Cooperative Sentinel Surveillance of Malaria in Laiza and Nearby Areas of Myanmar and Importation Threat Monitoring - China, 2019-2023.

Introduction: Laiza and nearby areas (LNA) in Myanmar are identified as the primary malaria hotspots in the bordering regions of Yunnan Province, China. Methods: Six sentinel surveillance sites were established at the China-Myanmar border in LNA to monitor malaria. Data from 2019 was used as a baseline to analyze malaria incidence and trends in LNA and Myanmar, as well as the importation of malaria cases into China from 2019 to 2023. Results: Plasmodium vivax was the predominant species, representing 99.95% (14,060/14,066) of confirmed malaria cases in LNA. A total of 8,356 malaria cases were identified in 2023, with an annual parasite incidence (API) of 19.78 per 100 person-years. Compared to 2019, the incidence rate ratio was 21.47 (95% confidence interval: 18.84, 24.48), indicating that the API in 2023 was 21.47 times higher than that in 2019. In Yunnan, out of 1,016 reported cases, 545 imported cases (53.64%) originated from LNA and spread to 18 (13.95%) out of 129 counties. Ten provinces in China, including Yunnan, reported imported malaria cases from LNA in Myanmar. Conclusions: The increase in population, particularly among internally displaced persons, along with inadequate healthcare services, has led to a notable resurgence of malaria in LNA. This resurgence poses a risk to preventing the re-emergence of malaria transmission in China. There is an urgent need for novel collaborative policies, as well as financial and technical assistance, to enhance malaria control efforts in LNA, Myanmar.

Implementing a novel capture and ligation probe-PCR method in mass screen and treatment to support malaria elimination efforts in the China-Myanmar border region.

BACKGROUND: Mass screening and treatment (MSAT) for malaria elimination lacks an ideal diagnostic tool to allow sensitive and affordable test of the target population in the field. This study evaluated whether Capture and Ligation Probe-PCR (CLIP-PCR) could be used in a field MSAT in Laiza City, Myanmar. METHODS: On day 0, two dried blood spots were collected from each participant. On day 1, all samples were screened for Plasmodium in a 20 m2 laboratory with workbench, a biosafety cabinet, a refrigerator, a benchtop shaking incubator and a qPCR machine, by four technicians using CLIP-PCR with sample pooling, at a health clinic of the Chinese bordering town of Nabang. On day 2, all positives were followed up and treated. RESULTS: Of 15,038 persons (65% of the total population) screened, 204 (1.36%) were CLIP-PCR positives. Among them, 188, 14, and 2 were infected with Plasmodium vivax, Plasmodium falciparum, and P. vivax/P. falciparum mix, respectively. The testing capacity was 538 persons/day, with a cost of US$0.92 /person. The proportion of submicroscopic infection was 64.7%. All positive individuals received treatment within 72 h after blood collection. CONCLUSION: Using CLIP-PCR in MSAT in low transmission settings can support the malaria elimination efforts in the China-Myanmar border region.

Screening for malaria infection in residents on the China-Myanmar border: RDT, microscopy and PCR / 中国热带医学

