EXPLAINER – What is Shamonda virus, detected in humans for 1st time?
Virus mainly affects livestock, spreads primarily through bites from Culicoides midges
- 1st documented human case involves ‘severely’ immunocompromised patient who died in early October
- French authorities say no risk to general population has been identified so far, but investigations continue
French health authorities reported Thursday the first documented human infection with the Shamonda virus, an emerging pathogen primarily affecting livestock.
France's Health Ministry said the infection was detected in a patient with "severe immunodeficiency" who was receiving treatment for a serious illness.
The patient died in early October, and clinical, biological and epidemiological investigations are ongoing.
What is Shamonda virus?
Shamonda virus is an orthobunyavirus transmitted primarily by Culicoides biting midges.
It belongs to the same broader group of viruses as Schmallenberg virus and Akabane virus, which are associated with infections in animals.
First detected in Nigeria in the mid-1960s, it was subsequently reported sporadically in parts of West, East and southern Africa, as well as Japan.
It was identified in Europe for the first time in summer 2026, including in France, Germany and Switzerland, according to the French Agriculture Ministry.
The UK's Animal and Plant Health Agency also detected the virus in cattle in Jersey, a British Crown dependency, in August.
What happened in France?
The patient was receiving treatment for a serious illness at the Hospices Civils de Lyon hospital group and had a severely weakened immune system.
French authorities said neurological complications observed before the patient's death were "very likely" linked to the infection, although the virus had previously been considered incapable of infecting humans.
They said the case shared characteristics with human infections caused by other orthobunyaviruses, including Oropouche virus.
Investigators believe the patient may have been infected through a Culicoides midge bite in eastern France, where the virus circulated among animals during spring and summer.
The case is considered exceptional because no human infection had previously been documented despite the virus circulating in parts of Africa and Asia for decades.
What symptoms does it cause in animals?
In cattle, the virus can cause fever, diarrhea, lethargy and reduced milk production. These symptoms are generally temporary, according to the French Agriculture Ministry.
Infections during pregnancy may also lead to reproductive complications, including abortions and fetal malformations, similar to those associated with Schmallenberg virus.
Although cattle are considered the main animal hosts, the virus has also been detected in small ruminants, including sheep and goats, as well as horses and alpacas in some European countries.
The UK agency reported detections in horses with neurological disease in Germany and Switzerland. Investigations are continuing into the relationship between the infection and those symptoms.
How does the virus spread?
Shamonda virus spreads primarily through bites from Culicoides midges, small biting insects that transmit several animal viruses.
According to the French Agriculture Ministry, there is no evidence of significant direct transmission between animals, apart from transmission from a pregnant animal to its offspring.
The ministry said no scientific evidence currently documents transmission through meat, milk or dairy products.
Even so, products from sick animals are excluded from consumption, it added.
Is there a vaccine or treatment?
No vaccine is currently available, and there is no treatment that eliminates the virus in infected animals, according to the French Agriculture Ministry.
Veterinarians can provide treatment to relieve symptoms. Farmers are advised to seek veterinary assistance if cattle develop fever, diarrhea or reduced milk production.
Veterinary monitoring is also recommended for potential reproductive complications following infection.
Authorities recommend reducing exposure to midges by eliminating breeding sites, including liquid manure and stagnant water and treating transport vehicles against insects.
The virus is not currently classified as a regulated animal disease under European Union animal health legislation, according to the French Agriculture Ministry.
No mandatory culling is required under the regulations in the event of an infection.
What happens next?
French authorities are continuing investigations involving specialists in human, animal and environmental health to better understand the infection and the virus's circulation.
No risk to the general population has been identified based on current knowledge of the virus, the Agriculture Ministry added.
France has notified the World Health Organization and the European Centre for Disease Prevention and Control.
