IDENTIFICATION, MOLECULAR CHARACTERIZATION AND QUANTIFICATION OF AEDES MOSQUITO-BORNE VIROME IN CAMEROON

Global health security is increasingly threatened by emerging and re-emerging pathogens originating mainly from wildlife whose consequences to human and animal health can be devastating. Many of these pathogens are vectored by blood-feeding arthropods, specifically mosquitoes. The mosquito is an efficient vector for a multitude of virulent pathogens such as Plasmodium spp., filarial nematodes, Zika virus, dengue virus, Rift Valley fever virus and yellow fever virus. Such Arthropod-borne viruses (or arboviruses) are responsible for over 35 human infections in Africa including Cameroon. There is therefore a developing specific interest to understand mosquito viromes, particularly in terms of virus diversity and composition. The majority of mosquito-borne viruses are highly divergent (<70% amino acid identity) and have unknown pathogenicity for humans. Surveillance of circulating viruses in specific mosquito species within a region is necessary because the outcome is fundamental and critical for formulating strategies on prediction, preparedness, prevention, and eventual control of diseases. Thus, mosquito virome studies have been proposed as a promising robust tool that could be applied in virus surveillance. In addition to arboviruses, which can replicate in vertebrates, mosquito viromes seem to harbor a large proportion of viruses that naturally infect insects and can replicate only in insect cell lines in vitro. Even though these insect-specific viruses seem not to replicate in vertebrates, some of them are phylogenetically related to known pathogenic arboviruses and it is speculated that they may evolve to become novel pathogenic viruses in vertebrates. Factors such as climate, vegetation and building density impact the distribution of Aedes species in Cameroon with Aedes aegypti distributed nationwide and Aedes albopictus limited to the southern part. Therefore, differences in the distribution of these mosquito species is reflected in the circulation of their respective viruses. Accurate identification of these insect specific and arboviral infections in resource-poor settings is challenging, and in Africa, many fevers of unknown origin tend to be recorded as malaria. Moreover, in such settings, response to emerging infectious arboviral diseases is inaccurate. Quick and accurate identification of these arboviruses is essential for both diagnosis and response to emerging infectious viral diseases. The advent of next-generation sequencing technology offers an unprecedented platform for rapid sequencing-based identification of novel viruses. In the present study, a metagenomic approach will be employed to identify the virome, determine the virome diversity and abundance in Ae aegypti and Ae albopictus mosquitoes in the different climatic zones in Cameroon. Results will not only provide important preliminary information on the virus status (identity, diversity and abundance) in populations of Aedes spp. in Cameroon but will also contribute to the growing and much needed knowledge, as mosquito viromes could be manipulated to prevent and control pathogenic arboviruses and thus adequately prepare for any eventual outbreaks.