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Objective To investigate the seasonal Aedes population fluctuation and the resistance of Aedes populations to common insecticides in Jiangsu Province in 2020, so as to provide insights into vector-borne infectious diseases control.. Methods One village was randomly sampled from each of Xinbei District of Changzhou City and Zhangjiagang County of Suzhou City in southern Jiangsu Province, Hai’an County of Nantong City and Yandu District of Yancheng City in Central Jiangsu Province, and Suining County of Xuzhou City and Sihong County of Suqian City in northern Jiangsu Province during the period between May and October, 2020. A small ponding container was sampled, and larval Aedes mosquitoes were collected using straws once each in early and late stages of each month. All larvae were bred in laboratory to adults for population identification. In addition, larval breeding were observed in all small ponding containers in and out of 30 households that were randomly sampled from six surveillance sites, and the larval mosquito density was estimated using Breteau index. Larval A. albopictus mosquitoes were sampled around Cuiyuan New Village in Jintan District of Changzhou City, and bred in laboratory to the first offspring generation, and the susceptibility of adult female mosquitoes to deltamethrin, lambda-cyhalothrin, malathion, and propoxur was tested using the filter-paper bioassay recommended by WHO. Results A total of 1 165 larval Aedes mosquitoes were captured from small ponding containers in six surveillance sites of Jiangsu Province in 2020, and all were identified as A. albopictus following eclosion. The largest number of Aedes larvae captured was found in July. A total of 1 152 households were investigated in six surveillance sites, and the mean Breteau indexes were 9.58, 13.20, 13.71, 13.20, 12.18 and 5.58 from May to October, respectively, while a high Aedes transmission risk was seen in Xinbei District of Changzhou City, with a higher Breteau index than in Suining (H = 23.667, Padjusted = 0.001) and Sihong (H = 22.500, Padjusted = 0.003) counties. The field-captured A. albopictus from Cuiyuan New Village in Jintan District of Changzhou City remained sensitive to malathion, but was resistant to propoxur, and developed high-level resistance to deltamethrin and lambda-cyhalothrin. Conclusions A. albopictus was present in southern, central and northern Jiangsu Province in 2020, and the larval density peaked in July. A. albopictus captured from Cuiyuan New Village in Jintan District of Changzhou City has developed high-level resistance to pyrethroid pesticides.
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Objective To understand the population,density,seasonal fluctuation and nocturnal pattern of malaria vectors in Jiangsu Province,thus to provide evidences for malaria elimination in this province. Methods Seven counties(cities,dis?tricts)were selected as the monitoring sites for malaria vectors in Jiangsu Province from 2013 to 2015. The mosquitoes were cap?tured by human bait trapping in bed nets and mosquito?lured lamp overnight,and the seasonal fluctuation and nocturnal pattern of malaria vectors were observed. Results A total of 11 041 Anopheles sinensis mosquitoes were captured by the mosquito?lured lamps in 7 counties of Jiangsu Province from 2013 to 2015,and no An. anthropophagous was found. Among all the 7 monitoring sites,the number of An. sinensis captured in Sihong County was the most(6 742 mosquitoes),while that in Xuyu County was the least(34 mosquitoes). During this period,the density peaks of An. sinensis were the first half of July,the first half of August and the second half of July. A total of 2 421 An. sinensis were collected in 7 monitoring sites from 2013 to 2015 by human bait trapping in bed nets overnight. Among all the 7 monitoring sites,the captured number of An. sinensis in Sihong County was the most(1 085 mosquitoes),while that in Ganyu County was the least(13 mosquitoes). The nocturnal peak of An. sinensis was from 19:00 to 20:00 and 525 An. sinensis mosquitoes were captured during this period of time,which accounted for 21.68%of the total. Hereafter,the captured number of An. sinensis reduced over time. Conclusion The density of An. sinensis mosquitoes is still high in individual areas in Jiangsu Province,so the epidemic and vector monitoring still should be strengthened to prevent the local transmission of imported malaria.