@#Abstract: Objective To compare the screening effects of RDT, microscopy and PCR for malaria among residents in low malaria areas and elimination areas, and to investigate the presence of malaria in residents of border Villages in Cangyuan Va County and asymptomatic infections in surrounding areas, providing a basis for preventing re-introduction of malaria after elimination. Methods From August 2020 to March 2021, the fingertip blood of the investigated subjects was collected from three survey sites in the border area between China and Myanmar, namely Banlao Township in Cangyuan Va Autonomous County of Lincang City, Banwai District, Mengmao County, the Second Special Zone of Shan State, Myanmar, Yongmo and Dayan Township, Nandeng Special Zone, the Second Special Zone of Shan State, Myanmar. The malaria parasite antigen detection test kit, malaria parasite microscopic examination, fluorescent quantitative PCR and nested PCR were used to detect the asymptomatic infection of malaria parasites. Results A total of 1 040 blood samples were collected, including 606 from China and 434 from Myanmar, with 506 males and 534 females. Among them, , there were 51 individuals aged 0 to <5 years, 283 aged 5 to < years, 187 aged 15 to < years, 232 aged 30 to <45 years, 205 aged 45 to < years, and 82 aged ≥60 years. All 1 040 people tested negative for plasmodium antigen detection kit. One case of Plasmodium vivax detected by plasmodium microscopic etiology, with a detection rate of 0.10%. One case of P. vivax was also detected by fluorescent quantitative PCR and nested PCR, with a detection rate of 0.10%. Among them, one case of P. vivax was detected in Banwai District, Mengmao County, the Second Special Zone of Shan State, Myanmar, with a detection rate of 0.35%. The detection rates of malaria parasites in Banlao Township in Cangyuan Va Autonomous County of Lincang City, Yunnan Province and Yongmo Township and Dayan Township, Nandeng Special District, the Second Special Zone of Shan State, Myanmar were both 0. The difference in the detection rate of malaria parasites among the three survey sites was not statistically significant (χ2 =2.682, P>0.05). The asymptomatic P. vivax infection was detected in a 6-year-old girl from Banwai District, Mengmao County, the Second Special Zone of Shan State, Myanmar. Conclusions RDT is not suitable for malaria screening in low malaria area and elimination area. Microscopic examination and PCR can be used for malaria screening, but PCR operation is complex and costly. In surrounding areas outside of China, malaria is still prevalent, while there is no source of malaria infection in border villages of Cangyuan Va County. However, there is a risk of importation, and timely and effective measures should be taken to prevent reintroduction and transmission.

The public health response to an outbreak of border-spill malaria along China-Myanmar border.

INTRODUCTION: Malaria importation can be caused by cross-border movement either of both people and anopheline mosquitoes. However, there still lacks robust evidence of imported malaria caused by Plasmodium spp. infected anopheles along international border areas (border-spill malaria). The objectives of this study were to confirm whether an outbreak of Plasmodium vivax malaria is border-spill malaria and assess the effects of China's public health response along China-Myanmar border. METHODS: Epidemiological, parasitological and entomological investigations were conducted to investigate the outbreak of border-spill malaria. Meanwhile, comprehensive interventions were carried out to prevent further transmission and reintroduction of malaria. RESULTS: Rapid diagnostic testing, microscopy and polymerase chain reaction were performed and the infections were confirmed as P. vivax. A total of 22 (9.21%) of 239 workers contracted P. vivax during the outbreak. Multivariate logistic regression analysis identified that the distance of worker shelters in China within 300 meters to the internally displaced person (IDP) camps in Myanmar was a risk factors associated with malaria infection (adjusted odds ratio 7.5920; 95% confidence interval, 2.6079-22.1013; P = 0.0002). After comprehensive interventions, malaria transmission was successfully interpreted and prevented at the project site till the completion of project on 14 January 2020, and recurrence of P. vivax malaria was not detected by the end of 2020. CONCLUSION: This study provided robust evidence of border-spill malaria along China-Myanmar border. Malaria parasite reservoir and distance travelled by female anopheline mosquitoes are two determinants for border-spill malaria. The public health response to the outbreak indicates that the malaria surveillance and response system works well in preventing reintroduction of malaria. However, prevention of border-spill malaria is still a major challenge in the Yunnan border area, China.

Historical review of malaria control and elimination in the border areas of China: A case study of Yunnan Province.

To understand how malaria could be eliminated in the original hyperendmic area for malaria along international borders in Yunnan Province, malaria situation and control were described on the basis of seven phases. At last the experiences and lessons of the program that reduced border malaria from hyperendmicity to malaria-free status were summarized. Malaria control and elimination area were particularly difficult in the Yunnan border. The achievement can be attributed to high political commitment, strategic and technical innovations based on the actual locality, effective collaboration and communication with neighbouring countries to carry out cross border interventions. Other border areas might perform their own pilot interventions based on their local context, including malaria burden, governing system, health service structure contextualized based on their socioeconomic development and ecology, and then a local decision could be made according to their own trial results.

Malaria from hyperendemicity to elimination along international borders in Yunnan, China during 2003‒2020: a case study.

