For a long time, malaria, dengue, and Zika were filed under “somewhere else.” In the U.S. and Europe most people encountered them in a textbook or a travel clinic and nowhere else. That is changing.
Climate shifts, international travel, and the sheer resilience of mosquitoes like Aedes aegypti have pushed these infections north. They are turning up in the southern U.S. and in parts of Europe now. Calling them tropical diseases is starting to be inaccurate.
Sanjay Gupta and Timothy Winegard made the scale of it plain in a CNN interview: mosquitoes kill more people than any other animal, and more than 700,000 people die each year from what they carry. That number is difficult to sit with.
The viral illnesses get most of the attention. Dengue, Zika, chikungunya, and West Nile are the familiar names. Dengue was once almost entirely tropical and now appears in Florida and Europe. Zika made headlines for the birth defects it caused. Chikungunya is remembered by anyone who has had it for the joint pain. West Nile is simply established across much of the U.S. at this point.
Malaria is a different animal, caused by protozoa rather than a virus. Most people still think of it as an African disease. Yet there have been locally acquired cases in the U.S. recently. Warm temperatures and standing water are all the transmission cycle really needs.
Parasitic worms belong in the conversation too. Lymphatic filariasis is still overwhelmingly tropical, but the movement of people and goods makes expansion more plausible than it used to be.
Prevention is unglamorous and effective. Emptying standing water around a house does more than people expect. Repellent, intact window screens, and long sleeves cut exposure. For travelers, treated bed nets and the right vaccines, yellow fever among them, still carry the load.
Clinicians need to reframe how we think about these illnesses. They are not filed under travel medicine anymore. With malaria reappearing in Florida and Texas, recognizing early symptoms and pushing prevention falls to us. I have had patients look genuinely surprised when I brought up insect repellent on a video visit for something unrelated. It struck them as beside the point. That reaction is the thing that has to change.
Mosquitoes are not slowing down, and the illnesses they carry keep moving closer to where our patients actually live. The questions are coming. We should have answers ready.
References
Gupta S, Winegard T. CNN interview on mosquito-borne disease, 2023.
Centers for Disease Control and Prevention. Malaria in the United States, 2023.
World Health Organization. Mosquito-borne diseases fact sheet, 2023.
Watch: Dr. Sanjay Gupta & Timothy Winegard discuss how to avoid mosquito bites and the diseases they carry.
Board Certified in Obesity Medicine and Family Medicine
This blog is for educational purposes only and does not constitute individual medical advice. Always consult your own physician before making changes to your health, medications, or treatment plan.
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