ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Culex pipiens pallens/Cx. pipiens quinquefasciatus is one of the mosquito species of widest distribution and greatest harm in China, and it is a major target of commonly used household insecticides. In order to know its resistance to the insecticides, surveillance and investigation on resistance of the insect were carried out at different times and in different areas of China using the WHO method, with a large amount of data, both published and non published. This review analyzes the characteristics and distribution of the resistance of Cx. pipiens pallens/Cx. pipiens quinquefasciatus to the commonly used household insecticides with the discussion on the factors associated resistance evolution, in order to provide evidence for mosquito prevention and control strategy development, for carrying out insecticide resistance surveillance smoothly in the net work of National Important Vectors Pesticides Resistance Surveillance System, and for insecticide resistance management in different areas.
Objective To determine the host selection and distribution of Ascoschoengastia indica on different small mammal hosts in different areas of Yunnan province. Methods A field survey was carried out in 19 counties of Yunnan province. The small mammal hosts were captured with mice cages and traps with baits. The chigger mites on the surface of two auricles were scraped off by a bistoury and then preserved in 70% ethanol. Species of each specimen of the chigger mites was identified using microscopy. Conventional statistical Methods were adopted to calculate the constituent ratios of A. indica on different hosts and in different areas, together with its prevalence and mean abundance on different hosts. Results A total of 1267 individuals of A. indica (1.36% of the total chigger mite species) were collected from the body surface of 3224 individual small mammal hosts of 7 species. The host specificity of A. indica was relatively high compared to that of other species of chigger mites, of which 94.40% were collected from the body surface of Rattus tanezumi. Conclusion The A. indica species are mainly distributed in southern and midwestern Yunnan with a high abundance, mostly on the body surface of R. tanezumi, a major reservoir host of tsutsugamushi disease.
Objective To observe the morphological changes of Hela human cervical carcinoma cells in vitro after treatment with the anticancer protein from Musca domestica larva hemolymph(MAC-1) protein derived from the immuned hemolymph of housefly larvae. Methods The growth inhibition rates and cytotoxic effects of Hela cells were measured with MTT assay. The treated cells were observed under inverted microscope and morphological changes were tested with HE and microscope. The ultrastructure changes were observed under transmission electron microscope. Results The MAC-1 protein could significantly inhibit the growth and proliferation of Hela cells in a dose- and time- dependent manner. Under inverted microscope, the Hela cells showed the apoptosis after treated with 12.5 μg/ml of the MAC-1 in 12 hours. The cells showed classic morphological features of apoptosis under light microscope and electronic microscope. Conclusion The MAC-1 protein inhibited proliferation and induced apoptosis of Hela cells in vitro.
Objective To identify Musca domestica insecticide resistance in Xianyang city for proper application of insecticides. Methods Topical dropping method was used to determine the LD50. Results The LD50 values of DDVP, beta- cypermethrin, deltamethrin and propoxur for M. domestica were 0.019, 0.098, 0.013 and 6.627 μ g/♀, respectively. The resistances ratios (R/S) to four insecticides were 4.71, 31.92, 20.63 and 31.02, respectively. Conclusion The resistance of M. domestica in Xianyang city to four insecticides in Xianyang city has developed to varying degrees, particularly that to beta- cypermethrin and propoxur. Development of resistance may be due to improper administration of insecticides in the agricultural and construction areas. Additional resistance monitoring, proper use of insecticides and comprehensive vector control strategies are key to preventing the occurrence of drug resistance in these vectors.
