Imported malaria cases in former endemic and non-malaria endemic areas in China: are there differences in case profile and time to response?

BACKGROUND: China has achieved zero indigenous malaria case report in 2017. However, along with the increasing of international cooperation development, there is an increasing number of imported malaria cases from Chinese nationals returning from malaria-affected countries. Previous studies have focused on malaria endemic areas in China. There is thus limited information on non-endemic areas in China, especially on the performance of malaria surveillance and response in health facilities. METHODS: A comparative retrospective study was carried out based on routine malaria surveillance data collected from 2013 to 2017. All imported malaria cases reported within the mainland of China were included. Variables used in the comparative analysis between cases in former endemic and former non-endemic areas, included age, gender and occupation, destination of overseas travel, Plasmodium species and patient health outcome. Monthly aggregated data was used to compare seasonal and spatial characteristics. Geographical distribution and spatial-temporal aggregation analyses were conducted. Time to diagnosis and report, method of diagnosis, and level of reporting/diagnosing health facilities were used to assess performance of health facilities. RESULTS: A total of 16 733 malaria cases, out of which 90 were fatal, were recorded in 31 provinces. The majority of cases (96.2%) were reported from former malaria endemic areas while 3.8% were reported from former non-malaria endemic areas. Patients in the age class from 19 to 59 years and males made the highest proportion of cases in both areas. There were significant differences between occupational categories in the two areas (P <  0.001). In former endemic areas, the largest proportion of cases was among outdoor workers (80%). Two peaks (June, January) and three peaks (June, September and January) were found in former endemic and former non-endemic areas, respectively. Time between the onset of symptoms and diagnosis at clinics was significantly different between the two areas at different level of health facilities (P <  0.05). CONCLUSIONS: All the former non-endemic areas are now reporting imported malaria cases. However, the largest proportion of imported cases is still reported from former endemic areas. Health facilities in former endemic areas outperformed those in former non-endemic areas. Information, treatment, and surveillance must be provided for expatriates while capacity building and continuous training must be implemented at health facilities in China.

Management of recurrent intracranial aneurysms after coil embolization: a novel classification scheme based on angiography.

OBJECTIVERecurrent aneurysms after coil embolization remain a challenging issue. The goal of the present study was to report the authors' experience with recurrent aneurysms after coil embolization and to discuss the radiographic classification scheme and recommended management strategy.METHODSAneurysm treatments from a single institution over a 6-year period were retrospectively reviewed. Ninety-seven aneurysms that recurred after initial coiling were managed during the study period. Recurrent aneurysms were classified into the following 5 types based on their angiographic characteristics: I, pure recanalization inside the aneurysm sac; II, pure coil compaction without aneurysm growth; III, new aneurysm neck formed without coil compaction; IV, new aneurysm neck formed with coil compaction; and V, newly formed aneurysm neck and sac.RESULTSAneurysm recurrences resulted in rehemorrhages in 6 cases (6.2%) of type III-V aneurysms, but in none of type I-II aneurysms. There was a significantly higher proportion of ophthalmic artery aneurysms and complex internal carotid artery aneurysms presenting as types I and II than presented as the other 3 types (63.3% vs 16.4%, p < 0.001). In contrast, for posterior communicating artery aneurysms and anterior communicating artery aneurysms, a higher proportion of type III-V aneurysms was observed than for the other 2 types, but without a significant difference in the multivariate model (56.7% vs 23.3%). In addition, giant (> 25 mm) aneurysms were more common among type I and II lesions than among type III and IV aneurysms (36.7% vs 9.0%, p = 0.001), which exhibited a higher proportion of small (< 10 mm) lesions (65.7% vs 13.3%, p < 0.001). A single reembolization procedure was sufficient to occlude 80.0% of type I recurrences and 83.3% of type II recurrences from coil compaction but only 65.6% of type III-V recurrences from aneurysm regrowth.CONCLUSIONSAneurysm size and location represent the determining factors of the angiographic recurrence types. Type I and II recurrences were safely treated by reembolization, whereas type III-V recurrences may be best managed surgically when technically feasible.

