Portugal’s veterinary authorities have confirmed the presence of the Shamonda virus (SHAV) in the country, an insect-borne infection affecting primarily cattle and sheep.
The Portuguese Veterinary Association issued an alert this week following a request from the Directorate-General for Food and Veterinary Affairs (DGAV), which is monitoring the epidemiological situation.
Despite concern within the livestock sector, veterinarians stress that there is currently no evidence that Shamonda virus can be transmitted to humans.
“There is no evidence that the Shamonda virus is zoonotic, with no known risk of transmission to humans,” the association said.
SHAV belongs to the Orthobunyavirus genus and the Simbu serogroup and is transmitted through the bites of tiny Culicoides midges.
In cattle, infection can cause fever, diarrhoea, lethargy and reduced milk production. The potentially more serious effects occur when pregnant animals become infected, as the virus has been associated with abortions and foetal abnormalities.
Sheep and goats can also become infected, although they generally display few or no obvious symptoms.
Experts say the greatest concern is therefore not usually illness in adult animals, where symptoms tend to be relatively moderate, but the effect on developing foetuses. Infection during pregnancy can lead to serious abnormalities affecting the nervous and musculoskeletal systems.
Virus spreading in Europe
Until relatively recently, Shamonda virus had been identified mainly in Africa and Japan.
However, cases have been confirmed in several European countries during 2026, including Switzerland, France, Germany, Austria and the Netherlands, pointing to a wider geographical spread of the virus.
There is currently no specific vaccine or treatment available for SHAV.
Authorities are consequently focusing prevention efforts on reducing animals’ exposure to the biting midges responsible for transmitting the infection.
Michael Bruxo
Journalist for the Portugal Resident.