Investigating Olfactory Preferences in Aedes aegypti Dependent on Location of Origin: A Determination of Animal vs. Human Preference, Analysis of Locational Determinants and Implication on the Spread of Disease in Resulting Urbanization

Abstract

Aedes aegypti mosquitoes, the vector of yellow fever, dengue, Chikungunya, and Zika, have proven to be one of the world’s deadliest organisms and given rise to global epidemics of disease. Using olfactory cues, this mosquito spreads disease by acquiring bloodmeals from either human or animal hosts. Previously thought to have been directly linked to morphological characteristics, the host preference of Aedes aegypti has proven to be as complex and polymorphic as many other aspects of the species. In search of potential determinants of host preference differences, this experiment aimed to acquire substantial data on host preference. Host preference, depending on olfactory cues, is quantified as “preference index” and compared by location. After determining the range of preference indexes by location, human population density, percentage (%) forest cover and other relevant ecological, economical, and social attributes of each location are discussed in conjunction with the resulting host preferences. Through this analysis, it was found that a major indicator of host preference was biodiversity; namely when the animal host population was larger than the human host population. Furthermore, this knowledge was used to postulate the potential effects of urbanization, stemming from the tested locations, on the spread of disease. It was estimated that in urban areas that expansion can result in epidemic outbreaks of vector-borne illness if the native Aedes aegypti mosquitoes originally held a human host preference. This is due to an increase in the volume of vectors in the human vector-disease chain. On the other hand, urbanization stemming from a location with a non-human preference encouraged no such effects. This information determines that urbanization must happen in conjunction with preservation of biota and maintenance of biodiversity to reduce the changes of epidemic outbreaks.