Progress towards malaria elimination in the Greater Mekong Subregion: perspectives from the World Health Organization.

Malaria remains a global health challenge, disproportionately affecting vulnerable communities. Despite substantial progress, the emergence of anti-malarial drug resistance poses a constant threat. The Greater Mekong Subregion (GMS), which includes Cambodia, China's Yunnan province, Lao People's Democratic Republic, Myanmar, Thailand, and Viet Nam has been the epicentre for the emergence of resistance to successive generations of anti-malarial therapies. From the perspective of the World Health Organization (WHO), this article considers the collaborative efforts in the GMS, to contain Plasmodium falciparum artemisinin partial resistance and multi-drug resistance and to advance malaria elimination. The emergence of artemisinin partial resistance in the GMS necessitated urgent action and regional collaboration resulting in the Strategy for Malaria Elimination in the Greater Mekong Subregion (2015-2030), advocating for accelerated malaria elimination interventions tailored to country needs, co-ordinated and supported by the WHO Mekong malaria elimination programme. The strategy has delivered substantial reductions in malaria across all GMS countries, with a 77% reduction in malaria cases and a 97% reduction in malaria deaths across the GMS between 2012 and 2022. Notably, China was certified malaria-free by WHO in 2021. Countries' ownership and accountability have been pivotal, with each GMS country outlining its priorities in strategic and annual work plans. The development of strong networks for anti-malarial drug resistance surveillance and epidemiological surveillance was essential. Harmonization of policies and guidelines enhanced collaboration, ensuring that activities were driven by evidence. Challenges persist, particularly in Myanmar, where security concerns have limited recent progress, though an intensification and acceleration plan aims to regain momentum. Barriers to implementation can slow progress and continuing innovation is needed. Accessing mobile and migrant populations is key to addressing remaining transmission foci, requiring effective cross-border collaboration. In conclusion, the GMS has made significant progress towards malaria elimination, particularly in the east where several countries are close to P. falciparum elimination. New and persisting challenges require sustained efforts and continued close collaboration. The GMS countries have repeatedly risen to every obstacle presented, and now is the time to re-double efforts and achieve the 2030 goal of malaria elimination for the region.

First Report of Bacterial Brown Rot Disease Caused by Ewingella americana on Cultivated Naematelia aurantialba in China.

Naematelia aurantialba (synonym Tremella aurantialba) is one of the jelly fungi and highly valued edible and medicinal mushrooms. It has been cultivated industrially in recent years and consumed popularly in China. In September 2022, brown rot disease of fruiting bodies was observed at the N. aurantialba factory in Tongzhou district, Beijing with a disease incidence of ~10%. Symptoms initially appeared as color changing from orange to light brown. The infected area expanded gradually until covered fully the fruiting body. Meanwhile, the interior of the fruiting body became rotten and dark brown. Finally, the whole fruiting body became wrinkled and brown, resulting in significantly reduced yield and economic loss. Isolations were made from 12 infected mushroom samples. Infected tissue within the fruiting body was mashed in sterilized 1.5 mL tubes containing 1 mL of sterile distilled water. After standing for 5-10 min, the suspensions were streaked on the Luria-Bertani (LB) medium and cultured at 37°C for 24h. The physiological and biochemical reactions of isolated strains were determined using the API 20E system (Reyes et al. 2004) according to the manufacturer's instructions. All the strains showed the same reaction results. The bacterial colonies were streaked on fresh LB medium at 37°C for 24 h, and a single pure culture was obtained with round, smooth and semitransparent. The bacterial cells were gram-negative, short-rod, (0.3) 0.8-2.0 (2.5) × (0.1) 0.6-1.0 (1.5) µm, and peri-flagellate. The isolates were further confirmed by sequence analysis of the 16S rRNA and gyrB genes with primer 27F/1492R and gyrB-UP1s/gyrB-UP2sr (Liu et al. 2018). Using EzBioCloud data searches, the 16S rRNA sequence of four strains (GenBank accession OP727593, OP727595, OP727596, OP727601) matched the sequence of E. americana type strain ATCC 33852 (accession JMPJ01000013) with identity of 99.65%~99.93 and 100% completeness. The GyrB sequence matched the E. americana in GenBank (MK460250) and showed 98.71% identity and 100% completeness. Finally, the pathogen was identified as E. americana based on morphological, physiological, biochemical, and molecular characteristics. The pathogenicity test was conducted by spreading bacterial suspensions cultured 48h onto 12 healthy cultivated fruiting bodies of N. aurantialba, with sterile distilled water as a control, and then cultured in a chamber at 23°C with 85% relative humidity. Brown symptoms, similar to natural symptoms, were observed on all inoculated fruiting bodies after 48h, whereas the controls remained symptomless. Pathogenic bacteria were isolated from the inoculated fruiting body and confirmed to be E. americana based on morphological and 16S rRNA molecular characteristics, thus fulfilling Koch's postulates. E. americana caused stipe necrosis on Agaricus bisporus in Egypt (Madbouly et al. 2014), the oak tree in Thailand, and pneumonia in Humans (Doonan et al. 2016), and brown blotch on Flammulina velutipes (Liu et al. 2018). To our knowledge, this is the first worldwide report of E. americana infecting jelly fungus N. aurantialba causing brown rot disease. E. americana is an opportunistic cross-kingdom pathogen (Liu et al. 2018). That will provide a critical alert on the prevention, effective monitoring, and control of the disease.

