Research supporting malaria control and elimination in China over four decades: a bibliometric analysis of academic articles published in chinese from 1980 to 2019.

BACKGROUND: China has accumulated considerable experience in malaria control and elimination over the past decades. Many research papers have been published in Chinese journals. This study intends to describe the development and experience of malaria control and elimination in China by quantitatively analysing relevant research using a bibliometric analysis. METHODS: A long-term, multistage bibliometric analysis was performed. Research articles published in Chinese journals from 1980 to 2019 were retrieved from the Wanfang and China National Knowledge Infrastructure (CNKI) databases. Year of publication, journal name and keywords were extracted by the Bibliographic Items Co-occurrence Matrix Builder (BICOMB). The K/A ratio (the frequency of a keyword among the total number of articles within a certain period) was considered an indicator of the popularity of a keyword in different decades. VOSviewer software was used to construct keyword co-occurrence network maps. RESULTS: A total of 16,290 articles were included. The overall number of articles continually increased. However, the number of articles published in the last three years decreased. There were two kinds of keyword frequency trends among the different decades. The K/A ratio of the keyword 'Plasmodium falciparum' decreased (17.05 in the 1980s, 13.04% in the 1990s, 9.86 in the 2000s, 5.28 in the 2010s), but those of 'imported case' and 'surveillance' increased. Drug resistance has been a continuous concern. The keyword co-occurrence network maps showed that the themes of malaria research diversified, and the degree of multidisciplinary cooperation gradually increased. CONCLUSIONS: This bibliometric analysis revealed the trends in malaria research in China over the past 40 years. The results suggest emphasis on investigation, multidisciplinary participation and drug resistance by researchers and policymakers in malaria epidemic areas. The results also provide domestic experts with qualitative evidence of China's experience in malaria control and elimination.

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.

An aquaporin and an aquaglyceroporin have roles in low temperature adaptation of mosquitoes (Anopheles sinensis).

Mosquitoes (Anopheles sinensis), widely geographically distributed in Asia including China, are the primary vector of the malaria parasite Plasmodium vivax and other parasitic diseases such as Malayan filariasis. An. sinensis can survive through low winter temperatures. Aquaporin channels are found in all life forms, where they facilitate environmental adaptation by allowing rapid trans-cellular movement of water (classical aquaporins) or water and solutes such as glycerol (aquaglyceroporins). Here, we identified and characterized 2 aquaporin (AQP) homologs in An. sinensis: AsAQP2 (An. sinensis aquaglyceroporin) and AsAQP4 (An. sinensis aquaporin). When expressed in frog (Xenopus laevis) oocytes, AsAQP2 transported water, glycerol, and urea; AsAQP4 transported only water. Water permeation through AsAQP2 and AsAQP4 was inhibited by mercuric chloride. AsAQP2 expression was slightly higher in adult female mosquitoes than in males, and AsAQP4 expression was significantly higher in adult males. The 2 AsAQPs were highly expressed in Malpighian tubules and midgut. AsAQP2 and AsAQP4 expression was up-regulated by blood feeding compared with sugar feeding. At freezing point (0 °C), the AsAQP4 expression level increased and An. sinensis survival time reduced compared with those at normal temperature (26 °C). At low temperature (8 °C), the AsAQP2 and AsAQP4 expression levels decreased and survival time was significantly longer compared with those at 26 °C. These results suggest that AsAQP2 and AsAQP4 have roles in water homeostasis during blood digestion and in low temperature adaptation of A. sinensis. Together, our results show that the 2 AQPs are important for mosquito diuresis after blood feeding and when exposed to low temperatures.

Mineralization Reduces the Toxicity and Improves Stability and Protective Immune Response Induced by Toxoplasma gondii.

Vaccination is an ideal strategy for the control and prevention of toxoplasmosis. However, the thermostability and effectiveness of vaccines limit their application. Here, calcium mineralization was used to fabricate Toxoplasma gondii tachyzoites as immunogenic core-shell particles with improved immune response and thermostability. In the current study, T. gondii RH particles coated with mineralized shells were fabricated by calcium mineralization. The mineralized shells could maintain the T. gondii tachyzoites structural integrity for at least 12 months and weaken the virulence. Immunization of mice with mineralized tachyzoites induced high levels of T. gondii-specific antibodies and cytokines. The immunized mice were protected with a 100% survival rate in acute and chronic infection, and brain cyst burdens were significantly reduced. This study reported for the first time the strategy of calcium mineralization on T. gondii and proved that mineralized tachyzoites could play an immune protective role, thus expanding the application of biomineralization in T. gondii vaccine delivery.

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.

Genetic Diversity Analysis of Surface-Related Antigen (SRA) in Plasmodium falciparum Imported From Africa to China.

