France reported the world’s first documented human infection with Shamonda virus (SHAV) on 22 October 2026. The patient was treated in Lyon and died in early October. Shamonda virus is an arbovirus found only in livestock until now, so the case signals a rare animal to human spillover.
What Is Shamonda Virus?
Shamonda virus (SHAV) is a midge borne RNA virus that infects cattle and other farm animals. It belongs to the genus Orthobunyavirus in the family Peribunyaviridae and sits in the Simbu serogroup, a cluster of more than 25 related ruminant viruses. Its closest relatives are Schmallenberg virus and Akabane virus, which cause similar reproductive disorders in livestock.
The virus was first isolated from cattle near Ibadan in Nigeria in 1965, during arbovirus surveys conducted between 1964 and 1969. For the next six decades it stayed a minor livestock pathogen. It was reported sporadically in cattle in West, East and southern Africa and in Japan. In Japan it was linked to deformed calves in 2015 and 2016. In South Africa it was found in Culicoides biting midges in 2017 and in an aborted goat fetus in 2021.
SHAV is an enveloped virus with a single stranded RNA genome in three segments. This structure is common in its family and helps the virus change through reassortment when two related viruses infect the same cell. Cattle are its main hosts. Infections have also been confirmed in sheep, goats, horses and alpacas.
What Is an Arbovirus?
An arbovirus, short for arthropod borne virus, is any virus that spreads between vertebrate hosts through blood feeding arthropods such as mosquitoes, midges, sandflies and ticks. The term groups viruses by mode of spread, not by family. Dengue, Zika, chikungunya and Shamonda are all arboviruses.
More than 500 such viruses are known and about 150 cause human disease. Most belong to four families.
- Flaviviridae: dengue virus, Zika virus, yellow fever virus, West Nile virus and Japanese encephalitis virus, mostly spread by Aedes and Culex mosquitoes
- Peribunyaviridae and other bunyaviruses: Shamonda virus, Schmallenberg virus, Oropouche virus and La Crosse virus, spread by midges, mosquitoes and sandflies
- Togaviridae, genus Alphavirus: chikungunya virus and equine encephalitis viruses, spread by mosquitoes
- Sedoreoviridae, including orbiviruses: bluetongue virus, spread by Culicoides midges
| Arbovirus Example | Family and Genus | Main Vector | Disease It Causes |
|---|---|---|---|
| Dengue virus | Flaviviridae, Flavivirus | Aedes mosquito | Dengue fever |
| Zika virus | Flaviviridae, Flavivirus | Aedes mosquito | Zika fever, birth defects |
| Chikungunya virus | Togaviridae, Alphavirus | Aedes mosquito | Fever with severe joint pain |
| Japanese encephalitis virus | Flaviviridae, Flavivirus | Culex mosquito | Brain inflammation |
| Shamonda virus | Peribunyaviridae, Orthobunyavirus | Culicoides midge | Fever and milk loss in cattle, rare brain disease in one human case |
| Bluetongue virus | Sedoreoviridae, Orbivirus | Culicoides midge | Bluetongue disease in sheep and cattle |
Most arboviral infections cause no symptoms or a short fever with headache, muscle pain, rash or vomiting. A small share turn neuroinvasive and cause meningitis or encephalitis, which is inflammation of the brain and its coverings. In India, dengue, chikungunya, Japanese encephalitis, Zika and the tick borne Kyasanur Forest Disease are the best known arboviral diseases.
How France Detected the First Human Infection
French health and agriculture ministries announced the case on 22 October 2026. Health authorities were first notified on 7 October 2026 after deep microbiological tests at the Hospices Civils de Lyon found the virus in several samples from the patient.
The patient was a man in his 60s from the Lyon area. He was severely immunocompromised and was being treated for a serious illness with a neurological condition. He died in early October. French authorities said brain related complications in the patient were very likely linked to the infection. The exact role of the virus in the death is still under investigation.
The leading hypothesis is a bite from an infected midge in eastern France. The virus had circulated among animals there during spring and summer. The specific Culicoides species involved is not yet identified. No human to human transmission has been found.
The World Health Organization (WHO), headquartered in Geneva and led by Director General Tedros Adhanom Ghebreyesus, said it is in contact with French authorities to trace the source and possible routes of spread. The European Centre for Disease Prevention and Control (ECDC), the European Union agency for infectious disease surveillance based in Stockholm, is monitoring the situation with the European Food Safety Authority (EFSA) and the European Commission.
