What is a Vector?

Vector Services & Information

A vector is any arthropod, insect, rodent or other animal of public health significance capable of harboring or transmitting the causative agents of human disease (e.g. malaria, plague) to humans. Under certain circumstances, insects or other arthropods that cause human discomfort or injury, but not disease, are sometimes referred to as vectors.

Is it a Mosquito?

A lot of people in L.A. County frequently see insects that are commonly mistaken for mosquitoes. If you are getting bites from small flying insects, then they may be mosquitoes! If they're swarming your yard or coming into your home, but they are not biting you, then they could be one of the many insects in our environment. Have you been fooled by any of these insects?

Insect Image Description
Crane Fly Crane fly image

Crane Fly

• Much larger than a mosquito

• Harmless: Does not bite!

• A problem from early spring to fall

• Develops in moist soil or water

Solution: Since crane flies are not vectors, our staff does not treat for these insects.

Midge photo of midge


• About same size as mosquito

• Harmless: Does not bite!

• Known to swarm

• Develops in mud on bottom of areas that can hold water like spreading basins, ponds and lakes

• Large swarms can pose a problem for homes, businesses, and other property

Solution: Although our staff monitors populations of midges, swarms or "midge blooms" are perfectly normal. If you are experiencing insect bites, however, please contact us as this can be serious.

Fungus gnat fungus gnat photo

Fungus Gnat

• About the same size as mosquito and looks very similar

• Harmless: Does not bite!

• Known to swarm

• A problem from winter to spring

• Devlops in fungus or moist decaying vegetation

Solution: Swarms of fungus gnats are perfectly normal. If you are receiving insect bites, however, please contact us as this can be serious.

mosquito mosquito photo


• Harmful: They can bite and transmit diseases!

• Think you have biting mosquitoes? Report them HERE for a free inspection.

• Learn more about mosquitoes HERE

District Programs

There are a number of Mosquito Species and Mosquito-Borne Diseases known to occur within the Greater Los Angeles County Vector Control District.

Click here to learn more.