BACKGROUND: Border malaria is one of the most intractable problems hindering malaria elimination worldwide. Movement of both the human population and anopheline mosquitoes infected with Plasmodium spp. can cause cross-border malaria transmission. The Yunnan border area was still hyperendemic for malaria in the early part of this century. The objective of this case study was to analyze the strategies, interventions and impacts of malaria control and elimination in the Yunnan border area. MAIN TEXT: A total of 10,349 malaria cases and 17.1 per 10,000 person-years of annual parasite incidence (API) were reported in the border area in 2003. Based on natural village-based stratification, integrated interventions, including mass drug administration for radical cures and preventive treatment, clinically presumptive treatment of all febrile patients for malaria and indoor residual spraying or dipping bed nets with insecticides were successfully carried out from 2003 to 2013. The overall API was reduced to 0.6 per 10,000 person-years by 2013, while effective cross-border collaboration interventions dramatically reduced the malaria burden in the neighbouring border areas of Myanmar. From 2014 forward, the comprehensive strategy, including universal coverage of surveillance to detect malaria cases, a rapid response to possible malaria cases and effective border collaboration with neighbouring areas, successfully eliminated malaria and prevented reintroduction of malaria transmission in the Yunnan border area. CONCLUSIONS: In Yunnan malaria burden has successfully reduced by dynamically accurate stratification and comprehensive interventions; and then the region achieved elimination and prevented reintroduction of malaria transmission through intensive surveillance, rapid response and border collaboration. Other border areas should perform their own intervention trials to develop their own effective strategy.

Estimation of Plasmodium falciparum transmission using multiepitope chimeric antigen in the postelimination phase in Yunnan, China.

BACKGROUND: The continuous monitoring of malaria transmission intensity is still required to maintain elimination status after reaching the malaria elimination stage. In this study, serological surveillance with multiepitope artificial antigen was used to assess the transmission of Plasmodium falciparum in Yunnan, China, where malaria elimination has just been achieved, to provide data to support malaria control in the postelimination period. METHODS: Samples were collected in three border counties and one inland county in Yunnan Province in 2016 using a stratified whole-group sampling method. Fingerstick blood was collected from all participants, and antibodies to Malaria Random Constructed Antigen-1 (M. RCAg-1) were detected by indirect ELISA. The transmission intensity of P. falciparum malaria was estimated using a catalytic conversion model based on the maximum likelihood of generating a community seroconversion rate (SCR). RESULTS: A total of 5566 samples were collected. There was no statistically significant difference in antibody level between the inland county and the nonendemic area, but the antibody level in border counties was significantly higher than those in the inland county and the nonendemic control area. No seropositive cases were found in Yanjin County, and the seropositivity rate increased with age in the three border counties. The highest intensity of P. falciparum malaria transmission was in Zhenkang County (SCR = 0.0030, CI: 0.0029, 0.0031), followed by Gengma County (SCR = 0.0013, CI: 0.0012, 0.0015) and Yingjiang County (SCR = 0.00088, CI: 0.00083, 0.00090). CONCLUSION: The transmission intensity of P. falciparum malaria in Yunnan Province has obviously decreased in recent years, but for the border areas where malaria has just been eliminated, the transmission intensity will not immediately drop to zero, and it still needs to be monitored for a period of time to maintain malaria elimination status.

Surveillance of Plasmodium vivax transmission using serological models in the border areas of China-Myanmar.

BACKGROUND: To understand the Plasmodium vivax malaria transmission intensity and to assess the effectiveness of prevention and control measures taken along the China-Myanmar border, a catalytic model was used to calculate the seroconversion rate, an important indicator of malaria transmission intensity with high sensitivity, which is particularly useful in areas of low transmission. METHODS: Five counties in Yunnan Province bordering Myanmar were selected as survey sites, and subjects were obtained in each county by stratified random sampling in 2013-2014. Fingerstick blood was collected from each subject and tested for antibodies to P. vivax Merozoite Surface Protein 1-19 (PvMSP1-19) using indirect ELISA. A catalytic conversion model was used to assess the transmission intensity of P. vivax malaria based on the maximum likelihood of generating a community seroconversion rate. RESULTS: A total of 3064 valid blood samples were collected. Antibody levels were positively correlated with age. The seroconversion rate (SCR) values for each village were Luoping (0.0054), Jingqiao (0.0061), Longpen (0.0087), Eluo (0.0079), Banwang (0.0042) and Banbie (0.0046), respectively. CONCLUSION: Overall, the intensity of P. vivax malaria transmission in the border areas of Yunnan Province is low and not entirely consistent across counties. Consecutive serological surveys are needed to provide a sensitive evaluation of transmission dynamics and can help to confirm areas where infection is no longer present.

