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ObjectiveTo identify the major ecological drivers for malaria vector density using the structural equation model (SEM) in the Three Gorges Reservoir.MethodAn 11-year longitudinal surveillance of malaria vector as well as its related ecological factors was carried out in the Three Gorges Reservoir. The Delphi method was used to identify associated ecological factors. The structural equation model was repeatedly corrected and improved by the corrected index, combined with the actual situation. The final model was defined by relative simplicity, best fitting as well as the practicality.ResultThe final model indicated that the direct effects of temperature, livestock, humidity, and breeding on the vector were 0.015, -0.228, 0.450, 0.516 respectively, their total effects on the vector were 0.359, -0.112, 0.850, and 0.043 through different pathways.ConclusionSEM was effective and convenient in elucidating the mechanism by which malaria vector dynamics operated in this study. It identified that the breeding had the highest direct effect on vector and played a key role for mediating effect of temperature and humidity.

The mosquito sampling efficiency of light-trap catches and electric motor mosquito catches were compared with that of human biting catches in the Three Gorges Reservoir. There was consistency in the sampling efficiency between light-trap catches and human biting catches for Anopheles sinensis (r = 0.82, P0.01), while the correlation between electric motor mosquito catches and human biting catches was found to be not statistically significant (r = 0.43, P>0.01) and its sampling efficiency was below that of human biting catches. It is concluded that light-traps can be used as an alternative to human biting catches of Anopheles sinensis in the study area and is a promising tool for sampling malaria vector populations.

Abstract Background Stunting and soil-transmitted helminth (STH) infections including ascariasis, trichuriasis and hookworm remain major public health problems in school-age pupils in developing countries. The objectives of this study were to determine the prevalence of stunting for children and its association with three major soil-transmitted helminths (STH) in rural areas of southern China. The study also aims to determine risk factors for stunting and to provide guidance on the prevention and control of stunting and STH infections for future studies in this field. Results A cross-sectional survey was carried out in the poor rural areas in Guangxi Autonomous Regional and Hainan Province where STH prevalence was higher between September and November 2009. Pupils were from 15 primary schools. All the school-age pupils aged between 9 and 12 years old (mean age 11.2 ± 3.2 years), from grades three to six took part in this study. Study contents include questionnaire surveys, physical examination and laboratory methods (stool checking for eggs of three major STH infections and haemoglobin determination was performed for the anaemia test). Finally 1031 school-age pupils took part in survey. The results showed that the overall prevalence of stunting (HAZ < 2SD) was 25.6%, based on the WHO Child Growth Standards (2007). Risk factors for stunting based on logistic regression analyses were: (1) STH moderate-to-heavy intensity infections (OR = 1.93;95%CI:1.19,3.11); (2) anaemia (OR = 3.26;95%CI: 2.02,5.27); (3) education level of mother (OR = 2.13; 95%CI: 1.39,3.25). The overall prevalence of major STH infections was 36.7%, STH moderate-to-heavy intensity infections was 16.7%. The overall prevalence of ascariasis, trichuriasis, hookworm and co-infection were 18.5%, 11.2%, 14.7% and 9.1% respectively. The prevalence of anaemic children (HB < 12 g/dl) was 13.1%. Conclusion The present study showed that stunting was highly prevalent among the study population and STH infection is one of the important risk factors for stunting, with moderate-to-heavy intensity infections being the main predictor of stunting. Hence, additional interventions measures such as to promote de-worming treatment, to enhance health education and to improve hygiene and sanitation in order to reduce stunting in this population, are needed throughout the primary school age group.

The article presents a study conducted to analyze the transmission of malaria in the Yangtze River located in China after the construction of three Gorges Reservoirs. In study six villages including Kaixian, Fengjie, Wanzhou were selected for investigating the transmission of malaria in the reservoir. It mentions that the transmission potential was estimated by the use of mathematical modeling and estimation of the local malaria situation. It reports that factors which influenced the transmission potential were analyzed by the Poisson regression analysis in combination with the Grey Systematic theory. The result revealed that the risk of malaria can be forecasted by transmission of malaria.

