New Cattle Virus Discovered in Europe as Scientists Race to Understand Emerging Orthobunyavirus

Sources: National Veterinary School of Toulouse (ENVT), France 24, and GDS Centre – Cattle News.

A mysterious disease spreading through dairy herds in France, Switzerland, and Germany has led scientists to the discovery of what appears to be a previously unidentified virus never before documented in continental Europe.

Researchers have identified a Shamonda-like orthobunyavirus, a member of the Simbu serogroup that includes the well-known Schmallenberg virus. While affected cattle are currently experiencing relatively mild illness, veterinary experts are watching closely for a much more concerning possibility: reproductive losses that may not become apparent until the next calving season.

The discovery highlights the growing role of advanced genomic sequencing in veterinary diagnostics and serves as another reminder that emerging vector-borne diseases continue to reshape livestock health across Europe.

An Unusual Disease Appears

The outbreak first drew attention in mid-July when dairy producers in eastern France began reporting cattle with fever, diarrhea, depression, and dramatic drops in milk production.

Some farms reported temporary decreases in milk yield approaching 50 percent.

As similar cases appeared in neighboring Switzerland and Germany, veterinarians realized they were dealing with something new.

Traditional diagnostic testing failed to identify a known pathogen.

Researchers at the National Veterinary School of Toulouse (ENVT) turned to metagenomic sequencing, a technique capable of detecting unknown organisms by analyzing all genetic material present in a sample.

The results revealed a previously unrecognized Shamonda-like virus closely related to Schmallenberg virus but genetically distinct from any strain currently recorded in international databases.

German and Swiss laboratories independently reached the same conclusion.

A Virus Never Before Seen in Europe

Before 2026, Shamonda viruses had been reported only sporadically in parts of Africa and Japan.

Its appearance in France represents the first documented detection of this virus lineage in continental Europe.

Scientists are still determining whether the virus represents a completely new strain or a reassortant—a virus created when related viruses exchange genetic material.

Either possibility raises important questions about how and when the virus entered Europe.

Why Veterinarians Are Watching Pregnant Cattle

Fortunately, the illness observed so far appears relatively mild.

Most cattle recover after experiencing several days of fever, diarrhea, depression, and reduced milk production.

French agricultural authorities have stated that the current impact on affected farms remains limited.

However, veterinarians are far more concerned about what may happen months from now.

Because the virus belongs to the same family as Schmallenberg virus, researchers worry it could produce similar reproductive consequences if pregnant animals become infected during critical stages of fetal development.

Schmallenberg virus became notorious after causing abortions, stillbirths, and severe congenital defects in calves and lambs across Europe beginning in 2011.

At this stage, no reproductive losses linked to the new virus have been confirmed, but surveillance is intensifying as pregnancies continue through the current vector season.

The real impact may not become clear until calves and lambs begin arriving later this year and into early 2027.

Tiny Midges, Big Consequences

Like Schmallenberg virus, the newly identified virus is believed to spread through Culicoides biting midges.

These tiny insects also transmit bluetongue virus and epizootic hemorrhagic disease (EHD), making them familiar adversaries for European livestock producers.

Warm summer conditions favor midge activity, providing ideal opportunities for rapid spread between herds.

Because transmission depends on insect vectors rather than direct animal-to-animal contact, new infections are expected to decline during the winter before potentially resurging when midge populations return next spring.

No Risk to People or Milk

One reassuring aspect of the outbreak is that there is currently no evidence the virus infects humans.

French authorities have emphasized that the virus poses no public health risk, including no concerns regarding the safety of milk or dairy products.

That finding is consistent with other members of the Simbu serogroup, which have not been associated with human disease.

A Race Against Time

Researchers are already developing diagnostic tests that can be distributed to veterinary laboratories throughout France, while pharmaceutical companies have begun early work on vaccine development.

Those efforts, however, will take time.

Unlike regulated diseases such as bluetongue, the newly identified virus is not currently subject to European surveillance requirements or mandatory control measures.

For now, veterinarians have few options beyond supportive care, monitoring affected herds, and reducing exposure to biting midges where possible.

What Comes Next?

Veterinary epidemiologists expect the outbreak to continue expanding while midge activity remains high.

The greatest concern isn't the acute illness being seen today—it's what might emerge months from now if infections during pregnancy result in abortions or congenital abnormalities similar to those caused by Schmallenberg virus.

For veterinarians working with cattle, sheep, and goats, the coming calving and lambing seasons will provide the first real indication of whether this newly discovered virus becomes another major challenge for European livestock production or remains a relatively mild seasonal disease.

Until then, the discovery stands as another example of how rapidly emerging pathogens can appear—and how advances in veterinary diagnostics are allowing scientists to identify them faster than ever before.