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Objective To explore the effect of different temperatures on the different development stages of Aedes albopic?tus. Methods The changes at different development stages of mosquitoes(egg,larva,pupae)and gonotrophic cycle were ob?served at different temperature conditions of 10,15,20,25,30,35℃and 40℃. The full developmental cycles were com?pared during different temperatures. Results All the stages of the mosquitoes could not develop at 10℃. Under the different temperatures of 15,20,25,30,35℃and 40℃,the hatchabilities of the mosquitoes were 0,32%,82%,83%,82%and 59%respectively;the pupation rates of the mosquitoes were 38%,53%,84%,88%,72%and 42%respectively;and the emer?gence rates of the mosquitoes were 92% 95% 97% 97% 83%and 17%respectively. The mosquitoes could well develop at 20 25 30℃and 35℃ the development time was 37.73 18.50 16.92 and 13.66 days respectively. Conclusion The devel?opment time of Aedes albopictus is shorter at the higher temperature. The optimum temperature for the mosquitoes to develop is between 25-30℃ and higher or lower the temperatures will suppress the development of the mosquitoes.
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Objective To understand the epidemic situation and influencing factors of malaria in Jiangsu Province and grasp its epidemic regularity and trend. Methods According to the malaria prevalence in Jiangsu Province,6 counties(city,dis-trict)including Yixing,Suining,Wujin,Hai’an,Ganyu and Xuyi were selected as provincial surveillance sites to survey malar-ia epidemic conditions. The basic information,blood test results of fever patients,case investigation information of malaria pa-tients,monitoring data of investigation and disposition of the malaria focus were collected and analyzed. Results In 2013,the blood tests of 66 723 fever patients were performed,the average blood smear checking rate was 1.10%,and the average positive rate was 0.08%(52 plasmodium positive individuals)in the 6 areas. For these 52 plasmodium positive individuals,the blood re-tests and case investigations were completed within 3 days after these cases were reported by the network system,and the investi-gation confirmed that they were foreign imported malaria cases. The malaria focus investigation and disposition were finished within 1 week and the data were reported by the Parasitic Diseases Information System. Four of 52 cases were recrudescence dur-ing the follow-up. Among the 52 cases,20 people went abroad themselves and 4 were labors of private enterprises,21 people came back without the accompanied. Conclusions With the development of the malaria elimination program in Jiangsu Prov-ince,the eliminating malaria“targeted 1-3-7”working pattern has been comprehensively implemented. The personnel monitor-ing for labors who returned from overseas working will be a key in the future.
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Objective To evaluate the toxic effect of Bacillus thuringiensis var. israelensis(Bti)wettable powder against Ae-des,Culex and Anopheles larvae. Methods The biological assay was applied to test the lethal concentration of 50%(LC50)of Bti wettable powder against Aedes,Culex and Anopheles larvae. Results The LC50(s) of Bti wettable powder against Aedes albopictus, Culex pipiens pallens and Anopheles sinensis larvae were 0.104,0.160μg/ml and 0.324μg/ml,respectively;its biological poten-cies against them were 0.125,0.192 IU/ml and 0.389 IU/ml,respectively. The LC50(s) of continuous contact of Bti wettable powder with An. sinensis stageⅢlarvae for 1,2 d and 3 d were 0.324,0.092μg/ml and 0.032μg/ml,respectively,and its biological po-tencies were 0.389,0.110 IU/ml and 0.038 IU/ml,respectively. The LC50(s) of the bacteria against An. sinensis stageⅠ,Ⅱ,Ⅲ,Ⅳwere 0.024,0.137,0.324 μg/ml and 0.450 μg/ml,respectively,and the biological potencies were 0.029,0.164,0.389 IU/ml and 0.540 IU/ml,respectively. Conclusion Bti wettable powder has a good toxicity to Aedes,Culex and Anopheles larvae,espe-cially for the latter two. It is better to apply the bacteria at the early stage of mosquito larvae.
