The Correlation Between Human Biting Specialization in Aedes aegypti and Modern Disease Outbreaks in Africa

Abstract

Aedes aegypti (Ae. aegypti), the vector for various arboviruses, is a major source of public health concern. Currently, there is not much known about their host-seeking behavior and their evolution from generalists to human-biting specialists. By investigating their evolutionary history, I hope to elucidate the factors that drove this subspecies to diverge from their ancestors and also connect the historical narrative with their present distribution. I hypothesize that since Ae. aegypti evolved into human-biting specialists in the Sahel region of Africa, these mosquitoes should still have a larger prevalence in this region, and correspondingly an increased disease burden regarding the viruses which the vector transmits. To investigate this relationship, I used World Health Organization data to track disease outbreaks in several countries of interest in and around the Sahel. By plotting this data on a map, I was able to analyze the burden of yellow fever and dengue on the Sahel. The results showed that there was an increased prevalence of yellow fever outbreaks in the Sahel region in West Africa, but an even distribution of dengue outbreaks throughout Africa. These findings imply that the relative presence of the host may not be the only variable influencing observed transmission patterns. The vector, as well as the diseases themselves, are sensitive to external factors such as temperature and human population density which can cause unexpected health outcomes.