The warning came as WHO reported more than five million dengue infections and 5,000 deaths from the disease worldwide this year.
Briefing journalists at the UN in Geneva, Dr. Diana Rojas Alvarez, WHO team leader for arboviruses, said the threat required “maximum attention and response from all levels” of the UN health agency to support countries in controlling current dengue outbreaks and preparing for the coming dengue season.
Global warming infection boost
Dengue is the most common viral infection transmitted to humans who are bitten by infected mosquitoes. It is mostly found in urban areas within tropical and subtropical climates.
The increase in the number of reported cases of dengue in several countries is explained by the fact that infected mosquitoes are now thriving in several countries due to global warming associated with increasing emissions.
“Climate change has an impact on 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 of dengue, most of those infected are symptom-free and usually recover within one to two weeks.
However, severe dengue infections are characterized by shock, severe bleeding or severe organ failure, according to the WHO.
It also highlighted that these dangerous symptoms often start “after the fever has gone”, catching carers and doctors unaware. Warning signs to look out for include intense abdominal pain, persistent vomiting, bleeding gums, fluid retention, lethargy, restlessness and liver enlargement.
Since there is no specific treatment for dengue, early detection and access to proper medical care are essential to reduce the likelihood of dying from severe dengue.
“Since the beginning of this year, over five million cases and about 5,000 deaths from dengue have been reported worldwide, and close to 80 percent of these cases have been reported in the Americas, followed by Southeast Asia and the Western Pacific,” reported Dr. Alvarez.
She added that “it is also worrying 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 distribution of mosquitoes has changed in the past few years due to the 2023 El Niño phenomenon, which highlighted the effects of global warming temperatures and climate change, the WHO said.
Home and Away
Both factors are linked to the fact that previously dengue-free countries such as France, Italy and Spain report cases of infections originating at home – so-called autochthonous infection – rather than abroad. The disease vector is Aedes aegypti mosquito which is widespread in Europe and also more commonly known as the “tiger mosquito”.
“Normally, 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 transmissions. As we know, summers are getting warmer”.