Competency of malaria laboratory diagnosis at national and provincial levels at the beginning of malaria post-elimination phase, China.

BACKGROUND: Qualified malaria diagnosis competency has contributed to the great achievement of malaria elimination in China. After eliminating malaria, it is still critical to the prevention of re-establishment of malaria transmission in China. This study was aimed to assess the malaria detection competency at national and provincial levels in China at the beginning of malaria post-elimination phase. METHODS: In the present study, different competency assessment activities on the laboratory malaria diagnosis were carried out for national and provincial malaria diagnostic laboratories based on the WHO scoring schedules, including malaria microscopy or nucleic acid amplification tests (NAAT), at the beginning of malaria post-elimination phase (2021-2022) in China. RESULTS: A total of 60 slides for malaria microscopy and 10 specimen for NAAT were included into the WHO External Quality Assessments of malaria parasite qualitative detection and species identification, and the scoring rate was 96.6% (microscopy: 171/177) and 85.0% (NAAT: 17/20), respectively. Moreover, 124 samples were included into the national NAAT quality assessment, and an accuracy of 87.9% (109/124) was found without significance among reference laboratories and non-reference laboratories. CONCLUSIONS: The findings suggest that there is still a need for sustained strengthening of malaria detection competency, particularly in the areas of parasite counting and detection of low-density parasitemia, to ensure prompt detection of the sources of infection and accurate identification of Plasmodium species, and contribute to case management and focus disposal, thereby effectively preventing the malaria re-establishment.

Risk assessment of imported malaria in China: a machine learning perspective.

BACKGROUND: Following China's official designation as malaria-free country by WHO, the imported malaria has emerged as a significant determinant impacting the malaria reestablishment within China. The objective of this study is to explore the application prospects of machine learning algorithms in imported malaria risk assessment of China. METHODS: The data of imported malaria cases in China from 2011 to 2019 was provided by China CDC; historical epidemic data of malaria endemic country was obtained from World Malaria Report, and the other data used in this study are open access data. All the data processing and model construction based on R, and map visualization used ArcGIS software. RESULTS: A total of 27,088 malaria cases imported into China from 85 countries between 2011 and 2019. After data preprocessing and classification, clean dataset has 765 rows (85 * 9) and 11 cols. Six machine learning models was constructed based on the training set, and Random Forest model demonstrated the best performance in model evaluation. According to RF, the highest feature importance were the number of malaria deaths and Indigenous malaria cases. The RF model demonstrated high accuracy in forecasting risk for the year 2019, achieving commendable accuracy rate of 95.3%. This result aligns well with the observed outcomes, indicating the model's reliability in predicting risk levels. CONCLUSIONS: Machine learning algorithms have reliable application prospects in risk assessment of imported malaria in China. This study provides a new methodological reference for the risk assessment and control strategies adjusting of imported malaria in China.

Epidemiologic Analysis of Efforts to Achieve and Sustain Malaria Elimination along the China-Myanmar Border.

Malaria cases have dramatically declined in China along the Myanmar border, attributed mainly to adoption of the 1-3-7 surveillance and response approach. No indigenous cases have been reported in China since 2017. Counties in the middle and southern part of the border area have a higher risk for malaria importation and reestablishment after elimination.

Molecular surveillance of pfcrt, pfmdr1 and pfk13-propeller mutations in Plasmodium falciparum isolates imported from Africa to China.

