Classification of induced malaria case in an elimination setting: investigation of transfusion-transmitted malaria cases.

BACKGROUND: Since the National Malaria Elimination Action Plan was launched in China in 2010, local malaria transmission has decreased rapidly. Zero indigenous cases were reported since 2017. However, after 2010, the proportion of imported cases in China increased from 45.7% in 2010 to 99.9% in 2016, and almost all provinces of China have reported imported cases in recent years. Prevention of the reintroduction of malaria into China is crucial for the maintenance of its malaria-free status. Hence, it is of utmost importance to correctly identify the source of malaria infections within the country. CASE INTRODUCTION AND RESPONSE: In 2016 and 2017, three laboratory-confirmed cases of malaria caused by Plasmodium falciparum were identified in patients with no previous travel history to endemic areas were reported in Jiangsu Province, China, where malaria due to P. falciparum was eliminated about 30 years ago. These were diagnosed after 41, 31 and 39 days of seeking treatment, respectively, and all of them had received blood transfusions. Further investigations indicated that two of the cases had received blood from foreign students (from Indonesia and Ghana), and the other had received blood from an individual who had worked in Equatorial Guinea. All three blood donors were traced, and found to be carrying asymptomatic P. falciparum infections by microscopic examination and PCR. Furthermore, five polymorphic microsatellite markers (C1M4, C4M62, C13M13, C14M17, and C13M63) were typed and used to link parasites from the donors with those of the transfusion-receiving patients. CONCLUSIONS: Three transfusion-transmitted malaria cases were identified in China, all of which were due to the transfusion of blood donated by individuals who had contracted malaria outside the country. These cases can provide a reference for those faced with similar challenges in malaria case identification and classification in other regions. In addition, a stricter screening policy including the use of appropriate detection methods for malaria parasites should be developed and adopted for blood donation in regions undergoing malaria elimination.

Development and application of an AllGlo probe-based qPCR assay for detecting knockdown resistance (kdr) mutations in Anopheles sinensis.

BACKGROUND: Anopheles sinensis is one of the most important malaria vectors in China and other Southeast Asian countries. High levels of resistance have been reported in this species due to the long-term use of insecticides, especially pyrethroids, for public health and agricultural purposes. Knockdown resistance (kdr) caused by a single base pair mutation in the gene encoding the sodium channel is strongly associated with pyrethroid insecticide resistance in many Anopheles mosquitoes. There are few methods currently available for detecting kdr mutations in An. sinensis. METHODS: A novel AllGlo probe-based qPCR (AllGlo-qPCR) method was developed to screen for the predominant kdr mutations in An. sinensis mosquitoes from the Jiangsu Province. The results from AllGlo-qPCR, allele-specific PCR (AS-PCR), and TaqMan-MGB probe-based qPCR (TaqMan-qPCR) were compared. A comparative analysis of the equipment required, ease of use and cost of the available methods was also performed. Finally, the AllGlo-qPCR method was used to detect the frequencies of kdr mutations from the other four provinces in central China. RESULTS: Six kdr genotypes were detected in An. sinensis from the Jiangsu Province by DNA sequencing. The AllGlo-qPCR method detected all of the kdr genotypes with a high level of accuracy (97% sensitivity and 98% specificity). AllGlo-qPCR correctly determined the kdr genotypes of 98.73% of 158 An. sinensis samples, whereas TaqMan-qPCR and AS-PCR correctly identified 96.84% and 88.61% of mutations, respectively. Furthermore, the AllGlo-qPCR method is simpler to perform, requires less equipment, and exhibits a moderate expense cost comparing with the other tested methods of kdr mutation detection. Samples collected from four of the other provinces in central China showed a high frequency of kdr mutation in An. sinensis, as detected by the established AllGlo-qPCR method. CONCLUSION: The novel AllGlo-qPCR method developed for kdr mutation detection in An. sinensis exhibits greater specificity and sensitivity than currently available methods and is more cost-effective; therefore, it represents a useful tool for entomological surveillance.

[Investigation on blood-sucking habit of Anopheles (Diptera:Culicidae) using multiplex polymerase chain reaction in malaria-endemic area of Chayu County, Tibet].