Abstract: Objective: Our objective was to systematically evaluate chemotherapy-based control of ascariasis and hookworm infection and make predictions of the effectiveness of repeated mass treatment at different levels of coverage in highly endemic areas of China. Methods: Field surveys were carried out to acquire the ascariasis and hookworm prevalence and intensity (mean worm burden) at baseline, one month and one year later. We calculated model parameters based on the survey data, then incorporated them into a quantitative framework to predict the prevalence and intensity one year later. Sensitivity analyses were performed to assess the influence of the chemotherapy measures on prevalence and intensity, and model simulations were performed to evaluate the feasibility of achieving the proposed transmission control criteria under different chemotherapy measures. Results: The predicted prevalence and intensity one year from baseline were within the 95% confidence interval of actual values. As treatment frequency or coverage increased, the prevalence and intensity decreased. Model simulations show that many rounds of treatment are needed to maintain the prevalence at a low level in highly endemic areas of China. Conclusion: We should select different combinations of treatment frequency, coverage and drug efficacy according to available resources and practical attainable conditions. Mathematical modeling could be used to help optimize the chemotherapeutic scheme aiming at specific parasitic species and areas, and to direct the establishment of soil-transmitted helminthiasis control criteria in China. [Copyright &y& Elsevier]

Background: Malaria is endemic in Linzhi Prefecture in the Tibet Autonomous Region (TAR), but the vector for malaria transmission had never been identified. Methods: Adult Anopheles spp. were collected in Motuo County, Linzhi Prefecture on the Sino- Indian border in July and August, 2007. Multiplex PCR was adopted for species identification, and a nested PCR approach was used to detect sporozoites in the salivary glands of the mosquitoes. Results: 3,675 mosquitoes of the Anopheles maculatus group were collected and processed for species identification. Among them, 3,602 (98.0%) were Anopheles pseudowillmori and 73 (2.0%) were Anopheles willmori. The Plasmodium vivax SSUrDNA fragment was amplified in two of 360 pooled An. pseudowillmori samples. Conclusion: The local An. maculatus group comprises the species An. pseudowillmori and An. willmori. Anopheles pseudowillmori is considered the sole malaria vector in Motuo County in Linzhi Prefecture. [ABSTRACT FROM AUTHOR]

Abstract: A versatile neutral metalloligand [Cu(PySal)2] (1) (PySal=3-pyridylmethylsalicylidene-imino) was exploited as a building unit to construct five complexes {Cu[Cu(PySal)2]2}(ClO4)2 (2), {Cd[Cu(PySal)2]2(H2O)2]} (NO3)2 ·2H2O·4CH3OH (3), {Zn[μ2-Cu(PySal)2]Cl2} n · nCH3OH (4), {Hg[μ2-Cu(PySal)2]I2} n (5) and {Cd[μ2-Cu(PySal)2]Cl2} n · nCH2Cl2 (6). [Cu(PySal)2] acts as a chelating ligand in discrete complexes 2 and 3 with unbound anions, but as a bis-monodentate bridging ligand in polymers 4, 5 and 6 when halogen anions coordinated cooperatively to metal cations. The coordination geometry of Cu2+ is well-defined square planar in bridging [Cu(PySal)2], analogous to that in free metalloligand (1), but it is distorted square planar in chelating [Cu(PySal)2]. [Copyright &y& Elsevier]

Background: Recent gains in reducing the global burden of malaria are threatened by the emergence of Plasmodium falciparum resistance to artemisinins. The discovery that mutations in portions of a P. falciparum gene encoding kelch (K13)-propeller domains are the major determinant of resistance has provided opportunities for monitoring such resistance on a global scale., Methods: We analyzed the K13-propeller sequence polymorphism in 14,037 samples collected in 59 countries in which malaria is endemic. Most of the samples (84.5%) were obtained from patients who were treated at sentinel sites used for nationwide surveillance of antimalarial resistance. We evaluated the emergence and dissemination of mutations by haplotyping neighboring loci., Results: We identified 108 nonsynonymous K13 mutations, which showed marked geographic disparity in their frequency and distribution. In Asia, 36.5% of the K13 mutations were distributed within two areas--one in Cambodia, Vietnam, and Laos and the other in western Thailand, Myanmar, and China--with no overlap. In Africa, we observed a broad array of rare nonsynonymous mutations that were not associated with delayed parasite clearance. The gene-edited Dd2 transgenic line with the A578S mutation, which expresses the most frequently observed African allele, was found to be susceptible to artemisinin in vitro on a ring-stage survival assay., Conclusions: No evidence of artemisinin resistance was found outside Southeast Asia and China, where resistance-associated K13 mutations were confined. The common African A578S allele was not associated with clinical or in vitro resistance to artemisinin, and many African mutations appear to be neutral. (Funded by Institut Pasteur Paris and others.).

