Establishing and applying an adaptive strategy and approach to eliminating malaria: practice and lessons learnt from China from 2011 to 2020.

ABSTRACTOn 30 June 2021, China was certified malaria-free by the World Health Organization. In this study, the evolution, performance, outcomes, and impact of China's adaptive strategy and approach for malaria elimination from 2011 to 2020 were analysed using 10-year data. The strategy and approach focused on timely detection and rapid responses to individual cases and foci. Indigenous cases declined from 1,308 in 2011 to 36 in 2015, and the last one was reported from Yunnan Province in April 2016, although thousands of imported cases still occur annually. The "1-3-7" approach was implemented successfully between 2013 and 2020, with 100% of cases reported within 24 h, 94.5% of cases investigated within three days of case reporting, and 93.4% of foci responses performed within seven days. Additionally, 81.6% of patients attended the first healthcare visit within 1-3 days of onset and 58.4% were diagnosed as malaria within three days of onset, in 2017-2020. The adaptive strategy and approach, along with their universal implementation, are most critical in malaria elimination. In addition to strengthening surveillance on drug resistance and vectors and border malaria collaboration, a further adapted three-step strategy and the corresponding "3-3-7" model are recommended to address the risks of re-transmission and death by imported cases after elimination. China's successful practice and lessons learnt through long-term efforts provide a reference for countries moving towards elimination.

Quantitative Microbial Risk Assessment of Cryptosporidium and Giardia in Public Drinking Water in China.

We aimed to assess the risks of Cryptosporidium and Giardia infections associated with drinking water for local residents, based on a quantitative microbial risk assessment, in three densely populated regions of China. In total, 45 source water samples and 45 treated water samples were collected from June to December 2014. Five Cryptosporidium-positive samples and 5 Giardia-positive samples were found. The annual probability of infection for individuals in Jintan (6.27 × 10 -4-2.05 × 10 -3 for Cryptosporidium and 7.18 × 10 -4-2.32 × 10 -3 for Giardia), Ezhou (6.27 × 10 -4-1.10 × 10 -2 for Cryptosporidium and 3.65 × 10 -4-1.20 × 10 -3 for Giardia), and Binyang (3.79 × 10 -4-1.25 × 10 -3 for Cryptosporidium) exceeded the tolerable risk of infection of 10 -4 set by the United States Environmental Protection Agency. Moreover, the corresponding disease burdens of cryptosporidiosis and giardiasis, due to direct drinking and residual water in these regions, exceeded the threshold of 10 -6 disability-adjusted life years per person per year set by the World Health Organization. These results provide insights into strategies to improve the safety of drinking water.

No evidence of amplified Plasmodium falciparum plasmepsin II gene copy number in an area with artemisinin-resistant malaria along the China-Myanmar border.

BACKGROUND: The emergence and spread of artemisinin resistance in Plasmodium falciparum poses a threat to malaria eradication, including China's plan to eliminate malaria by 2020. Piperaquine (PPQ) resistance has emerged in Cambodia, compromising an important partner drug that is widely used in China in the form of dihydroartemisinin (DHA)-PPQ. Several mutations in a P. falciparum gene encoding a kelch protein on chromosome 13 (k13) are associated with artemisinin resistance and have arisen spread in the Great Mekong subregion, including the China-Myanmar border. Multiple copies of the plasmepsin II/III (pm2/3) genes, located on chromosome 14, have been shown to be associated with PPQ resistance. METHODS: The therapeutic efficacy of DHA-PPQ for the treatment of uncomplicated P. falciparum was evaluated along the China-Myanmar border from 2010 to 2014. The dry blood spots samples collected in the efficacy study prior DHA-PPQ treatment and from the local hospital by passive detection were used to amplify k13 and pm2. Polymorphisms within k13 were genotyped by capillary sequencing and pm2 copy number was quantified by relative-quantitative real-time polymerase chain reaction. Treatment outcome was evaluated with the World Health Organization protocol. A linear regression model was used to estimate the association between the day 3 positive rate and k13 mutation and the relationship of the pm2 copy number variants and k13 mutations. RESULTS: DHA-PPQ was effective for uncomplicated P. falciparum infection in Yunnan Province with cure rates > 95%. Twelve non synonymous mutations in the k13 domain were observed among the 268 samples with the prevalence of 44.0% and the predominant mutation was F446I with a prevalence of 32.8%. Only one sample was observed with multi-copies of pm2, including parasites with and without k13 mutations. The therapeutic efficacy of DHA-PPQ was > 95% along the China-Myanmar border, consistent with the lack of amplification of pm2. CONCLUSION: DHA-PPQ for uncomplicated P. falciparum infection still showed efficacy in an area with artemisinin-resistant malaria along the China-Myanmar border. There was no evidence to show PPQ resistance by clinical study and molecular markers survey. Continued monitoring of the parasite population using molecular markers will be important to track emergence and spread of resistance in this region.

