ISSN 1003-8280 CN 10-1522/R 中国疾病预防控制中心 主办
Zika virus (ZIKV) disease is a mosquito-borne disease transmitted by Aedes mosquitoes. At present, the epidemic scope and magnitude of ZIKV and its vectors are extending constantly and have already constituted the focus of international communities. This article reviews the Zika epidemic situation, its main vectors, sustainable vector management and implication of dengue fever-based control strategies and relevant measures, the specific measures of vector control adopted by WHO memberships, and provides commendations for the prevention and control of ZIKV scientifically and effectively in future.
Objective To explore the relationships between mosquito density and land cover types. Methods Mosquito data in Guangzhou city were extracted from 1st-30th September 2014. Land cover types in towns of Guangzhou city were extracted based on geographical information system and remote sensing. The relationships between mosquito density and land cover types were explored based on epidemiological statistical method. The differences of mosquito density among towns were explored. Results Coverage ratios of irrigated croplands, water bodies and closed to open (>15%) grassland or woody vegetation on regularly flooded or waterlogged soil-fresh, brackish or saline water in towns with Breteau index (BI)>20, were 1.4%-35.7%, 0.1%-23.1% and 0-3.4%, respectively. These coverage ratios were higher than those in towns with BI≤5, amounting to 0-0.7%, 0-5.1% and 0, for the coverage types described previously. Compared with land cover types in adjacent towns with BI≤5, coverage ratios of irrigated croplands, water bodies and cropland/vegetation were higher and coverage ratio of rainfed croplands was even higher in towns with BI>20. Conclusion Mosquito density was closely related to irrigated croplands, water bodies and closed to open (>15%) grassland or woody vegetation on regularly flooded or waterlogged soil-Fresh, brackish or saline water.
Objective To preliminarily explore biochemical resistance mechanism by comparison the biochemical characteristic of carboxylesterase in pyriproxyfen-resistantand susceptible population of Culex pipiens pallens. Methods The activity of carboxylesteres (CarE) was determined by van Aspern(1962). Results The tendency of CarE activity change in hydrolyzing α-naphthyl acetate (α-NA) or β-naphthyl acetate (β-NA) depended on substrate concentration. The hydrolyzing activity was significantly higher in resistant population than in susceptible population with α-NA and β-NA as substrates within the certain concentration range. When substrate was β-NA, the Kinetic parameters (Km) and Vmax of CarE were 27.20×10-5 mol/L and 115.00×10-5 A/(mg·pro·min) in resistance population respectively, and that of CarE in susceptible population were 104.00×10-5 mol/L and 207.00×10-5 A/(mg·pro·min). Difference between them was significant (tb=2.74, tc=3.16). When substrate was α-NA, there was no significant difference between Km (131.00×10-5 mol/L) in resistance population and Km (75.20×10-5 mol/L) in susceptible population; but difference was significant between Vmax of them. The CarE from resistant population was more sensitive to DDVP (dichlorvos) and propoxur than that from susceptible population. Conclusion Enhanced CarE activity maybe attributable to the resistance of Cx. pipiens pallens to pyriproxyfen.
Objective Based on zoogeographical division of China, we analyzed the population characteristics of Culex pipiens pallens/Cx. pipiens quinquefasciatus including its composition, density, seasonal fluctuation and the distribution in different circumstances, it will be supportive for mosquito surveillance and control program. Methods The mosquito surveillance data based on light traps were extracted from the National Vectors Surveillance Networks in China. The data werer analyzed in accordance with the zoogeographical division of China respectively to obtain the species composition and distribution, the population density, the seasonal fluctuation by each zoological division. Results In 2014, the annual average density of Cx. pipiens pallens/Cx. pipiens quinquefasciatus was 1.20 mosquito/(trap·h). It was relatively low in January, February, November and December, and reaches the peak in July [3.45 mosquito/(trap·h)]. It was the predominant species both in the Southern [1.58 mosquito/(trap·h), 64.37%] and the Northern [2.31 mosquito/(trap·h), 81.97%] region of China. There was no record of Cx. pipiens pallens/Cx. pipiens quinquefasciatus in Mongolia-Xinjiang Region. The annual average mosquito density had significance variation (F=3.977, P=0.004) in different zoogeographical division, and the differences in the seasonal mosquito fluctuation were statistically significant (F=2.484, P=0.013). The mosquito density distribution of different habitats also showed with significance variation (F=4.569, P=0.001). Among them, the mosquito density of livestock sheds was relatively high [1.92 mosquito/(trap·h)]. Conclusion The Cx. pipiens pallens/Cx. pipiens quinquefasciatus' composition, density, and seasonal fluctuation showed difference with different zoogeographical distribution. The result is another evidence for the zoogeographical division of China, and the result might be a good example for analysis of mosquito surveillance. It may also serve as a basis for making the control decision in different zoogeographical divisions.
