Most mosquito bites in Florida are just itchy. A small number carry viruses that can make people sick, and in some years the risk rises enough for health officials to issue local warnings. On August 3, 2026, the Florida Department of Health in Palm Beach County issued a mosquito-borne illness advisory after a confirmed case of locally acquired dengue.

Here is what to know about the two infections most often in the news, dengue and West Nile virus, using information from the Florida Department of Health and the CDC.

Dengue

According to the CDC, about 1 in 4 people infected with dengue get sick. The most common symptom is fever, usually with aches and pains (including eye pain), nausea or vomiting, or a rash. Symptoms typically last two to seven days, and most people recover in about a week.

About 1 in 20 people who get sick develop severe dengue, which can cause shock, internal bleeding and death. The CDC’s warning signs usually begin in the 24 to 48 hours after the fever goes away, which is why people sometimes relax too early. Go to an emergency room right away for:

  • Belly pain or tenderness.
  • Vomiting at least three times in 24 hours.
  • Bleeding from the nose or gums.
  • Vomiting blood, or blood in the stool.
  • Feeling extremely tired or restless.

For fever and pain, the CDC advises taking acetaminophen and avoiding aspirin and ibuprofen, because of the bleeding risk. Rest and drink plenty of fluids. If you take a blood thinner or have kidney or liver disease, call your doctor for advice specific to you.

West Nile virus

West Nile spreads mainly through the bite of a mosquito that has fed on an infected bird. The CDC estimates that about 80 percent of infections cause no symptoms. Most people who do get sick have a mild illness, such as fever with headache or body aches. Fewer than 1 percent develop serious illness affecting the brain or spinal cord, such as encephalitis or meningitis.

The CDC notes that older adults, people with certain chronic conditions and people with weakened immune systems are at higher risk of severe illness. There is no licensed vaccine or specific antiviral medicine for West Nile in people; severe cases are treated with supportive care in the hospital. Seek care urgently for a high fever with severe headache, a stiff neck, confusion, weakness or trouble walking.

Drain and cover

Florida’s public health message is to drain standing water and cover your skin and home. In practice:

  • Drain. Empty anything that collects rain or sprinkler water: buckets, plant saucers, toys, trash can lids, tarps and old tires. Refresh birdbaths and pet bowls at least once or twice a week, and keep pools clean and chlorinated.
  • Cover your skin. When mosquitoes are out, wear long sleeves, long pants, socks and closed shoes, and use repellent on exposed skin.
  • Cover your home. Keep screens on windows, doors, porches and patios, and repair tears.

After a summer storm, take a few minutes to walk around the house and tip out anything holding water, which is exactly what the state health department asked Floridians to do in its September 2026 dengue reminder. The Palm Beach County advisory also asks residents to report dead birds to the Florida Fish and Wildlife Conservation Commission, since birds help health officials track West Nile activity.

The CDC lists EPA-registered repellent ingredients that work: DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol (PMD) and 2-undecanone. Follow the label. Permethrin is for clothing and gear only, never directly on skin.

Travel and when to call your doctor

Dengue is common in many parts of the Caribbean and Latin America. If you develop a fever after travel to one of those areas, or during a local advisory, tell your doctor where you have been. The CDC notes that a blood test is the only way to confirm dengue, but care can start based on symptoms. Anyone with the warning signs above should go to an emergency room, and anyone with signs of a stroke or severe confusion should call 911.

For other seasonal Florida concerns, see the hurricane season health checklist and skin cancer checks in Florida.

At Legacy Medical, members can reach the practice by phone at any hour about a new fever, and same or next business day visits allow a prompt exam and testing when needed. To meet Dr. Shtern, book a complimentary meet and greet.

This article is general information, not advice for your situation. Members can call the office with questions about their own care.