OBJECTIVE: To determine the blood-sucking habit of anopheline by mosquitoes bloodmeal identification in malaria endemic area Chayu County, Tibet Autonomous Region. METHODS: Three villages with different bio-environments were selected as the investigation spots. Light traps were set up outdoor and in livestock sheds from sunset (20:00) to sunrise (8:00) in 3-4 consecutive nights to collect mosquitoes. The trapped anophelines were counted and identified according to morphological criteria and multiple PCR method. A PCR-based methodology according to the mtDNA-cytb variations was used in different mammal hosts to identify bloodmeal sources in engorged mosquitoes. The human blood index (HBI) was assessed to determine the range of hosts. RESULTS: Among 1 442 anopheline mosquitoes collected by 108 light traps on 13 nights. 1436 (99.6%) belonged to Anopheles maculatus complex, with 85.5% An. pseudo-willmori and 14.5% An. willmori. Positive bloodmeal identification was found from 168 (83%) of 202 field-collected engorged mosquitoes. The crude HBI of An. pseudowillmori and An. willmori were 035 and 0.29, respectively. CONCLUSION: An. pseudowillmori and An willmori are both zoophilic and anthropophilic, and An. pseudowillmori shows a higher HBI.

The complete mitochondrial genome of major malaria vector Anopheles anthropophagus (Diptera: Culicidae) in China.

Anopheles anthropophagus (Xu and Feng 1975) is the major vector of malaria in Eastern and Southern China. The species An. anthropophagus is considered a synonym of An. lesteri (Baisas & Hu, 1936), although they differ in several key biological characteristics. Here, we report the complete mitochondrial genome of An. anthropophagus for the first time. The mitogenome of An. anthropophagus is a typical circular, double-stranded molecule with a total length of 15,413 base pairs, and contains 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and an AT-rich control region. A phylogenetic analysis of the complete mitogenomes of 16 species of Anopheles (Culicidae) revealed that An. anthropophagus is closely related to An. sinensis (Wiedemann 1828), in the family Culicidae. The An. anthropophagus mitogenome provides new data for further taxonomic and phylogenetic studies of the genus Anopheles.

Cost-effectiveness analysis of malaria rapid diagnostic test in the elimination setting.

BACKGROUND: As more and more countries approaching the goal of malaria elimination, malaria rapid diagnostic tests (RDT) was recomendated to be a diagnostic strategy to achieve and maintain the statute of malaria free, as it's less requirments on equipment and experitise than microscopic examination. But there are very few economic evaluations to confirm whether RDT was cost-effective in the setting of malaria elimination. This research aimed to offer evidence for helping decision making on malaria diagnosis strategy. METHODS: A cost-effectiveness analysis was conducted to compare RDT with microscopy examination for malaria diagnosis, by using a decision tree model. There were three strategies of malaria diagnostic testing evaluated in the model, 1) microscopy, 2) RDT, 3) RDT followed by microscopy. The effect indicator was defined as the number of malaria cases treated appropriately. Based on the joint perspective of health sector and patient, costs data were collected from hospital information systems, key informant interviews, and patient surveys. Data collection was conducted in Jiangsu from September 2018 to January 2019. Epidemiological data were obtained from local malaria surveillance reports. A hypothetical cohort of 300 000 febrile patients were simulated to calculate the total cost and effect of each strategy. One-way, two-way, and probabilistic sensitivity analysis were performed to test the robustness of the result. RESULTS: The results showed that RDT strategy was the most effective (245 cases) but also the most costly (United States Dollar [USD] 4.47 million) compared to using microscopy alone (238 cases, USD 3.63 million), and RDT followed by microscopy (221 cases, USD 2.75 million). There was no strategy dominated. One-way sensitivity analysis reflected that the result was sensitive to the change in labor cost and two-way sensitivity analysis indicated that the result was not sensitive to the proportion of falciparum malaria. The result of Monte Carlo simulation showed that RDT strategy had higher effects and higher cost than other strategies with a high probability. CONCLUSIONS: Compared to microscopy and RDT followed by microscopy, RDT strategy had higher effects and higher cost in the setting of malaria elimination.

Evaluating the implementation of rapid diagnostic tests in a malaria elimination setting.