Monitoring of malaria vectors at the China-Myanmar border while approaching malaria elimination.

BACKGROUND: Tengchong County was one of the counties located at the China-Myanmar border with high malaria incidence in the previous decades. As the pilot county for malaria elimination at the border area, Tengchong County is aiming to be the first county to achieve malaria elimination goal. A cross-sectional entomological survey was carried out to evaluate the feasibility of elimination approach and assess the receptivity of malaria reintroduction. METHODS: Light traps associated with live baits were used to investigate the abundance of adult mosquitoes in nine villages in Tengchong County. Light traps were set to collect adult mosquitoes in both human houses and cowsheds from dusk till dawn in each site. RESULTS: A total of 4948 adult Anopheles mosquitoes were collected from May to December in two villages. Of the mosquitoes were captured, 24.2% were in human houses and 75.8% in cowsheds. The peak of abundance occurred in July for An. sinensis and in September-October for An. minimus (s.l.) Ten Anopheles species were collected, the most prevalent being An. sinensis (50.3%), An. peditaeniatus (31.6%) and An. minimus (s.l.) (15.8%), contributing to 97.6% of the sample. Potential breeding sites were also investigated and a total of 407 larvae were collected, with An. sinensis (50.1%) and An. minimus (s.l.) (46.2%) as predominant species. Ponds and rice fields were the two preferred breeding sites for Anopheles mosquitoes; however, the difference between the number of adults and larvae captured suggest other breeding sites might exist. Both An. sinensis and An. minimus (s.l.) were found zoophilic with human blood index as 0.21 and 0.26, respectively. No Plasmodium positive Anopheles specimens were found by PCR among 4,000 trapped mosquitoes. CONCLUSIONS: Although no indigenous malaria cases have been reported in Tengchong County since 2013, there is still a risk from the presence of vectors in the context of human population movements from neighboring malaria endemic areas. The presence of An. sinensis, associated to rice fields, is particularly worrying. Sustained entomological surveillance is strongly suggested even after malaria elimination certification.

Mobile population dynamics and malaria vulnerability: a modelling study in the China-Myanmar border region of Yunnan Province, China.

BACKGROUND: The China-Myanmar border region presents a great challenge in malaria elimination in China, and it is essential to understand the relationship between malaria vulnerability and population mobility in this region. METHODS: A community-based, cross-sectional survey was performed in five villages of Yingjiang county during September 2016. Finger-prick blood samples were obtained to identify asymptomatic infections, and imported cases were identified in each village (between January 2013 and September 2016). A stochastic simulation model (SSM) was used to test the relationship between population mobility and malaria vulnerability, according to the mechanisms of malaria importation. RESULTS: Thirty-two imported cases were identified in the five villages, with a 4-year average of 1 case/year (range: 0-5 cases/year). No parasites were detected in the 353 blood samples from 2016. The median density of malaria vulnerability was 0.012 (range: 0.000-0.033). The average proportion of mobile members of the study population was 32.56% (range: 28.38-71.95%). Most mobile individuals lived indoors at night with mosquito protection. The SSM model fit the investigated data (χ2 = 0.487, P = 0.485). The average probability of infection in the members of the population that moved to Myanmar was 0.011 (range: 0.0048-0.1585). The values for simulated vulnerability increased with greater population mobility in each village. CONCLUSIONS: A high proportion of population mobility was associated with greater malaria vulnerability in the China-Myanmar border region. Mobile population-specific measures should be used to decrease the risk of malaria re-establishment in China.

Shrinking the malaria map in China: measuring the progress of the National Malaria Elimination Programme.

