Climate change worsened the outbreak of dengue and chikungunya in Argentina and the world, according to the WHO

The extraordinary increase in cases of dengue and chikungunya fever registered in Argentina so far in 2023 might have been aggravated by climate change, according to the World Health Organization (WHO), which warned on April 5 that these and other diseases caused by arboviruses transmitted by mosquitoes might cause global outbreaks.

In Argentina, according to the latest National Epidemiological Bulletin, 16,143 cases of dengue were registered. Of this number, 14,224 have no travel history, 1,529 are under investigation and 390 have a travel history.

Experts from the United Nations health agency sounded the alarm regarding the rising number of dengue and chikungunya cases, warning that new Zika epidemics might also be expected. All three are caused by arboviruses carried by Aedes aegypti mosquitoes, which are spreading into new territories as the planet warms. “We are seeing a transmission where we did not see it before,” they said.

Dengue and chikungunya fever in Argentina: cases grow and warn to avoid mosquito bites

Of these cases, 14 people lost their lives from the disease.

In relation to previous years, the accumulated cases registered in the current season are above those registered in the last two years, 10 percent below the number of cases registered in the same period of 2020 and 40 percent below of the cases that existed in 2016.

The circulation of this virus was identified in 14 jurisdictions: Buenos Aires, the Autonomous City of Buenos Aires (CABA), Córdoba, Entre Ríos, Santa Fe, Corrientes, Formosa, Chaco, Catamarca, Jujuy, Salta, Santiago del Estero, Tucumán and La Rioja.

In turn, 657 cases of chikungunya fever were registered in the country, of which 244 have no travel history, 159 are under investigation and 254 have a travel history.

In this case, it was confirmed in 7 jurisdictions: Buenos Aires (towns of Almirante Brown, Pergamino, Quilmes and San Martín); CABA, Córdoba (in Córdoba Capital and La Calera), Corrientes (Paso de la Patria), Formosa (Tres Lagunas, Las Lomitas and Formosa Capital); Misiones (Puerto Iguazú) and Santa Fe (Rosario and Capital).

Dengue outbreak: causes, symptoms and preventive measures

The WHO warning regarding the spread of dengue, zika and chikungunya

But the mosquito is also present in several countries in America such as Brazil, Uruguay, Bolivia, Peru, and also in southern Europe, which might cause “some cases” in spring and summer. Some 129 countries are at risk of contracting the virus, which is endemic in more than 100 countries.

The incidence of dengue has grown “exponentially”, from around half a million cases in the year 2000 to around 5.2 million in 2019, which was the worst year. In 2022, according to experts, there was “an increase in dengue in many parts of the world.” For example, in the Americas region they registered 2.8 million cases with more than 1,200 deaths.

At a press conference, the head of the Unit of the Global Program for the Control of Neglected Tropical Diseases at the WHO, Raman Velayudhan, and the technical chief of Zika and chikungunya, Diana Rojas Alvarezthey spoke of the great expansion of the mosquito.

The Aedes aegypti mosquito is the vector of dengue, Zika and chikungunya.

“With climate change, they have 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, ”they pointed out.

“The distribution of the mosquito is increasing and the countries where the mosquito has been introduced is increasing and where the mosquito has established itself is alarming”explained.

“We must be prepared to detect some cases during the spring and summer in Europe and in the northern hemisphere. Also in Southeast Asia, because the arbovirus season starts later than it usually is when the summer season starts,” Velayudhan explained.

“The geographic spread of dengue is expanding”, he said, explaining that only in South America, for example, “the countries affected by dengue are heading further and further south. Countries like Bolivia, Peru and Paraguay register cases of dengue.”

This shows, she added, that climate change “has played a key role in facilitating the spread of the vector, mosquitoes, to the south.” In this sense, the expert said that it is normal for these three viruses “to co-circulate in the same regions because they have the same vector”, the Aedes Aegypti mosquito.

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