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Background: Malaria is a major public health problem in the China–Myanmar border region. The genetic structure of malaria parasite may affect its transmission model and control strategies. The present study was to analyse genetic diversity of Plasmodium falciparum by merozoite surface proteins 1 and 2 (MSP1 and MSP2) and to determine the multiplicity of infection in clinical isolates in the China–Myanmar border region. Methods: Venous blood samples (172) and filter paper blood spots (70) of P. falciparum isolates were collected from the patients of the China–Myanmar border region from 2006 to 2011. The genomic DNA was extracted, and the msp1 and msp2 genes were genotyped by nested PCR using allele-specific primers for P. falciparum. Results: A total of 215 P. falciparum clinical isolates were genotyped at the msp1 (201) and msp2 (204), respectively. For the msp1 gene, MAD20 family was dominant (53.49%), followed by the K1 family (44.65%), and the RO33 family (12.56%). For the msp2 gene, the most frequent allele was the FC27 family (80.93%), followed by the 3D7 family (75.81%). The total multiplicity of infection (MOI) of msp1 and msp2 was 1.76 and 2.21, with a prevalence of 64.19% and 72.09%, respectively. A significant positive correlation between the MOI and parasite density was found in the msp1 gene of P. falciparum. Sequence analysis revealed 38 different alleles of msp1 (14 K1, 23 MAD20, and 1 RO33) and 52 different alleles of msp2 (37 3D7 and 15 FC27). Conclusion: The present study showed the genetic polymorphisms with diverse allele types of msp1 and msp2 as well as the high MOI of P. falciparum clinical isolates in the China–Myanmar border region. [ABSTRACT FROM AUTHOR]

Grid management is a grassroots governance strategy widely implemented in China since 2004 to improve the government's efficiency to actively find and solve problems among populated regions. A grid-based strategy surveillancing high-risk groups, including mobile and migrant populations (MMPs), in the China-Myanmar border region has played an indispensable role in promoting and consolidating the malaria elimination efforts by tracking and timely identification of potential importation or re-establishment of malaria among MMPs. A sequential mixed methods was implementated to explore the operational mechanism and best practices of the grid-based strategy including through the focus group discussions (FGDs), comparison of before and after the implementation of a grid-based strategy in the field sites, and data collection from the local health system.This paper distills the implementation mechanism and highlights the role of the grid-based strategy in the elimination and prevention of re-establishment of malaria transmission. [ABSTRACT FROM AUTHOR]

