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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 create risk predictive models of healthcare-seeking delay among imported malaria patients in Jiangsu Province based on machine learning algorithms, so as to provide insights into early identification of imported malaria cases in Jiangsu Province. Methods Case investigation, first symptoms and time of initial diagnosis of imported malaria patients in Jiangsu Province in 2019 were captured from Infectious Disease Report Information Management System and Parasitic Disease Prevention and Control Information Management System of Chinese Center for Disease Control and Prevention. The risk predictive models of healthcare-seeking delay among imported malaria patients were created with the back propagation (BP) neural network model, logistic regression model, random forest model and Bayesian model using thirteen factors as independent variables, including occupation, species of malaria parasite, main clinical manifestations, presence of complications, severity of disease, age, duration of residing abroad, frequency of malaria parasite infections abroad, incubation period, level of institution at initial diagnosis, country of origin, number of individuals travelling with patients and way to go abroad, and time of healthcare-seeking delay as a dependent variable. Logistic regression model was visualized using a nomogram, and the nomogram was evaluated using calibration curves. In addition, the efficiency of the four models for prediction of risk of healthcare-seeking delay among imported malaria patients was evaluated using the area under curve (AUC) of receiver operating characteristic curve (ROC). The importance of each characteristic was quantified and attributed by using SHAP to examine the positive and negative effects of the value of each characteristic on the predictive efficiency. Results A total of 244 imported malaria patients were enrolled, including 100 cases (40.98%) with the duration from onset of first symptoms to time of initial diagnosis that exceeded 24 hours. Logistic regression analysis identified a history of malaria parasite infection [odds ratio (OR) = 3.075, 95% confidential interval (CI): (1.597, 5.923)], long incubation period [OR = 1.010, 95% CI: (1.001, 1.018)] and seeking healthcare in provincial or municipal medical facilities [OR = 12.550, 95% CI: (1.158, 135.963)] as risk factors for delay in seeking healthcare among imported malaria cases. BP neural network modeling showed that duration of residing abroad, incubation period and age posed great impacts on delay in healthcare-seek among imported malaria patients. Random forest modeling showed that the top five factors with the greatest impact on healthcare-seeking delay included main clinical manifestations, the way to go abroad, incubation period, duration of residing abroad and age among imported malaria patients, and Bayesian modeling revealed that the top five factors affecting healthcare-seeking delay among imported malaria patients included level of institutions at initial diagnosis, age, country of origin, history of malaria parasite infection and individuals travelling with imported malaria patients. ROC curve analysis showed higher overall performance of the BP neural network model and the logistic regression model for prediction of the risk of healthcare-seeking delay among imported malaria patients (Z = 2.700 to 4.641, all P values < 0.01), with no statistically significant difference in the AUC among four models (Z = 1.209, P > 0.05). The sensitivity (71.00%) and Youden index (43.92%) of the logistic regression model was higher than those of the BP neural network (63.00% and 36.61%, respectively), and the specificity of the BP neural network model (73.61%) was higher than that of the logistic regression model (72.92%). Conclusions Imported malaria cases with long duration of residing abroad, a history of malaria parasite infection, long incubation period, advanced age and seeking healthcare in provincial or municipal medical institutions have a high likelihood of delay in healthcare-seeking in Jiangsu Province. The models created based on the logistic regression and BP neural network show a high efficiency for prediction of the risk of healthcare-seeking among imported malaria patients in Jiangsu Province, which may provide insights into health management of imported malaria patients.