Genomic Epidemiology of Antimalarial Drug Resistance in Plasmodium falciparum in Southern China.

Emerging artemisinin resistance in Southeast Asia poses a significant risk to malaria control and eradication goals, including China's plan to eliminate malaria nationwide by 2020. Plasmodium falciparum was endemic in China, especially in Southern China. Parasites from this region have shown decreased susceptibility to artemisinin and delayed parasite clearance after artemisinin treatment. Understanding the genetic basis of artemisinin resistance and identifying specific genetic loci associated with this phenotype is crucial for surveillance and containment of resistance. In this study, parasites were collected from clinical patients from Yunnan province and Hainan island. The parasites were genotyped using a P. falciparum-specific single nucleotide polymorphism (SNP) microarray. The SNP profiles examined included a total of 27 validated and candidate molecular markers of drug resistance. The structure of the parasite population was evaluated by principal component analysis by using the EIGENSOFT program, and ADMIXTURE was used to calculate maximum likelihood estimates for the substructure analysis. Parasites showed a high prevalence of resistance haplotypes of pfdhfr and pfdhps and moderate prevalence of pfcrt. There was no mutation identified on pfmdr1. Candidate SNPs on chromosomes 10, 13, and 14 that were associated with delayed parasite clearance showed a low prevalence of mutants. Parasites from Southern China were clustered and separated from those from Southeast Asia. Parasites from Yunnan province were substructured from parasites from Hainan island. This study provides evidence for a genomic population with drug resistance in Southern China and also illustrates the utility of SNP microarrays for large-scale parasite molecular epidemiology.

Artemisinin resistance-associated markers in Plasmodium falciparum parasites from the China-Myanmar border: predicted structural stability of K13 propeller variants detected in a low-prevalence area.

BACKGROUND: Malaria reduction and future elimination in China is made more difficult by the importation of cases from neighboring endemic countries, particularly Myanmar, Laos, and Vietnam, and increased travel to Africa by Chinese nationals. The increasing prevalence of artemisinin resistant parasites across Southeast Asia highlights the importance of monitoring the parasite importation into China. Artemisinin resistance in the Mekong region is associated with variants of genes encoding the K13 kelch domain protein (pf13k), found in specific genetic backgrounds, including certain alleles of genes encoding the chloroquine resistance transporter (pfcrt) and multidrug resistance transporter PgH1 (pfmdr1). METHODS: In this study we investigated the prevalence of drug resistance markers in 72 P. falciparum samples from uncomplicated malaria infections in Tengchong and Yingjiang, counties on the Yunnan-Myanmar border. Variants of pf13k, pfcrt and pfmdr1 are described. RESULTS: Almost all parasites harboured chloroquine-resistant alleles of pfcrt, whereas pfmdr1 was more diverse. Major mutations in the K13 propeller domain associated with artemisinin resistance in the Mekong region (C580Y, R539T and Y493H) were absent, but F446I and two previously undescribed mutations (V603E and V454I) were identified. Protein structural modelling was carried out in silico on each of these K13 variants, based on recently published crystal structures for the K13 propeller domain. Whereas F446I was predicted to elicit a moderate destabilisation of the propeller structure, the V603E substitution is likely to lead to relatively high protein instability. We plotted these stability estimates, and those for all previously described variants, against published values for in vivo parasitaemia half-life, and found that quadratic regression generates a useful predictive algorithm. CONCLUSION: This study provides a baseline of P. falciparum resistance-associated mutations prevalent at the China-Myanmar border. We also show that protein modelling can be used to generate testable predictions as to the impact of pfk13 mutations on in vivo (and potentially in vitro) artemisinin susceptibility.