Background: In order to achieve the goal of malaria elimination, the Chinese government launched the National Malaria Elimination Programme in 2010. However, as a result of increasing cross-border population movements, the risk of imported malaria cases still exists at the border areas of China, resulting in a potential threat of local transmission. The focus of this paper is to assess the Plasmodium vivax incidences in Tengchong, Yunnan Province, at the border areas of China and Myanmar. Methods: Time series of P. vivax incidences in Tengchong from 2006 to 2010 are collected from the web-based China Information System for Disease Control and Prevention, which are further separated into time series of imported and local cases. First, the seasonal and trend decomposition are performed on time series of imported cases using Loess method. Then, the impact of climatic factors on the local transmission of P. vivax is assessed using both linear regression models (LRM) and generalized additive models (GAM). Specifically, the notion of vectorial capacity (VCAP) is used to estimate the transmission potential of P. vivax at different locations, which is calculated based on temperature and rainfall collected from China Meteorological Administration. Results: Comparing with Ruili County, the seasonal pattern of imported cases in Tengchong is different: Tengchong has only one peak, while Ruili has two peaks during each year. This may be due to the different cross-border behaviors of peoples in two locations. The vectorial capacity together with the imported cases and the average humidity, can well explain the local incidences of P. vivax through both LRM and GAM methods. Moreover, the maximum daily temperature is verified to be more suitable to calculate VCAP than the minimal and average temperature in Tengchong County. Conclusion: To achieve malaria elimination in China, the assessment results in this paper will provide further guidance in active surveillance and control of malaria at the border areas of China and Myanmar. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Over the past two decades, dengue fever (DF) has emerged as a significant arboviral disease in Yunnan province, China, particularly in the China-Myanmar border area. Aedes aegypti, an invasive mosquito species, plays a crucial role in transmitting the dengue virus to the local population. Insecticide-based vector control has been the primary tool employed to combat DF, but the current susceptibility status of Ae. aegypti to commonly used insecticides is unknown. Assessment of Ae. aegypti resistance to pyrethroid insecticides and an understanding of the underlying mechanisms of this resistance in the China-Myanmar border region is of significant strategic importance for effectively controlling the DF epidemic in the area. Methods: Aedes aegypti larvae collected from Ruili and Gengma counties in Yunnan Province were reared to adults in the laboratory and tested for susceptibility to three pyrethroid insecticides (3.20% permethrin, 0.08% lambda-cyhalothrin and 0.20% deltamethrin) by the standard WHO susceptibility bioassay. Genotyping of mutations in the knockdown gene (kdr), namely S989P, V1016G and F1534C, that are responsible for resistance to pyrethroid insecticides was performed using allele-specific PCR methods. A possible association between the observed resistant phenotype and mutations in the voltage-gated sodium channel gene (VGSC) was also studied. Results: Aedes aegypti mosquitoes collected from the two counties and reared in the laboratory were resistant to all of the pyrethroids tested, with the exception of Ae. aegypti from Gengma County, which showed sensitivity to 0.20% deltamethrin. The mortality rate of Ae. aegypti from Ruili county exposed to 3.20% permethrin did not differ significantly from that of Ae. aegypti from Gengma County (χ2 = 0.311, P = 0.577). By contrast, the mortality rate of Ae. aegypti from Ruili County exposed to 0.08% lambda-cyhalothrin and 0.20% deltamethrin, respectively, was significantly different from that of Ae. aegypti from Gengma. There was no significant difference in the observed KDT50 of Ae. aegypti from the two counties to various insecticides. Four mutation types and 12 genotypes were detected at three kdr mutation sites. Based on results from all tested Ae. aegypti, the V1016G mutation was the most prevalent kdr mutation (100% prevalence), followed by the S989P mutation (81.6%) and the F1534C mutation (78.9%). The constituent ratio of VGSC gene mutation types was significantly different in Ae. aegypti mosquitoes from Ruili and those Gengma. The triple mutant S989P + V1016G + F1534C was observed in 274 Ae. aegypti mosquitoes (60.8%), with the most common genotype being SP + GG + FC (31.4%). The prevalence of the F1534C mutation was significantly higher in resistant Ae. aegypti from Ruili (odds ratio [OR] 7.43; 95% confidence interval [CI] 1.71–32.29; P = 0.01) and Gengma (OR 9.29; 95% CI 3.38–25.50; P = 0.00) counties than in susceptible Ae. aegypti when exposed to 3.20% permethrin and 0.08% lambda-cyhalothrin, respectively. No significant association was observed in the triple mutation genotypes with the Ae. aegypti population exposed to 3.20% permethrin and 0.20% deltamethrin resistance (P > 0.05), except for Ae. aegypti from Gengma County when exposed to 0.08% lambda-cyhalothrin (OR 2.86; 95% CI 1.20–6.81; P = 0.02). Conclusions: Aedes aegypti from Ruili and Gengma counties have developed resistance to various pyrethroid insecticides. The occurrence of multiple mutant sites in VGSC strongly correlated with the high levels of resistance to pyrethroids in the Ae. aegypti populations, highlighting the need for alternative strategies to manage the spread of resistance. A region-specific control strategy for dengue vectors needs to be implemented in the future based on the status of insecticide resistance and kdr mutations. [ABSTRACT FROM AUTHOR]

