Virus Seen Only in Animals for 60 Years Infects Human for First Time

Scientists are investigating a historic infection after a virus previously associated with animals was detected in a human patient.

World Health Organization confirms a historic human infection involving a virus previously associated with livestock, as scientists investigate its potential threat to public health. A virus that has circulated among animals for more than 60 years has now been detected in a human for the first time, raising fresh questions about emerging infectious diseases and how easily animal viruses could cross into the human population.

France reported the first documented human illness caused by Shamonda virus in October 2026. The infected patient, who was already suffering from a serious medical condition and had a severely weakened immune system, died earlier this month. However, health authorities have stressed that investigations are continuing to establish whether the virus caused or contributed to the death. 

The discovery has attracted international attention because Shamonda virus was previously associated with livestock, particularly cattle, sheep, goats and horses. Until this case, there had been no documented evidence of the virus causing illness in humans.

According to French public health authorities, the patient was receiving treatment at a hospital in Lyon when the infection was identified. The individual had experienced serious neurological complications, affecting the brain and nervous system, which investigators believe may have been associated with the virus. However, scientists cannot yet determine whether similar symptoms would occur in otherwise healthy individuals. 

Shamonda virus is not new. It was first identified in cattle in Nigeria in 1965 and has since been detected in animals across parts of Africa and Japan. What makes the latest development particularly significant is its recent arrival in Europe, where it was identified in livestock for the first time during the summer of 2026.

The virus has subsequently been detected in several European countries, including Germany, Switzerland, Austria, Belgium and France. The European Centre for Disease Prevention and Control (ECDC) has also confirmed its presence in livestock in Ireland, Spain, Italy and Jersey, among other locations. Unlike respiratory viruses that can spread through coughing or sneezing, Shamonda virus is believed to circulate among animals through the bites of infected midges. These tiny flying insects feed on blood and can carry viruses between animals.

French investigators suspect that the human patient may have contracted the infection through a bite from an infected midge in eastern France, where the virus had already been circulating among livestock. However, the precise source of the infection has not been confirmed.

In animals, Shamonda virus can cause fever, diarrhoea, reduced milk production and reproductive complications, including miscarriages and birth defects. Its potential effects on humans remain largely unknown because only one human case has been documented. 

One of the most pressing questions is whether the virus could spread between people. At present, French health authorities have found no evidence of human-to-human transmission and have identified no wider public health risk to the general population.

The WHO has also indicated that further spread among humans is currently considered unlikely, although a formal risk assessment has not yet been completed. Another concern is the absence of a vaccine or specific treatment for Shamonda virus. With so little information available about its effects on humans, researchers are working to understand how infection occurs, what symptoms it may produce and whether certain individuals could be particularly vulnerable.

The ECDC is monitoring developments alongside French authorities and international health organisations. Investigations are examining the patient's medical history, possible exposure to infected insects and the genetic characteristics of the virus.

For the United Kingdom, the discovery is also relevant because the virus has already been detected in livestock on Jersey. However, the presence of Shamonda virus in European animals does not mean that a human outbreak is developing or that the wider public faces an immediate threat. 

The case nevertheless highlights an important reality in modern public health: viruses that have circulated in animals for decades can still present unexpected challenges when they are detected in humans. For now, health authorities are urging continued scientific investigation rather than alarm. The first confirmed human infection represents a significant development, but a single case is not evidence of a wider epidemic.

The unanswered question is whether this was an exceptionally rare infection involving a medically vulnerable patient or the first indication of a virus whose potential effects on human health are not yet fully understood. As scientists continue their investigations, the case serves as a reminder of the importance of monitoring diseases that circulate between animals, insects and humans.

Sources: World Health Organization