High Frequency Mutations in pfdhfr and pfdhps of Plasmodium falciparum in Response to Sulfadoxine-Pyrimethamine: A Cross-Sectional Survey in Returning Chinese Migrants From Africa.

Background: Sulfadoxine-pyrimethamine (SP) is recommended for intermittent preventive treatment in Africa against Plasmodium falciparum infection. However, increasing SP resistance (SPR) of P. falciparum affects the therapeutic efficacy of SP, and pfdhfr (encoding dihydrofolate reductase) and pfdhps (encoding dihydropteroate synthase) genes are widely used as molecular markers for SPR surveillance. In the present study, we analyzed single nucleotide polymorphisms (SNPs) of pfdhfr and pfdhps in P. falciparum isolated from infected Chinese migrant workers returning from Africa. Methods: In total, 159 blood samples from P. falciparum-infected workers who had returned from Africa to Anhui, Shangdong, and Guangxi provinces were successfully detected and analyzed from 2017 to 2019. The SNPs in pfdhfr and pfdhps were analyzed using nested PCR. The genotypes and linkage disequilibrium (LD) were analyzed using Haploview. Results: High frequencies of the Asn51Ile (N51I), Cys59Arg(C59R), and Ser108Asn(S108N) mutant alleles were observed, with mutation frequencies of 97.60, 87.43, and 97.01% in pfdhfr, respectively. A triple mutation (IRN) in pfdhfr was the most prevalent haplotype (86.83%). Six point mutations were detected in pfdhps DNA fragment, Ile431Val (I431V), Ser436Ala (S436A), Ala437Gly (A437G), Lys540Glu(K540E), Ala581Gly(A581G), Ala613Ser(A613S). The pfdhps K540E (27.67%) was the most predominant allele, followed by S436A (27.04%), and a single mutant haplotype (SGKAA; 62.66%) was predominant in pfdhps. In total, 5 haplotypes of the pfdhfr gene and 13 haplotypes of the pfdhps gene were identified. A total of 130 isolates with 12 unique haplotypes were found in the pfdhfr-pfdhps combined haplotypes, most of them (n = 85, 65.38%) carried quadruple allele combinations (CIRNI-SGKAA). Conclusion: A high prevalence of point mutations in the pfdhfr and pfdhps genes of P. falciparum isolates was detected among Chinese migrant workers returning from Africa. Therefore, continuous in vitro molecular monitoring of Sulfadoxine-Pyrimethemine combined in vivo therapeutic monitoring of artemisinin combination therapy (ACT) efficacy and additional control efforts among migrant workers are urgently needed.

Application of community-based and integrated strategy to reduce malaria disease burden in southern Tanzania: the study protocol of China-UK-Tanzania pilot project on malaria control.

BACKGROUND: During the past six decades, remarkable success on malaria control has been made in China. The major experience could be shared with other malaria endemic countries including Tanzania with high malaria burden. Especially, China's 1-3-7 model for malaria elimination is one of the most important refined experiences from many years' efforts and key innovation measures for malaria elimination in China. METHODS: The China-UK-Tanzania pilot project on malaria control was implemented from April, 2015 to June, 2018, which was an operational research with two communities receiving the proposed interventions and two comparable communities serving as control sites. The World Health Organization "Test, Treat, Track" (WHO-T3) Initiative, which calls for every suspected case to receive a diagnostic test, every confirmed case to be treated, and for the disease to be tracked, was integrated with Chinese experiences on malaria control and elimination for exploration of a proper model tailored to the local settings. Application of China's 1-3-7 model integrating with WHO-T3 initiative and local resources aiming at reducing the burden of malaria in terms of morbidity and mortality by 30% in the intervention communities in comparison with that at the baseline survey. DISCUSSION: The China-UK-Tanzania pilot project on malaria control was that at China's first pilot project on malaria control in Africa, exploring the feasibility of Chinese experiences by China-Africa collaboration, which is expected that the strategies and approaches used in this project could be potential for scaling up in Tanzania and African countries, and contribute to the acceleration of malaria control and elimination in Africa.

[A case of neonatal congenital malaria accompanied with severe thrombocytopenia].

