West Nile Activity Reported in Duval County and Brooklyn: What Residents Should Know

Duval County Confirms a Second Locally Acquired Human Case

Florida health officials confirmed a second locally acquired human case of West Nile virus in Duval County on September 15, 2026, according to Jacksonville Today. The first case had been confirmed a little more than two weeks earlier.

“Locally acquired” means the infection was likely contracted in the area rather than during travel. The Florida Department of Health and Jacksonville Mosquito Control are coordinating surveillance and prevention efforts, including ground spraying.

Officials have not publicly identified where in Duval County either infection was likely contracted. Residents throughout Jacksonville should therefore focus on practical mosquito-bite prevention without assuming every neighborhood faces the same level of risk.

Brooklyn Has New York City’s Highest Reported Borough Case Count

As of mid-September, published reports citing New York City health data counted 30 diagnosed human cases citywide in 2026. Brooklyn had the highest borough total, with 11 cases.

These figures are a snapshot and may change as laboratories complete testing and health agencies update investigations. A higher borough total also does not mean every Brooklyn neighborhood has equal risk. Mosquito populations vary with standing water, vegetation, drainage, weather and local control efforts.

New Yorkers should monitor the New York City Department of Health and Mental Hygiene for updated data and neighborhood mosquito-control notices.

How West Nile Virus Spreads

West Nile virus is most commonly transmitted through the bite of an infected mosquito. Mosquitoes become infected after feeding on infected birds and can later transmit the virus to people and other animals.

The virus does not spread from person to person through ordinary contact such as touching, hugging, coughing, sneezing or sharing food. Rare transmission has occurred through blood transfusions, organ transplants, pregnancy, delivery, breastfeeding and laboratory exposure.

Mosquito season generally continues through the fall. The mosquitoes that spread West Nile are especially active around dusk and dawn, although bites can occur at other times.

Symptoms and Higher-Risk Groups

Most infected people develop no symptoms. Some experience a fever and other symptoms including headache, body aches, joint pain, vomiting, diarrhea, fatigue or rash.

In rare cases, West Nile virus can cause severe illness affecting the brain or spinal cord. Warning signs can include high fever, severe headache, neck stiffness, confusion, tremors, muscle weakness, seizures, numbness or paralysis.

People age 60 and older face the greatest risk of severe illness. Risk is also higher for people with weakened immune systems and certain chronic conditions, including chronic kidney disease, diabetes, cancer and hypertension.

Anyone with concerning symptoms should contact a healthcare professional. Confusion, severe headache, neck stiffness, seizures, sudden weakness or changes in alertness require prompt medical attention.

How Residents Can Reduce Their Risk

The Centers for Disease Control and Prevention says preventing mosquito bites is the best protection because no licensed human vaccine or preventive medicine is available.

Residents can take these steps:

• Use an EPA-registered insect repellent and follow its label directions.

• Wear loose-fitting long sleeves and long pants when mosquitoes are active.

• Keep mosquitoes outside with intact window and door screens or air conditioning when available.

• Empty standing water at least weekly from buckets, planters, toys, birdbaths, gutters, tarps and other containers.

• Maintain swimming pools and cover them when they are not being used.

• Check shared areas such as courtyards, rooftop drains, parking areas and construction sites for water-holding containers.

• Report persistent mosquito problems or neglected standing water to local mosquito-control authorities. In New York City, standing water can be reported through 311 during mosquito season.

Where to Find Reliable Updates

Case totals and control schedules can change. Residents should rely on current information from public-health agencies:

Duval County update:
https://jaxtoday.org/2026/09/15/west-nile-virus-duval/

NYC Health:
https://www.nyc.gov/site/doh/health/health-topics/west-nile-virus.page

CDC overview:
https://www.cdc.gov/west-nile-virus/about/index.html

CDC prevention guidance:
https://www.cdc.gov/west-nile-virus/prevention/index.html

This article provides general public-health information and is not a diagnosis or a substitute for advice from a qualified healthcare professional.