Argentina is in the grip of the worst dengue outbreak in its history, with the number of cases so far this year up 200 per cent compared with the same period in 2023. And Argentina is not alone. Last month, Brazil began its first vaccination campaign against dengue (which is potentially deadly) in the wake of record infections. In Argentina, President Javier Milei has rejected calls to fund public health information campaigns while he pursues economic austerity. Providing vaccines seems to` be out of the question but this is not a problem that Milei can shoo away. The Aedes aegypti mosquito that transmits dengue (as well as Zika virus and chikungunya) is becoming prevalent, with more infections in the Americas last year than any previous year. Climate change is leading to more mosquitos, which thrive in hot, steamy conditions.