France reports first known human case of Shamonda virus

French authorities have reported the first known human infection with Shamonda virus in a patient who died at a Lyon hospital in early October. Officials called it an exceptional case involving a severely immunocompromised person and said they had identified no current risk to the general public.

The patient was being treated for a serious illness and developed neurological complications that initial findings suggested were “very likely linked” to the virus, France’s health and agriculture ministries said. They stressed that the patient’s weakened immune system made them more vulnerable to illness. Investigators are still working to establish how the infection occurred.

The leading hypothesis is that the patient contracted the virus through the bite of an infected midge in eastern France, where it had circulated among animals in the spring and summer, according to the French authorities. “Clinical, biological and epidemiological investigations are continuing in conjunction with expertise in human, animal and environmental health,” the French announcement said, as reported by Al Jazeera.

Until this case, Shamonda virus had been considered unable to infect humans. “Until now, the Shamonda virus was considered non-transmissible to humans,” the French ministries said, according to the BBC. They noted that no human cases had been identified despite decades of circulation in Africa and Asia.

Shamonda is an orthobunyavirus, a group of viruses primarily carried by insects, Al Jazeera reported. Biting midges of the genus Culicoides spread it among animals, mainly cattle. The virus has also been found in sheep, goats, alpacas and horses, according to the BBC. In dairy herds, infection can cause fever, diarrhoea and reduced milk production.

Al Jazeera reported that the virus was first detected in Nigeria in the 1960s and was subsequently reported sporadically in East and Southern Africa and Japan. Europe’s first confirmed cases were identified in late July. According to Al Jazeera, genomic tests confirmed the virus in sick cattle in southern Germany, Switzerland and eastern France.

It has since been detected in farm animals elsewhere in Europe. Citing a French animal-health surveillance bulletin, Al Jazeera listed Austria, Belgium, Ireland, Italy, Liechtenstein, Luxembourg, the Netherlands, Portugal, Slovenia, Spain and Jersey among the places where the virus had been detected.

The European Centre for Disease Prevention and Control said it was monitoring the human case and working with French and European partners to examine its “potential public health implications.” The case has also been reported to the World Health Organization, the BBC reported.