France Reports First Known Human Shamonda Virus Infection in Immunocompromised Patient Who Died in Lyon

A livestock virus has infected a human for the first time on record.

French authorities announced on Thursday, Oct. 22, that Shamonda virus was detected in a patient at the Hospices Civils de Lyon. The man was severely immunocompromised and being treated for a serious illness. He died in early October.

What French authorities say happened

The health and agriculture ministries said in a joint statement that the virus had been considered non-transmissible to humans. They called the case "exceptional," involving a severely immunocompromised patient.

Preliminary findings point to a link with the man's death. The ministries said the neurological complications he showed before dying were "very likely" tied to Shamonda infection.

The ministries said no health risk to the general population has been identified at this stage.

Clinical, biological and epidemiological investigations are still underway. France has notified the World Health Organization and the European Centre for Disease Prevention and Control (ECDC).

How he may have been infected

The leading hypothesis is a bite from a Culicoides midge in eastern France. The virus was circulating among animals in that region during spring and summer 2026, the ministries said.

It is a hypothesis, not a finding. The ECDC said the specific midge species involved in transmission is still unknown.

The ministries have not said whether the patient had direct contact with livestock.

Cause of death is not settled

The French statement says the brain complications were very likely linked to the virus. The ECDC is more cautious. It said investigations into whether the virus caused or contributed to the death, and how the infection was acquired, are ongoing.

Those are two different bars. A patient with a severely compromised immune system can be killed by an infection that would do little to a healthy person. That is why French officials stress how unusual the case is.

The ECDC made the same point. It said the patient was more susceptible to infection and complications than the general population.

The virus in Europe

Shamonda is an insect-borne orthobunyavirus. It was first identified in Nigeria in the mid-1960s and has since been detected sporadically in animals in Africa and Japan. No human case had been documented anywhere until now.

It reached Europe this year. The ECDC said clinical signs in animals were reported from June and the virus was identified in late July. It has since turned up in farm animals in Austria, Belgium, France, Germany, Ireland, Italy, Liechtenstein, Luxembourg, the Netherlands, Portugal, Spain and Switzerland, as well as Jersey.

A bulletin from France's national animal-health research institute counts 14 western European countries, according to the ministries' statement as relayed by AFP.

Cattle are the main hosts. In cattle, infection causes fever, lethargy, diarrhoea and a drop in milk production, according to Belgium's public health institute Sciensano and the UK's Animal and Plant Health Agency (APHA).

The APHA also said abortions have been documented in infected cattle. It raised concern that infection during pregnancy could cause congenital abnormalities. Shamonda belongs to the same group as Schmallenberg virus, which is associated with such defects.

Sheep, goats, horses and alpacas have also been infected in several European countries. APHA flagged the potential for further spread across north-west Europe.

What comes next

Midge season is ending. The ECDC noted that the activity of most biting midge species in Europe is declining as temperatures cool. That may limit new animal infections over the coming weeks, though the agency has not said it expects the risk to vanish.

The agency is working with the relevant EU Reference Laboratory to strengthen testing capacity and help member states identify any other potential human cases. It is also in contact with the European Commission and the European Food Safety Authority.

That testing is the open question. Until labs start looking for Shamonda in people, nobody knows whether the Lyon patient is a true one-off or the first case anyone checked for. French authorities have not announced any screening of people who worked with infected herds.