Research progress on stable gene transfection methods of Plasmodium falciparum / 中国热带医学

@#Abstract: Transfection of Plasmodium falciparum is helpful to study the function of its genes, such as drug resistance. However, transgenic manipulation has been very challenging, mainly due to the high A/T base sequence structure (A+T content of about 82%) and low transfection efficiency of the Plasmodium genome. Electroporation-based transfection of Plasmodium falciparum has been successfully applied in the study of certain genes, and electroporation by preloading is currently the preferred method for introducing foreign DNA into Plasmodium falciparum. The site-directed editing of Plasmodium genes mostly adopts the method of two-plasmid transfection. It is generally believed that successful transfection of Plasmodium requires a large amount of high-purity plasmid DNA and an accurate transfection system. In addition to the evaluation of the current commonly used electrotransfection methods, this paper also introduces a new transfection method, namely lyse-reseal erythrocytes for transfection (LyRET). This paper also review the role of factors such as plasmid DNA concentration, the use of transfection reagents, the setting of transfection parameters, the addition of fresh red blood cells, and the markers of successful transfection in improving the success rate and efficiency of Plasmodium transfection, in the hope of providing a reference for study in this field.

[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.

[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.

[Surveillance of Oncomelania hupensis snails in Baoying and Gaoyou sections of Li Canal in east route of South-to-North Water Diversion Project].

OBJECTIVE: To understand the distribution and diffusion of Oncomelania hupensis snails in the Baoying and Gaoyou sections of the Li Canal in the east route of the South-to-North Water Diversion Project. METHODS: The retrospective survey method was used to investigate the distribution and diffusion of snails in the Baoying and Gaoyou sections of the Li Canal, the conventional survey and the methods of salvage of water and attracting snails were used to detect the distribution of snails in river banks and water. RESULTS: The earliest findings of snails in the Gaoyou section of the Li Canal was in 1955, the northernmost distribution of snails was Dilong ferry at the west dam and east slope of the Li Canal. The dynamic surveillance in the Gaoyou section of the Li Canal from 2001 to 2010 showed that the snail status was of low density and low fluctuation of area, and the distribution range was 119 degrees 24' 36" -119 degrees 25' 34", 32 degrees 48' 30" -32 degrees 54' 05". From 2006 to 2010, the snails were not found by the methods of salvage of water and attracting snails in the surveillance in the Baoying and Gaoyou sections of the Li Canal. CONCLUSIONS: So far, there is no evidence showing that the snails spread to northward in the Li Canal, however, it is still necessary to carry out the surveillance of snails and schistosomiasis in the east route of the South-to-North Water Diversion Project.

[A discussion on the CSP genotyping of Plasmodium vivax and malaria control in five southern provinces of China].

OBJECTIVE: To explore circumsporozoite protein (CSP) genotype structure of Plasmodium vivax in southern China and evaluate its epidemiological significance. METHODS: Filter paper blood samples were collected from 346 vivax malaria patients in 5 provinces (Autonomous Region) including Hainan, Yunnan, Guangxi, Guangdong and Guizhou for identifying CSP genotypes, by using the method of single-tube nested/multiplex PCR. The findings combined with relevant data were statistically analyzed. RESULTS: In Guangdong, Guangxi and Guizhou Provinces (Autonomous Region), the temperate zone family strains accounted for more than 90%, with only a few tropical zone family strains and no PV-type II each strain. In Yunnan Province, temperate strains and tropical strains accounted for 71.4% and 28.6% respectively, with occasional PV-type II strain. In Hainan Province, strains of temperate zone, tropical zone and PV-type II accounted for about one-third. CONCLUSIONS: The temperate zone family strains were the predominant ones in the Provinces (Autonomous Region) of Guangdong, Guangxi and Guizhou where malaria control was carried out effectively; while in Hainan and Yunnan Provinces the difficulties in malaria control may probably be related to the complex structure of P. vivax population and multiple infections of different genotypes. The findings indicate that the complexity of the P. vivax genotype structure might be an indicative epidemiological feature for malaria control and surveillance.