BACKGROUND: It was recommended that malaria rapid diagnostic tests (RDTs) should be available in all epidemiological situations. But evidence was limited on the implementation of RDTs and its effectiveness in malaria elimination settings. This study examined the implementation of RDTs and how it affected the diagnosis of imported malaria patients in Jiangsu Province, China. METHODS: To scale up RDTs, this study developed an intervention package with four major elements covering the supply of RDT test, the training on RDTs, the monitoring and management of RDT use, and the advocacy of RDTs. By using a pretest-posttest control group design, we implemented the interventions in 4 cities in Jiangsu Province with the rest nine cities as controlled areas, from January 2017 to January 2018. Difference-in-Difference approach was used to evaluate the impact of the scale-up of RDTs on the identification of malaria cases. Three binary outcome measures were included to indicate delayed malaria diagnosis, malaria cases with confirmed malaria diagnosis at township-level institutions, and severe malaria cases, respectively. Linear probability regression was performed with time and group fixed effects and the interaction term between time and group. RESULTS: Intervention areas received sufficient RDT test supply, regular professional training programs, monthly tracking and management of RDT supply and use, and health education to targeted population. The implementation of interventions was associated with 10.8% (P = 0.021) fewer patients with delayed diagnosis. But intervention areas did not see a higher likelihood of having confirmed diagnosis from township-level institutions (coefficient = -0.038, P = 0.185) or reduced severe malaria cases (coef. = 0.040, P = 0.592). CONCLUSIONS: The comprehensive package of RDT implementation in this study is promising in scaling up RDT use and improving access to care among malaria patients, especially in malaria elimination settings.

[Transcription profile of PfRON4 gene in Plasmodium falciparum erythrocytic stage].

OBJECTIVE: To reveal the transcription profile of PfRON4 gene in Plasmodium falciparum erythrocytic stage. METHODS: P. falciparum schizonts were purified by differential centrifugation on a Percoll-sorbitol gradient, after which the released merozoites were allowed to invade uninfected erythrocytes for 4 hours before the clearance of all remaining schizonts using 5% D-sorbitol. The cultured synchronous parasites were harvested for RNA assay immediately, 24 hours later, and then at every 6th hour. PfRON4 and related genes (PfAMA1 and PfRhopH2) were amplified by real-time PCR for establishing standard curves to evaluate the copy number of genes. RESULTS: P. falciparum parasites were well synchronized. Those quantative analyses were reliable because the R value of standard curves were more than 0.98 and the melting curve showed a single peak. When parasites were in the schizont stage, PfRON4 gene transcription reached a peak in 36-40 hours after invasion. CONCLUSION: The transcription of PfRON4 peaks at mature schizont stage, suggesting that the PfRON4 gene may involve in erythrocyte-invasion of P. falciparum.

Cost-effectiveness analysis of malaria rapid diagnostic tests: a systematic review.

BACKGROUND: Rapid diagnostic tests (RDT) can effectively manage malaria cases and reduce excess costs brought by misdiagnosis. However, few studies have evaluated the economic value of this technology. The purpose of this study is to systematically review the economic value of RDT in malaria diagnosis. MAIN TEXT: A detailed search strategy was developed to identify published economic evaluations that provide evidence regarding the cost-effectiveness of malaria RDT. Electronic databases including MEDLINE, EMBASE, Biosis Previews, Web of Science and Cochrane Library were searched from Jan 2007 to July 2018. Two researchers screened studies independently based on pre-specified inclusion and exclusion criteria. The Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist was applied to evaluate the quality of the studies. Then cost and effectiveness data were extracted and summarized in a narrative way. Fifteen economic evaluations of RDT compared to other diagnostic methods were identified. The overall quality of studies varied greatly but most of them were scored to be of high or moderate quality. Ten of the fifteen studies reported that RDT was likely to be a cost-effective approach compared to its comparisons, but the results could be influenced by the alternatives, study perspectives, malaria prevalence, and the types of RDT. CONCLUSIONS: Based on available evidence, RDT had the potential to be more cost-effective than either microscopy or presumptive diagnosis. Further research is also required to draw a more robust conclusion.

[Malaria epidemic situation in Jiangsu Province in 2006].

