French health authorities have confirmed the country's first human infection with Shamonda virus following the death of a man in his 60s from the Lyon area in early October.
The case is suspected to have resulted from a bite by an infected midge in eastern France, a region where the virus circulated among animals during spring and summer.
Officials stated that no risk to the general population has been identified so far.
Patient Had Serious Underlying Illness
According to the European Centre for Disease Prevention and Control (ECDC), the patient was being treated for a serious underlying condition that left him more vulnerable to infection than the wider population.
Investigators are still working to determine whether Shamonda caused or contributed to his death, and how he contracted the virus.
The Stockholm-based ECDC said it is coordinating with French authorities and European partners to evaluate the possible public health implications of the case.
"ECDC is in contact with the French authorities and European partners to investigate the potential public health implications," the agency said in its statement.
The agency has not yet established whether the virus played a role in the patient's death, and the transmission route remains under investigation.
French authorities stressed that current evidence does not point to a broader public health threat.
"Based on the knowledge available regarding this virus, no health risk to the general population has been identified to date," the French government said.
Livestock Virus With Limited EU Oversight
Shamonda is primarily associated with livestock and is spread by biting midges, according to the World Organisation for Animal Health (WOAH).
The virus has been found mainly in cattle, but infections have also been detected in horses, alpacas, sheep and goats.
It is not classified as a disease under the European Union's Animal Health Law and is not subject to official surveillance or control measures under that framework.
Shamonda was first identified in Nigeria in the mid-1960s and was confirmed in Europe for the first time in late July, when genomic testing detected it in sick cattle in southern Germany, Switzerland and eastern France.
France's weekly animal health surveillance bulletin later listed detections in Austria, Belgium, Ireland, Italy, Liechtenstein, Luxembourg, the Netherlands, Portugal, Slovenia, Spain and Jersey, a British Crown Dependency.
Beyond the human case, the virus has affected livestock production.
French animal health authorities cited a study of nine dairy farms in France that found milk production dropped by as much as 75% in affected herds.
Infected cattle have shown diarrhea, weakness and loss of appetite, with fever reported less frequently, according to the authorities.
