Know your Enemy: The Diseases Mosquitoes Carry Series 3

Understanding mosquitoes is the first step in protecting yourself from the diseases they carry. While the male mosquito buzzes around your ears, it’s the female that bites–seeking a blood meal to support egg development. Beyond being a nuisance, mosquitoes are dangerous disease vectors, capable of transmitting viruses and parasites to humans and animals.

What are Arboviruses?

Asian tiger mosquito is an arbovirus vector! (UF/IFAS File Photo)

Mosquitoes are among several arthropods that transmit viruses known as arboviruses. This is short for arthropod-borne viruses. These viruses are spread by joint-legged organisms such as mosquitoes, midges, ticks, and sandflies. These vectors use specialized mouthparts for piercing, cutting, and sucking to transmit pathogens to vertebrate hosts.¹

How Mosquitoes Transmit Disease

Despite their tiny size, mosquitoes can carry and transmit debilitating diseases. Here’s how it works:

A mosquito feeds on an infected host and picks up a virus or parasite.
The pathogen survives and reproduces inside the mosquito’s gut.
When the mosquito bites another host, the pathogen is transmitted through its saliva.

This internal survival mechanism allows diseases to spread locally, nationally, and globally, especially through human travel. For example, a study in Connecticut found that six out of nine arboviruses isolated from mosquitoes were known to cause human diseases, even though they didn’t originate in the northeastern U.S.²

Global Origins of Mosquito-Borne Diseases

Each week, the Centers for Disease Control and Prevention (CDC) and the Florida Department of Health release reports on mosquito-borne diseases by county. Many counties participate in the Sentinel Chicken Program, which tests chickens for mosquito-transmitted diseases and reports findings to health officials.

Most mosquito-borne diseases originate from regions such as Africa, Southeast Asia, and South America.

For example:

Chikungunya was primarily found in Africa and Asia.
West Nile virus was first detected in Uganda in 1937.

Today, these diseases are found throughout North America.³

Travel Advisory

If you are traveling to regions where mosquito-borne diseases are common, check the CDC travel health advisories. CDC Travel Notices. The CDC provides updates on global health risks and protective actions. In severe cases, advisories may recommend avoiding travel to certain areas.

In Florida, this species of mosquito (Culex nigripalpus) plays a major role in the transmission of disease-causing viruses. (UF/IFAS/File Photo)

Mosquito-borne Diseases in Florida

Florida sees several mosquito-borne diseases, with Dengue and Malaria being the most prevalent. These diseases can be contracted locally or while traveling abroad. Over the past five years, these two diseases have appeared more frequently in county health reports than others.

Historical Context

Outbreaks of Dengue and Malaria were common in Florida until the late 1940s. The widespread use of air conditioning and screened windows significantly reduced mosquito exposure.

Prevention Tip: Install or repair screens on windows and lanais to keep mosquitoes out.

Other Diseases Reported in Florida

While less frequent, the following diseases can cause severe illness: Eastern Eastern Equine Encephalitis, St. Louis Encephalitis, and West Nile virus.

These diseases can affect humans, birds, and horses. Symptoms vary and may include:

No symptoms
Mild fever or headache
Flu-like symptoms
Severe cases: brain inflammation (encephalitis), seizures, or death⁴

Past Incidences

Chikungunya: Last reported in Florida in 2014
Zika virus: Last reported in 2016
Yellow fever: Last reported in Bay County in 1918⁵

Protect Yourself

Mosquitoes are most active at dusk, dawn, and near standing water. To reduce your risk:

Avoid outdoor activities during peak mosquito hours.
Eliminate standing water around your home.
Use mosquito repellents and protective clothing.

If you experience symptoms such as high fever, purple rash, or other severe reactions⁴ after mosquito bites, seek medical attention immediately.

Stay Informed

Stay protected and informed by visiting our blogs or contacting your local UF/IFAS Extension office. Next month’s article will explore the connection between specific mosquito species and the diseases they carry.

Need Help? For more information on managing mosquitoes and other home pests, contact:

UF/IFAS Extension Hardee County
507 Civic Center Drive, Wauchula, FL 33873
(863) 773-2164
Lisa Hickey: lisa.hickey@ufl.edu
Jonael Bosques: jonael@ufl.edu

Resources:

¹Arboviral Diseases, Neuroinvasive and Non-neuroinvasive 2015 Case Definition. National Notifiable Diseases Surveillance System. 2015. https://ndc.services.cdc.gov/case-definitions/arboviral-diseases-neuroinvasive-and-non-neuroinvasive-2015/#:~:text=Arthropod%2Dborne%20viruses%20(arboviruses),breast%20feeding%2C%20and%20laboratory%20exposures

²Mosquito-Transmitted Diseases in Connecticut. https://portal.ct.gov/mosquito/diseases/mosquito-transmitted-diseases#:~:text=Certain%20mosquitoes%20can%20harbor%20and,some%20parts%20of%20the%20world.

³Florida’s mosquitoes can make you sick: Here’s how to protect yourself. 2024. https://epi.ufl.edu/2024/05/01/floridas-mosquitoes-can-make-you-sick-heres-how-to-protect-yourself/#:~:text=Dengue%2C%20malaria%20top%20list%20of,IFAS%20Photo %20by%20James%20Newman

⁴ Centers of Disease Control and Prevention. 2025. https://search.cdc.gov/search/?query=mosquito%20borne&dpage=1

⁵Yellow Fever. https://www.baycountyfl.gov/247/Yellow-Fever

⁶ Fighting to End Infectious Disease. 2025. https://epi.ufl.edu/