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Objective To understand the situation related to health seeking and diagnosis of imported malaria and to provide practical measures for malaria elimination in Jiangsu province.Methods Data on imported malaria cases in Jiangsu province was retrieved in CISDCP from 2014 to 2016.Relevant information on health seeking behavior,diagnosis and treatment of the disease was gathered.Results A total of 1 068 imported cases were reported in Jiangsu province from 2014 to 2016.Except for one malaria case that was caused by blood transfusion,the rest patients were all recognized as'imported'.Majority of the cases were migrant laborers working in African countries.The accurate rates on the diagnosis of ovale,vivax and quartan malaria and mixed infection were relatively low,as 79.3％ (107/135),29.5％ (18/61),52.9％ (18/34) and 0.0％ (0/2) at the primary health care settings,respectively.Rate of seeking health care on the same day of onset was more in 2015 than in 2014 and 2016 (X2=18.6,P=0.001).While only 65.4％ (699/1 068) of the patients were diagnosed correctly at the primary health care settings.There appeared no statistical difference in the 3-year-study period (x2=5.4,P=0.246).Capacity on'correct diagnosis' seemed stronger at the CDC than at the hospital levels (x2=13.2,P=0.000;x2=5.4,P=0.020).Totally,72.7％ (32/44) of the severe falciparum malaria cases did not immediately seek for health care when the symptoms started.Conclusions Migrant workers returning from the high endemic malaria areas seemed to have poor awareness in seeking health care services.Capability on correct diagnosis for malaria at the primary health care settings remained unsatisfactory and staff from these settings needs to receive adequate training.
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Objective To understand the situation related to health seeking and diagnosis of imported malaria and to provide practical measures for malaria elimination in Jiangsu province.Methods Data on imported malaria cases in Jiangsu province was retrieved in CISDCP from 2014 to 2016.Relevant information on health seeking behavior,diagnosis and treatment of the disease was gathered.Results A total of 1 068 imported cases were reported in Jiangsu province from 2014 to 2016.Except for one malaria case that was caused by blood transfusion,the rest patients were all recognized as'imported'.Majority of the cases were migrant laborers working in African countries.The accurate rates on the diagnosis of ovale,vivax and quartan malaria and mixed infection were relatively low,as 79.3％ (107/135),29.5％ (18/61),52.9％ (18/34) and 0.0％ (0/2) at the primary health care settings,respectively.Rate of seeking health care on the same day of onset was more in 2015 than in 2014 and 2016 (X2=18.6,P=0.001).While only 65.4％ (699/1 068) of the patients were diagnosed correctly at the primary health care settings.There appeared no statistical difference in the 3-year-study period (x2=5.4,P=0.246).Capacity on'correct diagnosis' seemed stronger at the CDC than at the hospital levels (x2=13.2,P=0.000;x2=5.4,P=0.020).Totally,72.7％ (32/44) of the severe falciparum malaria cases did not immediately seek for health care when the symptoms started.Conclusions Migrant workers returning from the high endemic malaria areas seemed to have poor awareness in seeking health care services.Capability on correct diagnosis for malaria at the primary health care settings remained unsatisfactory and staff from these settings needs to receive adequate training.
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Objective@#To investigate the current status of malaria rapid diagnostic test (RDT) strips application and malaria laboratory technicians' evaluation about them at primary healthcare provider level in Jiangsu Province.@*Methods@#From November to December 2016, 878 medical institutions and 118 CDCs of city, county and township/community level in Jiangsu Province were selected as study samples using stratified random sampling method. Self-designed questionnaire was distributed to investigate the institution's malaria work task, RDT strips application and evaluation status in 2015. We also investigated the socio-demographic information and collected the RDT strips evaluation score from the malaria laboratory technicians selected from the institutions investigated (one technician from each institution). Rank sum test was performed to compare the RDT strips evaluation scores between medical institutions and CDCs, and among different medical institutions and CDCs.@*Results@#In 2015, 405 cases of malaria were reported, 362 200 person-time of malaria blood testing task was conducted, and 100 000 RDT strips were procured and provided for healthcare providers in Jiangsu province for free. Of the 996 healthcare institutions investigated, 628 used RDT strips in the year 2015 and the median (P25, P75) of RDT strips volume used in these institutions was 10 (2, 25). The volume of RDT strips used in CDCs (15 (5, 52)) was significantly higher than that in medical institutions (10 (2, 25), (Z=3.42, P=0.001)). The investigated CDCs gave higher score on RDT strips' testing time per operation (10 (8.5, 10)) than medical institutions (9(8, 10), (Z=-2.20, P=0.028)). The employers of 614 investigated malaria laboratory technicians used RDT strips in 2015. The median of the scores given by CDC malaria laboratory technicians for RDT strips in terms of testing time per operation, testing operation and results judgement difficulties were 10 (9, 10), 10 (9, 10) and 10 (9, 10), respectively, which were significantly higher than those from technicians of medical institutions (9 (8, 10), 9 (8, 10), 9 (8, 10), (Z values were -2.55, -2.97 and -2.96, respectively; P values were all less than 0.05)).@*Conclusion@#RDT strips had been widely performed in health institutions in Jiangsu Province. The amount of RDT strips used in CDCs was significantly higher than that in medical institutions. Primary-level institutions and malaria laboratory technicians generally recognized RDT strips' advantage for application in terms of testing time and operational procedure. CDCs and malaria laboratory technicians from them gave higher regards on RDT strips in terms of testing time per operation, testing operation and results judgement difficulties compared with that of medical institutions.
