American Samoa's dengue outbreak has slowed, with no all-clear yet.

Are there mosquitoes in American Samoa? Yes, including the day-biting Aedes behind a dengue outbreak declared in early July 2025, which had slowed to a few cases a week by August 2026. There is no malaria. This briefing covers the US territory, which is separate from independent Samoa and its own dengue outbreak.

The dengue outbreak since July 2025

American Samoa's Department of Health declared a dengue outbreak and public health emergency in early July 2025. A CDC conference abstract called it the territory's first outbreak since 2018. It started with imported cases, four of them linked to travel to Samoa, and by October 2025 nearly all new cases were caught locally. Department of Health figures, as summarized by the French travel-health site MesVaccins, show monthly cases peaking at about 175 in January 2026, then falling to two or three a week in late July and early August. By mid-August 2026, laboratory-confirmed cases had passed 1,000, most of them in children and teenagers.

Dengue doesn't leave between outbreaks. The CDC classifies transmission in American Samoa as frequent or continuous, and a 2023 survey of schoolchildren, published in CDC's weekly MMWR in 2024, found that 60% of 9- to 16-year-olds had already been infected. The territory has no CDC travel notice and isn't on the CDC's global dengue list. The emergency was still in effect in mid-April 2026, and the latest published reports don't show it declared over. The wet season, which tends to run from about November to April, took in the outbreak's January peak, so check the Department of Health's latest update, and whether cases rose again with the rains, the week before you fly.

Aedes mosquitoes bite in daylight, with peaks after sunrise and in the late afternoon. Put repellent on over sunscreen in the morning, again after swimming and before sunset. Our dengue & Zika routine has the full schedule. The CDC also lists Zika, with no current outbreak, so if you're pregnant, talk to a healthcare provider before the trip.

Yards, villages and the park's trails

Two day-biting mosquitoes share the islands, and they bite in different places. Aedes polynesiensis, the more common one and a suspected dengue carrier, feeds mostly outdoors. In a 2017 CDC study, 83% of them were caught outside homes, while 90% of the Aedes aegypti were caught inside. Most bites tend to come outdoors, on village visits, in gardens, on the beach and on the rainforest trails of the National Park of American Samoa above Pago Pago. Put repellent on at the trailhead for Mount Alava and hike in long, light sleeves and pants. Indoors, a screened or air-conditioned room helps keep aegypti away.

The CDC also lists leptospirosis, which isn't spread by insects. Avoid floodwater and wading in fresh water or mud.

Where you're going

How Tutuila and the Manu'a Islands compare for a December–April trip.

Adding a neighbor? Our Samoa, Tonga and Fiji briefings cover dengue on those islands.

What travelers report

Paraphrased from a TripAdvisor review of the National Park and linked so you can read it in full. It isn't dated. For the disease list, rely on the CDC's American Samoa page, which lists dengue and Zika and no chikungunya.

• National Park of American Samoa, Tutuila

  A reviewer who hiked in the park called the scenery amazing and warned that the local mosquitoes carry chikungunya, dengue and Zika. TripAdvisor ↗

One rule outlasts the trip. Any fever during or after your trip means a doctor visit, and you tell them you were in American Samoa, especially if it comes with headache, rash or body aches in the two weeks after you get home. Our after-bites guide covers the warning signs.

Traveler questions