Objective To investigate the distribution features and laws of small mammals and ectoparasitic fleas in different landscapes in domestic rat plague foci in Southwest Yunnan and their relationship with plague prevalence. Methods Yunxian, Yongde, Jinggu, Ninger, Menghai and Mengla were sampling area of our research. The systematic investigation on small mammals and their ectoparasitic fleas distributed in different landscape ecosystem were carried out. The characteristics of the spatial distribution of diversity of small mammals and their ectoparasitic fleas were analyzed using community ecological indexes. Results There were 719 small mammals captured, which belonged to 19 species (subspecies), 12 genera, 6 families and 3 orders. Rattus tanezumi (55.77%) were dominant species. A total of 229 fleas were captured, and they were classified into 14 species (subspecies) of 11 genera in 5 families. Xenopsylla cheopis (57.21%) and Ctenophtha lmus lushuiensis (17.03%) were dominated species. Diversity index and evenness index of small mammals and ectoparasitic fleas in different landscapes was, in descending order, forest area> agricultural area> residential area. But the order of dominance index was opposite. Shannon-Wienne's diversity index(H') of small mammals captured in forest area, agricultural area and residential area was 2.28, 1.60 and 0.16 respectively, and that index of ectoparasitic fleas was 1.97, 1.75 and 0.15 respectively. Conclusion Landscape played a dominant role in community structure of host animals and fleas. Forest area helped to keep natural focus in domestic rat plague foci. Residential area was an important environment of plague prevalence. Agricultural area might be an important channel of transmission and prevalence of plague. Agricultural area played a pivotal role in long-term preservation, prevalence and diffusion of domestic rat plague foci.
Objective To understand the distribution of rodents, dynamics of rodent density and composition in hydro-fluctuation area of Three Gorges Reservoir after experimental storage, and provide evidence for the risk prediction and control of rodent-borne diseases. Methods Four surveillance sites were set in upper, middle and down reaches of the Three Gorges Reservoir and surveillance were carried out twice after water drainage and before water storage every year. The small mammal density and the species composition in different regions, altitude and periods were analyzed. Results During 2010-2014, a total of 116 small mammals were captured and the average capture rate was 1.10% and on the decline overall. The captured small mammals were classified into six species. Apodemus agrarius was the predominant species accounting for 46.55% and Anourosorex squamipes was next with 25.86%. The average capture rate after water drainage (1.23%) was higher than that before water storage (0.90%). All captured small mammals distributed in all three altitude and the composition decreased from high to low latitude. The predominant species was different in three altitude. The predominant species in 166-175 m altitude was A. squamipes accounting for 44.45%, followed by Rattus tanezumi (18.52% ); In 145-155 m and 156-165 m altitude, Ap. agrarius was predominant species accounting for 84.00% and 72.97%, respectively. Conclusion The average capture rate was low and there was various species of rodent in hydro-fluctuation area. The density and species composition of small mammals varies with different regions, altitude and monitoring time. The host animals of hemorrhagic fever of renal syndrome, Leptospinosis and commensal rodent plague may be of risks in hydro-fluctuation area of Three Gorges Reservoir. It should be strengthened to monitor the host animals and take the corresponding control measures in the area based on the risk assessment.