Multidrug-resistant genotypes of Plasmodium falciparum, Myanmar.

We performed a molecular epidemiologic survey of mutations associated with drug-resistance genes in Plasmodium falciparum in northeastern Myanmar. In this region, 3 highly mutated drug-resistance haplotypes and 1 associated with decreased quinine susceptibility were prevalent, which suggests that parasites may be resistant to multiple commonly used antimalarial drugs.

Protective effects of Salvia miltiorrhiza against cisplatin-induced ototoxicity in guinea pigs.

OBJECTIVE: The aim of the study was to investigate the protective effects of Salvia miltiorrhiza (SM) against cisplatin-induced ototoxicity in guinea pigs. METHODS: Thirty-nine guinea pigs were randomly divided into 3 groups. The first group (control group) received physiologic saline by intraperitoneal (i.p.) injection for 5 days. The second group (cisplatin group) was treated with cisplatin (2 mg/kg per day, i.p. injection) for 5 days. The third group (SM group) was given SM (8 g/kg per day, i.p. injection) for 2 days and then was given SM (8 g/kg per day, i.p. injection) and cisplatin (2 mg/kg per day, i.p. injection) for 5 days. Auditory brain stem response (ABR) and cochlea blood flow measurement were used to evaluate cochlea function. The structures of cochlea were observed by light microscope, scanning electron microscope, transmission electron microscope (TEM), and immunohistochemical examination. RESULTS: Cisplatin could cause severe acoustic damages including significant elevation of ABR threshold, substantial losses of outer hair cells and inner hair cells, and severe damage on the stria vascularis and spiral ganglion cells (SGCs). Although in SM group, the increased tendency of threshold was milder than that in cisplatin group. The damages in cochlea and stria vascularis were also less severe than those in cisplatin group. The expression of induced nitric oxide synthase in the cochlea and SGC in SM group was lower than that in cisplatin group. CONCLUSIONS: Salvia miltiorrhiza can significantly reduce the cisplatin-induced side effects.

[Therapeutic efficacy and safety of compound dihydroartemisinin/piperaquine for uncomplicated Plasmodium falciparum infection in Laiza City of Myanmar bordering on China].

