Dengue in Nepal: Yearly Cases, Deaths & District-Wise Data

Dengue is a viral, mosquito-borne infection that has moved from a rare, imported illness to one of Nepal's most predictable public-health emergencies. The first dengue case in the country was documented in 2004 in a foreign traveller, and the first confirmed local (indigenous) outbreak followed in 2006 in several lowland urban areas of the Tarai. Since then, larger and more frequent outbreaks have struck in 2010, 2013, 2016, 2019, 2022 and 2023, with the disease now reported almost every monsoon from all seven provinces.

The single worst year to date was 2022, when Nepal recorded roughly 54,784 dengue cases and 88 deaths, with infections reaching every one of the country's 77 districts. That year eclipsed the previous record of 17,992 cases in 2019 and marked the moment dengue became a genuinely nationwide, rather than mainly Tarai, problem. The Epidemiology and Disease Control Division (EDCD) under the Department of Health Services (DoHS), Ministry of Health and Population (MoHP), coordinates surveillance and publishes the situation reports on which this page draws.

Reported figures are best read as a floor, not a ceiling. Health experts estimate that around 90 percent of dengue infections are asymptomatic or mild, so many cases never reach a laboratory, and some deaths go unrecorded. The numbers below are therefore laboratory-confirmed or clinically reported counts from EDCD, useful for tracking trends and comparing years, but they understate the true burden of transmission in any given season.

The year-by-year record shows how sharply dengue can swing between seasons, driven by rainfall, temperature, the circulating serotype and the level of population immunity. The 2019 outbreak was, at the time, the largest ever, with 17,992 cases from 68 districts and 6 deaths. During the COVID-19 pandemic years of 2020 and 2021, reported dengue fell steeply to a few hundred cases nationwide, partly a real drop and partly a reflection of reduced testing and movement.

Transmission then exploded. In 2022 Nepal logged about 54,784 cases and 88 deaths, its worst outbreak on record and the deadliest, with a case-fatality rate near 0.16 percent. In 2023 the burden remained very high at roughly 51,243 reported cases but with far fewer confirmed deaths, about 20, as clinical management improved. In 2024 cases eased to around 41,865 with 15 deaths, and by late 2025 the season was much lighter, with about 8,109 cases and 6 deaths reported as of early December, even though the virus still reached 76 of 77 districts.

The broad pattern is one of a high but fluctuating plateau since 2022, punctuated by lighter years. Because immunity to a given serotype builds up after a big outbreak, a record year is often followed by a quieter one, only for cases to rebound when a different serotype spreads. Readers should treat single-year totals as provisional EDCD counts that can be revised as late reports and death audits are completed.

Where dengue hits hardest has shifted year to year. In the record 2022 outbreak, Bagmati Province and the Kathmandu Valley bore the brunt: Bagmati accounted for roughly 78 percent of national cases, and Kathmandu district alone reported around 14,000 cases, followed by Lalitpur and Bhaktapur. This urban concentration overwhelmed hospitals in the capital and showed that dengue was no longer confined to the hot lowland Tarai.

The geography then spread out. In 2024, Gandaki Province reported the highest number of cases, about 15,806, and by far the highest incidence rate at roughly 654.8 cases per 100,000 people, ahead of Bagmati and Koshi provinces. Pokhara and other mid-hill towns have become recurring hotspots. Eastern districts in Koshi Province, and Tarai districts such as Sunsari, Jhapa, Chitwan (Bagmati) and Kaski (Gandaki), also feature repeatedly among the worst-affected.

Perhaps the most striking trend is dengue's climb into the high hills and mountains. In 2024 and 2025, all mountain districts except Dolpa reported dengue, a distribution that would have been almost unthinkable a decade earlier. Because outbreaks are so district-dependent, the province and district ranking should always be read against the specific EDCD situation report and cut-off date it comes from, rather than assumed to be fixed from year to year.

Dengue in Nepal follows a clear seasonal rhythm tied to the monsoon. Cases typically begin rising in July, just after the pre-monsoon and monsoon rains (roughly June to September) fill artificial containers and create abundant mosquito breeding sites. The curve then climbs through August and peaks in the post-monsoon window of September and October, when warm temperatures and residual standing water are ideal for the Aedes vector.

