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Accueil du site → Doctorat → Oman → Influence of season, drug resistance, genetic complexity and anti-malarials on persistence and transmission of the malaria parasite : Plasmodium falciparum

Sultan Qaboos University (2015)

Influence of season, drug resistance, genetic complexity and anti-malarials on persistence and transmission of the malaria parasite : Plasmodium falciparum

Gadalla, Amal Azhari.

Titre : Influence of season, drug resistance, genetic complexity and anti-malarials on persistence and transmission of the malaria parasite : Plasmodium falciparum

Auteur : Gadalla, Amal Azhari.

Université de soutenance : Sultan Qaboos University

Grade : Doctor of Philosophy in Biochemistry 2015

Résumé partiel
Following marked reduction in malaria cases and deaths in the recent years, policies and research interests have now shifted toward elimination and eradication of the disease by 2050. Among the various challenges that face the prospect of malaria elimination/ eradication is the frequent carriage of the parasite as asymptomatic infection at levels not detectable by conventional methods. Thus asymptomatic parasitaemia is a hidden source of infection with great transmission potential. This thesis examined some biological characteristics of asymptomatic parasitaemia and factors affecting their transmission potential (gametocyte production) in seasonal transmission areas. The present work investigated the infection parameters ; parasite and gametocyte densities, multiplicity of infection and carriage of drug resistance genotypes among a cohort of 36 asymptomatic carriers, who were initially enrolled with microscopic confirmed P. falciparum during the transmission season, treated and then followed up monthly for 12 consecutive months, including 9 months of transmission-free and absence of therapy. The impact of season, parasite density and within host multiplicity of infection on gametocyte density was evaluated using generalized linear mixed model that consider longitudinal design and allows for extreme variability in gametocyte density between the transmission and the dry season. In addition, the relative abundance of wild-type compared to the mutant genotype of drug resistance genes and its association with gametocytes was examined. Also, the effect of therapy on gametocytogenesis was studied on a cohort of uncomplicated malaria (n=106) treated with chloroquine (CD) or sulfadoxinel pyrimethamine (SP) and then examined on weekly bases ; day 0, 7, 14 and 21. qPCR of 18S rRNA was used to quantify parasite density, while gametocyte stage specific genes qRT-PCR assays were used to quantify early (pfgel) and late (pfs25 and pfs230p) gametocytes stages. qPCR allelic discrimination was used to identify alleles of drug resistance genes pfort and pfmdr-1, and qPCR relative quantification was used to estimate relative density of sensitive compared to resistant alleles.

Présentation (SHUAA)

Annonce (Almandumah)

Page publiée le 4 juin 2022