While the hantavirus-affected cruise ship is already heading towards the Canary Islands, the unknowns about the origin of the outbreak remain open. The World Health Organization (WHO) has downplayed the possibility that the infection was caused by the presence of rodents on board the vessel, so the most probable hypothesis at this point is that the first two fatalities, a Dutch couple, had contracted the virus before boarding the ship and that, once there, they had infected other passengers. Argentina, from where the cruise ship departed, has reconstructed the journey of the man and woman before embarking on the sea voyage. In the last four months, they had been in a large part of this country, but also in Chile and Uruguay, on a bird-watching trip. The strain responsible for the outbreak is native to the Andes and circulates in some of the areas where the couple had been.

Dengue fever is no longer just an imported threat arriving on airplanes. It's a homegrown reality in Catalonia. By the summer of 2024, the outbreak of eight cases in Vila-seca (Tarragonès) –the largest recorded in Spain– forcefully confirmed it: the virus is circulating here, transmitted by native mosquitoes. This episode is not an anecdote, but an alarming sign that reflects a profound transformation: global warming and mass mobility have shattered old epidemiological boundaries. A patient with fever and bone pain can no longer rule out a tropical disease without traveling. Faced with this new normal, the response cannot be fragmented. Human, animal, and environmental health are intrinsically linked. The solution has a name, One Health', an integrative approach that becomes an imperative necessity.