BACKGROUND: Remarkable progress has been made towards the elimination of malaria in China since the National Malaria Elimination Programme (NMEP) was launched in 2010. The incidence of locally-acquired malaria cases has declined rapidly and endemic areas have also dramatically shrunk. In total, 3 078 malaria cases were reported in 2014, but only 56 cases were indigenous. In order to further promote the elimination programme, we reviewed the progress of and experiences associated with malaria elimination in China, and identified the challenges and priorities for the next stage of the programme. METHODS: Data were collected from the web-based China Information System for Disease Control and Prevention, and the China Annual Report of Malaria Elimination. The progress towards the elimination of malaria from 2010 to 2014 was measured. RESULTS: During the implementation of the NMEP from 2010 to 2014, local malaria incidence has declined continuously, only remaining in the Yunnan Province and Tibet Autonomous Region in 2014. By the end of 2015, 75.6 % (1 636/2 163) of the malaria-endemic counties passed the sub-national elimination assessment. The main challenges are cases of border malaria and imported malaria from other countries. Sustainable support and investment from the government, the establishment of an effective surveillance and response system, and risk assessments for the potential reintroduction of malaria are priorities for the next stage of the elimination programme. CONCLUSIONS: The NMEP in China has been successfully implemented thus far and the malaria map has shrunk dramatically. The priorities for malaria elimination are interventions to block transmission at border areas, management of imported malaria cases, preventing malaria reintroduction, capacity building, and sustainability of malaria surveillance and response.

[Malaria Situation in the People's Republic of China in 2015].

The 2015 malaria epidemiological data reported through the annual malaria statistics reporting system were collected and analyzed. Totally 3 288 malaria cases were reported in 664 counties of 31 Provinces/Municipalities/Autonomous Regions （P/M/A） in 2015, which increased by 6.8% in comparison to that of 2014 （3 078 cases）, and the incidence in 2015 was 0.024 0/10 000. The cases were reported primarily from Provinces of Yunnan （18.4%, 606/3 288）, Jiangsu （12.3%, 405/3 288）, Sichuan （8.8%, 290/3 288）, Guangxi （7.2%, 236/3 288） and Shandong（6.4%, 212/3 288）. Of all the cases, 40（1.2%, 40/3 288） were indigenous cases, mainly distributed in the border area of Yunnan （six counties）, Tibet （one county）, Liaoning （one county） and Hainan （one county）. There was one case of whom the source of infection was unknown. The locally-infected falciparum malaria was only found in Cangyuan County of Yunnan（1 case）. The prevalence of indigenous malaria in Motuo County of the Tibet Autonomous Region was over 1/10 000. Meanwhile, there were 3 248（98.8%, 3 248/3 288） abroad-imported cases which widely distributed in the 31 P/M/As. In addition, 3 265（99.3%, 3 265/3 288） of the reported cases were confirmed in reference laboratories, comprising 878 cases of Plasmodium vivax（26.9%, 878/3 265） 1 992 cases of P. falciparum（61.0%, 1 992/3 265）, 76 cases of P. malariae（2.3%, 76/3 265）, 272 cases of P. ovale（8.3%, 272/3 265） and 47 cases of mixed infection（1.4%, 47/3 265）. Furthermore, 163 cases（5.0%, 163/3 288） with severe clinical symptoms were reported in 14 P/M/As, with 20 deaths（0.6%, 20/3 288） in 10 P/M/As. Totally 3 116 malaria cases were reported through the China Information System for Disease Control and Prevention, including 39 indigenous cases. These data reflect achievements in malaria elimination, despite that challenges remain in boarder areas of Yunnan Province and in Motuo County of the Tibet Autonomous Region. Efforts are still needed in risk assesment for malaria re-transmission.

China's 1-3-7 surveillance and response strategy for malaria elimination: Is case reporting, investigation and foci response happening according to plan?

