Molecular surveillance of Plasmodium vivax dhfr and dhps mutations in isolates from Afghanistan

Abstract

BackgroundAnalysis of dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) mutations in Plasmodium vivax wild isolates has been considered to be a valuable molecular approach for mapping resistance to sulphadoxine-pyrimethamine (SP). The present study investigates the frequency of SNPs-haplotypes in the dhfr and dhps genes in P. vivax clinical isolates circulating in two malaria endemic areas in Afghanistan.MethodsP. vivax clinical isolates (n = 171) were collected in two different malaria endemic regions in north-west (Herat) and east (Nangarhar) Afghanistan in 2008. All collected isolates were analysed for SNP-haplotypes at positions 13, 33, 57, 58, 61, 117 and 173 of the pvdhfr and 383 and 553 of the pvdhps genes using PCR-RFLP methods.ResultsAll 171 examined isolates were found to carry wild-type amino acids at positions 13, 33, 57, 61 and 173, while 58R and 117N mutations were detected among 4.1% and 12.3% of Afghan isolates, respectively. Based on the size polymorphism of pvdhfr genes at repeat region, type B was the most prevalent variant among Herat (86%) and Nangarhar (88.4%) isolates. Mixed genotype infections (type A/B and A/B/C) were detected in only 2.3% (2/86) of Herat and 1.2% (1/86) of Nangarhar isolates, respectively. The combination of pvdhfr and pvdhps haplotypes among all 171 samples demonstrated six distinct haplotypes. The two most prevalent haplotypes among all examined samples were wild-type (86%) and single mutant haplotype I13P33F57S58T61N 117I173/A383A553 (6.4%).Double (I13P33S57R58T61N117I173/A383A553) and triple mutant haplotypes (I13P33S57R 58T61N117I173/G383A553) were found in 1.7% and 1.2% of Afghan isolates, respectively. This triple mutant haplotype was only detected in isolates from Herat, but in none of the Nangarhar isolates.ConclusionThe present study shows a limited polymorphism in pvdhfr from Afghan isolates and provides important basic information to establish an epidemiological map of drug-resistant vivax malaria, and updating guidelines for anti-malarial policy in Afghanistan. The continuous usage of SP as first-line anti-malarial drug in Afghanistan might increase the risk of mutations in the dhfr and dhps genes in both P. vivax and Plasmodium falciparum isolates, which may lead to a complete SP resistance in the near future in this region. Therefore, continuous surveillance of P. vivax and P. falciparum molecular markers are needed to monitor the development of resistance to SP in the region.

Mutational Analysis of Plasmodium vivax dhfr Gene Among Cases in South East of Iran

“…In comparison with the current survey, highly mutant alleles were reported from Thailand, Vanuatu, Indonesia, and Papua New Guinea. In line with previous studies, in this study haplotypes with double mutations at FRTN were also found in Sistan and Baluchistan isolates, which was almost similar to that of obtained data from malarial endemic areas, such as Afghanistan and Pakistan (16,25). Moreover, the distribution frequency of these haplotypes was not much different from previous studies (12).…”

“…The wild-type pvdhfr haplotype was present with a high percentage of P. vivax populations from this province. This was similar to reports from malaria endemic regions in Afghanistan (25) and Pakistan (26). In this study, the frequency of mutation in codon 58 (12.8%) and 117 (35.8%) was similar to the author's previous study (12).…”

“…The haplotypes with one point mutation in locations 58R, 117N, and 117T to form FRTS, FSTN, and FSTT were observed in this study, in which FSTN was the second frequent haplotype of P. vivax isolates in Iran (25). In comparison with the current survey, highly mutant alleles were reported from Thailand, Vanuatu, Indonesia, and Papua New Guinea.…”

“…The present study did not find triple and quadruple mutations in any of the P. vivax isolates. In this regard, triple mutant haplotype has been reported in Afghanistan, which could be a warning for the arrival of these haplotypes to Iran from neighboring countries (25). However, due to the development of multi-drug Jundishapur J Microbiol.…”

Malaria burden in human population of Quetta, Pakistan

“…According to the recent WHO report, about half of the world's population is at risk of malaria, and an estimated 250 million cases led to nearly 1 million deaths in 2006 [5]. Among them, Pakistan is also endemic for both P. vivax, and P. falciparum associated malaria infections [6,14,15].…”