Objective To develop a multiplex fluorescenct quantitative PCR assay for rapid and simultaneous detection of Borrelia burgdorferi, Toxoplasma gondii and Plasmodium falciparm carried by rodents. Methods Specific primers and probes were designed to amplify the 23S rRNA gene of B. burgdorferi, the B1 gene of T. gondii and the SSU gene of P. falciparm. The sensitivity of the assay was detected by the fold dilution method. The other eight strains of rodent-borne bacteria were used to examine the specificity of the assay. The method was evaluated to detect B. burgdorferi, T. gondii and P. falciparm simultaneously in mice blood. Results A highly sensitive and specific multiplex fluorescent quantitative PCR assay was established for detection of B. burgdorferi, T. gondii and P. falciparm. The sensitivity was 5.5 copies/μl for B. burgdorferi, 12.8 copies/μl for T. gondii and 17.2 copies/μl for P. falciparm. Conclusion A multiplex fluorescent quantitative PCR assay was developed for detection of B. burgdorferi, T. gondii and P. falciparm, significantly reducing the time needed for simultaneous detection of the three rodent-borne pathogens．
Objective To investigate the resistance of Rattus norvegicus to the first-generation rodenticide, warfarin, in Zhanjiang, Guangdong. Methods Rats sampled from the urban areas were screened with a trial test indoor for non-selective feeding with baits containing 0.005% warfarin to observe the dose-response relationship. Results Among 37 eligible candidates for the resistance test, 29 were dead due to administration. The resistance of R. norvegicus was 21.62%, indicating the formation of a resistant community. There was no significant difference in the lethal dose and time between male and female rats (P＞0.05). The average intake of poison baits was 19.14±5.44 mg/kg, and the average time to death 7.34±3.51 days. Conclusion The first-generation rodenticide was no longer an agent of choice for control of R. norvegicus in Zhanjiang. Monitoring the changes in the resistance among rodent population was necessary for optimal allocation of resources.
Objective To identify palatable baits for Myospalax aspalax for the basis of poisonous baits during the pairing season. Methods M. aspalax were fed with different baits such as carrots, potatoes, sweet potatoes, corns, peanuts and naked oats in laboratory for comparison of palatability. Results The palatability index of carrots to potatoes, sweet potatoes, corns, peanuts and naked oats were 0.65, 0.36, 0.39, 0.25 and 0.44 when feeding alone, and 0.50, 0.90, 0.01, 0.21 and 0.13 when group feeding, respectively. Carrots were the best bait, followed by potatoes and sweet potatoes, while corns, peanuts and naked oats were of poor palatability. Conclusion Carrots, potatoes and sweet potatoes are good ingredients for the preparation of poisonous baits for killing M. aspalax.
Objective To determine the susceptibility of Niviventer confucianus to warfarin. Methods Baits with 0. 025% warfarin were randomly given in single-sex groups of five feeding periods. The time to mortality was analyzed using the Bliss software. Results There was no significant difference in the susceptibility between sexes (Pb＞0.05, PLFP50＞0.05). The LFP50, LFP95 and LFP99 of warfarin for N. confucianus were 2.48 (1.97-3.13) days, 5.96 (3.92-9.06) days and 8.56 (4.65-15.78) days, respectively. Conclusion According to the WHO-recommended LFP99-based criteria for rodent warfarin resistance, N. confucianus surviving more than 9 days under exposure to 0.025% warfarin were classified into the resistant strains.
Objective To establish a rodent risk assessment system for major industries based on risk recognition and evaluation and apply the system to the nine major industries of Nanchang. Methods A indicator matrix was built on the three epidemiological factors with which the risk recognition was initiated to analyze the rodent risk in all industries. Results Different extents of rodent risks were found in the industries, while a high risk of plague, hemorrhagic fever with renal syndrome and other rodent-borne diseases was seen in construction sites, bus stations and farm product markets. Moderate risks were found in hotels, restaurants, hospitals and supermarkets. Conclusion The risk assessment system may be used to predict rodent encroachment on special sectors and provide early warning to inform targeted control strategies.