OBJECTIVE: To assess the efficacy and safety of compound dihydroartemisinin/piperaquine (DHAPIP) for treating uncomplicated falciparum malaria in Laiza city of Myanmar at the China-Myanmar border area. METHODS: A clinical trial was conducted in Laiza City and its four suburban natural villages bordering with China from September to December in 2008. Patients (aged 2-60 years) infected by Plasmodium falciparum without clinical complications (> or = 250 asexual parasite x microl(-1) of whole blood) were recruited for the assessment. The cases were given a 2-day course with DHAPIP tablets each containing 40 mg of dihydroartemisinin and 320 mg of piperaquine phosphate, and the total dosage varied with the body weight. For example, a patient with 50 kg body weight was given 8 tablets divided into 4 times at an interval of 8-10 h. The cases were then followed-up at DO, D1, D2, D3, D7, D14, D21 and D28 for observing their symptoms, the density of parasite, body temperature and side reaction. The therapeutic efficacy was assessed by using WHO classification of therapeutic response to the treatment of antimalarial drugs, including the time of fever subsidence, the clearance time of asexual parasites and the clearance rate of gametocytes. RESULTS: Among the 74 cases enrolled, 64 completed 28-day follow-up. The therapeutic efficacy reached 100% with adequate clinical and parasitological responses. The mean fever subsidence time was (22.5 +/- 8.2) h. The median of clearance time of asexual parasites in blood was 30.0 h [(17.1-168.2) h]. The rate of eliminating asexual parasites and fever subsidence in D3 and D7 was (93.8% and 100%) and (100% and 100%), respectively. The clearance rate of gametocytes in day-28 was 75.0%. It showed 9.9% of side reaction with 7 cases suffering from mild adverse responses among 71 of full-course medication. CONCLUSION: DHAPIP is efficacious and safe for the treatment of uncomplicated falciparum malaria in Laiza city of Myanmar in the border area.

Co-infections with Plasmodium knowlesi and other malaria parasites, Myanmar.

To determine the frequency of co-infections with Plasmodium species in southern Myanmar, we investigated the prevalence of P. knowlesi. More than 20% of patients with malaria had P. knowlesi infection, which occurred predominantly as a co-infection with either P. falciparum or P. vivax.

[Genotyping of Plasmodium vivax in China-myanmar border by circumsporozoite protein].

By using a series of type-specific primers for Plasmodium vivax circumsporozoite protein (CSP) gene and nested PCR, genotyping was conducted for the specimens of Plasmodium vivax isolated from China-Myanmar border. In 174 isolates of P. vivax, four genotypes, namely, tropical zone family strain, temperate zone family strain, genotype-mixed infection and PV-II type, were identified each accounting for 54.6%, 35.6%, 6.9%, and 2.9%, respectively. The tropical zone family strain was dominant in the border area. There was no significant difference on the P.v CSP genotype constitution between Laza isolate of Myanmar and Tengchong isolate of Yunnan, China.

[Serological detection of malaria for people entering China from 19 ports of entry covering 8 border prefectures of Yunnan].

OBJECTIVE: To evaluate malaria situation in areas of Yunnan Province bordering with Myanmar, Laos and Vietnam. METHODS: Blood samples on filter paper were collected from the entry people in March to December of 2007 involving 19 national and provincial ports of entry. Indirect fluorescent antibody test (IFAT) was carried out by using the blood samples collected before June 30 as the first half year and after July 1 as the second half year. Analysis was made on the relationship of IFAT positive rate and GMRT to malaria incidence in the province reported by the China information system for disease control and prevention. RESULTS: IFAT positive rate in the first half year (5.6%) was 20.9% higher than that of second half year (4.4%) (chi2=12.95%, P<0.05). There was a positive correlation between IFAT positive rate and the number of malaria cases reported in 2007 from the 8 bordering prefectures (r=0.8124, P<.05). The highest IFAT positive rate was found in Dehong (8.7%), Baoshan (7.1%), and Lingcang (65%). Among the 19 entry ports, the highest IFAT positive rate was found in 5 entry ports: Lvliang, Laying, Jiegao, Houqiao, and Qingshuihe, all in China-Myanmar border. The IFAT positive rate in the Chinese entry people increased with their days of staying outside the border. Among the entry people, the highest antibody positive rate was from those of Myanmar nationality (11.7%) followed by those from Yunnan (3.7%). CONCLUSION: To certain extent, higher malaria incidence outside the border impacts that of Yunnan Province.

[Sensitivity of Plasmodium vivax to chloroquine in Laza City, Myanmar].

Fourty-eight patients infected by Plasmodium vivax were randomly divided into chloroquine regimen groups A and B. Each case in group A received a total dosage of 1 200 mg(base) over a 3-day period (600 mg on the first day then 300 mg daily). Cases in group B each received total dosage of 1 500 mg (base) in 3 days (750 mg on the first day then 375 mg daily). Body temperature and blood smears were examined on days 0, 1, 2, 3, 7, 14, 21 and 28, respectively. All patients were negative for asexual parasites within 3 days. The cure rate on day 28 was 100%. Results showed that P. vivax is sensitive to chloroquine in Laza, Myanmar, and chloroquine can still be used for the imported vivax malaria cases at the China-Myanmar border.