Background: Oral disorders are still a major global public health challenge, considering their perpetuating and chronic nature. Currently, there is no direct index to measure the quality of care on a population scale. Hence, we aim to propose a new index to measure the quality of care for oral disorders worldwide. Methods: We generated our database using the data from the Global Burden of Disease (GBD) study 2017. Among different variables such as prevalence, incidence, years lived with disability, and disability-adjusted life years, we utilised principal component analysis (PCA) to determine the component that bears the greatest proportion of information to generate the novel quality of care index (QCI) for oral disorders. Results: Global QCI for oral disorders gradually increased from 1990 to 2017 (from 70.5 to 74.6). No significant gender disparity was observed during this period, and the gender disparity ratio (GDR) was considered optimal in 1990 and 2017. Between 1990 and 2017, the age-standardised QCI for all oral disorders increased in all the SDI regions. The highest QCI for all oral disorders in 2017 belonged to high-middle SDI countries (=80.24), and the lowest YLDs rate was seen in the low SDI quintile. In 1990, the quality of care in European, Central Asian, and Central and South American countries was in the lowest quintiles, whereas the North American, East Asian, Middle Eastern, and some African countries had the highest quality of dental care. Maynmar (=100), Uganda (=92.5), Taiwan (=92.0), China (=92.5), and the United States (=89.2) were the five countries with the highest age-standardised QCI. Nicaragua (=41.3), Belgium (=40.2), Venezuela (=38.4), Sierra Leone (=30.5), and the Gambia (=30.3) were the five countries with the least age-standardised QCI values. Conclusion: The quality of care for all oral disorders showed an increasing trend on a global scale from 1990 to 2017. However, the QCI distribution was not homogenous among various regions. To prevent the exacerbation of imminent disparities in this regard, better attention to total tooth loss in high-income countries and prioritising primary healthcare provision in low-income countries are recommended for oral disorders. [ABSTRACT FROM AUTHOR]

Background: Appropriate malaria treatment-seeking behaviour (TSB) is critical for timely detecting malaria, prompt treatment, and prevention of onward transmission of the disease in a community. This study aimed to compare treatment-seeking behaviours between malaria patients and non-malaria febrile patients, and to analyse the factors associated with appropriate TSB along the China-Myanmar border. Methods: A cross-sectional study was carried out to investigate the appropriate TSB of microscopy-confirmed malaria patients versus non-malaria febrile (NMF) patients. An unconditional logistic regression analysis (LRA) was used to identify factors associated with appropriate TSB. Results: Among 223 malaria patients and 446 NMF patients, 129 (57.8%) of the malaria patients versus 163 (36.5%) of the NMF patients firstly sought treatment in health facilities without laboratory testing for malaria (P < 0.0001). A total of 85(38.1%) of the malaria patients versus 278 (62.3%) of the NMF patients had appropriate TSB, namely, seeking treatment in health facilities with laboratory testing for malaria within 48 h (P < 0.0001). Multivariate LRA identified that the malaria patients with Chinese nationality had less appropriate TSB compared to those with other nationalities (adjusted odds ratio [AOR]: 0.21, 95% confidence interval CI 0.07–0.68, P = 0.0097), and malaria patients residing in urban areas had more appropriate TSB compared to those living in rural areas (AOR: 2.16, 95%CI 1.06–4.39, P = 0.0337). Conclusions: TSB was not appropriate in malaria patients. Chinese citizenship and rural residence were two independent factors associated with inappropriate malaria TSB. It is urgently necessary to improve appropriate malaria TSB through effective campaigns of information, education, and communication for malaria control in Myanmar and preventing reestablishment of malaria transmission in Yunnan, China. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: The World Health Organization (WHO) has certificated China malaria free, but imported malaria is a continuous challenge in preventing reintroduction of malaria in the border area of China. Understanding risk factors of malaria along China–Myanmar border is benefit for preventing reintroduction of malaria in China and achieving the WHO's malaria elimination goal in the Greater Mekong Subregion (GMS). Methods: This is a case–control study with one malaria case matched to two controls, in which cases were microscopy-confirmed malaria patients and controls were feverish people with microscopy-excluded malaria. A matched logistic regression analysis (LRA) was used to identify risk factors associated with malaria infection. Results: From May 2016 through October 2017, the study recruited 223 malaria cases (152 in China and 71 in Myanmar) and 446 controls (304 in China and 142 in Myanmar). All the 152 cases recruited in China were imported malaria. Independent factors associated with malaria infection were overnight out of home in one month prior to attendance of health facilities (adjusted odd ratio [AOR] 13.37, 95% confidence interval [CI]: 6.32–28.28, P < 0.0001), staying overnight in rural lowland and foothill (AOR 2.73, 95% CI: 1.45–5.14, P = 0.0019), staying overnight at altitude < 500 m (AOR 5.66, 95% CI: 3.01–10.71, P < 0.0001) and streamlets ≤ 100 m (AOR9.98, 95% CI: 4.96–20.09, P < 0.0001) in the border areas of Myanmar; and people lacking of knowledge of malaria transmission (AOR 2.17, 95% CI: 1.42–3.32, P = 0.0004). Conclusions: Malaria transmission is highly focalized in lowland and foothill in the border areas of Myanmar. The risk factors associated with malaria infection are overnight staying out of home, at low altitude areas, proximity to streamlets and lack of knowledge of malaria transmission. To prevent reintroduction of malaria transmission in China and achieve the WHO goal of malaria elimination in the GMS, cross-border collaboration is continuously necessary, and health education is sorely needed for people in China to maintain their malaria knowledge and vigilance, and in Myanmar to improve their ability of personal protection. [ABSTRACT FROM AUTHOR]

