A virus spread by biting midges never before seen in Switzerland is thought to be responsible for a surge in sickness in Swiss dairy cows, authorities said Monday.
Several Swiss regions have recorded a spike in illnesses since mid-July, with cows suffering from fever and diarrhoea and producing less milk, the Federal Food Safety and Veterinary Office (FSVO) said.
“Investigations by the Institute of Virology and Immunology (IVI) have detected an orthobunyavirus of the Simbu group in several acutely ill animals — a virus previously unknown in Switzerland,” the FSVO said.
Genetic testing is under way to determine the exact orthobunyavirus and whether it is the cause of the observed illnesses, the office added.
Orthobunyaviruses of the Simbu group are primarily transmitted by biting midges, and no vaccines are currently available, the FSVO said.
The IVI said its preliminary findings align with evidence from France and Germany, “where the suspicion that an orthobunyavirus is circulating… is also gaining traction”.
The IVI said viruses in the Simbu serogroup are found primarily in Africa, Asia and Australia.
“It is currently unclear whether there is a connection between the current heatwave and the reported cases of illness,” it added.
“However, high temperatures pose a significant stress, especially for high-yielding dairy cows, and can make them more susceptible to disease.”
