Dengue‑carrying mosquitoes expand their reach into new territories – including Florida

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The Florida Department of Health confirmed on Sept. 18, 2026, that the death of an elderly woman on Sept. 4 was due to dengue fever .

This is the first confirmed death in a larger dengue outbreak in Hillsborough County, which has seen 134 cases of the disease this summer . In August, the Hillsborough County Health Department issued a mosquito-borne illness alert due to reports of multiple locally acquired cases.

This cluster of locally spread cases is a stark reminder that a disease which most Americans associate with faraway tropical vacations is increasingly being caught at home.

Dengue is often called “breakbone fever,” and the nickname is earned. People who get sick typically develop a sudden high fever along with a pounding headache, pain behind the eyes and deep aches in the muscles, joints and bones. Many also feel nauseated, throw up or break out in a blotchy rash a few days in.

As an infectious diseases physician and tropical medicine specialist who directs a travel clinic, I see how easily dengue slips past both patients and doctors. In parts of the U.S. where the disease is still uncommon, it is easily mistaken for the flu or COVID-19, and that delay can be dangerous.

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Mosquitoes bite! 5 tips for making yourself less attractive to them

Dengue is not passed from person to person like a cold. It spreads through the bite of infected Aedes mosquitoes , mainly Aedes aegypti , a species commonly found in Florida. These mosquitoes thrive in warm cities and can breed in as little as a bottle capful of standing water. These mosquitoes bite during the day, not just at dusk.

The cycle is simple and hard to break: A mosquito bites an infected person, then bites someone else days later, giving them the virus.

Dengue is especially tricky because most infections cause no symptoms at all . Roughly 3 in 4 people who catch the virus never feel sick. For the 25% who are symptomatic, those symptoms don’t appear until four to 10 days after being bitten.

In addition, there are four different strains of the dengue virus, and surviving one gives you lasting protection against only that one. A second infection with a different type actually raises the odds of severe disease.

Most people suffer with dengue for a miserable week and then recover on their own. But about 1 in 20 patients progress to severe dengue , a life-threatening turn that tends to strike just as the fever breaks – often around days three to seven, when patients and their families may wrongly assume the worst is over.

In severe dengue, tiny blood vessels throughout the body start leaking fluid, blood pressure can crash and dangerous bleeding or organ damage can follow. Warning signs that someone is sliding into this phase include severe belly pain, repeated vomiting, bleeding from the gums or nose, extreme drowsiness or restlessness, and blood in vomit or stool.

Some groups face higher risk, including infants, pregnant women, adults over 65 and people with conditions like diabetes , obesity or kidney disease . Left untreated, severe dengue can kill up to 10% of patients. With prompt hospital care, that number drops below 1 in 100 – which is why recognizing it early matters so much.

A dengue vaccine exists, but it is not recommended for the average American traveler. The available shots are used only in select cases, such as children who live in high-transmission areas and have already had dengue once. So prevention still rests mostly on avoiding mosquito bites.

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The bugs are getting worse

There is no antiviral drug that cures dengue. Care is all about supporting the body while it fights the virus. For people well enough to stay home, that means rest, plenty of fluids and acetaminophen , commonly known in the U.S. by the brand name Tylenol, for fever and pain.

Patients who may have dengue must avoid aspirin, ibuprofen and other non-steroidal anti-inflammatory drugs . These drugs raise the risk of bleeding, which is already a danger with dengue.

Patients who develop more severe symptoms need to be admitted to the hospital, where doctors give carefully measured intravenous fluids and watch closely. Too little fluid and the patient can go into shock; too much and the lungs can flood.

Dengue is surging worldwide. The World Health Organization recorded more than 14 million cases in 2024 , its worst year on record, across some 100 countries. That’s a 2,600% increase from the more than 505,000 cases reported in 2000.

Warmer temperatures, rapid urban growth and global travel are all helping the mosquitoes – and the virus – expand into places where it has never been a problem before. South Asia, Southeast Asia and Latin America carry the heaviest burden, but the map is spreading north.

Why can’t we just get rid of mosquitoes? One fed-up community is trying

Most U.S. dengue cases are still picked up abroad. Travelers return home sick. In 2023 alone, the Centers for Disease Control and Prevention reported nearly 1,900 such travel-related cases .

But every infected traveler is a spark, and in warm states the tinder is already there.

In the U.S. territories, Puerto Rico and the U.S. Virgin Islands see the most cases by far. Florida has the highest risk among the 50 states, with Miami-Dade County recording more than 300 locally acquired dengue infections between 2010 and 2024. Local cases have also turned up in Texas, California, Arizona and Hawaii.

If you develop a sudden fever after traveling to a dengue-prone area, or after mosquito exposure in South Florida, see a doctor and mention where you’ve been. Rest, drink fluids and use acetaminophen – not ibuprofen or aspirin.

Most importantly, watch for the warning signs. Severe belly pain, repeated vomiting, bleeding or sudden drowsiness means get to an emergency room right away.

And to protect yourself and your neighbors: Use insect repellent, wear long sleeves and dump out any standing water in your yard where mosquitoes breed.

Republished under a Creative Commons license from The Conversation .