This review summarizes the endemic characteristics and influencing factors of malaria in the Tibet Autonomous Region of China, as well as the opportunities and challenges for malaria elimination in this region. Recommendations on strategies for malaria control are also made.

Objective: To establish a multiplex PCR detection system for identifying 4 human Plasmodium species and evaluate its applicability., Methods: The sequences of 18S rDNA gene of the 4 human Plasmodium species were compared using DNAman software, and 4 downstream primers were designed using Oligo 6.0 software, which targeted the region of variability between conserved regions 5 and 6 of the sequences. Using these primers, the specificity and sensitivity of the multiplex PCR system were evaluated, with plasmids containing the 18S rDNA gene sequence as a template. Further, a new nest PCR system (M-Nest) was established by combining the multiplex PCR system with the first-cycle genus-specific primer of the NP-1993 system. The sensitivities of the multiplex PCR system and the M-nest system were evaluated in serial dilutions of blood DNA samples from patients infected by P. falciparum and P. vivax. In addition, the NP-1993 and M-Nest systems were applied to screen the Plasmodium species in 307 blood samples from people returning to Guangxi from Ghana, a malaria epidemic area. And the NP-2002 and M-Nest systems were applied to re-check Plasmodium species in 66 blood samples collected in Guangxi from 2014 January to May, which were identified by microscopy to be infected mainly by P. ovale., Results: The sizes of multiplex PCR products for P. falciparum, P. vivax, P. ovale, and P. malariae were 268 bp, 323 bp, 394 bp, and 446 bp, respectively, located in-between 50-bp DNA ladders. However, their melting curves had similar Tm values, thus could not be used to identify the 4 species. The minimum detection limits of P. falciparum, P. malariae, P. ovale, and P. vivax 18S rDNA gene by the multiplex PCR system were 5.58x102, 1.56x103, 1.66x103, and 1.80 x 10(2) copies/[A. The minimum detection limit of blood DNA from falciparum malaria patients by the multiplex PCR system was 1.43 x 10(2)-8.84 x 10(3) copies/p.1 or 5.10 x 10-4.92 x 10(2) parasites/µl, higher than that of P. vivax (17.4-69.1 copies/L or 13.5-83.2 parasites/p). Compared with this multiples PCR system, The M-Nest system further reduced the minimum detection limit of Plasmodium by 10-100 folds. Further, the M-Nest and NP-1993 systems reached inconsistent detection results in 307 blood samples from people returned to from Ghana; the former detected 2 cases of P. ovale infection while the latter failed. In addition, the NP-2002 and M-Nest systems came to the same results in re-checking Plasmodium species in the 66 blood samples., Conclusion: The established multiplex PCR system can identify 4 human Plasmodium species simultaneously and has good applicability in practice.

In recent years, some microscopy-positive but nest-PCR negative (based on small subunit ribosomal RNA gene) ovale malaria cases were reported. The detection failure was due to the genetic variations between Plasomdoium ovale wallikeri and P. ovale curtisi. This paper reviews the discovery and validation processes of P. ovale wallikeri and the detection systems for identification of P. ovale.

