such resistance, suggesting the possibility of timely, rapid and accurate detection of this occurrence by identifying the changes by biochemical and molecular biological means. Advances in such techniques are summarized in this article.
