Swiss cow illness linked to new virus, officials say

A new virus spread by biting midges is thought to be behind a rise in sickness among Swiss dairy cows, authorities said on Monday.

Switzerland’s Federal Food Safety and Veterinary Office said several regions had recorded more illnesses since mid-July, with cows suffering fever and diarrhoea and producing less milk.

The office said the Institute of Virology and Immunology had detected an orthobunyavirus of the Simbu group in several acutely ill animals. It said the virus had not previously been known in Switzerland.

Genetic testing is under way to identify the exact orthobunyavirus and to determine whether it is causing the illnesses. The veterinary office said Simbu-group orthobunyaviruses are mainly transmitted by biting midges and that no vaccines are currently available.

The Institute of Virology and Immunology said preliminary findings were in line with evidence from France and Germany, where suspicion that an orthobunyavirus is circulating is also increasing.

The institute said it was unclear whether the current heatwave was connected to the cases. It said high temperatures can stress high-yielding dairy cows and make them more susceptible to disease.