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Dengue spike fuels concerns of public health threat with over five million cases reported in over 80 countries in 2023: WHO
This year's surprising spike in dengue infections globally in 2023 represents a potentially high public health threat, the UN World Health Organization (WHO) said on Friday.
The warning came as WHO reported more than five million dengue infections and 5,000 deaths from the disease worldwide this year.
Briefing journalists on Friday at the UN in Geneva, Dr. Diana Rojas Alvarez, WHO Team Lead on Arboviruses, said that the threat required “the maximal attention and response from all levels” of the UN health agency to support countries in controlling current dengue outbreaks and prepare for the upcoming dengue season.
Dengue is the most common viral infection transmitted to humans bitten by infected mosquitoes. It is mostly found in urban areas within tropical and sub-tropical climates.
The rise in the number of reported cases of dengue in more countries is explained by the fact that infected mosquitoes now thrive in more countries because of global warming associated with rising emissions.
“Climate change has an impact in dengue transmission because it increases rainfall, humidity and temperature,” said Dr. Alvarez. “These mosquitoes are very sensitive to temperature.”
Although four billion people are at risk from dengue, most of those infected are symptom-free and usually recover within one to two weeks.
However, severe dengue infections are marked by shock, severe bleeding or severe organ impairment, according to WHO.
It also highlighted that these dangerous symptoms often start “after the fever has gone away”, catching carers and medical professionals unawares. Warning signs to look out for include intense abdominal pain, persistent vomiting, bleeding gums, fluid accumulation, lethargy, restlessness and liver enlargement.
As there is no specific treatment for dengue, early detection and access to proper medical care is crucial, to lower the probability to die due to severe dengue.
“Since the beginning of this year, over five million cases and about 5,000 deaths of dengue have been reported worldwide and close to 80 per cent of those cases have been reported in the Americas, followed by Southeast Asia and the Western Pacific,” reported Dr. Alvarez. She added that “it is also concerning that dengue outbreaks are occurring in fragile and conflict-affected countries in the eastern Mediterranean region such as Afghanistan, Pakistan, Sudan, Somalia and Yemen.
The global prevalence of mosquitoes has changed in the last few years owing to the 2023 El Niño phenomenon which accentuated the effects of global warming temperatures and climate change, WHO said.
Both factors are associated with previously dengue-free countries such as France, Italy and Spain reporting cases of infections that originated at home – so-called autochthonous transmission - rather than abroad. The disease vector is the Aedes aegypti mosquito, which is widely distributed in Europe and also more commonly known as the “tiger mosquito”.
“Usually, Europe reports imported cases from the Americas, from the Western Pacific, from the endemic regions”, said Dr. Alvarez. “But this year we saw limited clusters of autochthonous transmission. As we know, the summers are getting warmer”.
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STORY: Global dengue situation – WHO
TRT: 2:48”
SOURCE: UNTV CH
LANGUAGE: ENGLISH
ASPECT RATIO: 16:9
DATELINE: 22 December 2023 - GENEVA, SWITZERLAND
SHOTLIST
- Exterior wide shot: UN building with UN flag, UN Geneva.
- SOUNDBITE (ENGLISH) – Dr. Diana Rojas Alvarez, Team Lead on Arboviruses at the WHO: “WHO has assessed the risk of dengue as high globally. What it means: it requires the maximal attention and response from all levels of the organization to support countries around the world, controlling the current dengue outbreaks and also preparing for the countries to respond to the upcoming dengue season.”
- Cutaway: Medium shot, UN building with UN flag
- SOUNDBITE (ENGLISH) – Dr. Diana Rojas Alvarez, Team Lead on Arboviruses at the WHO: “The main drivers of dengue transmission are mostly social and environmental factors. So, unplanned urbanization, population growth and other factors that are related with the globalization process are part of the transmission dynamics of dengue. Climate change has an impact in dengue transmission because it increases rainfall, humidity and temperature. So, these mosquitoes are very sensitive to temperature.”
- Cutaway: Medium shot UN entrance at Place des Nations
- SOUNDBITE (ENGLISH) – Dr. Diana Rojas Alvarez, Team Lead on Arboviruses at the WHO: “Mosquitoes can thrive in more countries because of increasing temperatures due to climate change many more countries are reporting cases. About four billion people are at risk of becoming infected with dengue virus, but most of the people won't get any symptoms. But for those who do, they will recover within 1 to 2 weeks.”
