Home Divisions & Offices Offices Office of Epidemiology Surveillance Emerging Diseases Communicable & Emerging Disease Program Mosquito Diseases

About Mosquito-borne Diseases

The Office of Epidemiology, Surveillance, and Emerging Diseases (OESED) provides disease surveillance, data analysis and interpretation, education, and guidance for healthcare providers and community partners. OESED offers resources within the community to decrease transmission of any high-incidence disease or a new emerging disease posing a threat to Harris County. This office collaborates with the Mosquito and Vector Control Division to conduct routine surveillance on multiple mosquito-borne diseases, including West Nile Virus (WNV), Dengue, Chikungunya, St. Louis encephalitis, and Zika. OESED complements this work by monitoring and investigating human cases, analyzing trends, and supporting public health response and community outreach efforts.

Signs, Symptoms, and Treatment

The most common mosquito-borne diseases in Harris County are West Nile Virus, Dengue, Zika, Chikungunya, and St. Louis Encephalitis. Each mosquito-borne disease has its own unique signs, symptoms, complications, and treatment protocols. Mosquito-borne diseases are transmitted from an infected mosquito to a human through a mosquito bite and are not contagious from human to human.

Mosquito bite signs:

  • A puffy and reddish bump appearing a few minutes after the bite
  • A hard, itchy, reddish-brown bump, or multiple bumps appearing a day or so after the bite or bites
  • Small blisters instead of hard bumps
  • Dark spots that look like bruises

More severe reactions:

  • A large area of swelling and redness
  • Low-grade fever
  • Hives
  • Swollen lymph nodes

To learn more about each condition, click on the mosquito icon below.

Mosquito_Control_3T_PUSHCARD_MVCD_2025

Tip water from open containers especially after rain
Toss items or debris that can hold water
Take action by protecting yourself from mosquito bites

HCPH Mosquito and Vector Control Division

The Mosquito and Vector Control (MVC) Division protects Harris County residents by preventing and controlling mosquito-borne diseases. MVC uses an Integrated Vector Management (IVM) approach to prevent, detect, and control vector-borne diseases. To learn more, click here.

Harris County Public Health 2025 Mosquito-borne Disease Dashboard

This interactive dashboard offers a comprehensive view of Mosquito-borne Disease counts in Harris County, focusing on West Nile Virus (WNV), Dengue, Chikungunya, St. Louis encephalitis, and Zika as these conditions are the most commonly acquired in Harris County. It brings together data from multiple public health surveillance systems to support informed monitoring and response. This dashboard is updated daily, date and time stamped at the bottom right corner.

Prevention

  • Wear Protective Clothing
    • Wear long-sleeved shirts and long pants
  • Avoid High Exposure Areas
    • Reduce outdoor activity during dawn and dusk, where mosquito activity is high
    • Keep mosquitoes out by keeping doors and windows closed and/or installing window screens.
  • Use Insect Repellent
  • Remove Breeding Habitats
    • Water is necessary for a mosquito’s survival. Follow the three T’s (Tip, Toss, Take Action). This involves emptying water containers, cleaning drains and gutters, and maintaining overall sanitation in personal surroundings.
  • Seek Guidance from a Healthcare Professional Before Travel
    • A healthcare provider can provide personalized guidance on health precautions and address any specific concerns related to relevant mosquito-borne diseases before departure.

Additional Mosquito-borne Disease Resources

Title Type

HCPH Vector-borne Disease in Harris County 2017-2022 Report

HCH Mosquito & Vector Control Division

Preventing Mosquito Bites While Traveling

About Mosquito Bites

Preventing Mosquito Bites

Mosquito Control at Home

HCPH Prevent the Bite

DSHS Mosquito-borne Diseases

DSHS List of Mosquito-borne Diseases

World Mosquito Program