Shamonda Virus: France Reports First Human Infection

A man who died in early October at a hospital in Lyon, a city in eastern France, is the first person known to have been infected with Shamonda virus, a cattle virus spread by biting midges.

France's health and agriculture ministries announced the case on 22 October 2026.

They said his immune system was severely weakened and that he was being treated for a serious illness.

It is the only human infection so far, the European Centre for Disease Prevention and Control (ECDC), the European Union's disease agency, said the same day.

The French ministries said that, based on what is known about the virus, no risk to the general population has been identified.

The brain illness, and what is not yet proven

The ministries said early checks suggest the brain problems he developed before dying were very probably linked to the infection.

They did not say the virus killed him.

ECDC said investigators are still working out whether it caused or contributed to his death, and how he was infected.

World Organisation for Animal Health (WOAH) said the same.

The World Health Organization (WHO) said in a question-and-answer page on 22 October that the patient was already seriously ill when he developed brain symptoms thought to be linked to Shamonda.

WHO said there are no treatments or vaccines for it.

Science magazine, reporting on a paper by French researchers in the journal Eurosurveillance, gave more detail.

It said the man had leukaemia, a cancer of the blood, and had taken a drug that nearly wiped out his white blood cells, which fight infection.

Science said he lost his sight, became confused and fell into a coma.

Ben Brennan, a virologist at the University of Glasgow, told the Science Media Centre in London on 22 October that the patient's serious illness left him unusually vulnerable.

Finding the virus in such a patient, he said, does not necessarily mean it is a significant risk to healthy people.

A cattle virus first found in Nigeria in 1965

Shamonda is spread by midges, tiny biting flies.

It was first found in cattle in Nigeria in 1965, WOAH said.

French authorities said it has since been reported in cattle in West, East and southern Africa and in Japan, and that no human case had been documented in all that time.

In animals it causes fever, diarrhoea and a drop in milk.

Pregnant animals can lose their young or give birth to deformed ones, WOAH said.

Europe's summer of sick cows

Dairy cows in eastern France began falling ill in June, researchers led by Jean-Luc Guérin of the National Veterinary School of Toulouse reported in Eurosurveillance on 20 August.

In the first nine herds, milk production fell by between 15% and 75%.

Between 28 July and 11 August the team tested animals from 51 herds and found the virus in every sample.

In all 18 herds where cows had lost their young, the mothers had shown fever and low spirits two to four weeks earlier.

Traces of the virus were found in the brains of six of the lost calves.

That raises the possibility that the virus can infect animals before birth.

ECDC said the virus was identified in late July.

By 22 October it had been found on farms in 12 countries and Jersey: Austria, Belgium, France, Germany, Ireland, Italy, Liechtenstein, Luxembourg, the Netherlands, Portugal, Spain and Switzerland.

France's animal-health bulletin also lists Slovenia, according to Al Jazeera.

WOAH said the quality of reporting varies from country to country, because it depends on each one's testing capacity.

Two versions of the virus

German researchers at the Friedrich-Loeffler-Institut, the country's federal animal-health institute, reported on 1 October in Eurosurveillance that two different versions of the virus are spreading.

They call them SHAV-EU1 and SHAV-EU2.

The first was found in southern Germany, Switzerland and France.

The second turned up in north-western Germany in mid-August, and is closest to strains found in Japan.

The team concluded they arrived separately, because they first appeared in different regions and differ genetically.

So far EU2 has been found only in cattle.

EU1 has also been found in horses with brain disease.

Immunity that cattle built up against Schmallenberg virus, a related virus that spread across Europe from 2011, does not appear to have slowed Shamonda, the German team wrote.

Both teams said how and when the virus reached Europe is unknown.

WOAH said the long-term effect on European herds cannot yet be judged.

A midge bite is the main theory

The French ministries said the main theory is a bite from a biting midge in eastern France, where the virus was circulating in animals in spring and summer.

It has not been confirmed.

ECDC said which midge species is involved is not known.

Guérin told Science that these midges do not normally bite people.

He said insect experts are checking whether mosquitoes might also carry the virus.

Science reported that the virus was already in blood taken from the man in early July, about three months before he died, and that it was the EU1 version.

ECDC said midges are becoming less active in Europe as temperatures fall.

Milk and meat

France's Ministry of Agriculture said no scientific data shows the virus passing to people through meat, milk or dairy products.

It added that products from sick animals are always kept out of the food supply.

The ministry said there is no vaccine, no treatment that clears the virus from animals, and no law requiring infected animals to be slaughtered.

Could others have been infected?

"First documented" does not mean "first ever."

The man was identified when he fell seriously ill, Science reported.

Tom Solomon, head of The Pandemic Institute in Britain, said on 22 October that it is not known whether healthy people can be infected without symptoms, what symptoms the virus usually causes, or how often it causes serious illness. He added that there is "no reason for public alarm."

In their August paper, the French researchers wrote that no evidence then showed the virus could infect people.

They said its potential should be judged without assuming it can cause human illness.

ECDC said it is working with the EU's main reference laboratory to strengthen testing and help countries find any other cases.

Science reported that a German research team plans to test donated blood for signs of infection.

Not the first time a related virus has struck a fragile patient

In 2019 a woman with a weakened immune system died of brain inflammation in France.

Doctors found a new virus from the same large family, called Cristoli virus, researchers reported in the journal Emerging Infectious Diseases in 2020.

Brennan said, in comments reported by Nation Africa, that no further cases followed, and that Schmallenberg virus swept through European livestock without causing human cases.

The French researchers noted in August that two other midge-borne relatives do affect people.

Oropouche virus has caused large outbreaks of fever, and Shuni virus has been found in people with brain illness in South Africa.

Between people: not reported, not ruled out

Grégory Emery, head of France's health directorate, said there had been no report of the virus passing from cattle to people or from person to person, NBC News reported on 22 October.

WOAH said there is no evidence of it passing between animals through contact, though it can pass from mother to unborn young.

Brennan said there is no evidence of lasting spread between people, and that the virus normally travels by midge bite, not through everyday contact.

What happens next

WHO Director-General Tedros Adhanom Ghebreyesus said on 22 October that WHO is working with France to find the source of the infection, the ways it could spread and any risk to public health, UN News reported.

ECDC said it is following developments with the European Commission and the European Food Safety Authority.

WOAH said it is working with WHO and the French authorities.

In the laboratory, the German team said tests of whether immunity to one version protects against the other are a high priority.

The French team listed testing of stored animal samples and monitoring of midges among its next steps.

The German team wrote that the effects of infection in unborn animals are largely unknown and may only show up much later.

Whether Shamonda alone caused the man's fatal brain illness, and whether it can infect people whose immune systems work normally, are the questions the Lyon investigation must answer.