Objective To identify the relationship between mosquito density and meteorological parameters for selection of appropriate predicting factors for the change of mosquito density in Yuncheng, Shanxi. Methods Spearman's rank correlation was used in the analysis of the correlation between meteorological parameters and mosquito density per month from 2007 to 2009. Stepwise regression analysis was performed to model the mosquito density change regarding meteorological parameters. Results Single wave was observed in the mosquito seasonal succession curve, indicating that mosquitoes arose early in July, reached a peak in August, and disappeared in October. It was found that mosquito density was correlated with temperature and atmospheric pressure other than sunshine time and relative humidity. Stepwise regression analysis showed that ap02 and ap1 could be used for predicting mosquito density, though ap1 was more practical. Ap02 reflected the average atmospheric pressure of the present month as well as the last two months, and ap1 indicated the atmospheric pressure in the last month. Conclusion Since mosquito density was correlated with meteorological parameters, its change could be predicted by an atmospheric pressure fitting model.
Objective To evaluate the application of black box method in mosquito surveillance by comparing the results from black box and lamp trap methods. Methods Two lamps were set at each surveillance site and one black box was put at a 10 m interval from each lamp. Surveillance was conducted twice every month. Results The total number of captured mosquitoes and the number of female mosquitoes by the lamp trap method was 3.50 times and 3.75 times higer than those monitored by black box method, respectively. The seasonal fluctuation curves reflected by both Methods were unimodal, with a peak in July. The monthly calculations of mosquitoes of the two Methods were highly correlated. Mosquitoes captured by the black box method included Culex pipens pallens (84.64%), Cx. tritaeriorhynchus (10.02%), and Anopheles sinensis (3.34%), and those by the lamp trap method were Cx. pipens pallens (80.47%), Cx. tritaeriorhynchus (11.79%), and An. sinensis (6.88%). Only a few Aedes albopictus and Armigeres subalbatus were trapped. The male-female ratios were similar between the two methods, whereas great difference in the mosquito number was found in distinct environments. Black box method was more effective in parks and hospitals than the other, while lamp trap was more effective in pasture lands and farms. Two peaks of mosquito density were shown on 05: 00 and 19: 00 with environmental difference between day and night. The day and night peaks of density were also present in parks, farms and pasture lands except hospitals and residential areas where only one night peak was shown. Conclusion With fewer requirements for equipment, operation skills and power supply, the black box method is an effective alternative to the lamp trap approach. Deployment before the night peak of density and collection after the early morning peak is recommended for mosquito monitoring.
Objective To investigate the effect of anisaldehyde on the olfactory behavior of Aedes albopictus. Methods Olfactory behaviors and host-seeking abilities of Ae. albopictus were tested with an olfactometer, and the inhibitory effects on their host-seeking abilities after delivery of anisaldehyde at a dose of 0.013-0.250 μg/cm3 for 24-96 h were observed. Results Anisaldehyde at 3.1%-99.0% effectively attracted Ae. albopictus when administered alone, though inhibited their host-seeking abilities (by 85.4%) at a high dose (99.0%) under exposure to the host odor. The host-seeking abilities of Ae. albopictus were noticeably reduced after administration of anisaldehyde at 0.050-0.250 μg/cm3 for 24-96 h, the inhibition rate being positively correlated with time and dosage. Conclusion Anisaldhyde was effective in attracting
Objective To analyze the epidemiological characteristics of dengue fever cases from 2006 to 2010 for determination of the risk of dengue fever outbreaks in Beijing. Methods Data of the reported dengue fever cases in Beijing were collected and analyzed for their epidemiological characteristics with SPSS software. CO2 trapping lamp method was used to monitor the constituent ratio and density of mosquitoes. Results A total of 23 imported dengue fever cases were confirmed, of which 95.65% (22/23) of the cases were at the age of 25-59 years. The male-female ratio was 4.75∶1. Among them, 69.57% (16/ 23) were office clerks. The constituent ratio and density of Aedes albopictus showed 25.71 times and 6.00 times increase in 2010 than in 2007, respectively. Conclusion The density of subdominant mosquito species (Ae. albopictus) has increased in recent years. Vector monitoring and control measures should be implemented effectively to reduce the outbreak risk.