Objective House fly (Musca domestica) is a mechanical vector of many diseases which can cause severe consequences for human and animal health. Cytochrome P450 monooxygenases play an important role in resistance to many insecticides in the house fly. Establishment of functional expression system of NADPH-cytochrome P450 reductase will be helpful for the characterization of P450 mediated insecticide resistance. Methods In this study, we cloned the open reading frame of MdCPR gene into the expression vector pB508. The constructed plasmid MdCPR-pB508 was transformed into Escherichia coli (DH5α). The production of MdCPR protein in E. coli was induced by isopropyl β-thiogalactoside (IPTG). Results MdCPR was expressed in E. coli with an expected molecule weight of around 76×103. The E. coli-produced MdCPR protein was mainly present in the membrane fraction, showing the catalytic activity of NADPH-dependent reduction of cytochrome C. Conclusion The successful functional expression of MdCPR can facilitate further investigation of the role of various cytochrome P450s in insecticide resistance in house flies.
Objective To explore the spatial-temporal characteristics of hemorrhagic fever with renal syndrome (HFRS) in mainland China. Methods Demographic information and the annual number of incident HFRS cases in mainland China from 2004 to 2013 were collected. Retrospective time-space analysis (based on discrete poisson model) was conducted to detect the spatial and spatio-temporal clusters of HFRS cases in SaTScan (Version 9.1.1) after geographical information system database constructed via ArcGIS software (Version 9.3). Gravity centers of HFRS cases were calculated and depicted with bubble charts in Excel 2010. Results The number of HFRS cases decreased from 2004 to 2009 and increased with a gravity center northeast to that of population. The gravity center of HFRS cases in 2013 moved to southwest for 307.87 km compared to that of 2004 with the directional angle as 241.69 degree. The distance in longitude was 119.52 km and 282.61 km in latitude. The most likely cluster was in Heilongjiang, Jilin and Liaoning during 2004 to 2008 with the relative risk 9.22. The secondary cluster included four geographical areas, Shaanxi area (2008-2012), Shandong, Tianjin and Hebei area (2004-2005), Zhejiang province (2004-2007) and Jiangxi (2011-2013), the relative risks varied from 1.32 to 6.33. Conclusion There are significant spatio-temporal cluster pattern for the distribution of HFRS cases in mainland China, the epidemic status showed a weakening trend and the gravity center moved from northeastern part to northern China.
Objective This paper was intended to analyze the spatiotemporal patterns of the Japanese encephalitis (JE) in Henan province from 2006 to 2010, and explore the connection between JE incidence and the geographical environmental driving factors. Methods The JE incidence from 2006 to 2010 in Henan was analyzed with epidemiological research, spatial autocorrelation, and correlation method. The multiple linear regression model was also built to identify the impact of meteorological, surficial and socio-economic factors on JE. Results The total number of JE case is 2 729 with yearly incidence of 0.547 4 per 100 thousand people and the overall death case was 119 with mortality rate of 4.36%. The incidence outbreak from July to September, accounting for 97.08% of the whole year cases and the annual incidence declined in 2008 and then fluctuated until 2010. JE cases were mainly concentrated in the southwest area, and "hot spots" agglomeration was significant in Luoyang, Nanyang, and northern Xinyang city. In terms of the meteorological driving factors, rainfall, the number of rainy days, >80% humidity days and >25℃ cumulated temperature promoted the outbreak of JE, while >30℃ cumulated days and the maximum above 30℃ cumulated temperature would reduce the incidence. For the surficial factors, watershed density and cultivated area illustrated the significant correlation with incidence of 99% confidence. With the increase of income per capita in farmers and total number of health technical staff, the possibility of an outbreak of JE also decreased. The overall predicted R2 of regression model was 0.643 with the adjusted R2 of 0.414. Conclusion The southwest area in Henan province is the key area for JE management. Research on the geographical driving factors of JE disease, will have a significant effect on the prevention and control of JE incidence.
Objective To understand the epidemic characteristics of endemic typhus nearly 10 years in Zhejiang province, and provide a scientific basis for prevention and control. Methods Through the National Disease Reporting Information system, typhus cases data were collected in Zhejiang province from 2005 to 2014, analyzed by descriptive epidemiological methods. Results In total 39 typhus cases were reported in Zhejiang province from 2005 to 2014, the average annual incidence rate was 0.0086/100000. The incidence of the high risk season was June to September, and the cases were distributed in 6 cities, 18 counties (districts), and mainly in rural areas (87.18%). The male to female ratio was (1.05:1), the median age was 47 years old. The average time of clinical diagnosis and laboratory diagnosis were 10.0 d and 14.5 d, two diagnosis regimens of occupational distribution had statistically significant difference (χ2=7.257, P=0.006); gender constitute no statistical difference (χ2=1.293, P=0.256). Conclusion The key area of prevention and control typhus were rural and rural-urban fringe zone of Zhejiang province, health education in tourists and enhanced detection are warranted and improve the ability to detect.