How Shamonda Virus Spreads and What It Does to Livestock
Shamonda virus spreads between animals through the bite of infected Culicoides midges. These are tiny blood feeding flies, only 1 to 3 mm long. A female midge picks up the virus while feeding on an infected animal during its short viraemic phase. The virus multiplies inside the insect and passes to the next animal at the next blood meal.
Direct spread from animal to animal has not been documented. The only known exception is from a pregnant animal to its fetus. Spread through milk, meat or contact with animals has not been shown. Midge activity peaks in warm and humid months from spring to autumn and falls as temperatures cool.
Clinical Signs in Cattle and Other Animals
In adult dairy cattle the illness is usually short and mild. Common signs are fever, diarrhoea, lethargy, loss of appetite and a sharp drop in milk production that can last up to three weeks. Infection spreads fast within a herd. Viraemia, which is the presence of virus in blood, lasts only three to five days, so blood testing must be timed early.
In pregnancy the effects are more serious. Infection can cause abortion, stillbirth and fetal malformations such as arthrogryposis, in which joints are fixed in bent positions, and hydranencephaly, in which parts of the brain are missing and replaced by fluid. Similar birth defects are seen with Schmallenberg and Akabane viruses. The World Organisation for Animal Health (WOAH), the Paris based intergovernmental body for animal disease standards founded in 1924, lists fever, reduced milk yield and reproductive disorders as the key effects.
There are no licensed vaccines or specific treatments for Shamonda virus in animals or people. Control depends on midge management, housing animals during peak biting hours and biosecurity on farms.
Shamonda Virus Across Europe in 2026
Animal illness was first noticed in June 2026 in dairy herds in southern Germany and Switzerland. Routine tests for Schmallenberg virus were negative. A team from the National Veterinary School of Toulouse and the French National Research Institute for Agriculture, Food and Environment then used metagenomic sequencing and recovered full genomes of a Simbu group virus. It was provisionally called European Shamonda virus. Formal identification followed in late July.
Since then the virus has been found in farm animals in Austria, Belgium, France, Germany, Ireland, Italy, Liechtenstein, Luxembourg, the Netherlands, Portugal, Spain and Switzerland, as well as Jersey in the Channel Islands. That makes 12 European countries plus one Crown Dependency. By early September, infections were confirmed on livestock farms in 37 provinces across France. Two genetic types, SHAV-EU1 and SHAV-EU2, have been reported circulating in Europe. Traces of SHAV-EU1 were found in the French patient.
France also reported sporadic infections in sheep, goats and members of the horse family in summer 2026. Genetic material of the virus has been reported in the brains of horses that died with neurological signs in Switzerland and Germany. The link is still being studied.
WOAH encourages countries to report Shamonda cases voluntarily, but reporting is not mandatory. This limits global data. ECDC is working with the European Union Reference Laboratory to strengthen testing capacity and find any other possible cases. Surveillance now covers sick people, virus sequencing in unusual cases, and monitoring of herds and people who work with them.
Why the Public Health Risk Remains Low
French authorities have said no health risk to the general population has been identified so far. WHO has called the case isolated and unlikely to lead to wider spread at this time, based on current knowledge of closely related Simbu viruses.
Three facts support that assessment. First, the only known human infection occurred in a severely immunocompromised patient, which points to opportunistic infection rather than a virus adapted to people. Second, there is no evidence of spread between people or from animals to people except through a midge bite. Third, midge activity declines with cooler autumn weather in Europe, which reduces transmission pressure.
The case still matters for One Health, the idea that human, animal and environmental health are linked. India runs a National One Health Mission on the same principle to improve coordination across human, veterinary and environmental sectors. Zoonotic spillovers, in which pathogens move from animals to people, often first appear as single severe cases in vulnerable patients. Careful testing of unexplained fevers and brain infections, rapid genome sequencing and joint work between health and animal husbandry departments help catch such events early.
Key Takeaways
- France reported the world’s first human infection with Shamonda virus (SHAV) on 22 October 2026 in a severely immunocompromised patient treated in Lyon.
- Shamonda virus is an arbovirus, short for arthropod borne virus, in the genus Orthobunyavirus and family Peribunyaviridae within the Simbu serogroup.
- The virus was first isolated from cattle in Nigeria in 1965 and was detected in Europe for the first time in June 2026.
- Shamonda spreads between animals through Culicoides midge bites and causes fever, diarrhoea and milk loss, plus abortion and fetal malformations in pregnancy.
- The virus has been found in livestock in 12 European countries plus Jersey, with no vaccines, no specific treatment and no risk identified so far for the general population.