BACKGROUND: The emergence and spread of multidrug resistance poses a significant risk to malaria control and eradication goals in the world. There has been no indigenous malaria cases reported in China since 2017, and China is approaching national malaria elimination. Therefore, anti-malarial drug resistance surveillance and tracking the emergence and spread of imported drug-resistant malaria cases will be necessary in a post-elimination phase in China. METHODS: Dried blood spots were obtained from Plasmodium falciparum-infected cases returned from Africa to China between 2012 and 2015, prior to anti-malarial drug treatment. Whole DNA were extracted and known polymorphisms relating to drug resistance of pfcrt, pfmdr1 gene, and the propeller domain of pfk13 were evaluated by nested PCR and sequencing. The haplotypes and prevalence of these three genes were evaluated separately. Chi-squared test and Fisher's exact test were used to evaluate differences among the different sub-regions of Africa. A P value < 0.05 was used to evaluate differences with statistical significance. The maps were created using ArcGIS. RESULTS: A total of 731 P. falciparum isolates were sequenced at the pfcrt locus. The wild type CVMNK was the most prevalent haplotype with prevalence of 62.8% and 29.8% of the isolates showed the triple mutant haplotype CVIET. A total of 434 P. falciparum isolates were successfully sequenced and pfmdr1 allelic variants were observed in only codons 86, 184 and 1246. Twelve haplotypes were identified and the prevalence of the wild type pfmdr1 NYD was 44.1%. The single mutant pfmdr1 in codons 86 and 184 was predominant but the haplotype NYY with single mutation in codon 1246 was not observed. The double mutant haplotype YFD was common in Africa. About 1,357 isolates were successfully sequenced of pfk13-propeller domain, the wild type was found in 1,308 samples (96.4%) whereby 49 samples (3.6%) had mutation in pfk13. Of 49 samples with pfk13 mutations, 22 non-synonymous and 4 synonymous polymorphic sites were confirmed. The A578S was the most common mutation in pfk13-propeller domain and three mutations associated with artemisinin resistance (M476I, R539T, P553L) were identified in three isolates. CONCLUSION: This study provides evidence that could give insight into potential issues with anti-malarial drug resistance to inform national drug policy in China in order to treat imported cases.

Ready for malaria elimination: zero indigenous case reported in the People's Republic of China.

BACKGROUND: Malaria was once one of the most serious public health problems in China. However, the disease burden has sharply declined and epidemic areas have shrunk after the implementation of an integrated malaria control and elimination strategy, especially since 2000. In this review, the lessons were distilled from the Chinese national malaria elimination programme and further efforts to mitigate the challenges of malaria resurgence are being discussed. METHODS: A retrospective evaluation was performed to assess the changes in malaria epidemic patterns from 1950 to 2017 at national level. The malaria data before 2004 were collected from paper-based annual reports. After 2004, each of the different cases from the Infectious Diseases Information Reporting Management System (IDIRMS) was closely examined and scrutinized. An additional documenting system, the National Information Management System for Malaria, established in 2012 to document the interventions of three parasitic diseases, was also examined to complete the missing data from IDIRMS. RESULTS: From 1950 to 2017, the occurrence of indigenous malaria has been steeply reduced, and malaria-epidemic regions have substantially shrunk, especially after the launch of the national malaria elimination programme. There were approximately 30 million malaria cases annually before 1949 with a mortality rate of 1%. A total of 5999 indigenous cases were documented from 2010 to 2016, with a drastic reduction of 99% over the 6 years (2010, n = 4262; 2016, n = 3). There were indigenous cases reported in 303 counties from 18 provinces in 2010, but only 3 indigenous cases were reported in 2 provinces nationwide in 2016. While in 2017, for the first time, zero indigenous case was reported in China, and only 7 of imported cases were in individuals who died of Plasmodium falciparum infection. CONCLUSION: Malaria elimination in China is a country-led and country-owned endeavour. The country-own efforts were a clear national elimination strategy, supported by two systems, namely a case-based surveillance and response system and reference laboratory system. The country-led efforts were regional and inter-sectoral collaboration as well as sustained monitoring and evaluation. However, there are still some challenges, such as the maintenance of non-transmission status, the implementation of a qualified verification and assessment system, and the management of imported cases in border areas, through regional cooperation. The findings from this review can probably help improving malaria surveillance systems in China, but also in other elimination countries.

[A retrospective analysis on the diagnosis and reporting of imported malaria in Jiangxi Province during 2012-2015].