Objective To investigate the species of small mammal hosts, ectoparasites, and infection of Yersinia pestis and Hantavirus at Guangdong 27 frontier ports, and to provide scientific evidence for implementing prevention and control interventions. Methods Small mammal hosts were captured by rat cages from May 2014 to April 2015. Lung specimens were collected, and followed by pathogen detection using PCR technique. Rodent borne disease was monitored in small mammal populations at frontier ports. Results In total 885 small mammal hosts were captured, the average density of small mammal hosts was 0.58%. The predominant species were Suncus murinus (47.68%) and Rattus norvegicus (33.67%). Xenopsylla cheopisi was collected. The flea-carrying rate was 0.79% and the flea index was 0.03. A total of 839 lung specimens were collected and SEO-type Hantavirus were positive in 10 entry-exit ports (positive rate: 2.74% ). The Hantavirus-carrying rate in R. tanezumi was the highest (7.45%). There were no significant differences of virus-carrying rate in four types of frontier ports. No Y. pestis was found. Conclusion The average density of small mammals was lower than control threshold and no plague infection was found among small mammals, but there were R. tanezumi and X. cheopisi, and high Hantavirus-carrying rate were found in several entry-exit ports. Prevention measures should be taken into consideration to prevent the rodent-borne diseases.
Objective To study the genotype of Yersinia pestis in Hebei plague foci by variable number of tandem repeat (VNTR). Methods Primers were designed according to the confirmed 14＋12 VNTR, to genotype the 116 Y. pestis DNA of Hebei province. Results All of the strains showed one genetype, but they were different from CO92 and EV. Conclusion There is only one genetype of plague, indicating a genetic stability in Y. pestis in Hebei province.
Objective The purpose of this paper was to evaluate the efficacy of 0.004% fipronil bait against Reticulitermes in the laboratory and the sites where Reticulitermes occurred. Methods Efficacy test of fipronil bait against Reticulitermes chinensis was conducted in the laboratory and efficacy test against R. chinensis and R. flaviceps of was conducted in the buildings where Reticulitermes occurred. Results In the laboratory, the death of R. flaviceps occurred massively after feeding with bait in three days. The average mortality rate reached to 78.00%. All of the workers and soldiers were dead in 8 d. The average feeding rate of baits was 5.15%. For the application studies, fipronil bait was used in 15 office buildings and residences for R. chinensis and R. flaviceps from 2009 to 2015. Reticulitermes were wiped out by a single application for 13 sites, and twice, three times for the other 2 sites, respectively. Conclusion Reticulitermes chinensis and R. flaviceps could be effectively controlled by 0.004% fipronil bait in the sites where they occur.
Objective To understand distribution and seasonality of Culex tritaeniorhynchus in Chaoyang district, Beijing. Methods According to the Surveillance Methods for Vector Density-Mosquito (GB/T 23797-2009), mosquitoes were collected by the CO2 traps. To determine the spatial distribution, the two types of sampling sites including park (or green spaces) with waters and human populated area were chosen in different geographical locations, and mosquitoes were trapped from August to September. To find out the seasonality, the mosquitoes were trapped per ten days from May to October in the same place. Results The proportions of sampling sites with Cx. tritaeniorhynchus between 2nd Ring Road and 3rd Ring Road, 3rd Ring Road and 4th Ring Road, 4th Ring Road and 5th Ring Road, outside 5th Ring Road were 1/2, 3/3, 4/8 and 3/6 respectively, and there were no statistically different in different area subdivided by ring road (P=0.570); the proportions of sampling sites with Cx. tritaeniorhynchus of parks (or green spaces) with waters and human populated areas were 76.92% (10/13) and 16.67% (1/6) respectively, and were statistically different (P=0.020); the Cx. tritaeniorhynchus densities between 2nd Ring Road and 3rd Ring Road, 3rd Ring Road and 4th Ring Road, 4th Ring Road and 5th Ring Road, outside 5th Ring Road were 0.09, 0.16, 0.31 and 4.97 mosquitoes per trap-hour respectively; the mean (m) and variance (S2) of densities of Cx. tritaeniorhynchus were 1.56 and 24.03, S2/m=15.42>1, which suggested that Cx. tritaeniorhynchus clumped distributed; the first appearance of Cx. tritaeniorhynchus was in the last twenty days of July, then its constituent ratio showed a trend from rise to decline and the peak period of its density was in September. Conclusion Culex tritaeniorhynchus tends to spread from suburb to city with the improvement of water conversation, and clumped distributed in urban area of Chaoyang district. Vigilance is needed to the epidemic risk of Japanese encephalitis, and public health department should strengthen the prevention and control measures.