In 2006, there were 767 reported malaria cases in Jiangsu Province with an incidence of 1.07 per thousand and increased by 16.57% in comparison to the previous year. Positive rate of blood examination in local febrile patients was 0.08% (293/361 896) but 1.23% (251/204 40) in mobile population (P<0.01). Cases with relapses occupied 9.00% of the total. The density of Anopheles sinensis was 0.61 per net and increased by 110% more than the year 2005 (0.29/net). It is indicated that the increase of A. sinensis density has been the main factor for malaria recurrence in the area north of Huaihe River in the Province.

[Establishment of malaria early warning system in Jiangsu Province IV Implementation of key measures to eliminate malaria in Jiangsu Province in 2013].

OBJECTIVE: To promote the malaria control process in the malaria elimination stage in Jiangsu Province. METHODS: The data from the network reporting system of medical institutions, the disease prevention and control institutions at all levels, and the special reports system of parasitic diseases were collected and analyzed statistically. RESULTS: There were 341 malaria cases directly reported from the Jiangsu provincial network in 2013. All were laboratory-confirmed cases. Except one case of blood transfusion infection, the rest were imported malaria cases abroad. All the malaria cases were reported after diagnosis within 24 hours through the directly reported network, and the implementation rate was 100%. All the malaria cases had an epidemiological investigation within 3 days with the implementation rate of 100%; in which 334 (97.95%) cases were investigated within 2 days. All the cases had an epidemical investigation and disposition within 7 days with the implementation rate of 100%, in which 319 cases (93.55%) were completed within 5 days. CONCLUSIONS: The implementation rate of malaria elimination work mode has reached 100% in Jiangsu Province in 2013, and there are no local infected malaria cases for two consecutive years. However, the inspection and supervision of case investigation and epidemic investigation and disposal are still need to he strengthened.

[Epidemic situation of malaria in Taixing City, 2005-2013].

OBJECTIVE: To analyze the malaria situation and control measures in recent years in Taixing City, so as to provide the evidence for formulating the reasonable countermeasures in the future. METHODS: The information of malaria prevalence, the reported data of blood examinations for fever persons and the epidemiological data were collected and the malaria incidence, population distribution, and the imported cases were analyzed. RESULTS: A total of 37 malaria cases were reported from 2005 to 2013 and the incidences were from 0.0078/10,000 to 0.0669/10,000 with the large ascensional range. There were 34 imported malaria patients (91.89% of the total malaria cases) including 2 patients infected outside Taixing City, 2 outside Jiangsu Province, and 30 outside China. Among the 30 patients overseas infected, there was 1 vivax malaria case, there were 2 ovale malaria cases, and 27 falciparum malaria cases. There were incidences throughout the year and no obvious seasonal characteristics. The cases were mainly distributed from 30 to 49 years old (83.78%). CONCLUSIONS: The malaria cases in Taixing City are mainly overseas imported, and the incidence presents a rising trend. Therefore, the relevant authority should enhance the malaria supervision and management, especially for floating population.

[Establishment of early warning system of malaria in Jiangsu Province V Es- tablishment of prevention and control system of imported falciparum malaria].

OBJECTIVE: To establish a system of the prevention and control of imported falciparum malaria in Jiangsu Prov- ince and provide the new scientific basis for the prevention and control of imported falciparum malaria. METHODS: The data- bases for overseas labor companies and labors in Jiangsu Province were built and the health education was conducted to the overseas labors. The "1-3-7" elimination strategy was established. A weekly reporting system for malaria case details was es- tablished. A system for screening accompanies of imported malaria patients was established. RESULTS: At the end of 2013, the database of companies engaged in labor export was built and1 405 companies were incorporated into the database. The time interval between the symptom onset and the first health facility visit was reduced to 3.07 days in 2013. The time interval be- tween the first health facility visit to malaria diagnosis was reduced to 1.57 days in 2013. The rate of laboratory confirmation was increased to 100% in 2013, and there was a statistically significant difference among the rates of laboratory confirmation from 2009 to 2013 (χ2 = 36.35, P < 0.05). The proportion of severe imported falciparum malaria cases was decreased to 3.15% in 2013 and there was a statistically significant difference among the proportions of severe cases from 2009 to 2013 (χ2 = 301.16, P < 0.05). No death malaria case was reported in the whole province in 2013. CONCLUSION: Jiangsu Province has built a preliminary system of the prevention and control of imported falciparum malaria, which plays an important role in the prevention and control of overseas imported falciparum malaria.