Objective: To provide scientific basis for malaria surveillance in the elimination phase by retrospectively analyzing the diagnosis and reporting of imported malaria in Jiangxi Province. Methods: Data on malaria endemic situation and individual cases during 2012-2015 were collected through the National Information Management System for Infectious Diseases and the Report and Information Management System for Parasitic Diseases Control and Prevention. Detailed information on primary medical units, laboratory testing units, reporting units, diagnostic methods, time from onset to first medical visit, time from first medical visit to reporting, and time from onset to reporting was analyzed with the descriptive analysis method. Results: A total of 207 malaria cases were reported during 2012-2015 in Jiangxi, all were imported cases and 96.62%(200/207) were diagnosed with laboratory tests. The main primary medical units were found to be county-level (29.95%, 62/207) and prefecture-level (25.60%, 53/207) medical institutions, while the main laboratory testing units were prefecture-level medical institutions(35.27%,73/207) and county-level CDCs (20.29%, 42/207). There was a significant difference in the proportion of different laboratory testing units among the years(P < 0.05). The median time from onset to first medical visit was 1 d (0-149 d), from first medical visit to reporting was 3 d (0-144 d), and from onset to reporting was 5 d (0-149 d). Conclusions: The first visit and the laboratory testing of malaria cases mainly occur in the prefecture-level and county-level medical institutions.

[Exploration of Using One-step Reverse Transcription PCR in Detection of Four Species of Human Malaria Parasites].

Objective: To explore the application and specificity of one-step reverse transcription PCR (RT-PCR) in detecting four species of human Plasmodium parasites. Methods: Blood samples were collected from a falciparum malaria case, a vivax malaria case, an ovale malaria case, and five quartan malaria cases. RNA and DNA were isolated. One-step RT-PCR and one-step real-time RT-PCR were performed on the RNA digested with DNase to amplify the Plasmodium 18S rRNA. Traditional PCR and one-step RT-PCR were used to amplify 18S rRNAs and 18S rDNAs in differentially diluted RNAs (with or without DNase digestion) and DNAs. The lowest detectable dilution concentrations for the two amplification systems were compared. Results: One-step RT-PCR produced specific bands of 310, 394 and 323 bp, which were sequenced to be 18S rRNA of P. falciparum, P. ovale, and P. vivax. No specific band for P. malariare was found. The one-step real-time RT-PCR results showed fluorescence for all the four species, and all had a melting curve with a single peak except for P. malariare. The lowest detectable dilution concentration by one-step RT-PCR varied from 1 to 10-4 based on the DNA or RNA template amount. Specifically, the lowest detectable dilution concentration of DNA was similar to or lower than that of original RNA by an order of magnititude, and both were lower than that of DNase-digested RNA. Further, the sensitivity of one-step RT-PCR evaluated in terms of lowest detectable dilution concentration was 10-1 000 times higher than that of the traditional PCR. Conclusions: The one-step RT-PCR technique can be applied in the detection of P. falciparum, P. ovale, and P. vivax in fresh blood samples. But its use in detecting P. malariae parasites needs further evaluation.

[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.

[Research Progress on Risk Assessment of Secondary Transmission of Imported Malaria].

In 2015, WHO issued the Global Technical Strategy for Malaria 2016-2030, which sets the target of reducing global malaria incidence and mortality rates by at least 90% by 2030. Although many countries have successfully achieved malaria elimination, they are facing the risk of imported malaria. In China, despite the acceleration of malaria elimination, imported malaria has become a potential threat to achieving complete malaria elimination. This paper reviews the worldwide research progress on risk assessment of secondary transmission of imported malaria, in the aim of providing reference for risk assessment of imported malaria and preventing secondary transmission in China.

[Risk Assessment for Malaria Transmission in the Border Area of Yunnan Province].

Objective: To assess the malaria transmission risk in the border area of Yunnan Province and provide evidence for adjustment of malaria intervention and elimination strategies. Method: Data concerning malaria prevalence, vector distribution, and institutional intervention capacity were collected in 197 towns of 20 counties in the border area of Yunnan Province during 2012-2014. The malaria transmission potential index （TPI）, intervention capacity index (ICI) and malaria risk index (MRI) were calculated for each town, based on the criteria formulated by a professional committee. The towns were categorized according to the indices aforementioned. The risk map was created with GIS software. Results: Based on the TPI, the 197 towns comprised of 2 grade-I towns (including Nabang in Yingjiang and Banlao in Cangyuan) with high transmission potential, 11 grade-II towns with moderate transmission potential and 184 grade-III towns with low transmission potential. Based on the ICI, the 197 towns comprised of 4 grade-III towns (including Zhongke in Ximen, Zhonghe and Diantan in Tengchong, and Menghan in Jinghong) with a weak control capacity, 20 grade-II towns with a moderate control capacity and 173 grade-I towns with a strong control capacity. Based on the MRI, the 197 towns comprised of 2 grade-I towns (including Nabang in Yingjiang, and Banlao in Cangyuan) with a high transmission risk level, 12 grade-II towns with a moderate level and 183 grade-III towns with a low level distributed in 20 counties. Conclusion: The grade I or II towns with moderate and high transmission risk constitute <5% of the 197 towns in the border area, suggesting a relatively low level of malaria transmission risk in most counties.