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Objective To understand the malaria epidemic situation and characteristics in Jiangsu Province in 2015,so as to provide the evidence for malaria elimination. Methods The data of malaria cases in Jiangsu Province in 2015 were collected from China's routine diseases surveillance information system. Results Totally 405 imported cases were reported in Jiangsu Province in 2015,and the cases increased by 14.08％compared with those in 2014. All the malaria cases were imported,and 5 cases(1.23％)were from Southeast Asia and 400(98.77％)were from 25 African countries or regions. The imported malaria cases were reported in 13 cities across Jiangsu Province,where Taizhou,Lianyungang,Nantong,Huaian and Yangzhou cities accounted for 68.64％of all the cases in the province. Jiangsu Institute of Parasitic Diseases(JIPD)reference lab checked all the cases and classified 299 falciparum malaria cases,13 vivax malaria cases,18 quartan malaria cases,71 ovale malaria cas-es,and 4 mixed Plasmodium infection cases. Conclusions In Jiangsu Province,there are no local malaria cases for 4 consecu-tive years,but the imported cases are on the rise. Compared to 2014,the imported vivax cases increased significantly in 2015. It should be the key points to strengthen the surveillance of imported malaria cases,improve malaria diagnosis and treatment abili-ties for all levels of medical institutions,and promote the abilities of Plasmodium check,and focus survey and disposal of all Center for Disease Control(CDC)staffs across Jiangsu Province.
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Objective To understand the integrated ability of parasitic disease prevention and control of professional person-nel of Jiangsu Province through the contest. Methods Totally 56 players from the whole province were selected,and all the players participated in the contest. The theory knowledge and skill scores were collected and the statistical analyses were con-ducted. Results The average theoretical score of the participants was 88.86±15.56 and the passing rate was 91.1％. The aver-age skill operating score was 69.16 ± 16.01 and the passing rate was 67.9％. The average Plasmodium microscopy score was 16.54±8.09 and the passing rate was 50％. The average helminth egg microscopy score was 34.27±10.66 and the passing rate was 67.9％. There were statistical differences among the age groups and different levels of schistosomiasis endemic situation (F =5.10,6.39,both P<0.01). The theoretical knowledge including schistosomiasis,malaria,hydatid disease and others and the score rates were 91.07％,90.94％,85.83％and 90.93％,respectively. The hydatid disease score rate was lower(χ2=19.17, P<0.01). The radar chart displayed that the score rates of tabletting and microscopy test in Kato-Katz film production ,malaria blood film production and microscopy test were all low. Conclusion In Jiangsu Province,the participants have higher score in the theory test. However,they have lower skill test score,especially in the parasite species identification. The operational skills still need to be strengthened for center for disease control(CDC)participants.