Objective To understand and analyze the relationship between fleas and their indoor small mammal hosts in Yunnan province. Methods During 2009-2013, small mammals were trapped and fleas were collected off the hosts indoor in residential areas in the mountain and dam areas in 43 counties (cities, districts) of 5 different zoogeographical areas of Yunnan province. Levins niche width formula and Shannon-Wiener diversity index formula were used, to analyze the host trophic niche breadth of the fleas and diversity index of fleas and their hosts. Results In total 1925 fleas belonging to 13 species 11 genera 5 families were collected off 1 582 hosts animals belonging to 14 species 10 genera 5 families. Among 13 species of fleas, Paradoxopsyllus custodies, Lentistivalius ferinus, Ctenocephalides felis felis, Monopsyllus anisus and Leptopsylla segnis has higher hosts niche breadth and they were 0.252 5, 0.252 5, 0.252 3, 0.214 5 and 0.202 3. The highest diversity index of parasitic fleas was Rattus nitidus(1.5179), the second Mus musculus(1.3522), and the third R. norvegicus(1.116 6). Conclusion There is no relationship between flea diversity, and diversity and density of host animal as well as richness; to some extent, host niche breadth can reflect the specificity of adult fleas to hosts.
Objective To explore the status of mosquito infestation in different types of underground garages in downtown Shanghai, and to analyze the causes and suitable countermeasures. Methods Randomly selecting 101 underground garages in Shanghai Huangpu district, conducting mosquito breeding status investigation during July and August, 2014. Results Of the 101 underground garages, the crude and adjusted positive breeding-rate was 35.64% and 39.13%, respectively, and the positive breeding-sites rate was 21.36%. Compared with the commercial building garages, the positive rate of underground collecting-wells(UCWs)in residential garage was significantly higher, and the positive rate of UCWs in bicycle garages are significantly higher than those in car garages. Comparison of different types of garages shows that the mosquito infestation in large-scale garages and multilayer ones are much higher (77.78% vs. 28.13%, χ2=11.434, P=0.001; 29.63% vs. 12.86%, χ2=6.740, P=0.009). Conclusion Featured with high density of underground garages and high degree of underground mosquito infestation, mosquito control still have a long way to go in downtown Shanghai. Compared to chemical mosquito-control measures, physical ones are recommended.
Objective To determine the situation of Simuliids infected with mermithid nematode parasites and its infection rate of seasonal dynamic changes in Qingyan, Guizhou province. Methods From March 2013 to February 2014, larval blackflies were collected in Qingyan stream each month. The infection rates of mermithid nematodes were investigated and the seasonal changes were analyzed. Results There are Simulium (Wilhelmia) xingyiense Chen and Zhang, 1998 and Simulium (Simulium) wuzhishanense Chen, 2003 in Qingyan stream. Except 2013 October, the number of S. (S.) xingyiense larvae was collected more than S. (S.) wuzhishanense every month. Two kinds of Simuliids were the hosts of the mermithid. The green mermithid nematode infected S. (S.) xingyiense. But the white mermithid nematode infected S. (S.) wuzhishanense. The mermith infected 4.70% of 12 649 larvae of S. (S.) xingyiense, ranging from 1.26% to 21.57%. The mermith infected 20.84% of 3 694 larvae of S. (S.) wuzhishanense, ranging from 1.33% to 43.05%. The peak incidences in S. (S.) xingyiense occurred during the autumn. The peak incidences in S. (S.) xingyiense occurred during the winter. The parasitic rate of S. (S.) wuzhishanense is higher than S. (S.) xingyiense. Conclusion The infection rate of mermithid nematodes in simuliids changed with seasonal variations.