- Cutaway: Wide shot, Ariana Park at the UN Geneva
- SOUNDBITE (ENGLISH) – Dr. Diana Rojas Alvarez, Team Lead on Arboviruses at the WHO: “Since the beginning of this year, over five million cases and about 5,000 deaths of dengue have been reported worldwide and close to 80 per cent of those cases have been reported in the Americas, followed by Southeast Asia and the Western Pacific. The distribution of the mosquitoes that transmit dengue and other mosquito borne viruses have changed in the last few years due to several social and environmental factors.”
- Cutaway: Wide shot, Ariana Park at the UN Geneva
- SOUNDBITE (ENGLISH) – Dr. Diana Rojas Alvarez, Team Lead on Arboviruses at the WHO: “It is also concerning that dengue outbreaks are occurring in fragile and conflict-affected countries in the eastern Mediterranean region such as Afghanistan, Pakistan, Sudan, Somalia, Yemen.”
- Cutaway: Medium shot, UN building with UN flag
- SOUNDBITE (ENGLISH) – Dr. Diana Rojas Alvarez, Team Lead on Arboviruses at the WHO: “Usually Europe reports imported cases from the Americas, from the Western Pacific, from the endemic regions. But this year we saw limited clusters of autochthonous transmission. As we know, the summers are getting warmer and there are two main vectors of this virus. One is Aedes aegypti mosquito which is widely distributed in Europe and it is called the tiger mosquito.”
- Cutaway: Wide shot, UN building with flag alley
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As world’s water reserves change, countries must prepare for a new reality: WMO
New data showing that rivers were at their lowest level for decades last year provides further evidence that the climate crisis is real and countries must act immediately to protect themselves from the increasing threat to communities and livelihoods, the UN World Meteorological Organization (WMO) said on Thursday.
The key findings from WMO’s State of Global Water Resources 2025 report covering the hydrological cycle and extreme events in the five-year period to last year:
- 2025 was one of driest years for river discharge in 35 years
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- Water storage on Earth’s land surface has decreased in past decade
- Widespread glacier loss across all regions for fourth consecutive year
- Asia and Africa are regions most affected by water-related disasters
- Water data availability has improved, but gaps remain in hard-hit areas
Highlighting the long-term decline in the Earth’s freshwater storage and glacier melt, WMO Secretary-General Celeste Saulo explained that the planet’s water reserves used to act as a planetary “savings account” that absorbed the occasional dry season, avoiding a water crisis. “One of the central stories of the 2025 report is what is happening to that savings account? And the simple answer is that we are depleting it,” she told journalists in Geneva.
Groundwater reserves are equally stretched and have been in decline since 2014, WMO’s report states, with nearly two-thirds of monitored wells worldwide showing levels lower than the historical norm and indicating a shift “further toward deficit…not recovery”.
“At the same time, we are seeing more water-related disasters,” Ms. Saulo said, while also stressing that the currently strengthening El Niño “will increase the risk of drought in some areas, and flooding in others”.
Glaciers disappearing
In 2025, for the fourth consecutive year, every major glaciated region on Earth lost ice mass, leading to short-term hazards including floods and long-term water insecurity, according to WMO.
Responding to a question about whether the changing global water cycle might have contributed to the deadly Nepal-China flooding disaster, Ms. Saulo explained that melting ice and rock was just one factor in the chain of events that ultimately sent a massive and deadly wall of water and debris downstream on 26 August, killing at least 1,367 people.
“You asked if it could happen again? Absolutely; the problem in this region is that there’s 63,700 glaciers at the last count,” she told a Press Conference in Geneva. “Even if you’re looking with remote sensing with satellites at these glaciers, you might see some faults, you might see some slight shifting, that does not mean necessarily catastrophic collapse. So, in order to plan for this, it’s very, very difficult. But the international community is looking very hard at ways in which we can bring people together to solve some of these monitoring issues.”
Data indicates that glaciers shrank between 2023 and 2025 with cumulative losses of 1,400 gigatonnes of water – or about one third of annual fresh water needs.
Every major glacier region on Earth lost ice for the fourth consecutive year.
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“After this point, the glacier gives less meltwater each year simply because there is less ice left to melt. That matters for every community downstream that relies on water during hot, dry summers,” he explained.
Narelle van der Wel, WMO’s Head of Cryosphere Monitoring, Predictions and Services, stressed that while some further glacier loss is unavoidable, the eventual scale of the decline is not predetermined.
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Preparing for moving baselines
The report does not attribute every observed change to climate change alone. WMO says pressure on water resources and natural variability also contribute.
Mr. Jenkinson said governments need to prepare for “moving baselines” as historical patterns become less reliable.
“The situation 30 years ago is not where we are today,” he said. Countries, he added, need to prepare “for those changes that have really already arrived”.
ends
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