Establishing a China malaria diagnosis reference laboratory network for malaria elimination.

BACKGROUND: In China, the prevalence of malaria has reduced dramatically due to the elimination programme. The continued success of the programme will depend upon the accurate diagnosis of the disease in the laboratory. The basic requirements for this are a reliable malaria diagnosis laboratory network and quality management system to support case verification and source tracking. METHODS: The baseline information of provincial malaria laboratories in the China malaria diagnosis reference laboratory network was collected and analysed, and a quality-assurance activity was carried out to assess their accuracies in malaria diagnosis by microscopy using WHO standards and PCR. RESULTS: By the end of 2013, nineteen of 24 provincial laboratories have been included in the network. In the study, a total of 168 staff were registered and there was no bias in their age, gender, education level, and position. Generally Plasmodium species were identified with great accuracy by microscopy and PCR. However, Plasmodium ovale was likely to be misdiagnosed as Plasmodium vivax by microscopy. CONCLUSIONS: China has established a laboratory network for primary malaria diagnosis which will cover a larger area. Currently, Plasmodium species can be identified fairly accurately by microscopy and PCR. However, laboratory staff need additional trainings on accurate identification of P. ovale microscopically and good performance of PCR operations.

[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.

[Malaria Situation in the People' s Republic of China in 2014].

The 2014 malaria epidemiological data reported through the annual malaria statistics reporting system were collected and analyzed. A total of 3 078 malaria cases were reported in 680 counties of 30 Provinces/ Municipalities/Autonomous Regions (P/M/A)(except Inner Mongolia) in 2014, decreased by 25.4% compared with the 4 128 cases in 2013. The incidence rate was 0.022 6/10 000. More cases distributed in Yunnan (17.3%, 533/3 078), Jiangsu (11.5%, 355/3 078), Sichuan (8.6%, 266/3 078), Henan (7.0%, 216/3 078) and Zhejiang (7.0%, 215/3 078) Provinces. Of all the cases, 56 (1.8%) were indigenous cases, mainly from the border area of Yunnan (comprising 9 counties) and the Tibet Autonomous Region (one county). Locally-infected falciparum malaria was only found in Yingjiang County (4 cases) and Cangyuan County (2 cases) of Yunnan. Indigenous malaria prevalence was of over 1/10 000 in Motuo County and Yingjiang County. There were 3 021 abroad-imported cases of malaria (98.1% ), which widely distributed in the 30 P/M/As. In addition, one case of quartan malaria with long latency was reported' in Guangdong Province. Of all the reported cases, 3 057 (99.3%) were further confirmed by plasmodium species, comprising 846 cases of vivax malaria (27.7%), 1 882 cases of falciparum malaria (61.6%), 3 cases of quartan malaria (1.7%), 231 cases of ovale malaria (7.6%), 44 cases of mixed infections, and one case of P. knowlesi malaria. Furthermore, 170 cases (5.5%) with severe conditions were reported in 16 P/M/As, and 25 deaths were reported in 15 P/M/As. In summary, remarkable achievements have been made in eliminating malaria in China, despite increases in imported cases. The border areas of Yunnan and Motuo County of Tibet Autonomous Region remain the key regions for malaria elimination. Efforts are needed to reinforce the management of imported cases and the treatment of complicated malaria.

[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.

[Preliminary Evaluation of Potential Transmission Risk of Malaria after Earthquake in Cangyuan County, Yunnan Province].

