Surge in Yellow Fever and Dengue Cases in South America Linked to Climate Crisis

Surging cases of yellow fever and dengue in South America are highlighting the escalating health threats posed by the climate crisis. According to the Pan American Health Organization, there have been 356 cases of yellow fever reported this year, resulting in 152 deaths, predominantly in the Amazon region.

This surge represents the highest incidence of yellow fever since 1960, aside from a notable spike in 2017 and 2018. The ongoing yellow fever outbreak follows one of Brazil's worst years for dengue, with nearly 6.5 million cases and about 5,000 deaths recorded in 2024.

The report indicates a significant increase in dengue cases in Europe as well, with 304 reported cases last year, surpassing the total from the previous 15 years combined. Both diseases are transmitted by the Aedes mosquito species, which thrive in warmer conditions and stagnant water, exacerbated by the climate crisis.

Scientists have determined that rising global temperatures and extreme rainfall are facilitating the spread of infectious diseases, as disease-carrying mosquitoes extend their range into temperate regions.

As the UN climate talks occur in Belem, Brazil, health has emerged as a focal point, with the UN declaring a health day at the COP30 summit. The newly introduced Belem Health Action Plan aims to support countries in managing climate-induced health issues through enhanced surveillance and best practices, with a coalition of 35 philanthropic organizations pledging $300 million in funding.

UN climate chief Simon Stiell emphasized that the climate crisis is a public health crisis, as rising temperatures, floods, and droughts contribute to increased mortality and disease prevalence. Health experts, including Maria Guevara from Doctors Without Borders, noted that environmental changes and human encroachment into animal habitats are driving the spread of zoonotic diseases.

This situation is compounded by the adaptability of pathogens and vectors, which outpace human efforts to combat them. Experts stress the need for collaborative resilience strategies across all nations to prepare for the growing threat posed by climate change to public health.

Rachel Vicente from Brazil's Federal University of Espirito Santo highlighted how urbanization near breeding sites is creating a perfect storm for disease transmission. The current health crisis underscores the urgent need for action to address the links between climate change and infectious diseases.