Vector-Borne Diseases

What to know

Climate is one of the factors that affects vector-borne diseases. Vectors are creatures such as fleas, ticks, and mosquitoes that carry and spread illnesses. Warmer weather, along with other factors, such as lifestyle and health care access, could increase a person's risk for vector-borne infections.

A mosquito biting into a person.

Climate Impact on Vector-Borne Diseases

Climate impacts the spread of vector-borne diseases. These diseases are transmitted by fleas, ticks, and mosquitoes carrying pathogens that cause illness. Vector populations and disease distribution depend on climate, as well as:

  • Land use
  • Socioeconomic and cultural factors
  • Pest control
  • Access to health care
  • Human responses to disease risk
  • Other factors

Climate changes can lead to vector/pathogen adaptations, causing shifts or expansions in their geographic ranges.

Such shifts can alter disease incidence depending on vector-host interaction, host immunity, and pathogen evolution. North Americans are currently at risk from numerous vector-borne diseases, including:

  • Lyme disease
  • Dengue fever
  • West Nile virus disease
  • Rocky Mountain spotted fever
  • Plague
  • Tularemia

Vector-borne pathogens not currently found in the United States, such as chikungunya, Chagas disease, and Rift Valley fever viruses, are also threats.

Global and Local Impacts

Climate change globally influences the spread of vector-borne diseases. This impact affects North Americans due to increased trade and travel to tropical and subtropical regions. The uncertainty of whether a changing U.S. climate will heighten the risk of diseases like dengue fever is influenced by vector-control measures and lifestyle factors. These factors include time spent indoors, which reduces human-insect contact.

Studying vector-borne disease

Infectious disease transmission is sensitive to:

  • Local, small-scale differences in weather
  • Human modification of the landscape
  • Diversity of animal hosts
  • Human behavior that affects vector-human contact
  • Other factors

Finer-scale, long-term studies are needed to help quantify the relationships among:

  • Weather variables
  • Vector range
  • Vector-borne pathogen occurrence
  • Consequences of shifting distributions of vectors and pathogens
  • Impacts on human behavior

Enhanced vector surveillance and human disease tracking are needed to address these concerns.

Watch a short video about disease vectors, and how communities can defend against them.

CDC resources