BACKGROUND: The China's 1-3-7 strategy was initiated and extensively adopted in different types of counties (geographic regions) for reporting of malaria cases within 1 day, their confirmation and investigation within 3 days, and the appropriate public health response to prevent further transmission within 7 days. Assessing the level of compliance to the 1-3-7 strategy at the county level is a first step towards determining whether the surveillance and response strategy is happening according to plan. This study assessed if the time-bound targets of the 1-3-7 strategy were being sustained over time. Such information would be useful to improve implementation of the 1-3-7 strategy in China. METHODS: This cross-sectional study involved country-wide programmatic data for the period January 1st 2013 to June 30th 2014. Data variables were extracted from the national malaria information system and included socio-demographic information, type of county, date of diagnosis, date of reporting, date of case investigation, case classification (indigenous, or imported, or unknown), focus investigation, date of reactive case detection (RACD), and date of indoor residual spraying (IRS). Summary statistics and proportions were used and comparisons between groups were assessed using the chi-square test. Level of significance was set at a P-value ≤ 0.05. RESULTS: Of a total of 5,688 malaria cases from 731 counties, there were 55 (1 %) indigenous cases (only in Type 1 and Type 2 counties) and 5,633 (99 %) imported cases from all types of counties. There was no delay in reporting malaria cases by type of county. In terms of case investigation, 97.5 % cases were investigated within 3 days with the proportion of delays (1.5 %) in type 2 counties, being significantly lower than type 1 counties (4.1 %). Regarding active foci, 96.4 % were treated by RACD and/or IRS. CONCLUSIONS: The performance of 1-3-7 strategy was encouraging but identified some challenges that if addressed can further improve implementation.

[Screening Radius of Active Case Detection and the Malaria Parasite Rate of Carriers in China-Myanmar Border].

OBJECTIVE: To explore the effective screening radii of active case detection of the 1-3-7 surveillance and response strategy, and investigate the malaria parasite rate of carriers in China-Myanmar border. METHODS: Three villages with indigenous malaria cases in Yingjiang County of Yunan Province were selected as study sites. The persons lived around the indigenous cases (index case) within the radius of 100 m, 300 m, 500 m, and 1 km were screened by microscopy and nested PCR. Parasite rate of asymptomatic carriers at different radii were calculated. RESULTS: Among 278 blood samples, the parasite rate of asymptomatic carriers was 1.1% (3/278) and 2.2% (6/278) using microscopy and nested PCR, respectively. Based on the results of nested PCR, all the asymptomatic carriers could be detected within a 300 m radius around the index case, and with the highest proportion (66.7%) in the radius of 101-300 m. CONCLUSION: The asymptomatic carriers of malaria parasites in the China-Myanmar border area can be effectively detected within a 300 m screening radius of index case by using nested PCR.

Spatio-temporal analysis of malaria vectors in national malaria surveillance sites in China.

BACKGROUND: To reveal the spatio-temporal distribution of malaria vectors in the national malaria surveillance sites from 2005 to 2010 and provide reference for the current National Malaria Elimination Programme (NMEP) in China. METHODS: A 6-year longitudinal surveillance on density of malaria vectors was carried out in the 62 national malaria surveillance sites. The spatial and temporal analyses of the four primary vectors distribution were conducted by the methods of kernel k-means and the cluster distribution of the most widely distribution vector of An.sinensis was identified using the empirical mode decomposition (EMD). RESULTS: Totally 4 species of Anopheles mosquitoes including An.sinensis, An.lesteri, An.dirus and An.minimus were captured with significant difference of distribution as well as density. An. sinensis was the most widely distributed, accounting for 96.25% of all collections, and its distribution was divided into three different clusters with a significant increase of density observed in the second cluster which located mostly in the central parts of China. CONCLUSION: This study first described the spatio-temporal distribution of malaria vectors based on the nationwide surveillance during 2005-2010, which served as a baseline for the ongoing national malaria elimination program.

Operational research on malaria control and elimination: a review of projects published between 2008 and 2013.