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Objective To explore the sample reIated factors affecting the short-term culture of erythrocytic Plasmodium dvax in vitro.Methods The vivax malaria blood samples were collected from the patients with malaria in endemic areas,and then incubated with McCoy's 5A medium in an incubator containing 5%CO_2 at 37℃.The factors affecting the short-term culture of Plasmodium vivax were analyzed.Results Plasmodium vivax could finish one asexual cycle in the selected medium.By analyzing the culture results of 74 samples.it was found that the factors affecting the short-term culture included long time delaying al room temperature(>4 h),single stage(only parasites in ring stage were found),patients taking antimalarials,antibiotics or sulfonamides.and low parasitemia.Conclusion The sample related factors are important to the short-term culture of erythrocytic Plasmodium vivax in vitro.
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Objective To establish a simple,convenient,quick and high sensitive method of loop-mediated isothermal amplification (LAMP) for detection of Plasmodium vivax-carrying mosquitoes.Methods The species conservative regions of P.v CSP gene were selected to design 2 pairs of primers which recognized 6 distinct regions.To evaluate the specificity of detection by LAMP,infected Anopheles,An.sinensis (An.s),Plasmodium falciparum (P.f),and healthy human blood DNA were selected as templates.To assess the sensitivity of detection,1.3×10~6,1.3×10~5,1.3×10~4,1.3×10~3,1.3×10~2,1.3×10~1 and 1.3×10~0 copies of P.v CSP plasmid DNA mixed with 1.0 μl An.s DNA were used as the templates of LAMP.The infected An.s DNAs were diluted with negative An.s DNA by 1:2,1:4,1:8,1:16,1:32,1:64,1:128 and 1:256 and then detected by LAMP to show the sensitivity of batch quantity detection.The applied value of this method was evaluated by detecting the same batch of 67 artificial infected An.s mosquitoes,and compared with the detection of microscopic examination and nested PCR in parallel.Results By using LAMP,the detection of infected An.s was positive,while the control samples were all negative.The limits of detection of different proportion dilutions of the mixture of P.v CSP plasmid DNA with An.s DNA were 1.3×10~2 copies.The limits of detection of different proportion dilutions of the mixture of infected An.s DNA with An.s DNA were 1:128.The positive rate of detecting the same batch of 67 artificial infected mosquitoes was 47.76% by LAMP,25.37% by the microscopic examination (X~2 = 7.24,P0.05).Compared with the test of the microscopic examination and then with a statistical analysis,the sensitivity of LAMP was 100%,which agreed well with the sensitivity of nested PCR (100%).Conclusion The method of LAMP is simple,convenient and high sensitive,and it is a potential method for detecting Plasmodium vivax-carrying mosquitoes in the field.
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Objective To observe the residual effect of Demand CS - impregnated bednets to Anopheles sinensis.Methods The numbers of adult mosquitoes which were knocked down at every minute after treatment were observed by using the enforced contact method recommended by WHO,and the mortality of mosquitoes tested after 24 h was calculated.Results The Kt_(50) of Demand CS - impregnated bednets with impregnations concentrations of 10,15,20 mg/m~2 to Anopheles sineasis were 21.40,16.20,15.70 min,respectively,and the 24 h mortality was 100%.The Kt_(50) of Responsar SC (12.5 % Beta - cyfluthrin) impregnated bednets with a impregnation concentration of 15 mg/m~2 to Anopheles sinensis was 16.06 min,and the 24 h mortality was 100%,too.Conclusions Both the Demand CS - impregnated bednets and the Responsar SC impregnated bednets can kill Anopheles sinensis.
