Shamonda virus reaches the Czech Republic: first case in cattle in South Bohemia — how the disease shows and what cattle and horse keepers should do

What was found in the Tábor district

On 23 October 2026 the Czech State Veterinary Administration (SVS) reported the country's first case of Shamonda virus. It was found in an aborted foetus on a cattle farm in the Tábor district of the South Bohemian Region. The diagnosis was made by the State Veterinary Institute in Jihlava.

Adult cows on the farm had signs typical of the virus: a fever that lasted several days and falling milk yields. On its own, an episode like this is easy to mistake for an ordinary bout of illness in the herd — only testing the aborted foetus showed what was going on. The Czech Republic is one of the last countries in the region to be reached by the virus: it was found in neighbouring Germany and Austria back in the summer.

How the Czech Republic is looking for the virus

Since 1 October a compulsory surveillance programme has been in force in the Czech Republic. At the state's expense, aborted cattle foetuses, calves born with deformities, and stillborn and non-viable calves are tested for Shamonda virus. The veterinary administration introduced this testing at the start of October, when it became clear how quickly the virus was spreading across Europe.

If an adult animal — a cow, horse, sheep or goat — shows acute signs of illness, the owner can also have it tested at one of the state veterinary institutes together with their private vet. The owner, however, pays for these tests.

Why test foetuses and calves in particular? In an adult cow the virus stays in the blood for only a few days, and by the time the farmer calls the vet it often can no longer be detected. Traces of infection last longer in the tissues of a foetus or newborn calf. That is why an aborted foetus is the most reliable way to find out whether the virus has been on a farm.

Where the virus has already been found

In central Europe, Shamonda virus appeared in cattle in summer 2026. According to the Czech veterinary service, it has already been confirmed:

• in Germany — in Baden-Württemberg, Hesse, Bavaria, Saarland and Saxony;
• in Austria — in Vorarlberg, Tyrol, Salzburg, Upper Austria and Styria;
• in Switzerland, France, the Netherlands, Belgium, Italy and Luxembourg.

In total, according to a bulletin from France's national animal health institute, the virus has now been detected in 14 countries in western Europe. It was first isolated from cattle in Nigeria in 1965 and later found in other African countries and in Asia. Scientists are still working out exactly how it reached Europe: midges can be carried long distances by the wind.

How cattle are affected

In cows the disease usually starts suddenly: temperature rises, the animal eats less, it may get diarrhoea, and milk yield drops sharply. In a study of nine dairy farms in France, milk yields in infected herds fell by up to 75%. After a few days most adult cows recover and the herd returns to normal. But even a short episode like this is costly for a farm: milk is lost, treatment and extra care are needed, and some cows later have fertility problems.

So the most dangerous thing about this disease is not the acute phase but what happens to pregnant cows. The virus can cause abortion, and calves that are still born may have deformities.

Why pregnancy is the main risk

Viruses in this group, which includes Shamonda and Schmallenberg virus, well known in Europe, are dangerous because they cross the placenta to the foetus. If a cow is infected early in pregnancy, the virus damages the calf's developing nervous system and muscles. The result can be abortions, stillbirths, and calves with twisted joints and limbs, a curved spine or brain malformations.

The Czech veterinary service names roughly weeks 8 to 14 of pregnancy as the most vulnerable period in cows. The trouble is that the farmer only learns about the infection months later — when affected calves are born. That is why monitoring abortions and deformities matters so much.

Horses, sheep and goats

The virus does not only infect cattle. In horses, according to the Czech veterinary service, inflammation of the brain and neurological problems have been described: the animal may stagger, coordinate its movements poorly or behave unusually. Sheep and goats are also susceptible, but there is little data yet on how the disease develops in them. In France this summer, isolated infections were found in small ruminants and horses.

Neurological signs in a horse are always a reason to call the vet urgently. Similar symptoms occur with West Nile fever, which is spread by mosquitoes, and with other diseases, and only a laboratory test can tell them apart. Horses do not catch Shamonda virus from each other: it is spread only by midges.

How to tell it apart from bluetongue and Schmallenberg

The same midges spread bluetongue virus and Schmallenberg virus in Europe, and the signs of these diseases partly overlap: fever, falling milk yields, abortions. Bluetongue more often causes swelling of the face, ulcers in the mouth and lameness, and in sheep it can be severe and fatal. But a diagnosis cannot be made from appearance alone — a laboratory test is needed. So whenever there are suspicious signs, the vet takes samples and sends them to the lab.

Why there is no quarantine

Under current Czech and EU law, Shamonda virus is not classed as a notifiable disease. A country where it appears is not required to take emergency veterinary measures such as culling, restriction zones or movement bans. The presence of the virus does not affect veterinary certificates for exporting animals either. By comparison, with bluetongue, which is on the EU list of animal diseases, restriction zones are set up around outbreaks, and moving animals out of them requires testing and vaccination.

This does not mean the disease is harmless. There is simply no vaccine against it, and the vectors — midges — fly freely, so a quarantine would not stop them. The main measures are therefore surveillance, protecting animals from bites and sensible planning of insemination.

What farmers should do

The Czech veterinary service advises:

• protecting susceptible animals from midges with repellents and insecticides authorised for those species — your vet can help you choose;
• planning insemination so that the vulnerable stage of pregnancy does not coincide with the midge season;
• restricting the movement and sale of animals while any on the farm show signs of illness;
• reporting every abortion, stillbirth and calf born with deformities to the vet — in the Czech Republic such cases are tested free of charge.

It also helps to reduce places where midges breed: clear away manure and avoid standing water and damp bedding around cattle sheds and paddocks. Keep a record of insemination dates and every case of illness in the herd: if calves with deformities are born in spring, these records will help the vet work out when the infection happened. In the UK, suspicious cases can be discussed with your vet and the Animal and Plant Health Agency.

The link to the human case in France

Almost at the same time, on 22 October, France reported the world's first human case of Shamonda virus infection — a patient with a severely weakened immune system, who died. The authorities called the case exceptional and see no risk to the public: the virus is not passed from person to person, nor through milk or meat. For farmers and vets, one sensible precaution applies: protect yourself from midge bites at dusk, when they are most active.

For horse owners and smallholders

The virus does not only concern large farms. If you keep a horse, a few goats or sheep, the same rules apply: in midge season bring animals under cover at dusk and dawn, use rugs, fly masks and repellents recommended by your vet, and call the vet straight away if there is fever, loss of coordination or an abortion. If you are buying or selling an animal, ask whether there have been signs of illness on the farm: there are no formal restrictions, but it is better not to move a sick animal. There is no data on this disease in dogs and cats, and no special measures are needed for them — normal protection against fleas, ticks and mosquitoes is enough.

What happens next

As the weather turns cold, midges become almost inactive, and there will be few new infections until spring. But farmers will see the consequences of this season later: calves conceived in summer and early autumn will be born in winter and spring. Vets are therefore asking farmers to watch calvings closely and report every suspicious case. In spring, with a new midge season, the virus may return — as happened with bluetongue and with Schmallenberg.

Experience with Schmallenberg also gives grounds for cautious optimism. After the first wave in 2011–2012, most animals that had been infected developed immunity, there were noticeably fewer cases in the following seasons, and a few years later vaccines became available. How Shamonda virus will behave is not yet known, so veterinary services will keep watching it next year as well.