Swiss health authorities have detected the Shamonda virus in dairy cows across multiple cantons for the first time this summer, following reports of unusual livestock illness in late July.
The pathogen, which is transmitted by biting midges and mosquitoes, causes fever, diarrhoea, and a marked decline in milk production among cattle.
The alert issued by Swiss health officials follows recent waves of lumpy skin disease contamination in France, raising heightened concern among regional agricultural authorities.
Livestock owners first reported worrying symptoms in several cattle herds at the end of July, according to the Federal Food Safety and Veterinary Office. The agency stated that affected animals suffered from high fever and diarrhoea, frequently accompanied by a sharp drop in milk yield.
The Federal Food Safety and Veterinary Office, known as OSAV, is the Swiss government agency responsible for veterinary public health, animal welfare, and food safety standards across the country.
Identification of the Shamonda virus
Laboratory analyses and genetic sequencing subsequently enabled health authorities to identify the pathogen as the Shamonda virus, a member of the orthobunyavirus family.
The Swiss Confederation confirmed that the virus has since been detected in aborted cow foetuses as well as brain tissue samples from horses displaying central nervous system disorders.
Orthobunyaviruses are a family of viruses primarily transmitted by arthropod vectors, including Culicoides biting midges. The Shamonda virus belongs to the Simbu serogroup, a category of pathogens historically established in parts of Africa, Asia, and Australia.
Health authorities emphasized that the Shamonda virus poses no threat to human health. As a strictly zoonotic agent targeting livestock and ruminants, neither handling infected animals nor consuming meat or dairy products from affected farms presents any human health risk.
Rapid spread across Swiss cantons and Europe
According to the Swiss Institute of Virology and Immunology, the disease has expanded significantly beyond the initial outbreaks recorded in late July.
Within a few weeks, the virus spread towards the south and east of Switzerland, reaching 22 cantons, including Ticino, Glarus, and Grisons, as well as the Principality of Liechtenstein.
Switzerland is composed of 26 cantons, which serve as member states of the federal republic. Ticino lies to the south of the Alps, while Grisons and Glarus occupy eastern alpine regions. Liechtenstein is a small landlocked principality bordering eastern Switzerland.
The institute reported that the pathogen is actively circulating across Europe, driven by insect population movements and livestock transportation. Confirmed infections have been documented in Germany, France, the Netherlands, and Austria.
Officials noted that summer heatwaves could further accelerate the spread of the virus by encouraging the proliferation of vector midges.
Control measures and disease management
Efforts to contain the virus are complicated by its transmission through flying insects rather than direct contact between animals.
The Institute of Virology and Immunology and the veterinary office stated that the main control strategy relies on rigorous epidemiological surveillance alongside measures to limit insect exposure, including the use of repellents and moisture management on farms.
Because no commercial vaccine currently exists for this strain of the virus, international health coordination between Switzerland and neighbouring European countries remains the primary mechanism to track and slow the epizootic.
An epizootic refers to an outbreak of an infectious disease that spreads rapidly among animal populations within a region. Regional veterinary authorities continue to monitor herds across affected areas.
