How do Mosquitoes Transmit Disease?

Did you know there are roughly 3,000 different mosquito species in the world? Out of those 3,000, about 200 species live in the United States. 

Many people may connect the height of mosquito season, occurring in the summer through early fall, to the itchy welts that accompany mosquito bites. But, there are far worse associations to make with these blood-sucking pests, such as the health threats they pose to humans in their daily lives—even in their own backyards.

Out of the thousands of mosquito species living all over the world, many have the potential for carrying and spreading various diseases. In the United States, mosquitoes are known to spread West Nile virus, eastern equine encephalitis, and chikungunya virus. These illnesses do not have specific vaccines or treatments, so year-round mosquito control is crucial. Other mosquito-borne illnesses include malaria, Dengue fever, and Zika virus.

How do mosquitoes contract a disease?

To fully understand the importance of mosquito control, let’s think about how mosquitoes can contract diseases in the first place. According to the Centers for Disease Control and Prevention, the process by which mosquitoes contract and transmit illnesses is somewhat complex and generally consists of five steps:

  1. A female mosquito takes a blood meal from a human or animal host
  1. If that blood meal contains a germ, the germ must pass from the mosquito’s gut into its body. Therefore, mosquitoes can only transmit germs that can grow or multiply in their bodies.
  1. After the germ multiplies in the mosquitoes body, it travels to the salivary glands in about 2-3 weeks.
  1. Now that the germ is in the salivary glands, the mosquito can transmit it to a host. The next time the mosquito bites a person or animal, the germ passes from the salivary glands to the blood of the host. 
  1. The person or animal bitten is at risk for contracting disease.

Which mosquito spread disease? 

Now that we know how mosquitoes contract and spread disease, we can see which mosquitoes are responsible for spreading which diseases.

Aedes: Aedes mosquitoes are responsible for many well-known diseases, such as Yellow Fever, Zika virus, Dengue, and Lymphatic filariasis. 

Anopheles: Anopheles mosquitoes are responsible for the spread of probably the most well-known mosquito-borne illness in the world: malaria. Malaria takes hundreds of thousands of lives every year, particularly in areas with tropical and subtropical climates. According to the CDC, nearly half of the world’s population lives in areas at risk of malaria transmission.

Culex: Culex mosquitoes are known for spreading diseases like Japanese encephalitis and West Nile Fever.
Mosquito control is not just necessary for your comfort, but for your health as well. To learn more about mosquitoes and the diseases they carry, visit the CDC or World Health Organization websites.