Palladium catalyst immobilized on functionalized microporous organic polymers for C-C coupling reactions.

Two microporous organic polymer immobilized palladium (MOP-Pd) catalysts were prepared from benzene and 1,10-phenanthroline by Scholl coupling reaction and Friedel-Crafts reaction, respectively. The structure and composition of the catalyst were characterized by FT-IR, TGA, N2 sorption, SEM, TEM, ICP-AES and XPS. MOP-Pd catalysts were found to possess high specific surface areas, large pore volume and low skeletal bone density. Moreover, the immobilized catalyst also had advantages, such as readily available raw materials, chemical and thermal stability, and low synthetic cost. The Pd catalyst is an effective heterogeneous catalyst for carbon-carbon (C-C) coupling reactions, such as the Heck reaction and Suzuki-Miyaura reaction, affording good to high yields. In these reactions, the catalyst was easily recovered and reused five times without significant activity loss.

[Epidemiological survey on malaria situation in Motuo County of Tibet, China].

OBJECTIVE: To make an epidemiological investigation on malaria in Motuo County, Linzhi Prefecture of Tibet. METHODS: In July of the year 2006, the following activities were conducted in 2 selected villages from each of the three townships, i.e., Motuo, Dexing and Beibeng: malaria history survey among inhabitants in recent 2 years; collection of blood samples of inhabitants for examining malaria parasites, IFAT and detecting G6PD, respectively; mosquito collection in human dwellings and cattle shelters at night and various resting sites at day-time; mosquito collection by outdoor human baiting capture; classification and composition calculation of mosquito species and man biting rates; ELISA for detecting sporozoite infection of Anopheles. RESULTS: The mean rate of two-year malaria history was 8.98% (118/1314) and the parasite rate was 3.13% (38/1216, all P. vivax) in the inhabitants. The parasite positive rate among the feverish patients was 7.14% (3/42). IFAT revealed a malaria antibody rate of 40.24% (472/1173). The G6PD deficiency rate was 1.74% (21/1208). Five hundred and thirteen anopheline mosquitoes were caught. They were An. maculatus (474) which occupied 92.4% (474/513), An. peditaeniatus (35), An. kochi (3) and An. sinensis (1). The mean indoor density of An. maculatus was 4.75/night in human houses, and 69.5/night in cattle shelters. The outdoor human biting rate was 22.75/half-night/person, and the sporozoite rate of An. maculatus in anopheline saliva glands was 0 by ELISA. CONCLUSION: Motuo County is an endemic area of vivax malaria with An. maculatus as the potential vector.

Malaria control along China-Myanmar Border during 2007-2013: an integrated impact evaluation.

BACKGROUND: Implementing effective interventions remain a lot of difficulties along all border regions. The emergence of artemisinin resistance of Plasmodium falciparum strains in the Greater Mekong Subregion is a matter of great concern. China has effectively controlled cross-border transmission of malaria and artemisinin resistance of P. falciparum along the China-Myanmar border. METHODS: A combined quantitative and qualitative study was used to collect data, and then an integrated impact evaluation was conducted to malaria control along the China-Myanmar border during 2007-2013. RESULTS: The parasite prevalence rate (PPR) in the five special regions of Myanmar was decreased from 13.6 % in March 2008 to 1.5 % in November 2013. Compared with the baseline (PPR in March 2008), the risk ratio was only 0.11 [95 % confidence interval (CI), 0.09-0. 14) in November 2013, which is equal to an 89 % reduction in the malaria burden. Annual parasite incidence (API) across 19 Chinese border counties was reduced from 19.6 per 10 000 person-years in 2006 to 0.9 per 10 000 person-years in 2013. Compared with the baseline (API in 2006), the API rate ratio was only 0.05(95 % CI, 0.04-0.05) in 2013, which equates to a reduction of the malaria burden by 95.0 %. Meanwhile, the health service system was strengthened and health inequity of marginalized populations reduced along the international border. CONCLUSION: The effective collaboration between China, Myanmar and the international non-governmental organization promptly carried out the core interventions through simplified processes. The integrated approaches dramatically decreased malaria burden of Chinese-Myanmar border.

Mapping the epidemiology of yaws in the Solomon Islands: a cluster randomized survey.

