Shamonda virus in French cattle: human case reported

A new Shamonda-type virus that has been spreading through dairy cattle in France since the summer has been detected in a human patient with a severely weakened immune system, according to results published Oct. 22 in the journal Eurosurveillance, as described by France’s national agricultural research institute INRAE.

INRAE said the findings do not mean the virus poses a public health risk to the wider population. The institute said its animal-virus unit at the Toulouse veterinary school (ENVT-INRAE) provided expertise to medical teams at the Hospices Civils de Lyon, in what it called a One Health approach. The report has driven a surge in searches for the virus in Canada.

Farms in France began reporting problems in June, INRAE said. Dairy cows developed acute diarrhoea, fever, lethargy and reduced milk production. The first cases were reported in eastern France, particularly in the Doubs, Ain, Savoie and Haute-Savoie departments, during a summer heat wave.

Investigators first looked at the high temperatures and the nutritional and metabolic problems they might cause in the animals, INRAE said. A second hypothesis was a viral enteritis or a febrile syndrome. A team from ENVT and INRAE then analysed faeces, plasma and aborted fetuses from affected animals and used metagenomic sequencing to identify a previously unknown Shamonda-type virus from the orthobunyavirus group.

INRAE said a test to detect the new virus has been developed. It said the virus is spreading rapidly in France and in Europe. Although the disease currently appears to be mild, the institute said its economic impact could become significant in the coming months, particularly in infected pregnant cows.

Orthobunyaviruses are enveloped viruses that cause a range of diseases around the world, INRAE said. Those in the Simbu serogroup, to which the new virus is related, are transmitted by Culicoides midges. Some infect cattle, while others infect humans, such as the Oropouche virus, which can cause acute fever, and the Shuni virus, which is associated with neurological disorders, the institute said.

The Eurosurveillance report concerns a single patient, and INRAE has not said the virus is passing between people. The detection involved the Shamonda-Europe virus, clade EU1, the institute said.

None of the reports reviewed by Canada News Media mention a detection of the virus in Canada. Canadians who want to follow the issue can check updates from the Public Health Agency of Canada and the Canadian Food Inspection Agency, which publish information on animal and human disease events.

This story is based on a report from INRAE. Canada News Media will update it as French health and agriculture authorities release more information.

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