The United Nations Organization (UN) issued a statement on July 21 in which it ensures that “climate change is taking dengue to areas where it did not exist before”. For this reason, the World Health Organization (WHO) has requested European countries and the American continent to be alert and prepared for possible outbreaks.
“Global warming, characterized by increased average temperatures, rainfall and prolonged dry spells, could cause a record number of dengue infections worldwide,” says the WHO.. And it is that, according to the director of the World Program for the Control of Tropical Diseases of the agency, about half of the world's population “is at risk of contracting dengue, which affects some 129 countries.”
An incidence on the rise by “altitude and latitude”
The countries of the European continent have already registered dengue transmissions by the 'Aedes aegypti' mosquito. Other factors that would explain its spread, in addition to the climate crisis, would be the flow of movement of people, goods, urbanization, pressure on water and sanitation.
“We estimate that each year there are between 100 and 400 million cases. This is basically an estimate, and only in the American region some 2.8 million cases and 101,280 deaths have been reported,” says Raman Velayudhan, the head of the Unit of the Global Program for the Control of Neglected Tropical Diseases at the WHO.
Dengue is a more common disease in tropical and subtropical climates, but “its incidence has increased dramatically worldwide in recent decades,” he added.
The spread of the 'Aedes aegypti' mosquito, which can transmit dengue, Zika and chikungunya, has grown. “With climate change, it has been increasing by altitude and by latitude. So now we're seeing streaming where we didn't before. So, for example, in South America, in Argentina, in the south of Brazil, Uruguay, and so on.. And if we go to the northern hemisphere, now there are autochthonous cases reported in southern Europe, for example,” says the WHO expert, Diana Rojas Álvarez.
Increase in vector-borne diseases
“The mosquito manages to survive even when there is a shortage of water,” says Raman Velayudhan. “So, in both a flood situation and a drought situation, dengue can increase. The virus and the vector multiply faster at higher temperatures. It's a well-known fact.”
Climate change causes “deaths and illnesses from increasingly frequent weather events.”
As detailed by the WHO, climate change is affecting the health of the population in multiple ways. “Causing death and disease from increasingly frequent extreme weather events such as heat waves, storms and floods, the disruption of food systems, the rise of zoonoses and food-, water- and vector-borne diseases, and mental health problems.”
“Ticks are moving across Europe”
But dengue is not the only vector-borne disease threatening the European continent.. As noted by Meteored Portugal's meteorology experts, “the spread of Crimean-Congo haemorrhagic fever (CCHF), a deadly tick-borne disease, is accelerating in Europe due to climate change.”
For this reason, the WHO classifies this disease as a threat to public health.. Professor Ali Mirazimi, a virologist at the Karolinska Institute in Sweden, underlines in statements collected by an article from the European Commission that “ticks are moving across Europe due to climate change, with longer and drier summers.”
Ticks that can be carriers of the FHCC virus are migrating to other areas of the world due to climate changes. The first death in Spain caused by Crimean-Congo hemorrhagic fever (CCHF) occurred in 2016. It was a 62-year-old man who was bitten by a tick, which carried the disease.