New research from the University of Massachusetts Boston reveals that mosquitos that lack beneficial bacteria are more likely to carry the West Nile virus, which sickened more than 2,000 people in the United States last year. Furthermore, climate change may be contributing to a lack of microbiota in mosquitos. Assistant Professor of Biology Doug Woodhams collaborated with Eva Novakova of the University of South Bohemia in the Czech Republic, on a new paper on this topic that was published in the April 2017 edition of Frontiers in Microbiology.
Woodhams and a team of researchers sampled mosquitos over three years in southern Ontario, examining all the bacteria found on their bodies. The mosquitos which lacked the naturally occurring Wolbachia bacteria were more likely to carry West Nile. The scientists postulate that Wolbachia helps protect mosquitos from diseases, which in turn prevents them from spreading those diseases to humans.
Woodhams also found that Wolbachia populations decrease as the temperature spikes. This is one reason that West Nile cases often increase in August, when temperatures are at their peak. Climate change also has an impact on Wolbachia bacteria--if there are too many warm days early in the season, there will be less Wolbachia to protect mosquitos.
This research could open up a new avenue for public health officials to prevent mosquito-borne illnesses like West Nile. Many health agencies use larvicide in still bodies of water to reduce the mosquito population. Adding a probiotic to water where mosquitos breed might encourage the growth of protective bacteria, and prevent mosquitos from becoming vectors for deadly diseases. A probiotic would help mosquitos' resistance to disease the same way that eating yogurt helps humans stay healthy.
“Mosquitos are becoming resistant to the pesticides we use. If we can make sure that those mosquitos that survive are healthy, we can avoid the spread of disease to humans,” said Woodhams.