Research
Monitoring resistance of Plasmdium vivax: Point mutations in dihydrofolate reductase gene in isolates from Central China
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* Corresponding author: Shuisen Zhou ccdczss@sh163.net
1 National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasia; Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai 200025, PR China
2 Department of Parasitology, Anhui Center for Disease Control and Prevention, Hefei 230061, PR China
3 Department of Parasitology, Henan Center for Disease Control and Prevention, Zhengzhou 450003, PR China
Parasites & Vectors 2011, 4:80 doi:10.1186/1756-3305-4-80
Published: 17 May 2011Abstract
Background
Malaria still represents a significant public health problem in China, and the cases dramatically increased in Central China after 2001. Antifolate resistance in Plasmodium vivax is caused by point mutations in genes encoding dihydrofolate reductase (pvdhfr) and dihydropteroate synthase (pvdhps). In this study, we used direct sequencing to investigate genetic variation in pvdhfr of malaria patients' samples from Central China.
Results
Among all the samples, 21.4% were wild-type, whereas mutations were detected at three codons (58, 61 and 117) including single mutant (34.6%) and double mutants (43.8%). The most prevalent mutant allele was the one with double mutation at codons 58 and 117 (24.6%). Three types of single mutation (S58R, T61M and S117N) were found in 2.1%, 11.8% and 20.9% of parasite isolates, respectively. The four P. vivax parasite populations in Central China also differed in pvdhfr allele frequencies.
Conclusions
This study suggested that P. vivax in Central China may be relatively susceptible to pyrimethamine. And it also highlights genotyping in the pvdhfr genes remains a useful tool to monitor the emergence and spread of P. vivax pyrimethamine resistance.