Effectiveness of joint 3 + 1 malaria strategy along China-Myanmar cross border areas.

BACKGROUND: Cross-border malaria in Laiza City of Myanmar seriously affected Yingjiang County of China and compromised reaching the goal of malaria elimination by 2020. Since 2017, a pilot project on 3 + 1 strategy of joint cross-border malaria prevention and control was carried out for building a malaria buffer in these border areas. Here, 3 were the three preventive lines in China where different focalized approaches of malaria elimination were applied and + 1 was a defined border area in Myanmar where the integrated measures of malaria control were adopted. METHODS: A 5-year retrospective analysis (2015 to 2019) was conducted that included case detection, parasite prevalence and vector surveillance. Descriptive statistics was used and the incidence or rates were compared. The annual parasite incidence and the parasite prevalence rate in + 1 area of Myanmar, the annual importation rate in Yingjiang County of China and the density of An. minimus were statistically significant indictors to assess the effectiveness of the 3 + 1 strategy. RESULTS: In + 1 area of Myanmar from 2015 to 2019, the averaged annual parasite incidence was (59.11 ± 40.73)/1000 and Plasmodium vivax accounted for 96.27% of the total confirmed cases. After the pilot project, the annual parasite incidence dropped 89% from 104.77/1000 in 2016 to 12.18/1000 in 2019, the microscopic parasite prevalence rate dropped 100% from 0.34% in 2017 to zero in 2019 and the averaged density of An. Minimus per trap-night dropped 93% from 1.92 in June to 0.13 in September. The submicroscopic parasite prevalence rate increased from 1.15% in 2017 to 1.66% in 2019 without significant difference between the two surveys (P = 0.084). In Yingjiang County of China, neither indigenous nor introduced case was reported and 100% cases were imported from Myanmar since 2017. The averaged annual importation rate from 2015 to 2019 was (0.47 ± 0.15)/1000. After the pilot project, the annual importation rate dropped from 0.59/1000 in 2016 to 0.28/1000 in 2019 with an overall reduction of 53% in the whole county. The reduction was 67% (57.63/1000 to 18.01/1000) in the first preventive line, 52% (0.20/1000 to 0.10/1000) in the second preventive line and 36% (0.32/1000 to 0.22/1000) in the third preventive line. The averaged density of An. Minimus per trap-night in the first preventive line dropped 94% from 2.55 in June to 0.14 in September, without significant difference from that of + 1 area of Myanmar (Z value = - 1.18, P value = 0.24). CONCLUSION: The pilot project on 3 + 1 strategy has been significantly effective in the study areas and a buffer zone of border malaria was successfully established between Laiza City of Myanmar and Yingjiang County of China.

Intensive surveillance, rapid response and border collaboration for malaria elimination: China Yunnan's ''3 + 1''strategy.

BACKGROUND: Eliminating malaria and preventing re-establishment of malaria transmission in border areas requires universal coverage of malaria surveillance and a rapid response to any threats (i.e. malaria cues) of re-establishing transmission. MAIN TEXT: Strategy 1: Intensive interventions within 2.5 km-wide perimeter along the border to prevent border-spill malaria. The area within 2.5 km along the international border is the travel radius of anopheline mosquitoes. Comprehensive interventions should include: (1) proactive and passive case detection, (2) intensive vector surveillance, (3) evidence-based vector control, and (4) evidence-based preventative treatment with anti-malarial drugs. Strategy 2: Community-based malaria detection and screening of migrants and travellers in frontier townships. Un-permitted travellers cross borders frequently and present in frontier townships. Maintenance of intensified malaria surveillance should include: (1) passive malaria detection in the township hospitals, (2) seek assistance from villager leaders and health workers to monitor cross border travellers, and refer febrile patients to the township hospitals and (3) the county's Centre for Disease Control and Prevention maintain regular proactive case detection. Strategy 3: Universal coverage of malaria surveillance to detect malaria cues. Passive detection should be consolidated into the normal health service. Health services personnel should remain vigilant to ensure universal coverage of malaria detection and react promptly to any malaria cues. Strategy + 1: Strong collaborative support with neighbouring countries. Based on the agreement between the two countries, integrated control strategies should be carried out to reduce malaria burden for both countries. There should be a clear focus on the border areas between neighbouring countries. CONCLUSION: The 3 + 1 strategy is an experience summary of border malaria control and elimination, and then contributed to malaria elimination in Yunnan's border areas, China. Nevertheless, Yunnan still has remaining challenges of re-establishment of malaria transmission in the border areas, and the 3 + 1 strategy should still be carried out.

