Key takeaways
- Vector-borne diseases cause more than 700,000 deaths a year worldwide, and mosquitoes carry many of the best known, from malaria to dengue (WHO).
- Florida reported 425 locally acquired dengue cases in 2026 through October 17, including 9 in Miami-Dade, 1 in Broward and 1 in Palm Beach.
- Miami-Dade counted 200 travel-associated dengue cases in 2026, more than any other Florida county, and was under a state mosquito-borne illness alert.
- Older adults, pregnant women, young children and dogs face the most serious consequences from mosquito-borne illness.
- Dog heartworm spreads through mosquito bites and can cause heart failure and death, so mosquito control protects pets too.
In this article
- Why Mosquitoes Are Called the World’s Deadliest Animal
- Mosquito-Borne Diseases in Florida Right Now
- Who Is Most Vulnerable to Mosquito-Borne Illness
- Disease-Carrying Mosquitoes Breed Close to Home
- Why Store-Bought Products Fall Short
- How Professional Mosquito Control Lowers the Risk
- Frequently Asked Questions
Mosquitoes are more than a nuisance because some of them carry viruses and parasites that make people and pets seriously ill. In South Florida, that is not a distant risk: hundreds of locally acquired dengue cases have been reported in Florida in 2026, Miami-Dade sees more travel-related cases than any other Florida county, and dogs here are exposed to heartworm through ordinary backyard bites.
Most bites cause nothing worse than an itch. The danger is that you cannot tell which mosquito is infected, and the ones that spread disease breed in the buckets, gutters and plant saucers around your own home. This guide explains the real health risks, who is most vulnerable, what the latest Florida numbers show and what actually lowers your family’s risk.
Why Mosquitoes Are Called the World’s Deadliest Animal
Mosquitoes do not kill with their bite; they kill with what they carry. According to the World Health Organization, vector-borne diseases account for more than 17% of all infectious diseases and cause more than 700,000 deaths every year. Mosquitoes spread a long list of them, including malaria, dengue, Zika and yellow fever.
The scale is hard to picture. WHO estimates that malaria, spread by Anopheles mosquitoes, causes about 249 million cases and more than 608,000 deaths a year, most of them in children under 5. More than 3.9 billion people in over 132 countries are at risk of dengue, with an estimated 96 million symptomatic cases each year.
The way infection works is simple. A mosquito picks up a virus or parasite when it bites an infected person or animal, then passes it on through later bites. That is why a disease brought in by one traveler can spread through a neighborhood when local mosquitoes are abundant.
Mosquito-Borne Diseases in Florida Right Now
Florida’s warm, wet climate supports the mosquitoes that carry several of these diseases. The Florida Department of Health’s weekly arbovirus report for October 11-17, 2026 shows where things stand this year.
| Disease | Florida, 2026 through October 17 | Why it matters |
|---|---|---|
| Dengue | 425 locally acquired, 320 travel-associated | About 1 in 20 people who get sick develop severe dengue, a medical emergency (CDC) |
| Chikungunya | 88 travel-associated, 1 locally acquired (Miami-Dade) | Most travel cases were linked to Cuba and Nicaragua, both with close ties to South Florida |
| West Nile virus | 5 symptomatic cases acquired in Florida | People 65 and older are three times as likely to develop neurologic illness (CDC) |
| Eastern equine encephalitis | 1 human case (Leon County) | Rare in people, but the virus was found in 48 sentinel chickens and 7 horses this year |
| Zika | 0 cases | Infection during pregnancy can cause serious birth defects (CDC) |
| Malaria | 43 travel-associated | Causes more than 608,000 deaths a year worldwide (WHO) |
Statewide, most locally acquired dengue in 2026 has been in the Tampa Bay area, with 346 cases in Hillsborough County. South Florida’s risk shows up in a different way: as of October 17, Miami-Dade had 9 locally acquired cases and was under a mosquito-borne illness alert, while Broward (1 local case) and Palm Beach (1 local case) were under an advisory. For a closer look at dengue, read are Floridians at risk for dengue fever, and for the other viruses, our guide to Zika, West Nile and chikungunya.
Why Travel Cases Matter So Much in South Florida
Most local outbreaks start with an infected traveler. Once that person is home, local Aedes mosquitoes can bite them, pick up the virus and pass it to neighbors. South Florida’s strong travel ties make this the main pathway here.
Source: Florida Department of Health, arbovirus surveillance week 41
Miami-Dade’s 200 travel-associated cases are more than any other Florida county reported, and 266 of the state’s 320 travel cases were linked to Cuba. Every one of those cases is a chance for local transmission if mosquitoes around the patient’s home are allowed to thrive.
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Who Is Most Vulnerable to Mosquito-Borne Illness
Anyone can be infected, but some groups face more serious outcomes.
