A new study from researchers at the University of Notre Dame suggests that light pollution may increase risk of human exposure to mosquito-borne diseases. The study, published in October in The American Journal of Tropical Medicine and Hygiene, focuses on how light pollution affects the behavior of Aedes aegypti in nocturnal settings.
Aedes aeypgti are well known for being active during daylight hours, and harboring at night. According to the study, however, increased usage of artificial lights encourages Ae. aegypti activity even after the sun sets. Ae. aegypti spread important arboviral diseases such as Zika, dengue, chikungunya, , and yellow fever, and have played a central role in many of the worst vector-borne epidemics across the globe.
The innovative study involved exposing caged mosquitos to artificial light during nighttime hours and tracking their bite frequency. These results were then compared with bite frequency under naturally-lit day and nighttime surroundings. The results were dramatic. Without artificial light, only 29 percent of Ae. aegypti bit after dark. With artificial light, that frequency more than doubled to 59 percent.
The findings have serious implications in a world undergoing urbanization on a massive scale. Also called “container mosquitos” Ae. aegypti are known to thrive in urban environments. Combining increased light pollution in urban and residential settings with the fact that more than 2/3 of the world’s population is projected to reside in urban areas by the year 2050, and you have a recipe for alarming increases in public health risk. As a disease vector, Ae. aegypti is a notorious threat given their reliance on humans as their main bloodmeal source.
Research such as the Notre Dame study is important because it helps biologists and other mosquito abatement professionals better understand the habits of Aedes aegypti. The better we understand their behavior, the better we can prevent the impact they have on human health. Knowing the effects of light pollution – a previously overlooked factor – could help researchers predict infection and disease rates in the future.
Authors of the study hope to conduct future research to test responses to other variables such as light intensity and duration. They also hope to discover more about why artificial light affects some mosquitos and not others—the answer may be tied to genetics.
Reference: https://doi.org/10.4269/ajtmh.20-0885