Malaria: elimination tale from Yunnan Province of China and new challenges for reintroduction.

BACKGROUND: Eradication of infectious disease is the sanctified public health and sustainable development goal around the world. MAIN BODY: Three antimalarial barriers were developed to control imported malarial cases, and an effective surveillance strategy known as the "1-3-7 approach" was developed to eliminate malaria from the Chinese population. From 2011 to 2019, 5254 confirmed malaria cases were reported and treated in Yunnan Province, China. Among them, 4566 cases were imported from other countries, and 688 cases were indigenous from 2011 to 2016. Since 2017, no new local malarial case has been reported in China. Thus, malaria has been completely eliminated in Yunnan Province. However, malaria is detected in overseas travellers on a regular basis, such as visitors from neighbouring Myanmar. CONCLUSION: Hence, the strategies should be further strengthened to maintain a robust public health infrastructure for disease surveillance and vector control programs in border areas. Such programs should be supported technically and financially by the government to avert the possibility of a malarial resurgence in Yunnan Province.

Seven decades towards malaria elimination in Yunnan, China.

BACKGROUND: Yunnan Province was considered the most difficult place in China for malaria elimination because of its complex malaria epidemiology, heterogeneous ecological features, relatively modest economic development, and long, porous border with three malaria endemic countries: Lao People's Democratic Republic, Myanmar, and Viet Nam. METHODS: Academic publications and grey literature relevant to malaria elimination in Yunnan covering the period from 1950 until 2020 inclusive were considered. The following academic indexes were searched: China Science Periodical Database, China National Knowledge Infrastructure Database, and MEDLINE. Grey literature sources were mainly available from the National Institute of Parasitic Diseases (NIPD), the Chinese Center for Diseases Control and Prevention, and the Yunnan Institute of Parasitic Diseases (YIPD). RESULTS: A malaria elimination campaign in the 1950-1960s, based mainly on mass administration of antimalarial drugs and large-scale vector control, reduced morbidity and mortality from malaria and interrupted transmission in some areas, although elimination was not achieved. Similar strategies were used to contain outbreaks and a resurgence of disease during the 1970s, when malaria services were discontinued. From the 1980s, malaria incidence declined, despite the challenges of large numbers of mobile and migrant populations and an unstable primary health care system in rural areas following economic transformation. Launch of the national malaria elimination programme in 2010 led to adoption of the '1-3-7' surveillance and response strategy specifying timely detection of and response for every case, supported by the establishment of a real-time web-based disease surveillance system and a new primary health care system in rural areas. Border malaria was addressed in Yunnan by strengthening the surveillance system down to the lowest level, cross-border collaboration with neighbouring countries and non-governmental organizations, and the involvement of other sectors. CONCLUSIONS: Seven decades of work to eliminate malaria in Yunnan have shown the importance of political commitment, technically sound strategies with high quality implementation, a robust surveillance and response system at all levels, community participation and effective management of border malaria. The experiences and lessons learned from elimination remain important for prevention re-establishment of malaria transmission in the Province.

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.

Receptivity to malaria in the China-Myanmar border in Yingjiang County, Yunnan Province, China.