Older Adults and People With Chronic Conditions
West Nile virus is the clearest example. According to the CDC, about 80% of infected people never develop symptoms and about 20% get a flu-like illness, but fewer than 1% develop severe illness affecting the brain or spinal cord. People 65 and older are three times as likely to develop that neurologic illness as younger people, and cancer, diabetes, high blood pressure, kidney disease or a weakened immune system also raise the risk. About 10% of people who develop it die.
Pregnant Women
Zika infection during pregnancy can cause serious birth defects, including microcephaly, brain and eye problems, hearing loss and seizures. The CDC reports that Zika-associated birth defects occurred in about 5% of babies born in the U.S. to women with confirmed or possible Zika infection during pregnancy, with the highest risk after infection in the first and second trimesters. Florida reported no Zika cases in 2026, but the mosquito that spreads it is common in urban South Florida. Read how the state handled its 2016 outbreak in Zika in Florida: community impact and control measures.
Young Children
Children tend to react more strongly to mosquito bites themselves, as explained in why mosquito bites itch, and they spend long daytime hours outdoors when the Asian tiger mosquito is most active. Worldwide, children under 5 account for most malaria deaths, according to WHO. For babies younger than 2 months, the Florida Department of Health recommends mosquito netting instead of repellent.
Dogs and Other Pets
Heartworm is the mosquito-borne disease most South Florida households actually meet. According to the FDA, the worms spread through the bite of a mosquito and mainly affect dogs, cats and ferrets. The disease can cause severe lung disease, heart failure, other organ damage and death, and treating it can itself cause significant side effects in dogs. Prevention is far easier than treatment, so talk to your veterinarian about a year-round plan.
Disease-Carrying Mosquitoes Breed Close to Home
The mosquitoes behind dengue, chikungunya and Zika are container breeders. They lay eggs just above the waterline in small amounts of water and stay close to where they hatch. In practice, that means the main risk around your home comes from your own yard and your neighbors’. Common breeding spots around South Florida homes include:
- Clogged gutters and roof drains
- Birdbaths, pet bowls and fountains
- Potted plant saucers and bromeliads
- Pool covers, tarps and boat covers
- Toys, buckets, coolers and recycling bins
- Irrigation that leaves puddles in low spots
Empty and scrub these at least once a week, as the CDC advises, and birdbaths and pet bowls at least twice a week, as the Florida Department of Health recommends.
Why Store-Bought Products Fall Short
Candles, sprays and backyard gadgets can give brief relief, but most of them do not touch the source:
- Foggers and sprays kill the adults they reach but not the larvae developing in water.
- Hidden breeding sites in gutters, drains and bromeliads keep producing new mosquitoes.
- Short-lived effect: a single application wears off, while a new generation emerges in about a week.
- Misuse risk: applying outdoor insecticides off-label can harm pollinators, fish and other beneficial insects.
Automatic systems have their own limits; see the truth about mosquito misting systems before you invest in one.
How Professional Mosquito Control Lowers the Risk
The most effective plan combines source reduction, larval control and treatment of the places where adults rest. Toro’s mosquito control service starts with a free inspection to find breeding sites and resting areas around your home or business. Technicians treat breeding sites with larvicide granules and growth regulators, apply a barrier treatment made with plant oils (rosemary oil, geraniol and peppermint oil) to the shrubs and plants where adults rest, and show you the containers and plants that keep holding water.
You can book a one-time treatment before an event or the 3-month plan of 4 treatments, one every 3 weeks, aimed especially at March through November. Toro has protected South Florida families since 1969, and if the bugs come back, so will Toro, at no additional cost to you.
No service replaces personal protection. Use a repellent with DEET, picaridin, oil of lemon eucalyptus or IR3535 when you are outside, keep screens repaired, and keep draining water every week. Together, those steps turn mosquitoes back into what they should be: an occasional nuisance, not a health threat.
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305-594-4767Frequently Asked Questions
Are mosquitoes the deadliest animal in the world?
Can you get sick from a single mosquito bite?
What are the first signs of a mosquito-borne illness?
Is dengue spreading in Miami right now?
Which mosquitoes spread disease in South Florida?
Sources
- Vector-Borne Diseases (fact sheet), World Health Organization
- Florida Arbovirus Surveillance Week 41: October 11-17, 2026, Florida Department of Health
- Symptoms of Dengue and Testing, Centers for Disease Control and Prevention
- Symptoms, Diagnosis, and Treatment of West Nile Virus, Centers for Disease Control and Prevention
- Congenital Zika Syndrome and Other Birth Defects, Centers for Disease Control and Prevention
- FDA Announces Draft Guidance for Heartworm Disease Prevention Products for Dogs, U.S. Food and Drug Administration
Educational content. This article is for general information about pests in South Florida and is not medical, legal or professional advice. If you have a bite, sting or allergic reaction, contact your doctor; in an emergency, call 911. Pest problems vary from home to home, so a licensed professional should inspect before treatment. When using any pesticide, always read and follow the product label.
