First reported human Shamonda virus infection ends in death in France

A case report published in Eurosurveillance describes the first known human infection with Shamonda virus, an orthobunyavirus detected in cattle during an ongoing livestock outbreak in Europe. The patient, a man in his sixties with leukaemia who was severely immunocompromised, lived in France’s Rhône–Alpes region, where the virus has been detected in cattle. The report says infection probably followed a midge bite, although contaminated food, transfusion and transplantation are also being investigated as less likely possibilities.

The man developed neurological symptoms, including vision loss and confusion, and then seizures and coma. He died on 9 October, 16 days after symptoms began. Antibiotics, an antiviral drug and high-dose corticosteroids did not lead to improvement; he required intubation and mechanical ventilation before life support was withdrawn.

The report authors say investigations into possible transmission routes are ongoing. Researchers quoted by Nature say the risk of person-to-person transmission is low, and no human-to-human transmission has been recorded for these viruses, although fetal transmission was reported during a 2024 Oropouche outbreak in Brazil. There are no vaccines or antiviral treatments for orthobunyaviruses. This is a single case in a severely immunocompromised patient, and little is known about Shamonda virus infection in people.