Cryptic severe Plasmodium falciparum malaria in Maremma (Tuscany, Italy), 2024: a case report from a historically receptive area.

In Italy Malaria is still mainly seen as a travel-related infection, with around 700 cases reported each year. We describe a severe, non-imported (cryptic) Plasmodium falciparum malaria case diagnosed in August 2024 in the Grosseto area (Tuscany) in an Italian patient with no travel to malaria-endemic countries and no alternative risk factors. Since June 2024, he had been staying in a nearby village on the Maremma coast. This is a well-known former malarious area (Italy was declared malaria-free in 1970) that remains receptive, with residual anophelism and the presence of Anopheles labranchiae, one of the most efficient malaria vectors in the Mediterranean basin. Marked thrombocytopenia was the initial clue and prompted blood smear microscopy, which showed 10% parasitaemia. The result was rapidly confirmed by LAMP and species identification. The patient was admitted and, once severe malaria was recognised, was treated immediately with intravenous artesunate, with subsequent clinical improvement. The case was promptly notified and investigated, but no index case, secondary cases, or transmission chain were identified. This episode is a reminder that receptive areas still need clinical suspicion, diagnostic readiness, and a surveillance response that can move quickly even when travel history is negative.