BACKGROUND: The re-establishment of malaria has become an important public health issue in and out of China, and receptivity to this disease is key to its re-emergence. Yingjiang is one of the few counties with locally acquired malaria cases in the China-Myanmar border in China. This study aimed to understand receptivity to malaria in Yingjiang County, China, from June to October 2016. METHODS: Light-traps were employed to capture the mosquitoes in 17 villages in eight towns which were categorized into four elevation levels: level 1, 0-599 m; level 2, 600-1199 m; level 3, 1200-1799 m; and level 4, > 1800 m. Species richness, diversity, dominance and evenness were used to picture the community structure. Similarity in species composition was compared between different elevation levels. Data of seasonal abundance of mosquitoes, human biting rate, density of light-trap-captured adult mosquitoes and larvae, parous rate, and height distribution (density) of Anopheles minimus and Anopheles sinensis were collected in two towns (Na Bang and Ping Yuan) each month from June to October, 2016. RESULTS: Over the study period, 10,053 Anopheles mosquitoes were collected from the eight towns, and 15 Anopheles species were identified, the most-common of which were An. sinensis (75.4%), Anopheles kunmingensis (15.6%), and An. minimus (3.5%). Anopheles minimus was the major malaria vector in low-elevation areas (< 600 m, i.e., Na Bang town), and An. sinensis in medium-elevation areas (600-1200 m, i.e., Ping Yuan town). In Na Bang, the peak human-biting rate of An. minimus at the inner and outer sites of the village occurred in June and August 2016, with 5/bait/night and 15/bait/night, respectively. In Ping Yuan, the peak human-biting rate of An. sinensis was in August, with 9/bait/night at the inner site and 21/bait/night at the outer site. The two towns exhibited seasonal abundance with high density of the two adult vectors: The peak density of An. minimus was in June and that of An. sinensis was in August. Meanwhile, the peak larval density of An. minimus was in July, but that of An. sinensis decreased during the investigation season; the slightly acidic water suited the growth of these vectors. The parous rates of An. sinensis and An. minimus were 90.46 and 93.33%, respectively. CONCLUSIONS: The Anopheles community was spread across different elevation levels. Its structure was complex and stable during the entire epidemic season in low-elevation areas at the border. The high human-biting rates, adult and larval densities, and parous rates of the two Anopheles vectors reveal an exceedingly high receptivity to malaria in the China-Myanmar border in Yingjiang County.

Assessment of malaria control consultation and service posts in Yunnan, P. R. China.

BACKGROUND: This paper seeks to assess the function of malaria control consultation and service posts (MCCSPs) that are located on the border areas of Yunnan province, P.R. China, as a strategy for eliminating malaria among the mobile and migrant population in these areas. METHODS: A retrospective descriptive analytical study was conducted. Blood smear examinations conducted at all MCCSPs in Yunnan from 2008 to 2014 were analysed. A cross-sectional survey was conducted in 2014 to understand how the MCCSPs function and to elucidate the quality of the blood smear examinations that they conduct. RESULTS: Out of the surveyed MCCSPs, 66 % (39/59), 22 % (13/59), and 12 % (7/59) were attached to local township hospitals, village health clinics, and the county centre for disease control and prevention or private clinics, respectively. More than 64 % (38/59) of the posts' staff were part-time workers from township hospitals and village health facilities. Less than 31 % (18/59) of the posts' staff were full-time workers. A total of 35 positive malaria cases were reported from seven MCCSPs in 2014. Four MCCSPs were unable to perform their functions due to under staffing in 2014. There was a small fluctuation in blood smear examinations from January 2008 to June 2009, with two peaks during the period from July 2009 to October 2010. The number of blood smear examinations has been increasing since 2011. The yearly mean number of blood smear examinations in each post increased from 44 per month in 2011 to 109 per month in 2014, and the number of positive malaria cases detected by blood smear examinations has declined (χ 2 = 90.67, P = 0.000). The percentage of people from Yingjiang county getting blood smear examinations increased between 2008 and 2014, while percentages of the mobile population including Myanmar people, people from other provinces, and people from other Yunnan counties getting blood smear examinations decreased. CONCLUSION: MCCSPs face challenges in the phase of malaria elimination in Yunnan, China. New case detection strategies should be designed for MCCSPs taking into account the current trends of migration.

[Efficacy of Capture and Ligation Probe-PCR with#br# Pooling Strategy in Detection of Plasmodium spp.].

The capture and ligation probe-PCR（CLIP-PCR） with pooling strategy method and microscopy were applied on 100 clinical samples（7 positive and 93 negative samples） from the malaria reference laboratory in Yunnan Province. By calculating the detection rate, sensitivity, specificity, detection time and detection cost, the efficacy of the CLIP-PCR with pooling strategy method in detecting Plasmodium spp. was evaluated. The CLIP-PCR with matrix pooling strategy successfully detected Plasmodium spp. in all the 7 positive samples. Its sensitivity and specificity relative to the microscopy as a gold standard were both 100%. The detection time for all the samples by CLIP-PCR was 5.0 h, 85.0% shorter than that by microscopy（33.3 h）, and the detection cost was 300 yuan, 75.0% less than that by microscopy （1 000 yuan）.