Dengue in the south of France: An emerging health threat due to climate change?

Dengue fever is an arboviral infection, caused by dengue virus and spread by Aedes sp. mosquitoes. Most infections are asymptomatic, but a small proportion of patients develop severe dengue with significant associated mortality. Historically, the Aedes sp. mosquito vectors were only found in the tropics. However, Aedes albopictus was identified in France in 1999, and has now reached a population density that supports autochthonous outbreaks of associated diseases. A 44-year-old previously fit and well female patient presented to an emergency department in the United Kingdom with a 3-day history of fevers, a retro -orbital headache, myalgia, and a maculopapular rash. She had returned one day previously from a six-week trip to the south of France. Dengue infection was suspected clinically, and subsequently confirmed with serological and molecular testing. She was managed supportively and made a full recovery. The unusual aspect of this case is the epidemiology, as dengue infection is rarely reported from the south of France. However, at the time of this case in 2022, there were 51 autochthonous dengue cases in this region. The important learning point is that the epidemiology of dengue is changing and patients with typical symptoms should be tested in countries where the vector Aedes albopictus is found.