Plasmodium falciparum surface-related antigen (SRA) is located on the surfaces of gametocyte and merozoite and has the structural and functional characteristics of potential targets for multistage vaccine development. However, little information is available regarding the genetic polymorphism of pfsra. To determine the extent of genetic variation about P. falciparum by characterizing the sra sequence, 74 P. falciparum samples were collected from migrant workers who returned to China from 12 countries of Africa between 2015 and 2019. The full length of the sra gene was amplified and sequenced. The average pairwise nucleotide diversities (π) of P. falciparum sra gene was 0.00132, and the haplotype diversity (Hd) was 0.770. The average number of nucleotide differences (k) for pfsra was 3.049. The ratio of non-synonymous (dN) to synonymous (dS) substitutions across sites (dN/dS) was 1.365. Amino acid substitutions of P. falciparum SRA could be categorized into 35 unique amino acid variants. Neutrality tests showed that the polymorphism of PfSRA was maintained by positive diversifying selection, which indicated its role as a potential target of protective immune responses and a vaccine candidate. Overall, the ability of the N-terminal of PfSRA antibodies to evoke inhibition of merozoite invasion of erythrocytes and conserved amino acid at low genetic diversity suggest that the N-terminal of PfSRA could be evaluated as a vaccine candidate against P. falciparum infection.

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.

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.

[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.

[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.

[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.

[Surveillance of malaria in provincial surveillance sites in Jiangsu Province, 2013].

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, district) including Yixing, Suining, Wujin, Hai'an, Ganyu and Xuyi were selected as provincial surveillance sites to survey malaria epidemic conditions. The basic information, blood test results of fever patients, case investigation, information of malaria patients, 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 retests and case investigations were completed within 3 days after these cases were reported by the network system, and the investigation 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 during 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 Province, the eliminating malaria "targeted 1-3-7" working pattern has been comprehensively implemented. The personnel monitoring for labors who returned from overseas working will be a key in the future.

[Research progress on malaria vector control].

Vector control plays a crucial role in the stages of malaria control and elimination. Currently, it mainly relies on the chemical control methods for adult mosquitoes in malaria endemic areas, however, it is undergoing the serious threat by insecticide resistance. In recent years, the transgenic technologies of malaria vectors have made a great progress in the laboratory. This paper reviews the challenges of the traditional methods and the rapid developed genetic modified technology in the application of vector control.

[Deltamethrin resistance, metabolic detoxification enzyme and kdr mutation in Anopheles sinensis in region along Huaihe River in Anhui Province].

OBJECTIVE: To understand the deltamethrin resistance level, GTS and P450 metabolic detoxification enzyme activities, and mutations in the para-type sodium channel gene that confers knockdown resistance (kdr) in Anopheles sinensis mosquitoes from malaria endemic areas along the Huaihe River in Anhui Province, China. METHODS: An. sinensis adult mosquitoes were collected in Lilou, Mohekou and Tuohu townships of Bengbu City, Anhui Province from August to September, 2011. The insecticide resistance bioassays were performed on adult mosquitoes by using the standard WHO susceptibility test with diagnostic concentrations of deltamethrin 0.05%, and the mosquito resistance status was classified based on the WHO resistance classification criteria. The metabolic detoxification enzyme activities were measured in randomly selected mosquitoes, and the IIS6 region of the para-type sodium channel gene was amplified by PCR and sequenced to detect mutations at the codon 1014. RESULTS: The knockdown rates within 60 min exposure to deltamethrin test paper were 4.1%, 7.0% and 8.2%, and the mortality rates were 8.2%, 12.0% and 12.8% for mosquitoes collected from Lilou, Mohekou and Tuohu townships, respectively. These three populations were classified as highly resistant populations based on the WHO resistance classification criteria. The GST and P450 enzyme activities of the three populations were significantly higher than those of the susceptible laboratory population (P < 0.001). L1014C and L1014F mutations were detected, and the wild type homozygote kdr genotype was not found. These three populations exhibited a small but insignificant difference in kdr allele frequencies. No mutation was found in the laboratory susceptible mosquitos. CONCLUSION: The An. sinensis mosquito populations from the regions along the Huaihe River in Anhui Province are strongly resistant to pyrethroid insecticides, and exhibit significantly higher metabolic detoxification enzyme activities than the laboratory susceptible population. The high frequency of kdr mutation is identified in the mosquito populations from the region along the Huaihe River in Anhui Province, China.

[Study on TaqMan-MGB real-time fluorescence quantitative PCR to detect gene mutation of kdr from Anopheles sinensis].

OBJECTIVE: To establish a Real-time Fluorescence Quantitative PCR to detect the kdr gene mutation in Anopheles sinensis. METHODS: One pair of primers and three TaqMan-MGB probes were designed based on kdr gene and its L1014 locus mutations of A. sinensis. After optimization, the Real-time Fluorescence Quantitative PCR was verified by using 6 types of A. sinensis samples with different kdr gene types. Additionally, 50 laboratory samples and 113 field samples were tested by this method. RESULTS: The established Real-time Fluorescence Quantitative PCR could identify 6 different kdr gene types in A. sinensis. The mutation could be detected by single-tube Fluorescence Quantitative PCR, and the detail mutation type could be further identified by double-tube Fluorescence Quantitative PCR. By using this method, 50 laboratory samples were confirmed as wild type homozygotes. Among 113 field samples, 12 were wild type homozygotes, others were L1014F or L1014C mutations, and the total mutation frequency was 87.61%. CONCLUSION: The new established TaqMan-MGB Real-time Fluorescence Quantitative PCR can be used to detect the kdr gene L1014 mutations of A. sinensis.