Evaluation of Efficacy of Coartem and Dou Cotecxin in Clearance of Gametocytes in Uncomplicated Plasmodium Falciparum Malaria

Malaria is a global life-threatening disease in human beings caused by four species of Plasmodium parasites, P.vivax, P.ovale, P. malariae and P. falciparum. Among these, P. falciparum is the most deadly form affecting about 240 million people worldwide every year, with 1 million deaths annually, 85% of which occur in children below 5 years of age. Malaria is a health problem in more than 90 countries and each year, between 300 and 500 million new cases are reported worldwide. Over 80 countries worldwide have now implemented WHO recommendations to use artemisinin-based combination therapy (ACT) as first-line treatment for Plasmodium falciparum malaria. Studies on efficacy and safety of the combination of Coartem and Dou-Cotecxin for the treatment of asexual parasites are well documented and is known to clear asexual stages of the parasites. However the effect of these drugs on gametocyte development has not been ascertained. Therefore there is need to determine whether these antimalarial drugs have effects on gametocytes. The sexual parasites are responsible for the transmission of malaria parasites to infectious mosquitoes. Studies on gametocytes are generally based on microscopic detection, which is not sensitive there is need for more sensitive molecular technique which can detect and quantify gametocytes at densities as low as 0.02-0.1 gametocytes per microliter. The objectives of this study was therefore, to determine the clearance rates of Coartem and Dou-Cotecxin in uncomplicated P. falciparum and compare the effectiveness of microscopy and reverse transcriptase polymerase chain reaction (RTPCR). The RT-PCR is able to detect gametocytes below the threshold of microscopy detection in a thick blood smear with field samples as low as one gametocyte per microliter. In this randomized controlled clinical trial gametocytes densities were quantified by microscopy by counting against 500 leukocytes in the thick smear converted to numbers of parasites per microliter by assuming a standard count of 800 leukocytes per microliter of blood after staining with 10% giemsa stain and by RTPCR using primers specific to pfs25 gene, involving 116 children administered with either Coartem and Dou-Cotecxin according to body weight, followed at day 3, 7, 14 and 28 after treatment. Results showed that there was no significant difference between the drugs in clearance of gametocytes (p<0.082) and the drugs cleared gametocytes in infected patients all by day 28 by microscopy. There was significant difference between the two methods in detection of gametocytes (p<0.001). RT-PCR was effective than microscopy in detection of gametocytes and detected 10 times more gametocytes compared to microscopy. The RT-PCR detected Pfs25 gene using primers specific for this gene with the gene size expected was of approximately 500 bp. This study showed that Coartem and Dou-Cotecxin have gametocytocidal effects on P. falciparum and the study on the clearances of gametocytes using both Coartem and Dou-Cotecxin may be carried out using higher sample size for policy implementation. Application of sexual stage RT-PCR assays may contribute to a better understanding of the biology and epidemiology of malaria transmission.