Objective To evaluate the trapping effect of MT-1 carbon dioxide light - traps on adult Aedes albopictus. Methods A factorial design was conducted to compare six CO2 flow groups and one blank control at 7 sampled sites during 10 surveillance periods. The traps were placed at each sample site to collect mosquitoes, and were replaced with new devices with the flow rate adjusted every two hours between 02:00-22:00. Results (1)A total of 1122 adult mosquitoes were collected and identified as two species, including 939 Ae. albopictus;(2)Mosquitoes were collected more efficiently in the CO2 flow groups (F＝3.05, P＝0.01), and the highest number of collected mosquitoes was observed at a flow rate of 6 L/min;(3)The numbers of captured Ae. albopictus were statistically different in distinct surveillance periods(F＝2.98, P＝0.03), and most of them were captured during 18:00-20:00 and 04:00-06:00;(4)No difference was found in the captured Ae. albopictus at the sample sites (F＝0.47, P＝0.80). Conclusion The MT-1 carbon dioxide light-traps could be used to collect adult Ae. albopictus at a recommended CO2 flow rate of 6 L/min at dusk.
Objective To determine the characteristics and dynamics of mosquito population during the process of rapid urbanization, and to identify the relationships between the dynamic of main vectors and rapid urbanization. Methods The mosquito density was investigated for the past four years using the human-bait method. Results Five species of mosquito were captured, including Culex tritaeniorhynchus, Culex pipiens quinquefasciatus, Anopheles sinensis, Aedes albopictus, and Armigeres subalbatus. Cx. pipiens quinquefasciatus was predominant (92.27%), followed by Ar. subalbatus (3.98%). The proportions of Ae. albopictus and Cx. tritaeniorhynchus were relatively small, accounting for 1.62% each. The smallest was An. sinensis (0.51%). During a four-year study period, significant changes had taken place in the proportions of mosquito populations by comparison among the data in 2006, 2008 and 2009. The population of Cx. pipiens quinquefasciatus decreased while increased of that of Ae. albopictus. An. sinensis gradually disappeared as the time elapsed. The poplation of Cx. tritaeniorhynchus fluctuated largely in the study periods. In the evening, varieties of mosquito species showed distinct activity patterns. The biting time of Cx. pipiens quinquefasciatus and Cx. tritaeniorhynchus was from 19: 00 to 22: 00 in the evening with a peak after 21: 00. Ae. albopictus could be caught all the night with the main peak before 20: 00. A similar activity pattern was observed from Ar. subalbatus and Ae. albopictus. Conclusion During the process of rapid urbanization, the population of the dengue vector, Ae. albopictus, increased gradually. The population of the Japanese encephalitis vector, Cx. tritaeniorhynchus, fluctuated greatly in different years. However, the malaria vector, An. sinensis, eventually was not found. Thus, we propose that the surveillance and control of Ae. albopictus and Cx. tritaeniorhynchus should be strengthened during the process of urbanization.
Objective To determine the current post - exposure treatment for rabies and analyze the risk factors for development of targeted intervention strategies. Methods Household survey based on multi - stage sampling method was adopted, and 40 villages from 4 counties was conducted followed by descriptive epidemiological analysis. Results A total of 38.68% households had cats or dogs at home with a dog density of 8.97/100 people. The coverage rate of rabies vaccine was 31.87%. The average annual exposure rate among the residents was 2.22%, and higher exposure rate was found in those having dogs or cats at home or aged less than 15 years old and students. Many exposures were related to visiting dog-keeping families. Injuries were mostly lower limb injury and grade Ⅲ exposure. However, only 28.23% of the patients self-treated immediately after exposure, and some used herbs or other improper approaches. Three quarters of the patients visited a doctor after exposure with an average cost of 416.68 RMB, but 4.30% of them refused to inoculate rabies vaccine. Moreover, 93.55% of those with Ⅲ level exposure had not obtained passive immunization. Conclusion Rural residents were at high risk of rabies exposure, most of which were caused by house dogs. Inadequate knowledge and economic support were the key factors which contributed to improper post-exposure treatment.