Background: Plasmodium vivax remains the predominant species at the China–Myanmar border, imposing a major challenge to the recent gains in regional malaria elimination. To closely supervise the emerging of drug resistance in this area, we surveyed the variations in genes potentially correlated with drug resistance in P. vivax parasite and the possible drug selection with time. Methods: A total of 235 P. vivax samples were collected from patients suffering uncomplicated malaria at Yingjiang, Tengchong, and Longling counties, and Nabang port in China, Yunnan province, and Laiza sub-township in Myanmar, from 2008 to 2017. Five potential drug resistance genes were amplified utilizing nested-PCR and analyzed, including pvdhfr, pvdhps, pvmdr1, pvcrt-o, and pvk12. The Pearson's Chi-squared test or Fisher's exact test were applied to determine the statistical frequency differences of mutations between categorical data. Results: The pvdhfr F57I/L, S58R, T61M and S117T/N presented in 40.6%, 56.7%, 40.1%, and 56.0% of the sequenced P. vivax isolates, and these mutations significantly decreased with years. The haplotype formed by these quadruple mutations predominated in Yingjiang, Tengchong, Longling and Nabang. While a mutation H99S/R (56.6%) dominated in Laiza and increased with time. In pvdhps, the A383G prevailed in 69.2% of the samples, which remained the most prevalent haplotype. However, a significant decrease of its occurrence was also noticed over the time. The S382A/C and A553G existed in 8.4% and 30.8% of the isolates, respectively. In pvmdr1, the mutation Y976F occurred at a low frequency in 5/232 (2.2%), while T958M was fixed and F1076L was approaching fixed (72.4%). The K10 insertion was detected at an occurrence of 33.2% in pvcrt-o, whereas there was no significant difference among the sites or over the time. No mutation was identified in pvk12. Conclusions: Mutations related with resistance to antifolate drugs are prevalent in this area, while their frequencies decrease significantly with time, suggestive of increased susceptibility of P. vivax parasite to antifolate drugs. Resistance to chloroquine (CQ) is possibly emerging. However, since the molecular mechanisms underneath CQ resistance is yet to be better understood, close supervision of clinical drug efficiency and continuous function investigation is urgently needed to alarm drug resistance. [ABSTRACT FROM AUTHOR]

