Genetic diversity of plasmodium falciparum isolated from Yemen based on the genes of merozoite surface proteins (msp-1 and msp-2) / Nazeh Mohammed Al-Abd Ali

Abstract

Malaria is a major health problem causing substantial morbidity and mortality with Plasmodium falciparum being the causative agent of the most severe and deadly form of malaria in humans. In Yemen Malaria is one of the most serious health problems. About 60% of the populations live in areas with malaria transmission. P. falciparum is the predominant species and accounts for more than 90% of malaria cases. Information on the nature and extent of genetic diversity within P. falciparum is essential for understanding the mechanism underlying the pathology of malaria, the acquisition of immunity, the spread of drug resistance and the condition of the transmission. This study was conducted in the high transmission area in Yemen (Taizz, Dhamar, and AL-Hudiydah) and was guided by the objective that were to establish molecular characterizations of field isolate P. falciparum in Yemen measured with polymorphic genetic markers of merozoite surface protein msp-1 and msp-2. Blood samples were screened for malaria parasites using Giemsa-stained thick and thin blood films. A total of 74 blood samples had P. falciparum, for which their MSP-1 and MSP-2 genes were studied using nested PCR. All the three families (K1, MAD20 and RO33) of MSP-1 and the two families (FC27 and 3D7) of MSP-2 were detected in this study. 3D7 allelic family was the most frequent (68%), followed by K1 (45%), RO33 (42%), FC27 (42%) and MAD20 (22%). The four allelic families, (MAD20, RO33, FC27 and 3D7), were significantly more prevalent in the hinterland areas as compared to coastland and highland areas (p < 0.05) of Yemen. The K1 allele type was most frequent in the highland (p 0.05) nor the different levels of parasitaemia (p > 0.05). MSP-2 had higher number of alleles than MSP-1 (42 vs 18). The highest number of alleles of MSP-1 and MSP-2 was observed in the coastland and the rural areas. In conclusion, significant differences in complexity and the distribution of the family alleles of MSP-1 and MSP-2 genes between hinterland, coastland and highland areas were observed, reflecting the intensity of malaria transmission between areas. This observation should be taken into consideration in implementing malaria control strategies in Yemen