Objective To determine the current resistance of the Blattella germanica (L.) to commonly used pesticides in Tianjin, and provide evidence for better cockroaches control. Methods The residual film method recommended by WHO was applied to measure the median knockdown time (KT50) for B. germanica. Batches of B. germanica were exposed to five insecticide residues (dichlorovos, acephate, propoxur, betacypermethrin and permethrin) in glass jars to determine their knockdown resistance levels. Resistance ratios were calculated as RR50＝KT50 of the test strain/KT50 of the susceptible strains. Results The KT50 for field-collected B. germanica in Nankai, Jinnan, Hexi, Tanggu, Dongli, Xiqing and Beichen were 6.15, 6.49, 8.37, 8.22, 7.84, 9.29 and 12.40 min to dichlorovos, 74.28, 65.36, 29.52, 30.23, 30.67, 58.64 and 33.08 min to acephate, and 24.97, 40.63, 27.17, 24.43, 40.73, 42.44 and 40.91 min to propoxur, respectively. The RR50 values for B. germanica of dichlorovos, acephate and propoxur were below 3. The KT50 to betacypermethrin for field populations in Nankai, Tanggu and Xiqing were 32.61, 36.50 and 51.00 min respectively, with the RR50 ranging from 6.48 to 10.71 times. The values for Jinnan, Hexi, Dongli and Beichen were all greater than 120.00 min, with the RR50 greater than 20. The KT50 to permethrin for field populations in Nankai, Jinnan, Hexi, Dongli and Beichen were all above 120.00 min, with the RR50 greater than 20. However, the KT50 value for Xiqing strains was 26.96 min, with the RR50 lower than 5, and the value for Tanggu population was 14.10 min, with the RR50 lower than 3. Conclusion B. germanica control in Tianjin requires reduced administration of betacypermethrin and permethrin along with increased carbamates such as propoxur and organophosphorus pesticides such as dichlorovos and acephate.
Objective To determine the species distribution of Ceratopogonidae from Heilongjiang province. Methods Biting midges were collected using human-baited net traps, light traps, animal-baited traps and insect nets to generate data on the species distribution in Heilongjiang province. Results A total of 421 000 biting midges were collected, which belonged to 3 subfamilies, 13 genera and 89 species, including one new species recorded Culicoides heilongjiangensis Liu et Ren sp. nov. The subfamily Dasyheleinae belonging to one genus and 5 species, subfamily Forcipomyiinae belonging to 3 genera and 23 species, subfamily Ceratopogoninae belonging to 9 genera and 61 species, and bloodsucking midges of 2 genera and 47 species were recorded. The distribution of 89 known species of biting midges in various cities of Heilongjiang was recorded. Conclusion The investigation informed the faunal distribution of Ceratopogonidae in Heilongjiang, China. C. heilongjiangensis Liu et Ren sp. nov. is alike to C. duddingstoni Kettle et Lawson, 1955 in the wing spots, but the latter is noticeably distinguishable by shape of male hypopygium. Shape of male hypopygium of this new species is also alike to C. poperinghensis Goetghebuer, 1960, but the latter is distinctly characterized by shapes of ninth sternum, ventral root of basistyle, and distal portion of aedeagus. The type specimen is stored at the Shenyang Command Center for Disease Control and Prevention, Shenyang 110034, Liaoning Province, China
Objective To determine the species of fleas infected with Yersinia pestis in the plague foci in Inner Mongolia and analyze the role of fleas in the epidemiology of plague. Methods Data on the species and location of infected fleas in this area were collected from the epidemiological surveillance in past years. Results Y. pestis were found from 30 out of 122 subspecies in Inner Mongolia. Conclusion The major vector fleas from three of the four foci in this area are able to carry the infection, and almost all minor fleas have been infected.