Background: HIV-transmitted drug resistance (TDR) is found in antiretroviral therapy (ART)-naïve populations infected with HIV-1 with TDR mutations and is important for guiding future first- and second-line ART regimens. We investigated TDR and its effect on CD4 count in ART-naïve youths from the China-Myanmar border near the Golden Triangle to better understand TDR and effectively guide ART.Methods: From 2009 to 2017, 10,832 HIV-1 infected individuals were newly reported along the Dehong border of China, 573 ART-naïve youths (16 ~ 25 y) were enrolled. CD4 counts were obtained from whole blood samples. HIV pol gene sequences were amplified from RNA extracted from plasma. The Stanford REGA program and jpHMM recombination prediction tool were used to determine genotypes. TDR mutations (TDRMs) were analyzed using the Stanford Calibrated Population Resistance tool.Results: The most common infection route was heterosexuals (70.51%), followed by people who inject drugs (PWID, 19.20%) and men who have sex with men (MSM) (8.90%). The distribution of HIV genotypes mainly included the unique recombinant form (URF) (44.08%), 38.68% were CRFs, 13.24% were subtype C and 4.04% were subtype B. The prevalence of TDR increased significantly from 2009 to 2017 (3.48 to 9.48%) in ART-naïve youths (4.00 to 13.16% in Burmese subjects, 3.33 to 5.93% in Chinese subjects), and the resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs), nucleoside and nucleotide reverse transcriptase inhibitors (NRTIs), and protease inhibitors (PIs) were 3.49, 2.62, and 0.52%, respectively. Most (94.40%, n = 34) of HIV-1-infected patients with TDRM had mutation that conferred resistance to a single drug class. The most common mutations Y181I/C and K103N, were found in 7 and 9 youths, respectively. The mean CD4 count was significantly lower among individuals with TDRMs (373/mm3 vs. 496/mm3, p = 0.013).Conclusions: The increase in the prevalence of HIV-1 TDR increase and a low CD4 count of patients with TDRMs in the China-Myanmar border suggests the need for considering drug resistance before initiating ART in HIV recombination hotspots. [ABSTRACT FROM AUTHOR]

Background: In the Greater Mekong sub-region, Plasmodium vivax has become the predominant species and imposes a major challenge for regional malaria elimination. This study aimed to investigate the variations in genes potentially related to drug resistance in P. vivax populations from the China–Myanmar border area. In addition, this study also wanted to determine whether divergence existed between parasite populations associated with asymptomatic and acute infections. Methods: A total of 66 P. vivax isolates were obtained from patients with acute malaria who attended clinics at the Laiza area, Kachin State, Myanmar in 2015. In addition, 102 P. vivax isolates associated with asymptomatic infections were identified by screening of volunteers without signs or symptoms from surrounding villages. Slide-positive samples were verified with nested PCR detecting the 18S rRNA gene. Multiclonal infections were further excluded by genotyping at msp-3α and msp-3β genes. Parasite DNA from 60 symptomatic cases and 81 asymptomatic infections was used to amplify and sequence genes potentially associated with drug resistance, including pvmdr1, pvcrt-o, pvdhfr, pvdhps, and pvk12. Results: The pvmdr1 Y976F and F1076L mutations were present in 3/113 (2.7%) and 97/113 (85.5%) P. vivax isolates, respectively. The K10 insertion in pvcrt-o gene was found in 28.2% of the parasites. Four mutations in the two antifolate resistance genes reached relatively high levels of prevalence: pvdhfr S58R (53.4%), S117N/T (50.8%), pvdhps A383G (75.0%), and A553G (36.3%). Haplotypes with wild-type pvmdr1 (976Y/997K/1076F) and quadruple mutations in pvdhfr (13I/57L/58R/61M/99H/117T/173I) were significantly more prevalent in symptomatic than asymptomatic infections, whereas the pvmdr1 mutant haplotype 976Y/997K/1076L was significantly more prevalent in asymptomatic than symptomatic infections. In addition, quadruple mutations at codons 57, 58, 61 and 117 of pvdhfr and double mutations at codons 383 and 553 of pvdhps were found both in asymptomatic and symptomatic infections with similar frequencies. No mutations were found in the pvk12 gene. Conclusions: Mutations in pvdhfr and pvdhps were prevalent in both symptomatic and asymptomatic P. vivax infections, suggestive of resistance to antifolate drugs. Asymptomatic carriers may act as a silent reservoir sustaining drug-resistant parasite transmission necessitating a rational strategy for malaria elimination in this region. [ABSTRACT FROM AUTHOR]