詹姆斯·加萨尼/美国疾病控制与预防中心/美联社

编者按：本文观点仅代表作者个人立场。CNN正在展示“对话”（The Conversation）的内容，“对话”是由记者和学者合作提供的新闻分析和评论平台。本文内容完全由“对话”制作。

佛罗里达州卫生部于 2026 年 9 月 18 日确认，一名老年妇女于 9 月 4 日死于登革热。

这是希尔斯伯勒县大规模登革热疫情中首例确诊死亡病例。今年夏天，该县已报告134例登革热病例。8月份，由于接到多起本地感染病例的报告，希尔斯伯勒县卫生部门发布了蚊媒疾病警报。

这一系列本地传播病例鲜明地提醒我们，这种大多数美国人认为与遥远热带度假有关的疾病，正越来越多地在国内传播。

登革热常被称为“断骨热”，这个绰号名副其实。患者通常会突然出现高烧，伴有剧烈头痛、眼后疼痛以及肌肉、关节和骨骼深处的酸痛。许多患者在几天后还会出现恶心、呕吐或斑驳的皮疹。

作为一名传染病医生和热带医学专家，同时也是一家旅行诊所的负责人，我亲眼目睹了登革热是如何轻易地被患者和医生忽视的。在美国一些登革热仍然不常见的地区，它很容易被误诊为流感或新冠肺炎，而这种延误可能会造成危险。

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蚊子会咬人！5个让你不那么招蚊子叮咬的小妙招

登革热不像普通感冒那样人传人，而是通过受感染的伊蚊叮咬传播，主要是埃及伊蚊，这种蚊子在佛罗里达州很常见。这些蚊子在温暖的城市里繁殖迅速，只需一瓶盖的积水就能繁殖。而且，这些蚊子白天也会叮咬，并非只在黄昏时分。

传播循环很简单，也很难打破：蚊子叮咬感染者，几天后再叮咬其他人，将病毒传染给他们。

登革热尤其棘手，因为大多数感染者根本没有任何症状。大约四分之三的感染者从未感到不适。而对于出现症状的25%的人来说，这些症状通常在被叮咬后4到10天才会出现。

此外，登革病毒有四种不同的毒株，感染其中一种毒株后只能获得针对该毒株的持久保护。如果再次感染其他毒株，反而会增加患重症的风险。

大多数人感染登革热后会痛苦地挣扎一周，然后自行康复。但大约五分之一的患者会发展成重症登革热，这种危及生命的病情往往在退烧后出现——通常在第三到第七天左右，此时患者及其家人可能会错误地认为最糟糕的时期已经过去。

在重症登革热中，全身的微小血管开始渗漏液体，血压骤降，并可能引发危险的出血或器官损伤。进入重症阶段的预警信号包括剧烈腹痛、反复呕吐、牙龈或鼻腔出血、极度嗜睡或烦躁不安，以及呕血或便血。

某些人群面临更高的风险，包括婴幼儿、孕妇、65岁以上的老年人以及患有糖尿病、肥胖症或肾病等疾病的人。如果不及时治疗，重症登革热的死亡率可高达10%。如果及时就医，死亡率可降至1%以下——这就是为什么早期识别登革热如此重要的原因。

目前已有登革热疫苗，但并不建议普通美国旅行者接种。现有疫苗仅适用于特定情况，例如居住在高传播地区且曾感染过登革热的儿童。因此，预防登革热的主要手段仍然是避免蚊虫叮咬。

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这些漏洞越来越严重了。

目前尚无抗病毒药物可以治愈登革热。治疗的关键在于支持身体对抗病毒。对于身体状况允许居家隔离的人来说，这意味着休息、多喝水，以及服用对乙酰氨基酚（在美国通常以泰诺的品牌名销售），以缓解发烧和疼痛。

疑似登革热患者必须避免服用阿司匹林、布洛芬和其他非甾体类抗炎药。这些药物会增加出血风险，而出血本身就是登革热的危险因素。

出现更严重症状的患者需要住院治疗，医生会通过静脉输液精确控制输液量并密切观察病情。输液过少会导致患者休克，输液过多则会导致肺部积液。

登革热在全球范围内肆虐。世界卫生组织记录显示，2024年登革热病例将超过1400万例，这将是该组织有记录以来最严重的一年，病例遍及约100个国家。与2000年报告的50.5万多例病例相比，这一数字增长了2600%。

气温升高、城市快速发展和全球旅行都在助长蚊子及其携带的病毒向以前从未出现过问题的地区扩散。南亚、东南亚和拉丁美洲受影响最为严重，但疫情正在向北蔓延。

为什么我们不能彻底消灭蚊子？一个不堪其扰的社区正在尝试

美国大多数登革热病例仍然是在国外感染的。旅行者回国后患病。仅在2023年，美国疾病控制与预防中心就报告了近1900例此类与旅行相​​关的病例。

但每个受感染的旅行者都是一个火星，而在气候温暖的州，火星早已埋下了隐患。

在美国属地中，波多黎各和美属维尔京群岛的病例数量最多。佛罗里达州是全美50个州中风险最高的，迈阿密-戴德县在2010年至2024年间记录了300多例本地感染的登革热病例。德克萨斯州、加利福尼亚州、亚利桑那州和夏威夷州也出现了本地病例。

如果您前往登革热流行地区旅行后，或在南佛罗里达被蚊子叮咬后出现突发发烧，请就医并告知医生您的旅行史。休息、多喝水，并服用对乙酰氨基酚——切勿服用布洛芬或阿司匹林。

最重要的是，注意观察预警信号。剧烈腹痛、反复呕吐、出血或突然嗜睡都意味着需要立即前往急诊室。

为了保护自己和邻居：使用驱蚊剂，穿长袖衣服，并倒掉院子里蚊子滋生的积水。

本文根据知识共享许可协议从 The Conversation 转载。