France confirms first human case of Shamonda livestock virus in immunocompromised patient

The French health authorities confirmed the first human case of the Shamonda virus infection in an immunosuppressed male in his 60s who died in early October 2026. The combined results of the French ministries of health and agriculture revealed that the patient's death was very probably associated with the neurological complications caused by the midge-borne virus that spread among European livestock this summer.

Human infection linked to severe immunocompromise

The patient, who was under treatment for the existing medical conditions in the Lyon region, got infected with the Shamonda virus after being bitten by a midge in eastern France.

Isolated case: As per WHO assessment, the incident is classified as an isolated case; thus, the public can be assured that no signs of the human-to-human transmission have been observed.

Public health monitoring: The European Centre for Disease Prevention and Control (ECDC) initiated the investigation to assess the public health significance of the infection while monitoring the pathogen's spread among European livestock.

Understanding the Shamonda virus: Hosts and pathogen's vector

Shamonda belongs to the Orthobunyavirus genus of the Simbu serogroup—that is a family of arthropod-borne viruses that affect ruminants such as cattle, sheep, and goats.

Vector: The virus is transmitted between hosts by biting midges, where the cattle remain the main hosts, but infections have also occurred in horses, sheep, and alpacas.

Teratogenic effects: Originating in Nigeria in the 1960s, studies in Japan found that in utero infections of the Shamonda virus result in severe congenital abnormalities (like arthrogryposis) and neurodevelopmental issues in calves.

European infections: Since its first detection in European livestock in July 2026 in Germany, Switzerland, and France, the virus has spread to 14 other countries, such as Italy, Spain, Belgium, and the Netherlands.

Symptoms and surveillance issues

For adult cattle, the Shamonda virus leads to acute debility, diarrhea, decreased appetite, and massive reductions in milk production, with dairy farmers report production declines of 75%.

"'As the Shamonda virus is not covered by the EU Animal Health Law and is not included in WOAH mandatory reporting, surveillance information at a European level is limited,'" said veterinary research analysts monitoring the outbreak.

Although other Simbu group pathogens, such as the Oropouche and Shuni viruses, can lead to neurological disease in humans, previous research on other related viruses like the Schmallenberg virus found zero livestock handler infections.