Dengue Outbreak 2026: Cases by Country (Map)

Dengue fever is surging across the Americas again. The Pan American Health Organization (PAHO) has declared a Grade-3 multi-country outbreak, its highest level of emergency response, after the Region of the Americas logged more than 1.1 million suspected dengue cases and 266 deaths in the first 20 weeks of 2026. Spread by the Aedes aegypti mosquito, dengue is now a year-round, multi-continent threat, and 2026 is shaping up as another heavy year even as it falls short of 2025’s record.

It is not just the Americas. The European CDC counted dengue in 78 countries and territories worldwide in the first three months of 2026 alone. The map below shows the global picture, with the Americas as the clear epicenter.

What is dengue, and how dangerous is it?

Dengue is a viral infection spread to people through the bite of an infected Aedes mosquito, mainly Aedes aegypti. It does not spread directly from person to person. There are four closely related types of the virus (DENV-1 to DENV-4), and recovering from one gives only short-term protection against the others, which is why people can catch dengue more than once.

Most infections are mild or cause no symptoms at all. When symptoms do appear, usually 4 to 10 days after a bite, they typically include:

• High fever (often 40°C / 104°F)
• Severe headache and pain behind the eyes
• Intense muscle, bone and joint pain, which earns dengue its nickname “breakbone fever”
• Nausea, vomiting, swollen glands and a skin rash

Most people recover within one to two weeks. The danger comes from severe dengue, which develops in a small share of cases (roughly 1 in 20 symptomatic patients). Warning signs such as severe belly pain, persistent vomiting, bleeding gums and rapid breathing can signal plasma leakage, internal bleeding and organ failure. Severe dengue is a medical emergency that can kill within hours if untreated, and the risk is higher on a second infection with a different serotype.

There is no specific antiviral cure; treatment is supportive, mainly fluids and careful monitoring, which is why early care matters so much. With prompt hospital treatment the case fatality rate is well under 1%, but it climbs sharply where health systems are overwhelmed. Two dengue vaccines now exist, and the best protection remains avoiding mosquito bites and clearing the standing water where the mosquitoes breed. The World Health Organization estimates that about half the world’s population now lives at risk of dengue, with up to 400 million infections a year.

The Americas are the epicenter

Through epidemiological week 20 of 2026, PAHO recorded 1,105,019 suspected cases across 44 reporting countries and territories, of which about 27% were laboratory-confirmed. Brazil alone accounts for roughly 811,000 cases, about three-quarters of the regional total, and is the only country with all four dengue serotypes circulating simultaneously, which raises the risk of severe disease.

Adjusted for population, the picture shifts. The map below shows reported cases per 100,000 people. Bolivia (389 per 100,000) edges out Brazil (383) for the most intense outbreak among the larger nations, with Panama and Paraguay also running high.

Beyond the Americas: Asia and the Pacific

Dengue is endemic across much of tropical Asia and the Pacific, where transmission runs year-round. In early 2026, Vietnam led the region with over 27,000 cases, roughly double its 2025 pace, with most cases in the south. Malaysia reported more than 11,000 cases on a trend similar to last year. In South Asia, Sri Lanka recorded about 13,700 cases, ahead of India (around 6,600) and Bangladesh (about 1,900).

Some of the sharpest increases came from smaller nations. Timor-Leste saw a roughly tenfold jump compared with the same period in 2025, and Cambodia tripled its case count. The Maldives also reported rising numbers, while Singapore and China stayed at relatively low levels.

Africa: an expanding frontier

Dengue is harder to track in Africa, where surveillance is thinner and the disease is often confused with malaria, so reported numbers almost certainly understate the true burden. According to the Africa CDC, the largest 2026 outbreak so far has been in Mali, with about 590 cases, followed by smaller numbers in Senegal, Mauritania and the Central African Republic. Public-health agencies warn that dengue’s range is steadily expanding across West and East Africa as the Aedes mosquito spreads.

Dengue cases by country worldwide

The table below brings together the affected countries across all regions, ranked by reported 2026 cases. Sort or filter by region to compare. Americas figures are cumulative to epidemiological week 20 (PAHO); Asia, Pacific and Africa figures are early-2026 snapshots (WHO, ECDC and Africa CDC) and are not directly comparable across regions.

Big, but far below 2025’s record

For all its scale, the 2026 outbreak in the Americas is actually 64% smaller than the same period in 2025 and 70% below the five-year average. That is because 2024 and 2025 were extraordinary: the Americas shattered all previous records, driven by an intense El Niño, high temperatures and the spread of the mosquito into new areas. The 2026 numbers are a partial retreat from that peak, not a sign that dengue is going away.

Why dengue keeps surging

The long-term trend is upward. A warming climate is extending the range and active season of the Aedes aegypti and Aedes albopictus mosquitoes that carry the virus, pushing dengue into higher altitudes and new countries. Rapid, unplanned urbanization creates ideal breeding sites in standing water, and increased global travel moves the virus and its four serotypes between regions. Because catching one serotype offers little protection against the others, large populations remain vulnerable year after year.

The bottom line

The 2026 dengue outbreak is a genuinely global event, with the Americas, led by Brazil and Bolivia, at its center and active transmission stretching from Vietnam to Mali. Cases are down sharply from 2025’s catastrophic record, but with more than a million infections already logged in the Americas by mid-year, dengue remains one of the fastest-spreading mosquito-borne diseases on the planet.

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