Shamonda Virus Found in Human for First Time After Decades of Being Considered Non-Transmissible

France reported the first documented human infection with Shamonda virus, which had long been considered non-transmissible to humans, on Thursday, 22 October 2026. The severely immunocompromised patient died in early October while receiving treatment for a serious illness at Hospices Civils de Lyon.

Officials said brain complications observed before the death were very likely linked to the virus. They have not established whether the infection caused or contributed to the patient's death.

Based on current evidence, France said no health risk to the general population had been identified.

The discovery marks a departure from the virus's decades-long history as an infection documented in animals. First identified in Nigeria in the mid-1960s, Shamonda virus was subsequently reported in cattle in parts of Africa and Japan.

Until the French case, no human infections had been documented. Authorities described the case as exceptional because of the patient's severe immunosuppression.

Shamonda Virus Investigation Examines Patient's Brain Complications

France's health and agriculture ministries said the patient was being treated for an existing serious condition. Investigators are examining clinical findings, laboratory evidence and possible exposure to the virus.

The initial assessment links the brain complications to the infection, but the virus's role in the death remains uncertain.

In an English translation of their statement, the ministries said, 'The neurological complications observed in the immunocompromised patient prior to his death are very likely linked to infection with the Shamonda virus.'

The finding remains preliminary while clinical, biological and epidemiological investigations continue. Officials have not identified a wider human outbreak.

The leading explanation for how the patient became infected is a bite from a Culicoides midge in eastern France. Shamonda virus was circulating among animals in that region during spring and summer 2026.

The precise circumstances of the patient's exposure have not been confirmed, nor has a particular midge species been identified as responsible.

Shamonda belongs to the orthobunyavirus group and is transmitted among animals by biting midges. The first documented human detection does not show how commonly human infection might occur or establish that people can transmit the virus to each other. No such human-to-human transmission was identified in the French announcement.

Shamonda Virus Found in Livestock in Jersey and County Cork

The human case emerged after Shamonda virus was detected in livestock across parts of Europe during 2026. The UK's Animal and Plant Health Agency identified the virus in cattle in Jersey in August and announced the finding on 24 September.

The agency said the detection confirmed the virus's presence in the British Isles, near Great Britain.

On 2 October, Irish Agriculture Minister Martin Heydon reported that a private laboratory had detected Shamonda virus in cattle samples from two County Cork farms. He described the findings as the first reported detection in Ireland.

Government laboratory services were working with the private laboratory on follow-up investigations.

Northern Ireland's Agriculture Minister Andrew Muir subsequently urged farmers and horse owners to watch for unusual illness in their animals. His department said there was no evidence of the virus in Northern Ireland at the time of its 5 October statement.

The livestock detections in Jersey and Ireland have not been linked to the patient's infection in France.

Cattle are considered the principal animal hosts, although infections have also been recorded in sheep, goats and horses. Reported symptoms in cattle include fever, diarrhoea, lethargy and reduced milk production. The UK agency has also documented abortions in infected cattle, while concerns remain about infection during pregnancy.

Shamonda is not currently a notifiable animal disease in Ireland or the European Union, according to Heydon's announcement. Its animal-disease reporting status does not determine the significance of the new human infection.

The UK agency has encouraged veterinary investigation where livestock show compatible signs of illness.

French Authorities Continue Shamonda Virus Inquiry

France has notified the World Health Organization and the European Centre for Disease Prevention and Control of the unprecedented human finding.

Its investigation follows a One Health approach, drawing on expertise in human, animal and environmental health.

As of the time of publication, French authorities said there was 'no health risk to the general public identified at this time'.

That statement is a current assessment rather than proof that further infections are impossible. The patient was severely immunocompromised, and the available findings cannot establish the implications for otherwise healthy people.

Investigators are continuing to examine the patient's medical findings and the possibility of exposure to an infected midge in eastern France. Neither the exact route of infection nor the virus's role in the death has been settled. Further clinical and epidemiological findings will be needed to clarify what the first documented human case means.