A literature review for operational research on malaria control and elimination was conducted using the term 'malaria' and the definition of operational research (OR). A total of 15 886 articles related to malaria were searched between January 2008 and June 2013. Of these, 582 (3.7%) met the definition of operational research. These OR projects had been carried out in 83 different countries. Most OR studies (77%) were implemented in Africa south of the Sahara. Only 5 (1%) of the OR studies were implemented in countries in the pre-elimination or elimination phase. The vast majority of OR projects (92%) were led by international or local research institutions, while projects led by National Malaria Control Programmes (NMCP) accounted for 7.8%. With regards to the topic under investigation, the largest percentage of papers was related to vector control (25%), followed by epidemiology/transmission (16.5%) and treatment (16.3%). Only 19 (3.8%) of the OR projects were related to malaria surveillance. Strengthening the capacity of NMCPs to conduct operational research and publish its findings, and improving linkages between NMCPs and research institutes may aid progress towards malaria elimination and eventual eradication world-wide.

Preparation of malaria resurgence in China: case study of vivax malaria re-emergence and outbreak in Huang-Huai Plain in 2006.

This chapter reviews the patterns of malaria re-emergence and outbreak that occurred in the Huang-Huai Plain of China in 2006, and the way of quick response to curtail the outbreak by mass drug administration and case management. The contribution of the each intervention in quick response is discussed. Particularly due to the special ecological characteristics in the Huang-Huai Plain, the intervention of vector control is not implemented. Finally, the challenges in the elimination of malaria in this region are highlighted.

[Risk assessment for malaria elimination in P. R. China].

OBJECTIVE: To identify the risk area in China during the malaria elimination process, and provide the evidence for promotion of the national malaria elimination programme and implementation of elimination strategy. METHODS: Data collection was conducted in 24 endemic provinces in 2010, including data of transmission capacity, potential risk of malaria transmission and the capacity of health professional team at county level. Quantitative assessment of the malaria transmission risk as well as the capacity of health facilities were conducted based on the calculation of malaria transmission risk index (MTI) and health facilities capacity index (CI). ArcGIS 10.0 was used to develop the risk map based on the outcome of quantitative assessment. RESULTS: The data of transmission capacity, potential risk of transmission and the capacity of health professional team were collected from 2147 counties in 24 provinces. Based on MTI and CI calculated for each county, statistic results showed that about 40% of the counties were under the average level of both MTI and CI. The relationship among potential risk of transmission, the capacity of health professional team and malaria incidence were analyzed in three dimensions, and four types were categorized among 2147 counties. Type I (super-high risk area) counties (20) distributed in Yunnan (9), Guangxi (5), Henan (1), Hunan (1), Hebei (1), Sichuan (1), Chongqing (1), and Tibet (1). 17 counties were classified into type II (high risk area) area, distributed in Yunnan (3), Guangxi (2), Guizhou (2), Shaanxi (2), Guangdong (1), Jiangxi (1), Hubei (1), Sichuan (1), Gansu (1), Hebei (1), Fujian (1) and Tibet (1). A total of 170 type III (moderate risk area) counties distributed in 19 provinces including Yunnan (15), Guizhou (14), Hebei (14), Sichuan (13), Shanxi (10), Guangxi (9), Hunan (9), Anhui (9), Jiangsu (9), Shaanxi (9), Shandong (9), Chongqing (8), Gansu (8), Jiangxi (7), Henan (7), Fujian (6), Guangdong (5), Hubei (5), and Zhejiang (4). 1940 type IV (low risk area) counties distributed in 24 provinces. CONCLUSION: The distribution of four types of risk area for malaria elimination is identified in China.

[Methods of detecting asymptomatic plasmodium parasites carriers].

More attention has increasingly been given to asymptomatic carriers of plasmodium parasites as a source of infection in malaria elimination settings. However, asymptomatic infections can hardly be detected by microscopy and rapid diagnostic tests (RDTs) because of no symptoms and low parasitemia. This review summarizes the evolution of methods or tests which are currently used in the field.

[Determination of key interventions for the transition from control to elimination of malaria in China].