[Effect of different temperatures on development of Aedes albopictus].

OBJECTIVE: To explore the effect of different temperatures on the different development stages of Aedes albopictus. METHODS: The changes at different development stages of mosquitoes (egg, larva, pupae) and gonotrophic cycle were observed at different temperature conditions of 10, 15, 20, 25, 30, 35 °C and 40 °C. The full developmental cycles were compared during different temperatures. RESULTS: All the stages of the mosquitoes could not develop at 10 °C. Under the different temperatures of 15, 20, 25, 30, 35 °C and 40 °C, 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 emergence rates of the mosquitoes were 92%, 95%, 97%, 97%, 83% and 17% respectively. The mosquitoes could well develop at 20, 25, 30 °C and 35 °C, the development time was 37.73, 18.50, 16.92 and 13.66 days respectively. CONCLUSION: The development time of Aedes albopictus is shorter at the higher temperature. The optimum temperature for the mosquitoes to develop is between 25-30 °C, and higher or lower the temperatures will suppress the development of the mosquitoes.

[Epidemiological analysis of malaria prevalence in Jiangsu Province in 2014].

OBJECTIVE: To understand the malaria epidemic situation and characteristics in Jiangsu Province in 2014, so as to provide the evidence for formulating and adjusting appropriate strategies and measures for malaria elimination in this province. 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 355 malaria cases were reported in Jiangsu Province in 2014, which was increased by 4.11% comparing to that in 2013 (341 cases), and the malaria incidence was 0.046/10 000. All the 355 cases were imported from other countries, among which, 4 cases (1.13%) were from Southeast Asia; the other 351 cases (98.87%) were from 21 African countries. Though the cases were distributed in all the 13 prefecture-level cities in Jiangsu Province, the number of cases in 5 of them namely Huai' an, Nantong, Lianyungang, Yangzhou and Taizhou accounted for 63.38% (225/ 355). A total of 292 falciparum malaria cases, 4 tertian malaria cases, 10 quartan malaria cases, 46 ovale malaria cases and 3 mixed infection cases were confirmed after re-checked by Jiangsu Provincial Reference Lab of Malaria. The follow-up observation of the cases showed that among the 355 cases, 6 falciparum malaria cases recrudesced, and 4 ovale malaria cases and 1 tertian malaria case recurred. CONCLUSIONS: There have been no local malaria cases reported from Jiangsu Province in the last three years, indicating the object of malaria elimination has been achieved initiatively. However, there are still many imported malaria cases from other countries, with a diverse species of plasmodium. Therefore, the surveillance of the imported malaria, the training for diagnosis and treatment of malaria as well as the health education to the key population should be strengthened.

[Establishment of malaria early warning system in Jiangsu Province VII Eliminating malaria surveillance sentinels].

OBJECTIVE: To understand the epidemic situation and influencing factors of malaria in Jiangsu Province and grasp the regularity and trend of the epidemic. METHODS: According to the provincial malaria transmission situation and characteristics, Sihong County of Suqian City, which had more original cases, and Baoying County of Yangzhou City, which had more import cases, were chosen as the malaria surveillance sentinels at the state level; six counties, Yixing County of Wuxi City, Suining County of Xuzhou City, Wujin District of Changzhou City, Haian county of Nantong City, Ganyu County of Lianyugang City, and Xuyi county of Huaian City were chosen as the malaria surveillance sentinels at the provincial level. The data of basic status, blood tests of feverish patients, case studies of malaria patients, investigations and disposals of epidemic focuses and others were collected and analyzed. RESULTS: There were 92,484 blood test samples from feverish patients in the eight surveillance sentinels in 2014, and the average rate of blood tests was 1.15%. Totally 61 cases were plasmodium positive, and the positive rata was 0.07%. All of the 61 cases were foreign imported patients diagnosed by laboratory. After the direct network reporting, the review of the blood slides and epidemiological individual surveys were finished in 3 days, and the investigations and disposals of epidemic focuses were finished in 7 days. The epidemiological individual surveys of these 61 cases showed that 37.70% (23/61) of the first-time consultancy was mainly in the county level CDC, and 50.82% (31/61) in county level medical organizations. The making definite diagnosis of malaria also focused on the county level, 45.90% (28/61) in county level CDC and 47.10% (29/61) in county level medical organizations. The definite diagnostic rate of fist-time consultancy was 90.16% (55/61). Totally 48 malaria patients had been sent to abroad by their companies, and 34 had fellow crew. CONCLUSIONS: The malaria surveillance sentinels in Jiangsu Province play a good role on the surveillance function of malaria, and effectively promote the elimination of malaria in whole province. In the future, the malaria surveillance should establish a multi-sectoral cooperation and investigation mechanism, and strengthen the screening of the high-risk population and health education.