Background: The malaria elimination plan of the Greater Mekong Subregion (GMS) is jeopardized by the increasing number of Plasmodium vivax infections and emergence of parasite strains with reduced susceptibility to the frontline drug treatment chloroquine/primaquine. This study aimed to determine the evolution of the P. vivax multidrug resistance 1 (Pvmdr1) gene in P. vivax parasites isolated from the China–Myanmar border area during the major phase of elimination. Methods: Clinical isolates were collected from 275 P. vivax patients in 2008, 2012–2013 and 2015 in the China–Myanmar border area and from 55 patients in central China. Comparison was made with parasites from three border regions of Thailand. Results: Overall, genetic diversity of the Pvmdr1 was relatively high in all border regions, and over the seven years in the China–Myanmar border, though slight temporal fluctuation was observed. Single nucleotide polymorphisms previously implicated in reduced chloroquine sensitivity were detected. In particular, M908L approached fixation in the China–Myanmar border area. The Y976F mutation sharply decreased from 18.5% in 2008 to 1.5% in 2012–2013 and disappeared in 2015, whereas F1076L steadily increased from 33.3% in 2008 to 77.8% in 2015. While neutrality tests suggested the action of purifying selection on the pvmdr1 gene, several likelihood-based algorithms detected positive as well as purifying selections operating on specific amino acids including M908L, T958M and F1076L. Fixation and selection of the nonsynonymous mutations are differently distributed across the three border regions and central China. Comparison with the global P. vivax populations clearly indicated clustering of haplotypes according to geographic locations. It is noteworthy that the temperate-zone parasites from central China were completely separated from the parasites from other parts of the GMS. Conclusions: This study showed that P. vivax populations in the China–Myanmar border has experienced major changes in the Pvmdr1 residues proposed to be associated with chloroquine resistance, suggesting that drug selection may play an important role in the evolution of this gene in the parasite populations. [ABSTRACT FROM AUTHOR]

Background: Recent emergence of artemisinin-resistant P. falciparum has posed a serious hindrance to the elimination of malaria in the Greater Mekong Subregion. Parasite clearance time, a measure of change in peripheral parasitaemia in a sequence of samples taken after treatment, can be used to reflect the susceptibility of parasites or the efficiency of antimalarials. The association of genetic polymorphisms and artemisinin resistance has been documented. This study aims to examine clearance time of P. falciparum and P. vivax parasitemia as well as putative gene mutations associated with residual or recurred parasitemia in Myanmar.Methods: A total of 63 P. falciparum and 130 P. vivax samples collected from two internally-displaced populations and one surrounding village were examined for parasitemia changes. At least four samples were taken from each patient, at the first day of diagnosis up to 3 months following the initial treatment. The amount of parasite gene copy number was estimated using quantitative real-time PCR based on a species-specific region of the 18S rRNA gene. For samples that showed residual or recurred parasitemia after treatment, microsatellites were used to identify the 'post-treatment' parasite genotype and compared such with the 'pre-treatment' genotype. Mutations in genes pfcrt, pfmdr1, pfatp6, pfmrp1 and pfK13 that are potentially associated with ACT resistance were examined to identify if mutation is a factor for residual or persistent parasitemia.Results: Over 30% of the P. falciprium infections showed delayed clearance of parasitemia after 2-3 days of treatment and 9.5% showed recurred parasitemia. Mutations in codon 876 of the pfmrp1 corroborated significance association with slow clearance time. However, no association was observed in the variation in pfmdr1 gene copy number as well as mutations of various codonsinpfatp6, pfcrt, and pfK13 with clearance time. For P. vivax, over 95% of the infections indicated cleared parasitemia at days 2-3 of treatment. Four samples were found to be re-infected with new parasite strains based on microsatellite genotypes after initial treatment.Conclusion: The appearance of P.falciparum infected samples showing delayed clearance or recurred parasitemia after treatment raises concerns on current treatment and ACT drug resistance. [ABSTRACT FROM AUTHOR]