[Establishment and Application of Multiplex PCR System for Detecting Four Human Plasmodium Species].

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 vivo monitoring of dihydroartemisinin-piperaquine sensitivity in Plasmodium falciparum along the China-Myanmar border of Yunnan Province, China from 2007 to 2013.

BACKGROUND: Artemisinin-based combination therapy (ACT) is the recommended first-line treatment of falciparum malaria in all endemic countries. Artemisinin resistance in Plasmodium falciparum has been confirmed in the Greater Mekong subregion (GMS). Dihydroartemisinin-piperaquine (DAPQ) is the most commonly used ACT in China. To understand the DAPQ sensitivity of P. falciparum, DAPQ resistance was monitored in vivo along the China-Myanmar border from 2007 to 2013. METHODS: Eligible patients with mono-infections of P. falciparum were recruited to this study after obtaining full informed consent. DAPQ tablets for different categories of kg body weight ranges were given once a day for three days. Patients were followed up for 42 days. Polymerase chain reaction (PCR) was conducted to distinguish between re-infection and recrudescence, to confirm the Plasmodium species. The data were entered and analysed by the Kaplan-Meier method. Treatment outcome was assessed according to the WHO recommended standards. RESULTS: 243 patients were completed valid follow-up. The fever clearance time (FCT) and asexual parasite clearance times (APCT) were, respectively, 36.5 ± 10.9 and 43.5 ± 11.8 hours, and there was an increasing trend of both FCT (F = 268.41, P < 0.0001) and APCT (F = 88.6, P < 0.0001) from 2007 to 2013. Eight (3.3%, 95% confidence interval, 1.4-6.4%) patients present parasitaemia on day three after medication; however they were spontaneous cure on day four. 241 (99.2%; 95% CI, 97.1-99.9%) of the patients were adequate clinical and parasitological response (ACPR) and the proportions of ACPR had not changed significantly from 2007 to 2013 (X(2) = 2.81, P = 0.7288). CONCLUSION: In terms of efficacy, DAPQ is still an effective treatment for falciparum malaria. DAPQ sensitivity in P. falciparum had not significantly changed along the China-Myanmar border of Yunnan Province, China. However more attentions should be given to becoming slower fever and parasite clearance.

[Opportunities, Challenges and Strategies for Malaria Elimination in the Tibet Autonomous Region of China].

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.

Lessons from malaria control to elimination: case study in Hainan and Yunnan provinces.

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.

Transition from control to elimination: impact of the 10-year global fund project on malaria control and elimination in China.

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.

Application of Auto-regressive Linear Model in Understanding the Effect of Climate on Malaria Vectors Dynamics in the Three Gorges Reservoir.

It is important to understand the dynamics of malaria vectors in implementing malaria control strategies. Six villages were selected from different sections in the Three Gorges Reservoir for exploring the relationship between the climatic factors and its malaria vector density from 1997 to 2007 using the auto-regressive linear model regression method. The result indicated that both temperature and precipitation were better modeled as quadratic rather than linearly related to the density of Anopheles sinensis.

Monitoring Plasmodium vivax chloroquine sensitivity along China-Myanmar border of Yunnan Province, China during 2008-2013.

BACKGROUND: Plasmodium vivax is the most widespread of the malaria parasites infecting human hosts. In malaria-eliminating settings, both imported and local malaria predominantly occurs in border areas, and most of them are P. vivax. Chloroquine (CQ) is the first-line drug for P. vivax treatment in China. To understand CQ sensitivity in P. vivax, in vivo monitoring of CQ resistance was conducted along the China-Myanmar border from 2008 to 2013. METHODS: Eligible patients with mono-infections of P. vivax were recruited to this study after obtaining full informed consent. CQ tablets for different categories of kg body weight ranges were given once a day for three days. Patients were followed up for 28 days. PCR was conducted to distinguish between re-infection and recrudescence, to confirm the Plasmodium species. The data were entered and analysed by the Kaplan-Meier method. Treatment outcome and sensitivity were classified according to the WHO recommended standards. RESULTS: 603 patients were completed valid follow-up. The fever clearance time and asexual parasite clearance times were, respectively, 22.2 ± 10.2 and 38.1 ± 12.6 hours. 594 (98.5%) patients were adequate clinical and parasitological response (ACPR), and nine (1.5%) patients, who were late clinical failure (LCF) or resistant response level I (RI), were imported from the neighbouring districts of Myanmar. CONCLUSION: In terms of efficacy, CQ is still effective for vivax malaria treatment. Plasmodium vivax CQ sensitivity had not significantly changed along the China-Myanmar border of Yunnan Province, China.