OBJECTIVE: To evaluate the transmission risk and the prevalence potential of malaria in Cangyuan ounty after earthquake. METHODS: The malaria epidemiological data were collected through the web-based reporting system and the malaria statistics annual reporting system from 2005 to April 2015, and the epidemic factors of nalaria after earthquake in the recent three years in Cangyuan County of Yunnan Province were analyzed. RESULTS: according to the web-based reporting system, 799 malaria cases were reported in Cangyuan County from 2005 to April 2015, of which 652 w6re vivax malaria, 127 falciparum malaria, and 20 unclassified. The highest number of cases occurred in 2006 (n=326), and one indigenous falciparum malaria case was reported after earchquake. In iddition, the cases were mainly distributed in Mangka (n=320, 40.1%), Banlao (n=191, 23.9%), Banhong (n=98, 12.3%) and Mengdong (n=92, 11.5%). According to the annual reporting system, there were a total of 519 ndigenous cases (58.4%) and 370 imported cases (41.6%) from 2005 to April 2015. The proportion of indigenous ,ase was above 65% in each year except for 2006, when it was less than 15%. The risk indicator in western ownships of Canyuan County was higher, especially in Mangka and Mengjiao. CONCLUSIONS: There is a potential isk of malaria transmission in Cangyuan County of Yunnan province, due to the huge natural, social and biological ilterations after earthquake and the yet presence of malaria transmission vehicle.

[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.

[Malaria situation in the People's Republic of China in 2013].

OBJECTIVE: To analyze the malaria situation and epidemic characteristics in 2013 in China, and provide evidence for implementing the National Malaria Elimination Program (NMEP). METHODS: The epidemiological data of malaria cases reported through the annual malaria statistics reporting system in 2013 were collected, and analyzed by using Microsoft Excel 2010 and ArcGIS 10.0. RESULTS: A total of 4128 malaria cases were reported from 605 counties of 31 Provinces/Municipalities/Autonomous Regions (P/M/A) in 2013, representing 51.9% increase compared with 2718 cases in 2012, and the annual incidence was 0.0305/10,000. The cases were mainly reported from Guangxi (30.3%, 1251/4128), Yunnan (14.0%, 576/4128), Jiangsu (8.3%, 341/4128), Sichuan (5.8%, 238/4128), and Zhejiang (5.0%, 208/4128). The laboratory confirmed cases took 99.0% (4087/4128) while the other 1.0% (41/4128) were clinically diagnosed. Among the laboratory confirmed cases, 22.8% (930/4087) were vivax malaria cases, 71.2% (2908/4087) were falciparum malaria cases, 1.2% (51/4087) were quartan malaria cases, 3.3% (133/4087) were ovale malaria cases, and 1.6% (65/4087) were mixed infection cases. A total of 48 (1.2%, 48/4128) indigenous cases were reported from 12 counties in 3 provinces including 10 counties of Yunnan, 1 county of Tibet, and 1 county of Anhui. The indigenous falciparum malaria cases were reported in Cangyuan (4), Ruili (1), and Yingjiang (1) of Yunnan Province. The incidence of indigenous cases between 1/10,000 and 10/10,000 was found only in Motuo County of Tibet. Out of the 4128 malaria cases, a proportion of 97.9% (4042/4128) were reported as the abroad-imported cases who distributed in 30 provinces, and the remaining 0.9% (38/4128) were domestically-mobile cases reported from 9 provinces. Totally 156 (37.8%, 156/4128) severe cases were reported from 16 provinces and 23 (0.6%, 23/4128) malaria deaths were from 14 provinces. The monitoring and evaluation result of "1-3-7" indicators demonstrated that the proportion of cases reported within 1 day and investigated within 3 days after diagnosis was 100.0% and 96.1%, respectively, and the number of malaria foci disposed within 7 days were 1678. CONCLUSION: NMEP have yielded remarkable achievements in 2013, while the abroad-imported cases have increased significantly. The border areas of Yunnan and Motuo County of Tibet are still the key areas for malaria elimination in China. At the same time, domestically-mobile cases should be further managed.

[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.

[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.

[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.