Reduction patterns of Plasmodium falciparum and P. vivax malaria transmission and the role of an integrated strategy of case management and vector control are compared between different ecological zones. The epidemiology of malaria in Hainan and Yunnan provinces was disparate, even though distinct malaria control strategies have been adapted to different situations based on risk group, vector behaviours, local health infrastructure, and environmental conditions. The island Hainan appears to be victorious in eliminating malaria. However, there is still a long way to go to prevent the reintroduction of malaria in Hainan province and eliminating malaria in the border areas of Yunnan province. This review of the experiences and challenges from malaria control to elimination in Hainan and Yunnan provinces of southern China will provide a basis for the future elimination of malaria in the whole country., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The Global Fund to Fight AIDS, Tuberculosis and Malaria (GFATM) supported a project on the control and elimination of malaria in People's Republic of China which was one of the biggest-scale international cooperation programmes to control malaria in the country during the past 10 years. The project promoted the effective implementation of the Chinese national malaria control programme. On the basis of epidemiologic data, an overview of the project activities and key performance indicators, the overall impact of the GFATM project was evaluated. We also reviewed relevant programme features including technological and management approaches, with a focus on best practice, innovations in implementation and the introduction of international standards. Last, we summarised the multi-stakeholder cooperation mechanism and comments on its sustainability in the post-GFATM period. Recommendations for the future management of the Chinese national malaria elimination programme are put forward after considering the challenges, shortcomings and lessons learnt during the implementation of the GFATM project in China to sustain past achievements and foster the attainment of the ultimate goal of malaria elimination for the country., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The Malaria Elimination Action Plan has been launched in China since 2010, to pursue the goal of national wide malaria elimination by 2020. To ensure the achievement of the goal, the strategy and interventions should be transited from control to elimination, based on the better understanding of malaria elimination. In this article, we delineate the difference between malaria control and elimination phase, and explain the importance of transition of the goal, strategy and interventions from control to elimination, also decrypt the background, definition, critical points and challenges of China's current malaria elimination strategy and interventions, to improve health workers' understanding and implementation of national elimination program at different levels, and eventually impact the progress of national elimination program.

Objective: To understand the ecological behaviors of Anopheles pseudowillmori and A. willmori in medium or high altitude areas of Motuo County, Tibet Autonomous Region, and their transmission potential for malaria., Methods: The methods of human net traps, cow baited trap, house baited trap, pig baited trap and CDC light traps were adopted for investigating the mosquito density, biting activity at night and in or out door preference of biting. All mosquitoes morphologically identified as A. maculatus group were labeled in accordance with the capture time, place and method, and PCR were used to identify the species. The resting habits were investigated with the morning capture and daytime collecting methods, and the larvae collected in different wa- ter bodies were reared to adults to study the breeding place., Results: A total of 1,053 A. maculatus group were collected, and of which, 331 (31.43%) were identified as A. pseudowillmori, and 722 (68.57%) as A. willmori. The number of A. willmori were higher than A. pseudowillmori in both outer and inner doors (P < 0.01, P < 0.05) , while no statistically significant difference was found of the constituent ratio of the anopheles between outer and inner doors. The multiparous ratios of A. pseudowillmori and A. willmori were 65.90% and 69.86%, respectively, (P > 0.05). The A. pseudowillmori preferred to biting outer doors (P < 0.05), while A. willmori preferred both outer and inner doors (P > 0.05). Both mosquitoes had one biting activity peak in the night, and the biting activity peak of A. willmori was from 21 to 22 o'clock, while the peak of A. pseudowillmori was from 24 to next morning 1 o' clock., Conclusion: In the Anopheles, the constituent ratio and density of A. willmori are higher than those of A. pseudowillmori in semi-high altitudes area of Motuo County, Tibet, and there are obvious differences of ecological behaviors between A. willmori and A. pseudowillmori, and A. willmori has the more capacity of transmitting malaria than A. pseudowillmori.

Objective: To apply moving percentile method on surveillance and early-warning on visceral leishmaniasis in Kashgar Region and evaluate its effect., Methods: Incidence data of visceral leishmaniasis in Kashgar Region were collected from the National Web-based Infectious Diseases Report System. Monthly detection was carried out by using moving percentile method. The 50th percentile (P50), 70th percentile (P70) and 90th percentile (P90) of historical baseline data were calculated for drawing a control chart, and P70 was adopted as the warning threshold to determine whether an epidemic would appear. If the number of cases in one month is higher than the corresponding P70 of historical baseline data, the warning signal will be generated. The sensitivity, specificity and positive predictive value were calculated for the evaluation of early-warning effect., Results: During the study period, 61.0% cases were reported in the year of 2008 and 2009, the incidence peak was from September to December, accounting for 51.9%, and infants under 3 years old were the population most threatened by visceral leishmaniasis, accounting for 62.7%. A total of 58 detections were performed, and 17 warning signals were generated by the threshold on P70. Among them, the numbers of cases in 9 detections were higher than the corresponding P90 of historical-baseline data. Based on the actually epidemic status of visceral leishmaniasis in study period, according to the threshold on P70, a total of 10 warning signals of 11 epidemics were detected, and the sensitivity of the warning model was 90.9% (10/11). 7 wrongly signals of 47 non-epidemics were detected, and the specificity was 85.1% (40/47). 10 of 17 signals were proved to be correct, and the positive predictive value was 58.8% (10/17)., Conclusion: The moving percentile method can effectively perform surveillance and early-warning on visceral leishmaniasis in Kashgar Region.

