Ticks and Mosquitoes
in the United States

Researchers and public health agencies continually work to track the geographic distribution of ticks and mosquitoes across the United States and provide this information to the public.

It is important to recognize that the distributions of these animals can change across time. This means that we need to think about their geographic distribution in two ways:
  1. Transient populations: when a sample of a species is temporarily found in a new location. This can happen when a single tick takes a ride on a migrating bird, or when a mosquito appears in a port town during the summer months.
  2. Established populations: When a species survives and reproduces in an area year after year.

The resources listed below should be reviewed with these two types of geographic distribution in mind.

Diseases & Geography of Ticks
Diseases & Geography of Mosquitoes

Diseases & Geography of Ticks

Tick-Borne Diseases

The following tick-borne diseases are transmitted by ticks with established populations in the Northeast region of the US. For more information on tick-borne diseases across the US, please visit the CDC's Tickborne Disease site
American Dog Tick (Dermacentor variabilis)
Source: CDC
Source: CDC
Source: CDC
Source: USDA
Blacklegged (Deer) Tick (Ixodes scapularis)
Brown Dog Tick (Rhipicephalus sanguineus)

Geographic Distribution of Ticks

The Centers for Disease Control and Prevention have developed a series of maps that detail the geographic distribution of ticks that bite humans in the United States.
The Connecticut Agricultural Experiment Station has developed a guide for the Prevention of Ticks and Tick-Associated Disease in Companion Animals that showcases the distribution of several tick species that bite humans and domestic animals. You can view maps of these distribitions below.
All maps above orginally produced and published by: Biggs HM, Behravesh CB, Bradley KK, et al. Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States. MMWR Recomm Rep 2016;65(No. RR-2):1–44. DOI: http://dx.doi.org/10.15585/mmwr.rr6502a1

Diseases & Geography of Mosquitoes

The following mosquito-borne diseases are transmitted by mosquito species with established populations in the United States. To identify if these diseases have been reported in the Northeast region of the US, please follow the links below or visit the Disease Maps website. This site is maintained by the US Geological Survey and CDC ArboNET.
Source: CDC
Source: CDC
Source: CDC
For more detailed information on the identification of mosquitoes, you can access the Identification Guide for Connecticut Mosquitoes , developed by the Connecticut Agricultural Experiment Station.

Borne Diseases

Anopheles Mosquitoes
* Additional groups of mosquitoes can act as vectors for these diseases.
Many mosquito species that can carry and transmit diseases to humans have widespread geographic distributions. Several of the links below can help you find out if these mosquitoes might be in your area.

The Centers for Disease Control and Prevention have produced maps with the estimated geographic distribution of Aedes aegypti and Aedes albopictus mosquito species in the United States, available on their Zika virus webpage , and can be viewed below.

Geographic Distribution of Mosquitoes

The Pan-American Health Organization/World Health Organization has created an interactive map identifying the geographic distribution of several mosquito-borne diseases in North and South America.

You can also view the maps below for recent estimates for Aedes albopictus and Aedes aegypti mosquito distributions, generated by Kraemer et al. in 2015 (eLife 2015;4:e08347 doi: 10.7554/eLife.08347 ).