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Objective To analyse the epidemic characteristics and control measures of malaria in Jiangsu Province during the past fifty years, evaluate the control effect and explore the current appropriate control strategy and measures. Methods The historical data about malaria cases and control measures from 1951 to 2008 in Jiangsu Province were collected, and the effects of malaria control in different stages were assessed. Results The integrated control measures with emphasis on the control of infectious source were adopted during the stage of two outbreaks of malaria. In the stage of basical elimination of malaria, the comprehensive measures with emphasis on the vector control in the areas of Anopheles anthropophagus were adopted, and the measures with emphasis on the surveillance of infectious source surveillance and early treatment of malaria in other areas were adopted. In the stage of consolidation, the measures including the surveillance of infectious source and management, surveillance of vector and epidemic situation, management of floating population, etc, were adopted. The malaria incidence dropped from 2 495/10 000 in 1960 to 0.09/10 000 in 2008, and was under 1/10 000 in all the counties of Jiangsu Province during the past 2 years, which demonstrated the various measures were feasible and effective in different stages of malaria. Conclusions Malaria has been controlled effectively in Jiangsu Province, however, the improvement of early diagnosis and norm treatment of malaria cases, the enhancement of health education and promotion, as well as the malaria surveillance and management among floating population, are still necessary for achieving the goal of malaria elimination.
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Objective To investigate the differences of HCV infection rates among blood donors of different Chinese nationalities.Methods Anti-HCV results from more than 300000 blood donors of 41 nationalities from 8 provinces or autonomous regions were investigated and analyzed.Serum anti-HCV antibody was tested by ELISA.Results(1)The anti-HCV prevalence rate was 0.98%(676/68782) among first time blood donors;0.71%(1750/245137) among repeated donors;and the overall anti-HCV prevalence rate among all the blood donors was 0.77%(2426/313919).The anti-HCV prevalence rate was higher among first time donors,compared to repeated donors(P
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Objective To investigate the clinical application of suspended red blood cells in Liuzhou,in order to make the transfusion of blood components more reasonable and safer.Methods Retrospective data were collected from 226 patients,who had received the transfusion of 980 units of suspended red blood cells between 2000 and 2006.Results Suspended red blood cells could be used widely to different kinds of patients,and most patients benefit from the treatment.The transfusion of leuko-reduced RBC was even more effective.The age,gender,category of disease,disease severity,hemoglobin level and the amount of transfusion were the key points that affect the therapeutic effect of transfusion.Traumatic hemorrhage was another important factor.Unreasonable clinical transfusion still exists.Conclusion Transfusion of suspended red blood cells is an effective treatment.But when and how to transfuse depend on individual cases.
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Objective To analyze the genetic characteristics of ribosomal DNA ITS 2 region for differenciating anopheline mosquitoes within Hyrcanus group. Methods The ribosomal DNA ITS 2 region of both laboratory line and filed collected An. anthropophagus and An. sinensis as well as the field collected An. yatsushiroensis and An. lester i were amplified and sequenced. The sequencing data were then analyzed for the restriction mapping using Omega Sequencing analysis program. Results and Conclusion The length of the sequences of An. sinensis, An. anthropophagus, An. yatsushiroensis and An. lesteri are 472, 452, 456 and 456 bp respectively. The restriction mapping showed that there were different restriction digesting sites among the ribosomal DNA ITS2 region sequences from An. sinensis, An. anthropophagus, An. yatsushiroensis and An. lesteri . On the basis of the sequence differences among the anopheline species within Hyrcanus group, it is possible to develop new technique for genetic identification of anopheline mosquitoes.
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Objective To study the relationship between P450 (CYP6 and CYP4) genes and deltamethrin resistance in Anopheles anthropophagus. Methods The real-time RT-PCR technique was used for semi-quantitative analysis of mRNA copy numbers of CYP6 and CYP4 gene from susceptible and deltamethrin-resistant strains. Results It is found that the mRNA copy numbers of CYP6 gene in deltamethrin-resistant strain were about 1. 39 times higher than those in susceptible strain, and the mRNA copy numbers of CYP4 gene in deltamethrin-resistant strain were about 3. 63 times higher than those in susceptible strain of Anopheles anthropophagus. Conclusion The higher expressions of CYP6 and CYP4 mRNA are observed in deltamethrin resistance strain and indicate that both CYP6 and CYP4 genes may be involved in the deltamethrin resistance in Anopheles anthropophagus.
