[BUENOS AIRES, SciDev.Net] A new international platform now enables monthly monitoring of dengue trends across 88 countries, aiming to support the global response to a disease that reached historic highs in 2024.

The mosquito-borne disease is now endemic in more than 100 countries, with around half the world’s population is at risk, according to the World Health Organization (WHO). Concentrated around tropical regions, Latin America has the highest prevalence, with even high-altitude cities experiencing record outbreaks.

The Global Dengue Observatory, developed by the London School of Hygiene & Tropical Medicine (LSHTM), draws on data from the WHO and LSHTM’s OpenDengue Project to give researchers, policymakers and the public a global picture of dengue activity.

“[The Global Dengue Observatory] could enable those managing programmes, departments and ministries to make better decisions, particularly when the figures show a worrying or escalating situation.”
Tomás Orduna, infectious diseases specialist, Muñiz hospital, Buenos Aires

Researchers say it will strengthen surveillance of the viral disease and support faster, better-informed public health decisions to control it.

Bridging delays

A major challenge in understanding dengue’s true global burden is the delay in reporting cases.

Katie Milligan Susong, an infectious diseases researcher at LSHTM, told SciDev.Net: “When a dengue case occurs, it doesn’t appear in international databases immediately. The case must be identified, reported to local health authorities, aggregated at the national level, and then shared with international bodies like the WHO.”

This process can take days or even months, meaning the most recent figures often underestimate the real number of infections, she explained.

Compounding the issue, countries report dengue data at different intervals and with varying surveillance capacities.

“Harmonising that into a single coherent picture is a constant challenge,” added Milligan.

“In Latin America the data exists but arrives late. In much of Africa, routine dengue surveillance is still developing.”

To address these gaps, LSHTM researchers designed algorithms that estimate the likely final number of cases based on reporting delays and missing data. For now, these corrections apply only to Latin America, as the region most affected by dengue.

The platform currently tracks countries that reported at least five cases per month over the past five seasons. As such it excludes countries like France and Italy, where the disease is emerging but case numbers are low.

Outbreak control

According to Doris Kemunto Nyamwaya, an LSHTM expert on Africa who was not involved in the project, the platform could significantly strengthen surveillance on the continent.

“The Global Dengue Observatory has the potential to transform this landscape by providing accessible, real-time insights that can help countries strengthen surveillance, anticipate outbreaks, and shape more effective dengue control policies,” she told SciDev.Net.

Similarly, Tomás Orduna, an infectious diseases specialist at the Hospital Muñiz in Buenos Aires, believes the observatory could help authorities respond more quickly when warning signs emerge.

“It could enable those managing programmes, departments and ministries to make better decisions, particularly when the figures show a worrying or escalating situation,” he said.

“Up-to-date knowledge of what is happening in a particular place is also valuable for those travelling from one country to another,” added Orduna, who is also a former president of the Latin American Society for Travel Medicine.

He suggests that additional features on the platform to facilitate regional comparisons could help neighbouring countries coordinate preventive measures.

Dengue on the move

By the end of February, the observatory had recorded 314,783 cumulative dengue cases worldwide, including 235,075 in South America.

Although these numbers are below the average for the previous five years, dengue remains a major global health threat. The number of reported cases has risen dramatically in recent decades—from 505,430 in 2000 to 14.6 million in 2024, the highest global total on record, according to the WHO.

The UN agency attributes this surge to several factors, including expanding mosquito habitats, climate change, weak health systems and political instability in some regions.

A study published in Virology Journal highlights how these dynamics are pushing dengue into new environments. In 2024, the Bolivian city of Cochabamba—located 2,550 metres above sea level—experienced its largest outbreak to date.

This represents an exceptional instance of the virus circulating at high altitudes. Historically confined to low-lying tropical areas, dengue cases in the city rose from around 130 before 2018 to 1,400 in 2019, and more than 8,000 in 2024.

Researchers attribute this expansion partly to the spread of the mosquito vector Aedes aegypti, whose geographical range is increasing as temperatures rise. In Cochabamba, spring 2023 and the autumn and summer of 2024 recorded the highest temperatures on record.

Despite warming temperatures, the WHO reported 4.4 million dengue cases in Latin America in 2025, representing a 66 per cent drop from the previous year’s record. The decline is largely explained by short-term immunity following the massive outbreaks of 2024, which temporarily reduced the number of people susceptible to infection.

However, some countries remain exceptions. Cuba, Guyana and Suriname continue to report high infection levels.

Milligan says the surge in Cuba may be linked to a shift in the dominant dengue serotype, combined with a fuel shortage that disrupted fumigation programmes, waste collection and water distribution. Water shortages often lead affected communities to collect water in open containers, creating ideal breeding sites for Aedes mosquitoes.

Meanwhile, Guyana and Suriname form a coastal corridor with a shared tropical ecology and highly connected populations, while historically low case numbers mean their populations have relatively low immunity.

These localised spikes highlight why real-time monitoring is essential, Milligan says, noting that regional averages can mask dangerous local increases.

This piece was produced by SciDev.Net’s Latin America and Caribbean desk.