Molecular Epidemiology and Drug Resistance among Malaria Parasite Isolates From Sennar Area – Central Sudan

Abstract

The aim of this work was to characterize the malaria parasite population in Central Sudan Sennar State. A total of 434 blood sample were collected from malaria suspected patients, who attend Abyay clinical center during September to October 2006 . 268 samples out of 434 samples (62%) were detected to be positive for malaria by microscopic examinatiot and rapid ICT test ,all the positive samples due to P.falciparum Prevalence of malaria was found to be ( 38%) . Based on the clinical data, the malaria patients were classified as mild symptoms 14 (5.2%), moderate symptoms222 (82 %) and sever symptoms 32 (11.9%). Among malaria patients 221 (82.3%) were detected as mild anemia , 8 (3.4%) as sever anemia and 39 (14.3%) as subject with normal hemoglobin level .Among malaria patients there are 3 patients with cerebral malaria .Patients were categorized in to five groups <=5 years 54 patients (20.1%), 6-14 years 144 patients (53.7%), 15-40 years 59 patients (22.0%), 41-60 years 9 patients (3.4%), >=61 years 2 patients (0.7%). Malaria prevalence is high in despite of control effort produced by the Roll back malaria program. Allelic diversity was analyzed in the highly parasite polymorphic genes encoding the merozoite surface protein-1 and merozoite surface protein-2 by polymerase chain reaction. Different size polymorphism was detected in all genes analyzed with 10 & 9 variants for Msp1 & Msp2 alleles. Moreover based on the studied genetic markers, most infections consisted of more than one genetically distinct parasite colone. This results suggest that the parasite population circulating in this region are genetically homogeneous and point to an association between the extent of parasite genetic diversity and the intensity of malaria transmission. Different genotypes were found to be associated with severity of disease. In this respect, association between parasitemia and anemia (P=0.001), parasitemia and age (P=0.002), and between parasitemia and polymorphism regions of Msp1 and Msp2 (P=0.004 & 0.001). In addition some variants of allelic families found to be associated with malaria in children (5-14 years of age.) Individuals living malaria endemic areas generally harbor multiple parasite strains which known by multiplicity of infection (MOI) and can be used as an indicator of immune status. One of goals of this study was re-examine the MOI in P.falciparum infected patient, and to relate in to severity of disease. Result of genotyping reveal that MOI was significantly higher at the peak of transmission season and the majority of PCR positive subjects had multiple infections at that time points (64%). There was significant correlation between MOI and parasite density(P=0.00), as the higher parasite counts increases the probability of having multiple infections. Also significant correlation between MOI and variants of Mad20, K1, and RO33 (P=0.000). P.falciparum isolates of this area were genotyped for detection of mutations in P.falciparum chloroquine transporter (Pfcrt 76T) and multidrug resistance (Pfmdr1 86Y) genes. High levels of Chloroquine resistance have been found in the study area, also there was strong significant association between the prevalence of Pfcrt 76T and Pfmdr1 86Y which are located into two different chromosomes and conferring resistance against chloroquine. Significant correlation was observed between Pfcrt 76T and anemia ((P=0.003), Fc27 allele (p=0.03) and Pfmdr1(P=0.00).