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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 analyze the channels of going abroad of imported malaria patients in Jiangsu Province,so as to provide the evidence for the control of imported malaria and health intervention for high?risk population. Methods The data of imported malaria cases in Jiangsu Province in 2015 were collected and the channels of going abroad were analyzed. The Quan?tum GIS 1.7.4 software was applied to map. Results Totally 405 imported cases were reported in Jiangsu Province in 2015, and the cases increased by 14.1%compared with those in 2014. All the patients were migrant workers. The migrant workers were mostly sent abroad by construction companies[43.21%(175/405)]. The dispatching companies were mainly concentrated in Taizhou,Lianyungang,Zhenjiang and Yangzhou cities,accounting for 6.17%(25/405),3.21%(13/405),2.72%(11/405) and 2.22%(9/405),respectively. Totally 176(43.46%)patients returned to China having accompanied workers,and 1.21%(9/745)of accompanied workers were found having symptoms of malaria later. Conclusions It is difficult to monitor malaria in overseas migrant works in Jiangsu Province. The channels of going abroad of migrant workers are various and complicated ,for?mulating the main difficulty and challenge of imported malaria control.
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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 epidemiological characteristics of malaria in Jiangsu Prov?ince from 2005 to 2014,so as to provide the evidence for formulating and adjusting the strategies and measures on malaria elimi?nation in this province. Method The epidemiological data of malaria in Jiangsu province from 2005 to 2014 were collected, and the prevalence situation,infection sources as well as the temporal,regional and population distribution of the cases were an?alyzed. Result A total of 5 069 malaria cases were reported in Jiangsu Province form 2005 to 2014,there were 3 422 cases (67.51%)of vivax malaria,1 497 cases(29.53%)of falciparum malaria,and 150 cases(2.96%)that were unclassified. Among all the reported cases,2 139(42.20%)were local cases,1 131 were(22.31%)imported cases from other places in Chi?na ,and 1 799(35.49%)were imported cases from abroad. There were 3 809 male cases and 1 260 female cases,with a sex ratio of 3.02∶1. The patients were mainly aged from 25 to<60 years(accounting for 67.15%),and were mainly young adult farmers (40.26%)and migrant workers(23.63%),who mainly distributed(accounting for 60.58%)in Xuzhou,Suqian,Huai’an,Su?zhou and Nantong cities. The predominant malaria type from 2005 to 2009 were vivax malaria,while after 2010,it changed to falciparum malaria. Conclusions The malaria epidemic situation has been effectively controlled in Jiangsu Province,which re?flects the initiative achievements of malaria elimination. However,there are still many imported malaria cases from abroad,and the species of the Plasmodium are diverse. Therefore,the imported malaria from abroad still remains the key of malaria control in Jiangsu Province.
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Objective To understand the malaria epidemic situation and characteristics in Jiangsu Province in 2013,so as to provide the evidence for formulating and adjusting effective malaria elimination strategies and measures. Methods The re-ported malaria cases from the Internet Reporting System and the epidemiological data of malaria in Jiangsu Province were collect-ed and analyzed. Results A total of 341 malaria cases were reported in Jiangsu Province in 2013 with the incidence of 0.050/10 000,which increased by 72.22% compared with that in 2012(198 cases). All the cases were imported from other countries including one infected by blood transfusion resulted from imported infection. The cases were mainly distributed in Li-anyungang City(15.84%,54 cases),Nantong City(14.08%,48 cases),Yangzhou City(14.08%,48 cases),Huaian City (11.44%,39 cases)and Yancheng City(8.50%,29 cases). All the cases were confirmed in Jiangsu Provincial Reference Labo-ratory and there were 286 cases of Plasmodium falciparum,8 cases of P. vivax,9 cases of P. malariae,30 cases of P. ovale and 8 cases of mixed infections. Conclusions There were no local malaria cases reported from Jiangsu Province in the last two years which reflected effective achievements of malaria elimination. However,the situation of imported malaria is more serious and the species of infected plasmodium are more diverse. Imported malaria from other countries remains the key of malaria con-trol in Jiangsu Province.