Objective To understand the status and developmental trend of vector-borne diseases, so as to provide reference for researchers of vector-borne diseases. Methods Using the GoPubMed database on-line analysis software, study the vector-borne disease articles by making analysis of years, country and city distribution, source journals, research topics and the authors. Results There were 3 214 matched literatures for vector-borne disease retrieved with an increasing number year by year, among which the United States rank the first in countries, Fort Collins in cities, American Journal of Tropical Medicine and Hygiene in journals and Roehrig J in authors. Conclusion GoPubMed is an excellent tool for retrieval and statistics function, it can show a vivid picture of the current situation and developmental trend of vector-borne diseases. Further improvements are needed both in the quality and quantity of management in vector-borne diseases in China.
Objective To explore the distribution of mosquito vectors and communicable disease pathogens, and provide the scientific reference for control of mosquito-borne communicable diseases in Zhoushan archipelago. Methods Mosquito larvae were collected by dipping and adult mosquitos were captured by light trapping. The species of all samples were identified and descriptively analyzed. The harborage of dengue fever, Chikungunya fever and Japanese encephalitis viruses were tested by polymerase chain reaction in adult mosquitos. Results We collected 106 mosquito larvae and 1 358 adult mosquitos. After identified, all mosquitos are classified to 2 subfamilies and 5 genus and 11 species. Aedes albopictus, Ae. togoi and Culex pipiens quinquefasciatus are predominant species in mosquito larvae. The predominant species indexes are respectively 0.472, 0.283 and 0.114. Adult Cx. tritaeniorhynchus (79.90%) and Cx. pipiens quinquefasciatus (19.86%) are widely distributed in Zhoushan city. Cx. annulus and Tripteroides aranoides are new species in Zhoushan city. Target viruses are negative in all mosquito samples. Conclusion Aedes albopictus, Ae. togoi, Cx. pipiens quinquefasciatus and Cx. tritaeniorhynchus are predominant species in Zhoushan city. The target viruses were not found in mosquito vectors in the city. We should pay more attentions to control mosquito-borne diseases due to the risk of outbreak caused by imported cases with corresponding vector-borne diseases.
Objective To isolate Gordonia from the gut of Periplaneta americana, and to carry on classification, identification and phylogenetic analysis on the Gordonia. Methods Taking the gut was acquired from captured P. americana by opening the abnormal with scalpel from the side after surface disinfection. After grinding, the homogenate was be diluted to the required concentration (10, 0.005, 0.0025 μg/ml). An aliquot of 0.1 ml was drawn on the tablet, and cultured at 28℃ for at least one week, to isolate the Gordonia. Finally, morphological observation and 16S rDNA gene sequences analysis were utilized to study their classification and identification. The sequence data were analyzed using Mega 5.1 software, maximum likelihood method, and phylogenetic tree. Results Six Gordonia were isolated and identified from the gut of wild P. americana. The gram stain was positive, the colonies were small, orange red, granular, the slightly wetsurface, with production of orange red pigment. The thalli was short rod. The mycelium was straight rod or spiral, without transverse septum, consistent with the basic characteristics of Gordon's bacteria. After the amplification of 16S rDNA gene, 1% agarose gel electrophoresis, six samples all showed target bands (1.5 kb), the sequencing results showed that the isolates were Gordonia. Phylogenetic tree analysis showed that the isolates obtained were close to the Gordon's genetic relationship in soil, plant and marine. Conclusion There is existing Gordonia in the gut of P. americana. The Gordonia isolated from soil, plants and marine have the function of degrading the biological macromolecules and absorbing heavy metals, which can lay foundation for further study of symbiont flora in P. americana.