OBJECTIVE: To determine the key interventions transferring from the control to elimination of malaria in China so as to provide the basic information for achieving malaria elimination. METHODS: Based on the data collected from the document entitled of The National Annual Report on Schistosomiasis, Malaria and Echinococcosis, published by the National Institute of Parasitic Diseases of Chinese Center for Disease Control and Prevention, the malaria incidence and intervention data were selected only in the typical endemic provinces during the period of 2004-2010. The correlation between the incidence and interventions in the target provinces was analyzed based on the Panel Data Regression Model, and the key interventions were determined. RESULTS: Four provinces namely Anhui, Yunnan, Hainan and Henan were targeted with 87.56% of the national malaria figures from 2004 to 2010. When Y was given as vivax malaria incidence, X1 as the log of the number of historical cases receiving radical treatment in the pre-transmission stage (RTPT) (F = 14.53, P < 0.01, R2 = 0.72), X2 as the log of risk population receiving RTPR (F = 15.90, P < 0.01, R2 = 0.71) and X3 as the number of technicians trained in microscopy (F = 11.53, P < 0.01, R2 = 0.61), three space-fixed effect models were established respectively, and X1, X2, as well as X3 had negative effects on Y value. When Y was given as falciparum malaria incidence, X1 as the accumulated technicians trained in microscopy (F = 11.06, P < 0.01, R2 = 0.87), X2 as the log of technicians trained in entomology (F = 15.28, P < 0.01, R2 = 0.89) , two two-way (space and time) fixed effect models were established respectively, and both X1 and X2 had negative effects on Y value. CONCLUSION: RTPT among historical patients and at-risk populations as well as microscopy training influences the variation of vivax malaria incidence, while the significant interventions of microscopy training and vector control training indicate that the integrated measures with strengthened capacity in diagnosis and vector control are of importance in the control of falciparum malaria transmission.

[Analysis report of the national technique competition for diagnosis of parasitic diseases in 2012: I. Capability analysis of Plasmodium detection].

OBJECTIVE: To analyze the result of the national technique competition for diagnosis of parasitic diseases in 2012, so as to understand the capability of detection on Plasmodium parasites among professionals from institutes for disease control and prevention at different levels. METHODS: Four professionals from institution were selected as contestants (age < or = 45 and at least two contestants from county-level institution). The content of the competition included making thick and thin blood slides of Plasmodium (3 slides in 30 min, 10 scores as full marks and 6 as passing score) and identification of species and number with microscopy (5 slides, 8 min per slide, 30 scores as full marks and 18 as passing score). All contestants were grouped by gender, age, professional title, level of institution, classification according to malaria endemicity, geographical location and economic development of the province. Their scores were statistically analyzed by SPSS 16.0 software. RESULTS: The average score of blood smear making test in 120 contestants from 30 provinces was 8.7, the highest was 10 and the lowest was 5.8, 118 (98.3%) contestants passed the test. The average score of blood smear reading was 16.0, the highest was 29 and the lowest was 0, 52 (43.3%) contestants passed the test. There were no significant differences for the scores among genders, ages (< or = 30, 31-40, > 40), professional titles (junior, intermediate and senior), institution levels (provincial, municipal or county level) (P > 0.05). However, there was a significant difference among provinces with different malaria endemicity, geographical location and development status (P < 0.05). For the blood slide-making and film-reading, scores of contestants from malaria endemic provinces including Class I (9.29 +/- 0.41, 18.17 +/- 6.42), Class II (8.92 +/- 0.79, 18.31 +/- 6.94) and Class III (8.61 +/- 0.89, 15.63 +/- 7.52) were higher than those from non-endemic provinces (7.95 +/- 1.00, 10.19 +/- 7.01) (P < 0.01). Scores of contestants from southern provinces (9.16 +/- 0.61, 18.82 +/- 6.78) were significantly higher than that from northern ones (8.30 +/- 0.99, 13.23 +/- 7.45) (P < 0.01). The film-reading scores were significantly higher in those from eastern provinces (18.20 +/- 6.88) than those from western (13.39 +/- 7.60) (P < 0.05), while no significant difference was found in blood slide-making (P > 0.05). CONCLUSION: The capability of malaria parasite detection is imbalanced.