[Overviews on Plasmodium ovale wallikeri and its genetic detection system].

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.

[Ecological behavior comparison between Anopheles pseudowillmori and A. willmori in villages with malaria outbreaks in Motuo County, Tibet Autonomous Region].

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.

[Changes of pyrethroid resistance and P450 monooxygenase activity with age in Anopheles sinensis in Huainan City, Anhui Province, China].

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.

Endemic characteristics of infantile visceral leishmaniasis in the People's Republic of China.

BACKGROUND: Visceral leishmaniasis (VL) was once a severe parasitic disease in China. Thanks to the great efforts of integrated control, VL was eliminated in most epidemic areas, except for certain western provinces (autonomous region) at the end of 1950s. From then on, VL gained less attention and has seemed to spread, especially in the last 15 years. Infants are the most important population threatened by VL. However, there have been few studies on the endemic characteristics of infantile VL in China. METHODS: Infantile VL cases were collected from the online National Infectious Diseases Reporting System (NIDRS). Statistical description and inference was used to reveal the endemic characteristics in gender, age group, time and regionalism. Spatial analysis was carried out to explore the high risk area for infantile VL in China. RESULTS: A total of 1093 infantile VL cases were reported from 2006 to 2012. There was no statistically significant difference in gender over time. The minimum, maximum and mean age of these cases was 1.1, 35.9 and 13.8 months, respectively. Among them 86.92% were under 2 years of age, and there was a statistically significant difference among age groups over time. An incidence peak appeared in 2008-2009, most cases were distributed in the months September to December, and there was a tail-raising effect in the coming two months of the next year. More than 98% of cases were reported in Xinjiang Uygur Autonomous Region, Gansu Province and Sichuan Province, accounting for 61.02%, 32.75% and 4.57%, respectively. A total of 56 counties reported infantile VL cases, with the cumulative incidence ranging from 0.02 to 24.57%. There were two main zones of high endemicity for infantile VL in China. The monthly incidence clearly coincides with the number of towns where infantile VL cases were reported. Three fatalities were reported during the study period, the case fatality rate was 2.75‰. CONCLUSIONS: The endemic situation of infantile VL is serious, and there are several active foci of infantile VL prevalence in China. VL has emerged as a severe threat to infants of endemic regions in China.

Malaria transmission potential in the Three Gorges Reservoir of the Yangtze River, China.

OBJECTIVE: To define and evaluate the malaria transmission potential in the Yangtze River, following construction of the Three Gorges Reservoir. METHODS: Six villages, namely, Kaixian, Fengjie, Wanzhou, Fuling, Yubei, and Zigui were selected for investigating the malaria transmission potential in the reservoir. Transmission potential was estimated by mathematical modeling and evaluation of the local malaria situation. Factors that influenced the transmission potential were analyzed using Poisson regression analysis in combination with Grey Systematic Theory (based on evaluation by the Delphi method). RESULTS: Indirect fluorescent antibody data and the incidence of malaria in the local population were consistent with the malaria transmission potential calculated for the area. Multivariate Poisson regression analysis showed a statistically significant association between the riparian zone and the man-biting rate. CONCLUSION: The risk of a malaria epidemic can be forecasted using the malaria transmission potential parameters investigated here which was closely correlated with the riparian zone.

[Preliminary application of moving percentile method on surveillance and early-warning on visceral leishmaniasis in endemic areas].

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.

[Malaria from control to elimination in China: transition of goal, strategy and interventions].

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.

[Study on the correlation between land use and cover change and malaria transmission in the areas along the Yellow River and Huai River].

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.