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Objective To establish a fast and sensitive method to detect Plasmodium sporozoites in mosquitoes. Methods Anopheles anthropophagus (An.a) artificially infected with Plasmodium vivax (P.v), Anopheles dirus (An.d) infected with Plasmodium falciparum (P.f) and both of P.v and P.f, field mosquitoes of Anopheles sinensis (An.s) captured in epidemic seasons were detected by nested-PCR. Results The results of 28 batches of An.a infected with P.v, 2 batches of An.d with P.f and 1 batch of An.d mixed with P.v and P.f by nested-PCR were accorded with the microscopical examination absolutely. Two positives of 589 An.s field mosquitoes were discovered with a positive rate of 0.34%. Conclusion The nested-PCR is fast and sensitive for detecting different species of Plasmodium in mosquitoes.
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Objective To analyze the genetic characteristics of deltamethrin resistant strain of Anopheles anthropophagus. Methods The study was performed with LC-P curve method for the genetic mode of deltamethrin resistant of An. anthropophagus. Results The resistant coefficient of F_1 generation from cross and reciprocal cross were 15.19 and 16. 66 respectively. The LC-P curve of F_1 generation got near to that of resistant parents (D=0.651). There were no obvious platforms in 50% mortality of BC generation and 25% - 75% mortality of F_2 generation.There were significant differences between the determining curve and theoretical cure in both BC and F_2 generations, P
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Objective To compare the susceptibility of Anopheles anthropophagus from Jiangsu, Guangdong and Liaoning provinces in China to Plasmodium vivax.Methods The blood samples of patients with P. vivax in endemic areas of China were collected to feed the mosquitoes of An. anthropophagus from different areas by using the artificial in vitro membrane feeding system in the lab, and then the mosquitoes were dissected during the 7-9th day and on the 14th day after the feeding and the oocysts and sporozoites in the stomach and salivy gland of mosquitoes were counted. Results The mosquitoes from Jiangsu, Guangdong and Liaoning were simultaneously fed with the blood of 35 cases of P. vivax. The oocyst positive rates of An. anthropophagus from Jiangsu, Guangdong and Liaoning during the 7-9th day after the feeding were 68.57%, 60.00% and 68.57%, as well as the sporozoite positive rates of them on the 14th day after the feeding were 22.86%, 14.29% and 22.86%, respectively. On the 7th day after the feeding, 228, 235, 228 mosquitoes of An. anthropophagus from Jiangsu, Guangdong and Liaoning were dissected, and the positive mosquito rates with oocyst infection were 28.07%, 25.11% and 26.75%, respectively. On the 14th day after the feeding, 150, 142, 135 mosquitoes of An. anthropophagus from the three areas were dissected, the positive rates with sporozoite infection were 10.67%, 8.45% and 11.85%, respectively. The num-bers of mosquitoes dissected with infective grade("+","++","+++","++++") of sporozoites of An. anthropophagus from Jiangsu, Guangdong and Liaoning were 4, 3, 2, 7; 2, 2, 3, 7 and 1, 6, 3, 8, respectively. Conclusions An. anthropophagus from Jiangsu, Guangdong and Liaoning is susceptible to the parasites of Plasmodium vivax and there is no significant difference among the susceptibilities of An. anthropophagus from the three areas to Plasmodium vivax.
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Objective To compare the growth of Plasmodium vivax in Anopheles sinensis(An.s) and Anopheles anthropophagus(An.a) during the periods of malaria clinic attack and diapause. Methods The blood samples of patients during the clinic attack and diapause of vivax malaria patients in the vivax epidemic area in China were collected, feeding the mosquitoes of An.s and An.a by using the artificial membrane feeding system in vivo in the lab, and the mosquitoes were dissected during the day 7-9th and 14th after the infection and the oocysts and sporozoites in the stomach and gland of the mosquitoes were counted, respectively. Results The oocyst positive rate in An.s fed by Plasmodium vivax during the fever stage was lower than that in non-fever stage, the sporozoite positive rate in An.a fed by Plasmodium vivax during the fever stage was lower than that in non-fever stage. The positive mosquito rate with oocyst and sporozoite infected by Plasmodium vivax in the fever stage to An.s and An.a were lower than those in non-fever stage. The infective sporozoite intensity of An.s fed by Plasmodium vivax in the fever stage was lower than that in non-fever stage, but the reverse result was found to An.a. Conclusion There is a significant difference between the periods of malaria clinic attack and diapause of the oocyst and sporozoite infection to An.s and An.a.
