Dengue Fever Alert Issued in Florida Keys After Locally Acquired Cases Detected

A female Aedes aegypti mosquito is the primary vector for the spread of Dengue fever. Courtesy of James Gathany/Centers for Disease Control and Prevention

A dengue fever alert has been issued in the Florida Keys after the mosquito-borne illness was detected in two people, according to Florida Department of Health officials in Monroe County.

The alert, issued on June 29, stated that the cases were locally acquired, not travel-related, but did not provide further details.

The alert said that the department will work with the Florida Keys Mosquito Control District to carry out surveillance and prevention efforts, such as door-to-door mosquito inspections and mosquito treatments.

A total of 10 locally-acquired dengue cases have been reported in four Florida counties this year as of June 29, according to a report by the state’s health department. Of those, two cases were reported in Monroe, six in Miami-Dade, and one each in Hillsborough and Pasco counties.

Additionally, a total of 244 dengue cases have been reported in people in Florida with a travel history to a dengue-endemic area this year, according to the report.

Dengue is caused by a virus transmitted through the bite of an infected Aedes species mosquito and can appear as a flu-like illness with other symptoms. Symptoms will appear within 14 days after being bitten.

The Florida Keys is an archipelago of about 1,700 islands in the southern tip of Florida.

CDC Warns Increased Risk of Dengue

The dengue alert was issued days after the Centers for Disease Control and Prevention (CDC) released a health advisory warning about an increased risk of dengue virus infections across the United States.

“Global incidence of dengue in 2024 has been the highest on record for this calendar year; many countries are reporting higher-than-usual dengue case numbers,” the CDC stated in a June 25 advisory.

“In 2024, countries in the Americas have reported a record-breaking number of dengue cases, exceeding the highest number ever recorded in a single year.”

A total of 2,241 cases have been reported across 50 states this year, and another 1,498 cases in Puerto Rico, a U.S. territory. Puerto Rico declared an emergency for dengue in March amid a rise in cases.

In Latin America, nearly 10 million cases of the virus have been reported, or about twice as many as all the cases reported in 2023, the CDC advisory said.

The CDC advised doctors to be aware of the symptoms of the viral infection and to ask patients about where they recently traveled. Doctors are also advised to order tests for dengue fever if needed.

The advisory noted that doctors should “recognize the critical phase of dengue” when the fever begins to decline and lasts between 24 and 48 hours.

“During this phase, some patients require close monitoring and may deteriorate within hours without appropriate intravenous (IV) fluid management,” according to the advisory.

Those infected with dengue will develop fever and other symptoms like nausea, vomiting, rash, muscle aches, joint pain, bone pain, pain behind the eyes, and headache, according to the CDC.

In some cases, dengue can progress to a “severe disease,” with symptoms like abdominal pain, persistent vomiting, clinical fluid accumulation, mucosal bleeding, and lethargy, the advisory said.

Jack Phillips contributed to this report.