Yaws, a non-venereal treponemal disease, is targeted for eradication by 2020 but accurate epidemiological data to guide control programs remain sparse. The Solomon Islands reports the second highest number of cases of yaws worldwide. We conducted a cluster randomized survey of yaws in two provinces of the Solomon Islands. One thousand four hundred and ninety-seven (1,497) children 5-14 years of age were examined. Clinical signs of active yaws were found in 79 children (5.5%), whereas 140 children (9.4%) had evidence of healed yaws lesions. Four hundred and seventy (470) (31.4%) children had a positive Treponema pallidum particle agglutination assay (TPPA). Two hundred and eighty-five (285) children (19%) had a positive TPPA and rapid plasma regain assay. Risk of yaws increased with age and was more common in males. The prevalence of yaws at village level was the major risk factor for infection. Our findings suggest the village, not the household, should be the unit of treatment in the World Health Organization (WHO) yaws eradication strategy.

A multicenter study on etiology of acute pancreatitis in Beijing during 5 years.

OBJECTIVES: The aim of this study was to determine the etiology tendency of acute pancreatitis (AP) in the Beijing region and the relationship with influencing factors. METHODS: This retrospective multicenter study enrolled 8 representative general hospitals from January 1, 2006 to December 31, 2010. The etiology tendency was analyzed, and the relationship was defined with sex, aging, severity, mortality, recrudesce rate, length of stay, and hospitalization cost. RESULTS: The study enrolled 2461 patients. The total number was increasing year by year. Causes included biliary (1372, 55.75%), alcoholism (246, 10%), hypertriglyceridemia (255, 10.36%), and the others (588, 23.89%). Biliary AP was the most frequent primary cause. Hypertriglyceridemic AP increased at a faster rate than alcoholic AP. There was higher proportion of alcoholic and hypertriglyceridemic AP in men than in women. There is an increase of AP patients with ages 40 to 49 years and older than 70 years. Alcoholic and hypertriglyceridemic AP were higher in patients younger than the age of 50 years, and biliary pancreatitis was higher in patients older than 70 years. Severe AP was classified among 736 patients (29.9%). Etiology distribution was different between severe AP and mild AP (P < 0.001). Mortality in the hospital was 1.54%, and there was no difference in each group. Recrudesce of hypertriglyceridemic AP was higher (P < 0.01). CONCLUSIONS: Acute pancreatitis patients increased year by year in Beijing. Gallstones were the predominant etiological factor. There were different etiology proportion of AP according age, sex, and severity.

Mekong malaria. II. Update of malaria, multi-drug resistance and economic development in the Mekong region of Southeast Asia.

In an expansion of the first Mekong Malaria monograph published in 1999, this second monograph updates the malaria database in the countries comprising the Mekong region of Southeast Asia. The update adds another 3 years' information to cover cumulative data from the 6 Mekong countries (Cambodia, China/Yunnan, Lao PDR, Myanmar, Thailand, Viet Nam) for the six-year period 1999-2001. The objective is to generate a more comprehensive regional perspective in what is a global epicenter of drug resistant falciparum malaria, in order to improve malaria control on a regional basis in the context of social and economic change. The further application of geographical information systems (GIS) to the analysis has underscored the overall asymmetry of disease patterns in the region, with increased emphasis on population mobility in disease spread. Of great importance is the continuing expansion of resistance of P. falciparum to antimalarial drugs in common use and the increasing employment of differing drug combinations as a result. The variation in drug policy among the 6 countries still represents a major obstacle to the institution of region-wide restrictions on drug misuse. An important step forward has been the establishment of 36 sentinel sites throughout the 6 countries, with the objective of standardizing the drug monitoring process; while not all sentinel sites are fully operational yet, the initial implementation has already given encouraging results in relation to disease monitoring. Some decreases in malaria mortality have been recorded. The disease patterns delineated by GIS are particularly instructive when focused on inter-country distribution, which is where more local collaborative effort can be made to rationalize resource utilization and policy development. Placing disease data in the context of socio-economic trends within and between countries serves to further identify the needs and the potential for placing emphasis on resource rationalization on a regional basis. Despite the difficulties, the 6-year time frame represented in this monograph gives confidence that the now well established collaboration is becoming a major factor in improving malaria control on a regional basis and hopefully redressing to a substantial degree the key problem of spread of drug resistance regionally and eventually globally.

