Shamonda virus in Switzerland
On 31 July 2026, the IVI detected the Shamonda virus in samples taken from cattle with fever, diarrhoea and a drop in milk yield. This is the first occurrence of another virus of the Simbu serogroup in Switzerland since the first Schmallenberg virus outbreak in 2012.
The virus has since also been detected in aborted bovine foetuses and in horses with central nervous system disorders.
Updates on the evolving situation regarding the Shamonda virus in Switzerland
Update of 16 September 2026: from October 2026, the focus of surveillance in Switzerland will shift to abortions and malformed/affected young animals: the IVI will continue to test samples from aborted foetuses and from malformed/affected young animals for Shamonda virus free of charge. The costs of these tests are covered by the Federal Food Safety and Veterinary Office FSVO.
This targeted approach will help detect persistent virus-associated diseases and provide a more meaningful picture of the clinical impact of SHAV in Switzerland.
Free tests for Shamonda virus (SHAV) in samples from adult animals will only be offered until the end of September 2026. As the vector season is gradually coming to an end and the likelihood of an acute infection in adult animals is rapidly decreasing, large-scale testing of such samples is no longer expected to yield significant additional findings.
Such samples should no longer be submitted for SHAV testing, and from 1 October, testing will be subject to a fee (CHF 100).
Update of 9 September 2026: A large proportion of the submitted samples from aborted foetuses are still testing positive for Shamonda virus. In samples from adult cattle, however, a smaller proportion are testing positive. This indicates that the acute wave of Shamonda virus infections is subsiding.
Our publication on the experiences of the first weeks of the Shamonda virus outbreak in Switzerland is now available online. Identification, Isolation and Genomic Characterization of an Emerging Shamonda Virus Variant Associated with Bovine Disease in Switzerland
A significant observation was that a second type of Shamondavirus had been detected in Belgium, the Netherlands, northern Germany and north-western France. This one is independent of the first type that is circulating in France, southern Germany, Austria and Switzerland. At present there are no indications that the two types cause different symptoms, but investigations are in full swing in all countries.
The animals had been tested for WNV at the IVI due to neurological symptoms in recent weeks. It was not (no longer?) possible to detect the Shamonda virus in the available samples from these animals, only antibodies. The detection of antibodies indicates previous exposure to the virus, but does not allow any conclusions to be drawn regarding a causal link between a potential Shamonda virus infection and the observed neurological symptoms.
Diagnostic testing for the Shamonda virus in horses is currently only offered by the IVI following a test for the WNV : Epizootic disease diagnostics – Equines
In the brain of one diseased horse, genetic material of a Shamonda virus was found using untargeted sequencing (metagenomic NGS) at the Neurocenter of the Vetsuisse Faculty in Bern. The IVI detected the Shamonda-like virus in brain samples from this and another horse using pan-Simbu PCR.
While it is clear from the literature that orthobunyaviruses of the Simbu serogroup – to which the Shamonda virus belongs – mainly infect ruminants, they can also affect horses in rare cases. However, the virus has never previously been detected in horses in Europe.
Over the last few weeks, Equinella (Equinella: Report overview table) has received increasing reports of unexplained central nervous system disorders in horses from various regions of Switzerland, with affected animals being treated at the equine clinics of the Vetsuisse Faculty in Bern (Institut suisse de médicine équine, ISME) und Zürich (Universitäres Tierspital).
It was only possible to detect the virus in brain tissue, while blood and cerebrospinal fluid tests were negative, which may be due to an even shorter viraemia in horses than in cattle. Further investigations are needed to understand more about the infection in horses. The IVI is working intensively to enable diagnostic testing in live horses too.
In affected horses, only the symptoms can currently be treated. Based on current knowledge, the disease is transmitted by midges. Consistent protection against midges therefore reduces the likelihood of infection.
More information: Institut suisse de médicine équine, ISME
Cattle in Ticino, Glarus and Graubünden have also tested positive, taking the number of affected cantons to 22. Following outbreaks already reported in the Netherlands, cases have now also been confirmed in Austria (Vorarlberg and Upper Austria) by the Austrian Agency for Health and Food Safety (AGES).
In order to monitor any infections and impacts of the Shamonda-like virus on small ruminants and new world camelids, the BGK (Swiss competence and health service centre for small ruminants) has launched a questionnaire that should also be completed when submitting samples to the IVI (see link below).