[Analysis of epidemic situation of malaria in Jiangsu Province from 2005 to 2014].

OBJECTIVE: To understand the epidemic situation and epidemiological characteristics of malaria in Jiangsu Province from 2005 to 2014, so as to provide the evidence for formulating and adjusting the strategies and measures on malaria elimination 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 analyzed. 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 China, 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, Suzhou 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 reflects 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.

[Establishment of malaria early warning system in Jiangsu Province VI Regular surveillance of eliminating malaria and its effect].

OBJECTIVE: To analyze the regular surveillance and evaluate its effect during the elimination stage of malaria in Jiangsu Province from 2012 to 2014 and discuss the best way for surveillance and management, so as to provide the evidence for formulating and adjusting the strategy and methods for malaria elimination. METHOD: The data of network malaria reports, blood tests of feverish patients, epidemiology investigation forms of case study of malaria patients in the report system, and investigation and disposition forms of epidemic regions were collected and analyzed statistically. RESULTS: From 2012 to 2014, there were 894 malaria cases in total. Totally 1 625 034 feverish patients had blood tests, and 892 of them showed positive and the positive rate was 0.05%. The epidemiological case study showed that all the patients were foreign infection import patients except one was foreign import cases by blood transfusion. These cases were mainly distributed in Nantong City (125 cases), Yangzhou City (123 cases), Huai'an City (112 cases), Lianyungang City (111 cases) and Taizhou City (88 cases), and the total cases of the five cities accounted for 62.53% (559/894) of total cases of entire province. These cases were mainly diagnosed in country level CDC and medical organizations, and city level medical organizations. These units accounted for 87.02% of all the diagnostic organizations (778/894). CONCLUSIONS: From 2012 to 2014, there are no reports of local malaria infection cases in Jiangsu Province, meaning the preliminary realization of eliminating malaria. However, we still should strengthen the regular surveillance and treatment of import malaria cases.

[Analysis of the sequences of the ribosomal DNA ITS2 region for differentiating anopheline mosquitoes within hyrcanus group].

OBJECTIVE: To analyze the genetic characteristics of ribosomal DNA ITS2 region for differentiating anopheline mosquitoes within Hyrcanus group. METHODS: The ribosomal DNA ITS2 region of both laboratory line and filed collected An. anthropophagus and An. sinensis as well as the field collected An. yatsushiroensis and An. lesteri 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.

[Establishment of malaria early warning system in Jiangsu Province III effect of automatic early warning information system on the response of malaria elimination].

OBJECTIVE: To evaluate the effect of automatic early warning information system on the response of malaria elimination 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 information 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 application 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 including 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 July, August, September and October were significantly different by chi2 test ( chi2 = 10.66, P < 0.05). The completion rates of foci investigation and action within 7 days in Jiangsu Province were all 100% from July to December in 2012. CONCLUSIONS: The completion 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 important role for the timely confirmation and diagnosis of malaria cases.

[Experimental observation of toxic effect of Bacillus thuringiensis var. israelensis against Aedes, Culex and Anopheles larvae].

OBJECTIVE: To evaluate the toxic effect of Bacillus thuringiensis var. israelensis (Bti) wettable powder against Aedes, 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, 0.160 microg/ml and 0.324 microg/ml, respectively; its biological potencies 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 stage III larvae for 1, 2 d and 3 d were 0.324, 0.092 microg/ml and 0.032 microg/ml, respectively, and its biological potencies were 0.389, 0.110 IU/ml and 0.038 IU/ml, respectively. The LC50(s) of the bacteria against An. sinensis stage I , II, III, IV were 0.024, 0.137, 0.324 microg/ml and 0.450 microg/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, especially for the latter two. It is better to apply the bacteria at the early stage of mosquito larvae.