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Objective To understand the malaria epidemic situation and characteristics in Jiangsu Province in 2012,so as to provide the evidence for formulating and adjusting effective malaria elimination strategies and measures. Methods The reported malaria cases from the Internet Reporting System and the epidemiological data of malaria in Jiangsu Province were collected and analyzed. Results A total of 198 malaria cases were reported in Jiangsu Province in 2012 with the incidence of 0.026/10 000, which decreased by 47.06%compared with that in 2011(374 cases). A total of 198 malaria cases were reported from 13 prefec-tures of Jiangsu and the cases were mainly distributed in Yangzhou(34 cases),Nantong(31 cases),Nanjing(22 cases),Tai-zhou(21 cases),Xuzhou(17 cases)and Huaian(17 cases),which accounted for 71.72%(142/198)among the total cases of the province. There were no local malaria cases reported from Jiangsu in 2012,and the imported malaria cases from other countries de-creased by 45.15%compared with that in 2011. Conclusions For the first time,there are no local malaria cases reported from Ji-angsu in 2012. However,the imported case distribution is further expanded and the infected plasmodium parasites are more di-verse. Imported malaria from other countries remains the key for malaria control in Jiangsu Province.
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Objective To evaluate the effect of automatic early warning information system on the response of malaria elimi-nation in Jiangsu Province through the operation of the national automatic early warning system of infectious diseases. Methods The malaria early warning information was collected from the automatic early warning information subsystem in the national infor-mation system for diseases control and prevention. Malaria early warning signals were analyzed from September 1 to December 31, 2012. The statistical analysis was conducted for the completion rates of case investigation within 3 days before and after the applica-tion of malaria early warning information system. Results Jiangsu Province received 85 mobile phone short messages(SMS)of malaria case from early warning system from September 1 to December 31,2012. After judgments,23 cases were deleted includ-ing 8 repeated cases and 15 cases that were excluded through the microscopy examination and epidemiological investigation by the confirmation of county CDC. From July to December in 2012,the monthly completion rates of case investigation within 3 days were 55.56%,78.57%,90.00%,100%,100%and 100%,respectively. The completion rates of case investigation within 3 days in Ju-ly,August,September and October were significantly different by χ2 test(χ2=10.66,P<0.05). The completion rates of foci in-vestigation and action within 7 days in Jiangsu Province were all 100%from July to December in 2012. Conclusions The comple-tion rates of case investigation within 3 days are associated with SMS from the early warning system. The malaria warning system from the national infectious diseases can effectively improve the response to malaria cases for primary CDC. It also plays an impor-tant role for the timely confirmation and diagnosis of malaria cases.
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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 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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Resistance of Plasmodium spp. to anti-malarial drugs is the primary obstacle in the fight against malaria, and molecular markers for the drug resistance have been applied as an adjunct in the surveillance of the resistance. In this study, we investigated the prevalence of mutations in pvmdr1, pvcrt-o, pvdhfr, and pvdhps genes in temperate-zone P. vivax parasites from central China. A total of 26 isolates were selected, including 8 which were previously shown to have a lower susceptibility to chloroquine in vitro. For pvmdr1, pvcrt-o, and pvdhps genes, no resistance-conferring mutations were discovered. However, a highly prevalent (69.2%), single-point mutation (S117N) was found in pvdhfr gene. In addition, tandem repeat polymorphisms existed in pvdhfr and pvdhps genes, which warranted further studies in relation to the parasite resistance to antifolate drugs. The study further suggests that P. vivax populations in central China may still be relatively susceptible to chloroquine and sulfadoxine-pyrimethamine.
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Humanos , Antimaláricos/farmacologia , China , Cloroquina/farmacologia , DNA de Protozoário/química , Resistência a Medicamentos/genética , Antagonistas do Ácido Fólico/farmacologia , Genótipo , Malária Vivax/epidemiologia , Plasmodium vivax/efeitos dos fármacos , Mutação Puntual , Polimorfismo de Nucleotídeo Único/genética , Prevalência , Proteínas de Protozoários/genética , Análise de Sequência de DNA , Sequências de Repetição em Tandem/genéticaRESUMO
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.