This article reports the process of diagnosis and treatment of one case of neonatal congenital malaria accompanied with severe thrombocytopenia.

[Effect of malaria surveillance and control of Guangxi Zhuang Autonomous Region in 2013].

OBJECTIVE: To evaluate the effect of malaria surveillance and control of Guangxi Zhuang Autonomous Region in 2013, and explore the suited surveillance and management of imported malaria cases, so as to provide the evidence for formulating the scientific control measures of imported malaria. METHODS: The endemic data and control measures of malaria in Guangxi in 2013 were collected and analyzed statistically. RESULTS: A total of 1 251 malaria cases were found in Guangxi in 2013, with 88.25% (1,104 cases) of falciparum malaria, 8.63% (108 cases) of vivax malaria, 0.64% (8 cases) of quartan malaria, 1.52% (19 cases) of ovale malaria, and 0.96% (12 cases) of mixed infection; 93.21% (1 166 cases) were off-farm workers; 96.56% (1,208 cases) were imported from Africa and mainly consisted of falciparum malaria cases; 3.44% (43 cases) were imported from southeast Asia and mainly consisted of vivax malaria cases. The cases of imported malaria were increasing and the infection rate in 2013 was increased by 464% compared with that in 2012. CONCLUSION: The imported malaria cases in Guangxi mainly come from Africa at present. Promoting the health education and professional skill of malaria control and treatment, as well as the diagnosis and treatment of the patients in early time are important measures to control the imported malaria.

[Status of malaria epidemic and feasibility of malaria elimination in Guangxi Zhuang Autonomous Region].

OBJECTIVE: To analyze the status of malaria epidemic and discuss the feasibility of malaria elimination in Guangxi Zhuang Autonomous Region. METHODS: The data of blood smear examinations of febrile patients among local residents, focus residents and mobile population in Guangxi Zhuang Autonomous Region were collected, described and analyzed statistically from 2001 to 2011. RESULTS: A total of 4 916 343 blood smear slides of local residents who had fever, 195 967 slides of focus residents, 282 461 slides of returned emigrants, and 228 341 slides of immigrants were examined, and the average positive rates of blood examinations were 0.004 8%, 0.007 7%, 0.480% and 0.127%, respectively. The indigenous malaria cases reduced from 51 in 2001 to 1 in 2009. There were no indigenous malaria cases during the period of 2010-2011. The malaria incidence has been under 1/100 000 for 11 years. The imported malaria cases were dominated in the whole region. CONCLUSIONS: Malaria situation in this region has entranced the consolidating phase of elimination according to the WHO criteria of malaria elimination. The goal of malaria elimination in Guangxi would be achieved in 2018 as long as the government and other departments pay enough attention to the imported malaria control, and the technical measures are further strengthened.

[Surveillance of malaria in Global Fund Malaria Project counties of Guangxi Zhuang Autonomous Region in 2011].

OBJECTIVE: To analyze the monitoring results and epidemic trend of malaria in the Global Fund Malaria Project counties of Guangxi Zhuang Autonomous Region in 2011, so as to provide the evidence for improving the preventive measures. METHODS: The data about malaria surveillance were collected and statistically analyzed in 7 Global Fund Malaria Project counties of Guangxi in 2011. RESULTS: A total of 8 cases of malaria were reported in the Global Fund Malaria Project counties of Guangxi in 2011, the average annual incidence rate was 0.04 per 10000 which increased by 100% compared with that in 2010, accounting for 7.14% (8/112) of the total number of cases in Guangxi. Totally 42 064 residents with fever were examined with blood tests and no case was found; 3 867 floating people were examined with blood tests and 8 cases of malaria were found (0.21%), including 5 cases of vivax malaria and 3 cases of falciparum malaria. The 8 malaria cases distributed in Longlin, Tiane, Nandan, Youjiang counties (district), and they all had ever worked in Africa or Southeast Asia. There were no input secondary cases or deaths throughout the year. CONCLUSIONS: The preventive measures of malaria are effective in the Global Fund Malaria Project counties of Guangxi, and the malaria epidemic situation is stable. It is the key to strengthen the malaria surveillance of the floating population who returned from Africa or Southeast Asia for consolidating the achievement of malaria prevention and control.