Abstract
Malaria remains a public health problem in Cameroon and antimalarial drug resistance hampers proper control of the disease. Several studies have been carried out on antimalarial drug resistance but regular monitoring of mutations associated with national drug policy changes are missing. In addition, previous studies mostly focused on symptomatic patients, and very few on asymptomatic carriers despite the fact that they represent a large reservoir of parasites. In malaria hyperendemic areas such as Cameroon, malaria infections harbour multiple clones of parasites but the dynamics of transmission of the different genotypes of P. falciparum from humans to mosquitoes and during their development within the mosquito has received few attentions so far.Our study updates the malaria epidemiological situation in Tibati located in the Adamawa region of Cameroon, an area of seasonal malaria transmission and Mfou, located in the central region and characterised by perennial malaria, to assess the malaria prevalence and describe the trends in antimalarial resistance markers in these two epidemiologically distinct areas. Additionally, we performed next generation sequencing using high throughput Illumina Miseq in human and mosquito infections to compare the genetic diversity of parasite populations, and the carriage of mutations associated with antimalarial drug resistance between symptomatic and asymptomatic individuals and throughout the developmental stages in the mosquito. We also carried out entomological survey in Tibati where we confirmed for the first time in Cameroon, the infection of Anopheles coluzzii with P. vivax. At the individual level, we observed a drop in the Pfcrt K76T mutation which is responsible for chloroquine resistance, even though the mutation persisted at the population level. We also observed the presence of parasites fully and super resistant to the sulphadoxine - pyrimethamine. More so, we did not observe known artemisinin resistance mutations, but observed for the first-time in the country, rare mutations such as the R255K and L258M. Using Ampseq, we determined a higher number of mixed infections in asymptomatics, that showed that resistant genotypes persist at lower levels. Comparing the genetic diversity between asymptomatic and symptomatics, showed that Asymptomatics had higher MOI and helps maintain parasite diversity. Preliminary analyses of the diversity of parasites in mosquitoes indicated that the mosquito has a role in the transmission of minority genotypes and also helps in maintaining parasite genetic diversity.