Objective To identify the major vectors of mosquito-borne diseases and their geographic distribution after the outbreak of dengue fever (DF) in Yiwu, providing basis for further prevention and control. Methods Light traps and dippers were used to collect mosquito adults and larvae, respectively, based on random sampling. Results At least 8 species in 4 genera belonging to 2 subfamilies were found in the region. Culex pipiens pallens coquillett was the dominant species found in 234 villages and 13 towns. Although there were few Aedes albopictus (Skuse) and other species collected from the traps, it was the only vector of DF in Yiwu that distributed in 10 towns and 18 villages, a result of the breeding place survey on mosquito larvae. Ae. albopictus larvae accounted for the highest proportion (51.7%) of the mosquito population, followed by Cx. tritaeniorhynchus, while other species including Cx. mimulus were limited. Conclusion In view of the widely distributed vectors of mosquito-borne diseases in Yiwu and regional concentration of high density, breeding sites should be eliminated to cut off the primary transmission route of vector-borne diseases in order to lay a sound foundation for further prevention and control.
Objective To survey the species, distribution, habitat, behavior of vectors of Japanese encephalitis in Zichuan district and Gaoqing county of Zibo, Shandong. Methods The human baited net traps, mosquito nets, lamp baited traps and labor-hour Methods were employed to investigate the mosquito counts of three habitats-rice field, domestic fowls shed, and household. The environmental factors were documented. Fifty mosquitoes from each group were preserved in liquid-nitrogen jars for viral isolation under laboratory settings. Results Of the 3116 mosquitoes collected, 7 species of 5 genera were found. Most mosquitoes were captured from the rice field, followed by the domestic fowl shed and the household, accounting for 61.6%, 24.1% and 14.3% , respectively. Culex tritaeniorhynchus and Cx. pipiens pallens were dominant species, accounting for 66.1% and 19.1%, respectively. In Zichuan district where there were no rice fields, Cx. pipiens pallens was dominant (43.6%). In contrast, in Gaoqing county where rice field was common, Cx. tritaeniorhynchus was dominant (68.5%). Of the mosquitoes captured, 62.4% were by the human baited net traps, 16.6% by lamp baited traps, 14.6% by labor-hour methods, and only 6.4% by net traps. The peak of activity of Cx. tritaeniorhynchus and Cx. pipiens pallens occurred 0.5-1 h after sunset, while the latter showed obviously activity 20 min later than the former. Conclusion The probable main vector was Cx. tritaeniorhynchus. Human baited net trap and lamp baited trap could be most suitable for investigation and surveillance of mosquitoes in field, combined with the labor-hour and net catching approaches.
Objective To investigate the species distribution and population composition of bloodsucking mosquitoes and midges at Raohe port in Heilongjiang province. Methods Bed curtains, light traps and insect nets were used to collect mosquitoes and bloodsucking midges. Results From 2008 to 2009, 90 214 mosquitoes and bloodsucking midges were captured in the region, which belonged to 63 species of 6 genera, 2 families, including 28 species, 4 genera of Culicoidae and 35 species, 2 genera of Ceratopogonidae. Culicoides haerbalingensis were recorded for the first time at Raohe port. The predominant species of mosquitoes was Aedes vaxans (84.94%). The predominant species of bloodsucking midges were Culicoides sinanoennis (37.19%), C. obsoletus (20.03%) and C. punctatus (20.04%). The population composition of mosquitoes and bloodsucking midges varied in different habitats. Conclusion This investigation provided baseline data on bloodsucking mosquitoes and midges for formulation of the prevention and control strategies.
Objective To compare the efficacy of light and CO2 trapping lamps in laboratory and field settings. Methods The Methods of CO2 trapping lamp and light trapping lamp were used in this study. Results The two trapping lamps were both effective in attracting mosquitoes. The capture rates were 45.33% for light lamps and 71.67% for CO2 lamps in the laboratory, and the captured mosquito density was 10.56/lamp·hour and 20.43/lamp·hour, respectively. Culex pipiens pallens, Anopheles sinensis and Aedes albopictus were collected with a female-to-male ratio of 0.88∶1 and 4.57∶1 using the two methods, respectively. Conclusion Both trapping lamps could be used alone or in combination for accurate mosquito monitoring dependent on the habitat and purposes.