[Report of analysis of National Technique Competition for Diagnosis of Parasitic Diseases in 2011--II Analysis of capabilities of Plasmodium detection].

OBJECTIVE: To analyze the results of the National Technique Competition for Diagnosis of Parasitic Diseases in 2011, so as to understand the capability of detection on Plasmodium among professionals from institutes for disease control and prevention at different levels. METHODS: All the contestants were grouped by the gender, age, professional title, level of institution, epidemic degree of malaria of provinces, coverage status of the project of the global fund to fight malaria, and geographical location of the provinces, and their scores were statistically analyzed by SPSS 17.0 software. RESULTS: There were no significantly differences among the scores grouped by the different genders, ages, professional titles, and levels of institution (all P > 0.05). However, there were significantly differences among the scores grouped by the different epidemic degrees of malaria of the province, coverage statuses of the project of the global fund to fight malaria, and geographical locations of the province (all P < 0.05). For the contestants who came from the provinces with malaria epidemic counties of Class I and Class II types, provinces covered by the project of the global fund to fight malaria, and provinces located in the south, their scores of blood slides making and films reading under a microscope were significantly higher than those of the contestants from the provinces without epidemic counties of Class I and II types, not covered by the project of the global fund, and provinces located in the north, respectively. CONCLUSIONS: The overall level of the capabilities of detection on Plasmodium is imbalanced, and the capability of films reading under a microscope is especially low. It is urgent to promote the personnel training and strengthen the capability of pathogenic detection of parasitic diseases.

[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.

Spatial correlation between malaria cases and water-bodies in Anopheles sinensis dominated areas of Huang-Huai plain, China.

BACKGROUND: Malaria re-emerged in the Huang-Huai Plain of central China during 2006-2008, dominated with Anopheles sinensis as a vector. However, there is no information on strategies based on multi-factor analysis to effectively control the re-emergence of malaria in these areas. Previous experience indicates some relationship between the distribution of water bodies and malaria cases, but more detailed data are not available and in-depth studies have not been conducted up to now. The objective of this study was to identify the relationship between the distribution of water bodies and presentation of malaria cases using spatial analysis tools in order to provide guidance to help formulate effective strategies for use in controlling the sources of malaria infection, based on the identification of risk areas and population. METHODS: The geographic information of malaria cases and their surrounding water bodies were collected from Suixi, Guoyang, Guzhen, Yingshang, Fengyang and Yongqiao County in Anhui province, Yongcheng and Tongbai County in Henan province. All malaria cases distributed in 113 villages in these 8 counties were collected from the China Information System for Disease Control and Prevention and confirmed by household investigation. Data on GIS and malaria cases were mapped and analyzed with the software of ArcGIS 9.2 to identify the spatial correlation between malaria cases and water bodies. The distance from households with malaria cases to the nearest water bodies was used to calculate the OR value by Chi-square test. The risk area was identified through the comparison of OR values in different distances. RESULTS: 357 malaria cases and their GPS data as well as surrounding water bodies were collected and analyzed. 74% of malaria cases were located within the extent of 60 m proximity to the water bodies. The risk rate of people living there and presenting with malaria was significantly higher than others (OR = 1.6,95%CI (1.042, 2.463),P < 0.05). CONCLUSIONS: The results revealed that distribution of water bodies is an important factor influencing the occurrence and distribution of malaria cases in the An.sinensis areas, and implies that the scope and population within 60 m around water bodies are at risk and could be a targeted population for case management of malaria.

[GIS/RS/GPS application in the study of relationship between natural factors and malaria transmission].

Malaria transmission is highly related to the natural factors such as temperature, rainfall and topography. Recently, the GIS/RS/GPS techniques were developed based on computer science and spatial analysis technology, which were widely used in data collection and analysis, establishment of mathematics model. This paper reviews the applications and development of GIS/RS/GPS techniques in the studies of relationship between natural factors and malaria transmission.