[Evaluation of the enzyme-linked immunosorbant assay in detecting circumsporozoite protein of anopheline vectors in Yunnan].

OBJECTIVE: To detect circumsporozoite protein (CSP) in anopheline vectors from south Yunnan and to evaluate ELISA in the detection. METHODS: Salivary glands of the anopheline mosquitoes were taken for finding sporozoites by microscopy and part of the glands was used for detecting CSP by ELISA. An. minimus was experimentally infected by blood from vivax malaria patient (with Plasmodium vivax) and examined for sporozoites and CSP. Eight species of anopheline mosquitoes were caught in the field and examined. Monoclonal antibodies to P. falciparum (Pf2A10) and P. vivax (Pv210, Pv247) were used in ELISA for detecting CSP. RESULTS: Sporozoites were found in the salivary glands of 27 out of 36 An. minimus experimentally infected (75.0%), 29 were ELISA CSP positives (80.6%), and 26 of the 27 mosquitoes showed Pv210 CSP positive. Among 1010 parous anopheline mosquitoes from the field, 7 were found sporozoite positive (0.69%), 8 were ELISA CSP positive (0.79%), and 6 of the 7 mosquitoes showed CSP positive. Of 4675 wild mosquitoes in 8 anopheline species with different ages, 11 were found CSP positive (0.24%) including An. minimus, An. sinensis and An. maculatus with a positive rate of 0.20%, 0.24% and 0.39% respectively. Among the 11 mosquitoes, 9 were Pv210 positive and 2 were Pf2A10 positive. CONCLUSION: CSP detection by ELISA is a useful method to monitor the malaria transmission capacity of anopheline vectors.

Assessment of therapeutic efficacy of chloroquine against falciparum malaria in an outbreak area in Xishuangbanna, Yunnan.

OBJECTIVE: To investigate the failure of treatment with chloroquine in Yunnan in order to help formulate adequate antimalarial drug policy. METHODS: A World Health Organization 28-day in vivo test on therapeutic response for uncomplicated falciparum malaria in area with low or moderate transmission was adopted. Patients of age > or = 6 months old were admitted without limitation in density of parasitaemia and body temperature. Clinical and parasitological observation was conducted for patients on day 0, 1, 2, 3, 4, 7, 14, 21, 28 and 35. RESULTS: Of 62 patients identified as malaria cases infected by Plasmodium falciparum only, Plasmodium vivax only or by both species, 52 cases infected by Plasmodium falciparum only were included in the study. The overall treatment failure rate was 40.7%, with early treatment failure (ETF) rate of 1.8% and late treatment failure rate (LTF) of 38.9%. CONCLUSION: The treatment failure rate was much higher than the rate of 25% recommended by WHO. It is suggested that use of single chloroquine should be stopped in the treatment of falciparum malaria cases in such area. No relationship was found between the failure rate and the density of malaria parasites.

Evaluation of a rapid diagnostic test for yaws infection in a community surveillance setting.

Yaws is a non-venereal treponemal infection caused by Treponema pallidum ssp. pertenue. The WHO has launched a worldwide control programme, which aims to eradicate yaws by 2020. The development of a rapid diagnostic test (RDT) for serological diagnosis in the isolated communities affected by yaws is a key requirement for the successful implementation of the WHO strategy. We conducted a study to evaluate the utility of the DPP test in screening for yaws, utilizing samples collected as part of a community prevalence survey conducted in the Solomon Islands. 415 serum samples were tested using both traditional syphilis serology (TPPA and quantitative RPR) and the Chembio DPP Syphilis Screen and Confirm RDT. We calculated the sensitivity and specificity of the RDT as compared to gold standard serology. The sensitivity of the RDT against TPPA was 58.5% and the specificity was 97.6%. The sensitivity of the RDT against RPR was 41.7% and the specificity was 95.2%. The sensitivity of the DPP was strongly related to the RPR titre with a sensitivity of 92.0% for an RPR titre of >1/16. Wider access to DPP testing would improve our understanding of worldwide yaws case reporting and the test may play a key role in assessing patients presenting with yaws like lesions in a post-mass drug administration (MDA) setting.