Thirty four simuliid species from Xinjiang Autonomous Region, China are treated, comprising 8 new species and 26 named species. Belong in the genus three, Genus Metacnephia Crosskey (3 named species), Genus Sulcicnephia Rubtsov (2 named species) and Genus Simulium Latreille (8 new species, 21 named species), the subgenera Boophthora Enderlein (1 named species), subgenus Byssodon Enderlein (1 named species), subgenus Eusimulium Roubaud (1 new species, 1 named species), subgenus Gomphostilbia (3 new species), subgenus Schoenbaueria Enderlein (2 named species), subgenus Simulium Latreille (1 new species, 11 named species), subgenus Wilhelmia Enderlein (2 new species, 6 named species).
Objective To investigate the basic fauna and geographical distribution of blackflies in Huang Mountain and Jiuhua Mountain, Anhui province. Methods Immature stages of blackflies were collected from five different representative areas in Huang Mountain and Jiuhua Mountain by conventional methods, and were reared in the lab to produce adults. After the identification of the slide specimens, a list of blackfly species in Huang Mountain and Jiuhua Mountain and a discussion were provided. Results All the six species including a new species of blackflies from Huang Mountain and Jiuhua Mountain of Anhui province were reported. Conclusion There is a rich diversity of blackflies in Huang Mountain and Jiuhua Mountain of Anhui province, reflecting the fauna characteristics of central China region and Oriental realm of the junction zone.
Objective The study was conducted on Musca domestica for a better understanding of the distribution, density and seasonality, as well as the correlation between the M. domestica density and total flies density, thus providing basic evidence in fly control and prevention. Methods According to the National Vector Surveillance Guidelines (2005), three vector surveillance sites were selected in Tonghua. Fly-trap, using sugar-vinegar as baits, was placed at 09:00-10:00 and retrieved on 15:00-16:00 to determine the density of flies in four habitats: agricultural markets, restaurants, green belts and residence communities. Results Musca domestica was one of the predominant species in Tonghua, accounting for 15.91%-44.90% of all the collected flies. Musca domestica density reached highest in August. The proportion of M. domestica in the four habitats described previously were 48.03%, 61.07%, 4.40% and 10.03% respectively. There was a significant positive correlation between the density of M. domestica and that of the total flies with r=0.703, P<0.01. Conclusion Musca domestica populations can be an indicator of the total flies population. The critical period for controlling flies ranges from June to August when the fly density is very high. Musca domestica density is still high in residential environments in September, and prevention and control should be implemented.
Objective To evaluate enzyme immunostaining technique for detection of F1 antigen of Yersinia pestis in rodents. Methods Visceral organ specimens of 266 mice infected with virulent Y. pestis and 207 control rodent specimens were detected by horseradish peroxidase labeled plague F1 monoclonal antibody (HRP-F1McAb) enzyme immunostaining technique, and in comparison with the RIHA and RGICA methods．Results Coincidence was 98.52% between HRP-F1McAb enzyme immunostaining technique and RIHA, Kappa=0.970, and the difference was statistically significant in the positive detection rates (χ2=5.140, P=0.016); Coincidence was 98.50% between HRP-F1McAb enzyme immunostaining technique and RGICA, Kappa=0.901, with statistically insignificant difference in the positive detection rates (χ2=0.250, P=0.625). Sensitivity of HRP-F1McAb enzyme immunostaining technique was 100%, specificity was 97.02%, positive predictive value was 97.14%, negative predictive value was 100%, and Youden index was 0.970． Conclusion The enzyme immunostaining technique is sensitive and specific, fast and simple in detection of plague F1 antigen. It is a valuable detection technique in early and rapid diagnosis of plague in rodents．
Objective To investigate the species composition and distribution of mosquitoes, as well as the arbovirus harborage status in Xinjiang Uigur Autonomous Region, China. Methods Mosquito samples were collected via ultraviolet (UV) light traps and net. After being identified, the samples were preserved in liquid nitrogen. The virus carried by the samples was detected through molecular biological methods. Results A total of 3 550 mosquitoes were collected, which cover 7 species in 4 genera. In the aspect of species, Culex pipiens Linnaeus consists the largest part among the samples, which accounts for 54.28%. Followed the Cx. pipiens is Aedes caspius, accounting for 29.38%. Remaining 5 species accounted for 16.34%. The results of the molecular biological examination showed that following 8 virus are negative among our samples, which are genera of flavivirus, alphavirus, Bunia virus and Japanese encephalitis virus, Liaoning virus, Tahyna virus, tick-borne encephalitis, and West Nile virus. Conclusion The study demonstrates a general landscape of the species composition and distribution of mosquitoes in Xinjiang Uigur Autonomous Region. Although the result of the molecular biological examination were negative, it should not be ignored the risk of arbovirus infection, further and more developed researches are still required in this aspect.