Objective To investigate the distribution of Aedes aegypti in Mangshi to inform dengue fever control. Methods Aedes adult mosquitoes were captured by human-landing catches around villages at both designated and random locations in the daytime to identify the composition and distribution of local mosquito species. Aedes larvae were collected in various types of water container inside and outside residential areas to calculate the mosquito larvae container positive index (CI), breteau index (BI), house index (HI) and thousand-person index. Results In designated villages, 38 adult mosquitoes from four species were captured, including 18 Ae. albopictus (47.37%); seven Aedes larva-positive water containers were found from 408 water containers, and the larval CI, BI, HI and thousand-person index were 1.72, 0.92, 1.23, and 12.26, respectively. In random locations, 4132 adult mosquitoes were collected, including seven Ae. aegypti (0.17%) and 2614 Ae. albopictus (63.23%); 170 water containers were investigated outside the villages, in which 20 water containers were positive with a larva-positive container index of 11.76. Nine positive containers were found from 152 water containers in 31 households, and the larva-positive CI, BI, HI and thousand- person index were 5.92, 6.12, 22.58, and 60.80, respectively. Conclusion Ae. aegypti were found in Mangshi for the first time. Ae. albopictus was widely distributed and locally predominant. Thus, the competent authority shall strengthen vector monitoring for aggressive dengue fever control.
Objective To determine the species composition and density of vectors in Yushu quake-stricken areas to inform vector control. Methods The mosquito and fly density was investigated by visual estimation for five types of habitat at five tents or mobile houses in each of the temporary shelter. The rodent density was measured by bite-stealing method. Results No mosquito activity was found in the areas. The densities of flies and rats were 0.69/m2 and 4.12%, while the highest fly density was observed in June, as well as in toilets and garbage. The overall density of rats peaked in May and inside the Dangdai community. Conclusion The overall fly and rodent density was generally low, though the fly density from June to July was high enough to justify an additional vector control action. Vector control is required based on the surveillance Results in the area to maintain environmental and public health.
Objective To compare the killing effects of smoke generator, aluminium phosphide and bromadiolone baits against rodents in the port of Erlianhaote, Inner Mongolia. Methods The rodent density was investigated by powder tracking and burrow-checking both indoor and outdoor, respectively. Integrated management such as 0.005% bromadiolone once-baiting, sanitation and rodent - proofing program were adopted in warehouses; and smoke generators, aluminium phosphide and bromadiolone baits were deployed in hungriness region of Meriones unguiculatus. Results The rodent density was 15.85% in warehouses and 19 to 23 holes/hm2 outdoor. After treatment, the killing rate was 89.53% in warehouses and 100% in the other 3 outdoor sample sites. Conclusion Indoor rodent control should be taken using integrated management approaches, and baits used in the outdoor regions. Smoke generator and aluminium phosphide had good killing effects. Under emergency situation, doubling the rodenticide dosage may achieve complete rodent control.
Objective To investigate the community density and carrying status of flies to inform the related control strategies in Kalamay. Methods Cage traps were deployed to monitor fly density. Captured flies were anesthetized, counted and identified. Colony count, coliform and pathogens were detected in accordance with the National Standard Test Method (GB/T 4789-2003). Results The average density of flies was 9.6 per cage in the area. The dominant species was Musca, which accounted for 57.0 % of the total captures, while Lucilia accounted for 30.9% and Sarcophaga for 9.1%. Colony count, yeast and fungi and coliform were respectively 4.3×105 CFU, 1.2×105 CFU and 973 MPN per fly. Conclusion Despite low density, the flies in Kalamay are carrying a wide range of microorganisms, including a number of conditioned pathogens.