Objective: To study the effect of mosquito age on the pyrethroid resistance and P450 monooxygenase activity in Anopheles sinensis in Huainan City, Anhui Province, China, as well as the molecular mechanism of pyrethroid resistance., Methods: Anopheles mosquito larvae were collected in fields, and were emerged to adults. Then the pyrethroid resistance and P450 monooxygenase activity of female mosquitoes were detected 1, 3, 6, 9, 12, 15 d and 20 d after emergence. Meanwhile, the resistance level and P450 monooxygenase activity of the sensitive mosquitoes in lab were detected as the control group., Results: curves of pyrethroid resistance and P450 monooxygenase activity changes with the mosquito age presented unsymmetrically reversed "U" type. At 1 d after emergence, the resistance level and P450 monooxygenase activity were lower, and then they increased quickly. When 3-9 d after emergence, the resistance level and P450 monooxygenase activity rose to the highest level, and entered into plateau, then declined gradually. Compared to the sensitive mosquitoes in lab, the P450 monooxygenase activity of those in the field was higher at 3-12 d after emergence, but lower at 1 d after emergence, and at 15 and 20 d after emergence, they were almost equal to each other., Conclusion: The mosquito age is a confounding factor in the detection of resistance level and enzyme activity. The promotion of activity of P450 monooxygenase may be one of the reasons of the resistance. Using female adults with different ages in the field as study subjects may underestimate the real resistance level of mosquitoes, and mislead the use of insecticides.

The malaria situation in Tibet has been in an active status and the malaria incidence reached the second in China in 2010. Malaria vector prevention and control is one of the important methods for malaria control, while the malaria vectors are still unknown in Tibet. The author summarized the past researches on malaria vectors in Tibet, so as to provide the evidence for improving malaria control investigation in malaria endemic areas of Tibet, with hopes to provide useful vector message for other researcher.

Objectives: To study the major ecologic factors influencing the re-emergence of malaria in the areas along the Yellow River and Huai River by analyzing the relationship between the malaria incidence and the land use and cover change (LUCC)., Methods: The data of annual parasite incidence (API) and LUCC in the counties of Huaiyuan, Yongcheng and Tong ai in 1990-2006 were collected retrospectively. Considering the hysteresis effect of LUCC played on malaria transmission, analysis of LUCC in these counties were conducted based on the data of 1990-1995 and 1996-2000, while the API data in 1996-2000 and 2001-2005 were used to analyze the trends and changes of malaria incidence. The correlation and trend analyses were conducted between LUCC and malaria incidence change in the periods., Results: The LUCC in 1990-1995 in Tongbai County was significant, being 3 265.79% in the farmland and -90.42% in paddy field. The increase of malaria incidence in Tongbai was also significant in 1996-2000, the change rate was 2 799.70%, showing a positive correlation. The LUCC of other 2 counties in 1990-1995 was -0.27% and -0.78%, respectively, while the rate of malaria incidence change in 1996-2000 was 206.25% and 0.00%. The LUCC of the 2 counties in 1996-2000 was -0.08% and -0.50%, while the rate of malaria incidence change in 2001-2005 was 153.22% and 2 500.00%, respectively. It indicated that there was no significant relationship between malaria re-emergence and LUCC in Huaiyuan and Yongcheng Counties., Conclusion: It seems that the LUCC shows no significant impact on malaria re-emergence in areas along the Yellow River and Huai River since 2001, though there was a positive correlation between the two in Tonghai County in the late 1990s.