Objective To understand the enzootic plague epidemic characteristics of Inner Mongolia Spermophilus dauricus plague natural foci in the ChaHaEr hill-Song Liao plains during 2001-2013, provided a scientific basis for future plague surveillance and management. Methods Collected plague monitoring data from 2001 to 2013 in the Inner Mongolia S. dauricus plague natural foci, used descriptive epidemiological method to analyze the data. Results From 2001 to 2013, 18 937 S. dauricus were captured, rat density was 0.88; In total 38 203 S. dauricus were combed for fleas, flea infection rate was 48.60%. Together 76 452 fleas were collected, fleas index was 2.00;One strain Yersinia pestis was identified from Meriones unguiculatus and 93 positive serum samples of S. dauricus were detected by IHA from 2001 to 2013. Conclusion Enzootic plague persists in natural foci which is mainly maintained by S. dauricus, while there has been no human cases reported.
Objective To understand the characteristics of rabies in recent 7 years in Shijiazhuang. To analyze the related epidemic factors of rabies and to provide basic evidence for management. Methods Collect the data about rabies in 2008-2014 of Shijiazhuang, analyze the characteristics and related epidemic factors. Results The number of rabies cases was 91 from 2008-2014, among which 83 cases were investigated. The ratio of male to female is 2.96:1, focused on above 40 years old. Mainly cases are famers, occupied 84.61%. Most of cases occurred in May to November, occupied 76.92%. Injury location was associated with incubation period, head bitten ones with the shortest incubation period of the injured. We found 53.01% cases haven't any preventive treatment after exposure. Total 75% of Ⅱ level exposure cases without full vaccination. The antiserum/immune globulin and vaccination were not done at the same time for Ⅲ level exposure cases. All of the animal's hurt cases were dogs, only 1.20% of dogs once were vaccinated. Conclusion The rabies occurred in summer and fall. Main cases are male, famers and above 40 years. The relevant factors as low rate of post-exposure prophylaxis and failed to have finished the necessary post-exposure treatment (PET) of the cases, nonstandard PET in hospital or local clinic, low rabies vaccination coverage in dogs might be responsible for rabies epidemics in Shijiazhuang.
Wolbachia is a genus of endosymbiotic alphaproteo bacteria infecting a wide range of arthropods and filarial nematodes, which can manipulates the reproductive mode of its hosts in various kinds of ways. Multilocus sequence typing (MLST) was proposed as a nucleotide sequence-based approach that could be applied to many bacteria. It analyzed allelic variation at multiple housekeeping loci by nucleotide sequencing of internal fragments. Here we make an overview on the state of Wolbachia genotypes and phylogeny, and the development of MLST analysis on Wolbachia. We also make a prospect on the application of MLST in the biological control of mosquito-borne diseases.
The plague is caused by Yersinia pestis, and happened in rodents. It could cause human infections. Research shows that the elements of plague existed in specific areas or the distribution of space attributes, those elements were Y. pestis, host and vector. The data with spatial attributes often depend on each other, every data was not independent, not completely satisfied for the classical statistical analysis. Using the spatial epidemiology method could solve this problem, and predicted plague outbreak more accurately. This article overviews the application status of spatial epidemiology for plague prevention and control in China.
High resolution melting (HRM) curve analysis technology is a new method applied to genotyping and detection of gene mutations and single nucleotide polymorphism. The new method on the basis of the melting curve analysis, replaces the unsaturated dye with the saturation one, and with the aid of the professional high resolution instruments. HRM has received much concerns in the related fields for its advantages, such as high sensitivity and specificity, contamination avoidance, ease of operation, higher speed and flux, it has been widely used in the identification of insects, bacteria, fungi, protozoa and the classification of virus.