Background Malaria within the Greater Mekong sub-region is extremely heterogeneous. While China and Thailand have been relatively successful in controlling malaria, Myanmar continues to see high prevalence. Coupled with the recent emergence of artemisinin-resistant malaria along the Thai-Myanmar border, this makes Myanmar an important focus of malaria within the overall region. However, accurate epidemiological data from Myanmar have been lacking, in part because of ongoing and emerging conflicts between the government and various ethnic groups. Here the results are reported from a risk analysis of malaria slide positivity in a conflict zone along the China-Myanmar border. Methods Surveys were conducted in 13 clinics and hospitals around Laiza City, Myanmar between April 2011 and October 2012. Demographic, occupational and educational information, as well as malaria infection history, were collected. Logistic models were used to assess risk factors for slide positivity. Results Age patterns in Plasmodium vivax infections were younger than those with Plasmodium falciparum. Furthermore, males were more likely than females to have falciparum infections. Patients who reported having been infected with malaria during the previous year were much more likely to have a current vivax infection. During the second year of the study, falciparum infections among soldiers increased signficiantlyConclusions These results fill some knowledge gaps with regard to risk factors associated with malaria slide positivity in this conflict region of north-eastern Myanmar. Since epidemiological studies in this region have been rare or non-existent, studies such as the current are crucial for understanding the dynamic nature of malaria in this extremely heterogeneous epidemiological landscape. [ABSTRACT FROM AUTHOR]

The article focuses on the performance of rapid diagnostic tests (RDT) for diagnosis of malaria at the China-Myanmar border area. It discusses the importance of RDT in malaria control and management programmes in the world. It states that the performance of RDT under different endemic conditions suggests its requirement for malaria diagnosis. It reports the effect of humidity and extreme temperatures on the performance of RDT.

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

Background: Sensitive methods for detecting asymptomatic malaria infections are essential for identifying potential transmission reservoirs and obtaining an accurate assessment of malaria epidemiology in low-endemicity areas aiming to eliminate malaria. PCR techniques to detect parasite nucleic acids (DNA or RNA) are among the most commonly used molecular methods. However, most of these methods are of low throughput and cannot be used for large-scale molecular epidemiological studies. A recently developed capture and ligation probe-PCR (CLIP-PCR) is claimed to have the sensitivity of molecular techniques and the high throughput capacity needed for screening purposes. This study aimed to compare several molecular methods for detecting asymptomatic and submicroscopic Plasmodium infections in healthy residents of a malaria-hypoendemic region in Southeast Asia, where malaria elimination is in sight., Method: This study compared three molecular detection methods side-by-side, namely nested PCR targeting the rRNA genes, nested RT-PCR to detect parasite rRNA, and CLIP-PCR to detect parasite rRNA in 1005 healthy individuals in northeastern Myanmar. For nested PCR and RT-PCR, parasite DNA and total RNA were extracted from ~100 µL of blood, whereas RNA used for CLIP-PCR was from a 3 mm disk of dried blood filter paper. The sensitivity and specificity of these methods were compared with those of conventional light microscopy. In addition, RT-PCR and quantitative RT-PCR (qRT-PCR) targeting the Pvs25 gene in Plasmodium vivax were used to assess gametocyte prevalence in the samples., Results: Light microscopy detected Plasmodium infections in only 1.19% of the residents harbouring the parasites. CLIP-PCR had slightly better performance and detected Plasmodium infections in 1.89% of the population. Further improvement was achieved by nested PCR to detect parasite DNA, which detected P. vivax and Plasmodium falciparum infections in 2.39% of the residents. The nested RT-PCR targeting rRNA, however, detected as many as 187 (18.61%) individuals having Plasmodium infections with P. vivax being the predominant species (176 P. vivax, 5 P. falciparum and 6 P. falciparum/P. vivax mixed infections). Of the 210 Plasmodium-positive samples detected by all molecular methods, 115 were Pvs25-positive by qRT-PCR, indicating that a large proportion of asymptomatic individuals were gametocyte carriers., Conclusion: Nested RT-PCR based on the detection of asexual-stage parasite rRNA was the most sensitive, with a more than sixfold higher sensitivity than the other two molecular methods of parasite detection. CLIP-PCR has an increased throughput, but its sensitivity in this study was much lower than those of other molecular methods, which may be partially due to the smaller amount of RNA input used.