Transmission usually falls away with the onset of winter, as temperatures drop below the range in which the mosquito and the virus can complete their cycle; the coldest months are largely dengue-free in most of the country. This is why prevention campaigns, source reduction and hospital preparedness are concentrated from June through November, before and during the peak.

That seasonal window, however, has been lengthening and shifting to higher elevations as the climate warms. Recent seasons have seen cases persist later into the year, and thermal-suitability studies point to a growing risk across Nepal's mid-hills. Warmer, wetter conditions extend the period in which Aedes mosquitoes can survive and breed, which is one reason outbreaks now reach towns and districts that were historically too cool for sustained transmission.

Dengue is caused by four closely related but distinct virus serotypes: DENV-1, DENV-2, DENV-3 and DENV-4. Infection with one serotype gives lifelong immunity to that serotype but only short-term, partial protection against the others. All four serotypes have been detected in Nepal since serotyping began around the 2006 outbreak, and their changing dominance helps explain why big years and quiet years alternate.

The predominant serotype has rotated over time: DENV-1 was common in the 2010 and 2016 outbreaks, DENV-2 dominated in 2013 and 2019, and the record 2022 outbreak was driven mainly by DENV-1 and DENV-3 co-circulating, with DENV-2 also present. This co-circulation of multiple serotypes in the same season is a warning sign, because a second infection with a different serotype substantially raises the risk of severe dengue (dengue haemorrhagic fever and dengue shock syndrome).

For a population like Nepal's, where immunity is now spread unevenly across four serotypes, this means future outbreaks are hard to predict and can be severe even in people who have had dengue before. It also shapes vaccine policy: newer dengue vaccines target all four serotypes, but prior-infection status and serotype circulation both matter for how and where they might be deployed.

Dengue is spread by the bite of infected female mosquitoes of two species: Aedes aegypti and Aedes albopictus. Aedes aegypti, the more efficient vector, was first formally recorded in Nepal around 2009, close to the country's first dengue outbreak, while Aedes albopictus is more widespread in hilly and forested areas. Both bite mainly during the day, especially early morning and late afternoon, which limits the protective value of night-time bed nets.

These mosquitoes breed in small collections of clean, standing water in and around homes rather than in dirty drains or large water bodies. Typical breeding sites include discarded tyres, plastic containers, flower pots and plant saucers, water-storage drums, blocked gutters, coolers and construction pits. Because the breeding habitat is largely man-made, community-level source reduction, emptying, covering and cleaning water containers, is the single most effective control measure.

Climate change is a major driver of dengue's spread into new territory. As Nepal's mid-hills and even mountain valleys warm, they increasingly meet the temperature thresholds Aedes mosquitoes need to survive, breed and transmit the virus. This helps explain why cities such as Pokhara and hill districts that once saw little dengue now record large outbreaks, and why nearly all mountain districts reported cases in recent seasons.

Classic dengue symptoms usually appear 4 to 10 days after an infective bite and include sudden high fever (jaro), severe headache, pain behind the eyes, intense muscle and joint pain, nausea, vomiting and a skin rash. The joint and bone pain is so characteristic that dengue is often called 'breakbone fever'; in Nepali it is commonly referred to as dengue jaro. Most people recover within a week or two with rest and fluids.

A minority progress to severe dengue, which is a medical emergency. The critical warning signs, which typically appear as the fever falls, include severe abdominal pain, persistent vomiting, bleeding from the gums or nose, blood in vomit or stool, extreme fatigue or restlessness, and fast, difficult breathing. Anyone with these signs needs urgent hospital care. There is no specific antiviral cure for dengue; treatment is supportive, with fluids and paracetamol, and patients should avoid aspirin and other NSAIDs, which raise the risk of bleeding.

Because there is no widely deployed dengue vaccine in Nepal and treatment is only supportive, prevention centres on stopping mosquito breeding and avoiding bites. During the monsoon and post-monsoon months, households and communities are urged to run 'search and destroy' drives against breeding sites, use repellents and screens, and wear protective clothing, especially in the daytime hours when Aedes mosquitoes are active.