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Objective To understand the current status of malaria prevalence,its impacts and malaria transmission trends in Jiangsu Province.MethodsThe malaria incidence,and its symptoms,mosquito preventive measures,Anopheles density,mosquito biting rates and related factors were investigated in malaria epidemic villages as surveillance sites such as Guanshan Town of Suining County,Tangzhang Town of Tongshan County,Tianganghu town of Sihong County,Qiuji Town of Xuyi County and Zhangzhu Twon of Yixing City.ResultsIn 2006,the bednet coverage was 20.29% and bednet-using rate was 34.32% in 27903 residents of 7921 households of 15 administrative villages.In 2005,750 Anopheles sinensi were captured from 50 bednets in the early morning,the human biting ratio was 0.17/person per night,and in 2006,1927 Anopheles sinensi were captured from 50 bednets in the early morning,human biting ratio was 0.38/person per night.The average blood smear checking rate was 2.72%(6089 people)and the average positive rate was 0.48%(29 plasmodium positive individuals).ConclusionThe lower blood smear microscopy testing,few positive rates of febrile patients and increased Anopheles sinensis density were the main factors of malaria relapses in the area of the North Huaihe River in Jiangsu Province.
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ObjectiveTo observe the effectiveness of Responsar against Anopheles sinensis and Anopheles anthropophagus. MethodsThe cotton and nylon gauze absorbing Responsar solutions of 10,15 and 20 mg/m~2 (effective dosage) were used in the test. An. sinensis and An. anthropophagus raised in the lab were used as probational worms, having the knockdown power, lethiferous power and effective keeping observation. ResultsWith Responsar of 10,15 and 20 (mg/m~2) impregnating two different kinds of bednets, the KT_(50(s)) of An. sinensis and An. anthropophagus were between 3.98 and 7.30 min after touching the bednets. The knocked down mosquitoes were resumed breeding for 24 h, and the mortality was 100%. Touching nets 3 min, resuming breeding for 24 h, the mortality of mosquitoes was more than 90%. The nets hung for 180 d after impregnated with the insecticide and the knockdown power was still between 8.57 and 16.31 min for Anopheles vector, and resuming breeding for 24 h, the mortality was still 100%. ConclusionThere is strong deadly effect of Responsar to Anopheles sinensis and Anopheles anthropophagus, and the effect can keep more than 180 d.
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Objective To obtain cDNA fragment of CYP6 gene from Anopheles anthropophagus. Methods The degenerate RT-PCR technique was used to amplify the CYP6 mRNA from susceptible and deltamethrin-resistant strains of An.anthropophagus. The specific cDNA fragments were sequenced and analyzed. Results The 250 bp specific cDNA fragments of CYP6 gene from both susceptible and resistant strains were cloned and sequenced by the Direct Cloning Method. Total of 10 sequences, including 2 from susceptible strain and 8 from resistant strain, were obtained. Compared with P450 sequence databases from GenBank, all of the 10 sequences obtained were new P450 sequence and were lodged in GenBank (Accession numbers: AY273927-AY273936). According to being checked up by Nomenclature Committee of Cytochrome P450, 7 of them were confirmed as the new CYP6 genes and the others were alleles and all of them belonged to the subfamilies CYP6Z, CYP6P, CYP6N and CYP6M in CYP6 family, respectively. Conclusion The cloned 10 sequences are gene fragments from members of CYP6 family.[