Update of 17 August 2026: Since the first confirmed case of the Shamonda-like virus in Switzerland, it has been detected in blood samples and several aborted foetuses in 17 cantons and the Principality of Liechtenstein over the past two weeks. The virus continues to spread across Europe. In recent days, it has also been found in the Netherlands.
Update of 13 August 2026: The IVI has also detected the virus for the first time in cattle from Liechtenstein. There is a risk of further spread to the east. The IVI is working closely with the competent laboratory in Austria.
Important information regarding abortion testing: The IVI is unable to test any further foetuses. Please note the information on this page about the sample material to be submitted.
Update of 10 August 2026: analysis of the full viral sequencing of several individual animals from different cantons conducted at the IVI provides conclusive evidence that this is indeed the Shamonda-like virus. The virus is practically identical to the one detected in Germany and also shows only slight differences between individual herds. Further investigations on the exact taxonomic classification of the virus are under way.
Since 6 August 2026, the IVI has, for the first time, detected the Shamonda-like virus in samples from several aborted bovine foetuses from different herds. Other possible causes of the abortions and related factors are currently being investigated. These cases confirm the assumption that the virus can be transmitted transplacentally to bovine foetuses, which may also lead to abortions. The current situation is being closely monitored by the IVI, together with the FSVO, the RGS (organisation for bovine health in Switzerland) and other partners.
Update of 3 August 2026: on 31 July 2026, the IVI detected viruses of the Simbu serogroup in samples from cattle in Switzerland for the first time.
Viruses of the Simbu serogroup – to which the Shamonda virus and Schmallenberg virus belong – mainly occur in Africa, Asia and Australia and, like the bluetongue virus, are transmitted by blood-sucking midges of the genus Culicoides.
The results obtained by the IVI to date match the findings from France and Germany, where the virus is also circulating.
It is still not clear whether there is also a connection between the current heatwave and the reported disease occurrences. However, high temperatures place a severe stress on animals, particularly on high-yielding dairy cows, and can make them more susceptible to disease.
Sympoms and diagnotics
Non-specific symptoms such as fever, diarrhoea and a drop in productivity can also indicate a highly infectious animal disease. Animal keepers should therefore notify their vet immediately so that the necessary examinations can be carried out where necessary.
Clinical symptoms observed in cattle
Nearly all affected cattle farms report a disease lasting around 14–21 days. The most common clinical symptoms are:
- Fever (>40 °C) over 1–2 days
- A huge drop in milk yield
- Loss of appetite
- Diarrhoea
Sample material to be submitted
- Live animal: serum and (optionally) EDTA blood.
- Dead adult animal: if possible serum, otherwise spleen and body cavity fluid, in the case of neurological symptoms: brain tissue.
- Aborted foetuses: brain, spleen, blood from the heart/body cavity fluid – no placentas, no whole foetuses/whole heads.
Cost coverage
Free tests for Shamonda virus (SHAV) in samples from adult animals will only be offered until the end of September 2026, and samples will only be tested for a fee (CHF 100) from 1 October.
However, it is important that:
- details regarding the nature and duration of the symptoms in the animals from which samples were taken are provided on the IVI test application form:
- the questionnaire on symptoms at herd level, drawn up by Rindergesundheit Schweiz (RGS), needs to be completed (German)
Fragebogen “Fieberhafte Durchfallerkrankungen bei Rindern”
Aborted foetuses: samples from aborted foetuses and from malformed/affected young animals will continue to be tested free of charge for Shamonda virus SHAV at the IVI. The costs of these tests are covered by the Federal Food Safety and Veterinary Office FSVO.
For small ruminants
Here is the questionnaire drawn up by the competence centre and health service for small ruminants (BGK/SSPR) on the symptoms at herd level:
‘Fieberhafte Durchfallerkrankungen bei Schafen, Ziegen und Neuweltkameliden’
Horses
Horse owners should contact their veterinarian if they have any questions.
Veterinarians: In the event of a suspected case, veterinarians should contact the ISME equine clinic in Bern (+41 (0)31 684 22 43) or the equine clinics in Zurich (+41 (0)44 635 81 15) before any possible referral. Please report these cases as ‘case without a diagnosis’, stating the observed symptoms and currently available test results to Equinella.
More information: Institut suisse de médicine équine, ISME