Objective To determine the population distribution and seasonal dynamics of cockroaches for effective prevention and control in Lanzhou. Methods The sticky recapture method was used with sweet fresh bread baits (2 g/slice), one trap deployed for each 15 m2. Results Blattella germanica was the dominant indoor species. The average encroachment rate was 17.10%, as the vector was mostly found in hotels (33.57%) and residential areas (19.40%) with an average density of 2.95 on each sticky piece. The highest density was seen in hotels (4.45 per piece a night). Cockroach activities were present throughout the years with a peak period from May to November. Conclusion B. germanica was the dominant species in Lanzhou, encroaching mainly on hotels, residential areas, farm produce markets and catering establishments. Additional prevention and control measures should be delivered to these places.
Objective To determine the epidemic dynamics and epidemiological patterns to inform the prediction, warning and countermeasure developmens to plague in Dali. Methods Monitoring of plague hosts, vectors and etiology was conducted in the state from 2008 to 2010 in accordance with the National and Yunnan Provincial Plague Monitoring Programs. Results Rodents belonging to 15 species, 7 genera, 3 families of 2 orders were collected. Rattus tanezumi and R. norvegicus were the dominant species both indoor and outdoor. Apodemus chevrieri and Eothenomys miletus were predominant in the field. Nine species, 9 genera, 4 families of 1 order of rodent-borne fleas were found. Leptopsylla segnis and Xenopsylla cheopis were mainly seen on R. norvegicus, X. cheopis and L. segnis on R. norvegicus, Frontopsylla spadix and Neopsylla specialis specialis on A. chevrieri, and Ctenophthalmus quadratus on E. miletus. F. spadix and N. specialis specialis were the secondary vectors. A total of 17 649 animal samples, 7549 vector samples and 7391 rodent serum samples were detected and found negative. Conclusion Despite stable composition of hosts, vectors, density and indices in the natural foci of plague in Dali, continuous occurrence of plague epidemics in recent years along Lijiang region warranted an intensified monitoring and sound preparation.
North to Torrid Zone, Hainan province has favorable natural conditions to arthropod reproduction and the spread of arboviruses, as evidenced by several outbreaks of dengue fever and endemic Japanese encephalitis (JE). Arboviruses, including four alphaviruses (Chikungunya virus, Mayaro virus, Getah virus, Ross River virus), two flaviviruses (JE virus and Dengue virus) and one seadornavirus, have been isolated from various vectors and host animals in this province. This article reviews current studies on arboviruses and arboviral infections to humans and livestocks, in order to inform prevention and control both locally and nationwide.
Wide application of insecticides has resulted in severe resistance in the German cockroach (Blattella germanica). This study reviews the discovery and molecular and evolutional mechanisms of the knockdown resistance (kdr), also known as the sodium channel resistance, with emphasis on the molecular structure, functional research Methods of kdr mutations and up-to- date representative results. In addition, the latest findings are summarized to inform the prevention, control and resistance monitoring of the cockroaches.
Objective To investigate the patterns of supervision on pest control services for the external environment. Methods The performance of pest control in the environment of external community throughout the city that pest control operation (PCO) companies contracted with was evaluated by a project supervision panel through public bidding, as the third- party specialist agency, on a commission basis by Office of Patriotic Health Movement of Wuhan, according to its internal “supervision scheme.”Results The Results of evaluation on the performance of pest control in 683 to 784 external-community environment units that PCO companies contracted with from 2007 to 2010 were obtained. The four-year rodent density was ≤ 1.25% (bait stealing), the positive rate of mosquito larvae and pupae ≤2.19% (visual method), and the positive rate of cockroach adults and nymphae indoor ≤0.51% (drug induced or visual method). The Results met the required standards set forth by the National Patriotic Health Campaign Committee. Conclusion Through the supervising evaluation campaign, the quality of pest control in PCO companies was improved, the density of the four pests in the environment of external-community of Wuhan city under control, the living environment of residents bettered, and both local government and residents satisfied. Suggestions for improvement of the common issues found during the supervising evaluation process are put forward.
