Why Mosquitoes?#
In this lesson, we’ll be looking at why we’re studying mosquitoes and mosquito-borne diseases.
Mosquitoes are considered the world’s deadliest vector of disease#
A disease vector is an organism that transmits disease-causing pathogens, usually feeding on an infected host and then spreading that disease to the next human or animal it feeds on.
They are one of the main animal agents of disease and have been a selective force of human evolution.
Understanding Mosquitos#
Understanding mosquitoes and their biology, ecology, and behavior allows for the development of strategies to prevent and monitor the spread of mosquito-borne illnesses.
Mosquitoes exist everywhere where there aren’t harsh cold conditions, but climate change is leading to their ecosystems becoming bigger and bigger every year.
88 of known species are vectors for 78 human-disease causing pathogens
Another 6.8% were identified as potential or likely vectors
Mosquito Life Cycle
Image from Centers for Disease Control and Prevention
Controlling Vectors#
Vector-control, specifically targeting mosquitoes, is vital as more populations become susceptible in order to prevent infection and reduce disease transmission. Climate change is shifting conditions so that they can breed and lay eggs in more places, as well as for longer periods. Wet conditions allow for female mosquitoes to lay eggs; they thrive in humidity. They prefer stagnant water, like ponds, and need healthy vegetation. The eggs can survive in dry conditions for months. Many breeds of mosquitoes are also becoming resistant to pesticides, so they need to be targeted specifically.
Remote sensing can be used to find areas with healthy vegetation and sitting water, satellite imagery can also be used to find things like birdbaths or tires where mosquitoes can breed, tracking conditions where they have the potential to breed in order to track their habitats.
It’s hard to eliminate them specifically because of how many variations there are of the species, 3500~.
Work needs to be focused on small, geographically restricted networks in order to focus on specific pathogens.
Targeted mosquito efforts have the highest rate of success.
Mosquito-Borne Illnesses#
Most mosquito-borne illnesses are found in tropical climates, where mosquito colonies thrive.
Malaria#
Malaria is a life-threatening disease spread by the bite of an infected female Anopheles mosquito. It cannot spread from person-to-person and is preventable and curable. There were an estimated 263 million malaria cases and 597,000 malaria deaths in 2023. Symptoms incluhde fever, chills, and headache, with severe symptoms including fatigue, difficulty breathing, or even seizures.
Dengue#
Dengue virus is a form of Flavivirus, mostly spread by the Aedes mosquito, either Ae. aegypti or Ae. albopictus. It causes high fever and rashes, as well as muscle and joint pain. Pregnant women are at high risk if they contract dengue, potentially leading to premature birth, low birthweight, or even loss of the fetus. There is no specific medicine in which to treat dengue and it has the potential to become severe, which needs emergency medical treatment.
Image from Centers for Disease Control and Prevention
Zika#
Zika virus is a mild form of dengue virus, mostly spread by the Aedes aegypti mosquito. It’s a vector-borne disease, so once a person is infected, they’re able to infect others through sexual contact. It’s typically asymptomatic, but sometimes causes a infection consisting of a fever or rash. It was identified in Africa and later found in other tropical regions, including in South & Central America. It is especially dangerous for pregnant women, causing microcephaly or a abnormal smallness of the head in their infants. This abnormality is typically associated with incomplete brain development.