Early detection of bovine besnoitiosis
- Heather Graham
- Researcher
“The question is not if bovine besnoitiosis will reach the Netherlands, but when. That is precisely why early detection is so important.”
A parasite that is already present across large parts of Europe can spread unnoticed through the international trade in cattle. In 2025, we detected antibodies against Besnoitia besnoiti in an imported cow in the Netherlands for the first time. This finding highlights the importance of early detection to prevent the parasite from becoming established. That is why we are investing in both scientific knowledge and veterinary diagnostics. “To support these efforts, we are temporarily offering free testing for antibodies against bovine besnoitiosis,” explains project leader Heather Graham.
Bovine besnoitiosis is caused by the parasite Besnoitia besnoiti. The disease is mainly found in Southern Europe, Africa and Asia. However, outbreaks or positive cases have now also been reported in Switzerland, Hungary, Greece, Ireland, Germany and Belgium. In Belgium, a single imported infected breeding bull eventually led to outbreaks on multiple cattle farms. This demonstrates how important early detection and surveillance are before infections become clinically apparent.
Antibodies
During the screening of imported cattle in 2025, we detected antibodies against Besnoitia besnoiti in the Netherlands for the first time. The antibodies were found in a cow that had been imported for slaughter. The animal showed no clinical signs of disease and remained in the Netherlands only briefly.
This discovery demonstrates that the introduction of the parasite into the Netherlands is a realistic possibility. Every year, the Netherlands imports more than 10,000 cattle from countries where bovine besnoitiosis is present. It is therefore essential that we are well prepared for the arrival of this parasite. Diseases that initially spread unnoticed require vigilance long before an outbreak becomes visible.
Early signs
The first signs of bovine besnoitiosis often resemble those of other diseases. Fever, reduced milk production, swollen lymph nodes and general malaise are all non-specific symptoms that can occur in many conditions. Only later do the characteristic skin lesions and tissue cysts develop, for example around the eyes and vulva.
This silent progression makes early recognition challenging. By combining epidemiology, veterinary diagnostics and practical field knowledge, we help detect infectious diseases such as bovine besnoitiosis at an earlier stage.
Diagnostics as the first line of defence
There is currently no effective treatment or widely available vaccine for bovine besnoitiosis. Animals that test positive are generally culled. According to parasitologist Heather Graham, the greatest opportunity lies in prevention.
“It is essential that we identify risks before the disease starts to spread,” she emphasises. “At Wageningen Bioveterinary Research in Lelystad, we have diagnostic tests that can detect antibodies in imported cattle. These tests contribute to the early detection of infections.”
Free testing for bovine besnoitiosis
To help prevent the establishment and spread of this parasite, we are expanding our knowledge and diagnostic capacity for the early detection of antibodies against Besnoitia besnoiti. As part of this initiative, Dutch cattle owners can temporarily have their imported cattle tested free of charge for antibodies against bovine besnoitiosis.
Bovine besnoitiosis is not a notifiable disease, and a positive test result has no regulatory consequences. When submitting a serum sample, information is requested about, among other things, the year of import, the animal's age and its medical history.
A free test can be requested using the Rund-besnoitiosetest submission form, available on the Animal Disease Testing Request Forms page.
The number of free tests is limited. Testing will remain available while supplies last.
Frequently Asked Questions about Bovine Besnoitiosis
Bovine besnoitiosis is a disease of cattle caused by the parasite Besnoitia besnoiti. The disease can result in skin lesions, fertility problems, and reduced milk and meat production.
In the acute stage, clinical signs are non-specific and may include reduced appetite, decreased milk production, high fever and general weakness. Eye and nasal discharge may also occur, and pregnant animals may abort as a result of the high fever. Later in the acute phase, swelling develops around the head and neck, followed by swelling around the joints, which may result in lameness.
In the chronic stage, tissue cysts develop in the sclera (the white of the eye) and in the vulva of female cattle. The skin may also become thickened, wrinkled and hairless, and in severe cases may even peel away. By this stage, affected animals have often lost a considerable amount of body weight.
The disease is endemic in Southern Europe, including Spain, France, Portugal and Italy. However, outbreaks and individual cases have also been reported in Belgium, Germany, Ireland, Hungary, Switzerland and Greece. During the screening of imported cattle in 2025, Wageningen Bioveterinary Research detected antibodies against Besnoitia besnoiti in a cow imported from France.
The parasite is primarily transmitted by blood-feeding insects, such as stable flies and horseflies. Transmission may also occur through natural mating, direct contact with open wounds, or by using the same needle on multiple animals.
Yes. Most infected animals have subclinical infections and show no visible signs of disease. Nevertheless, these animals may remain lifelong carriers and continue to spread the parasite.
In non-endemic countries such as the Netherlands, a higher proportion of infected animals are expected to develop clinical disease than in countries where the parasite is endemic. As a result, outbreaks can cause substantial economic losses.
The diagnosis of bovine besnoitiosis is based on the clinical presentation, with cysts in the sclera or vulva considered characteristic of the disease, in combination with laboratory diagnostics. During the acute stage, before antibodies have developed, the parasite can be detected by PCR testing of blood or tissue samples. For the chronic stage, histopathological examination of biopsy samples or serological testing (ELISA) is available. Serological testing is the only method for identifying subclinical carrier animals. A positive ELISA result should always be confirmed using a Western blot test to exclude cross-reactivity with other parasites. In the Netherlands, Wageningen Bioveterinary Research offers an ELISA test for screening and confirming bovine besnoitiosis by means of serological testing.
No. There is currently no effective treatment or vaccine available in Europe.
A strict purchasing policy is the most important measure to prevent the introduction of bovine besnoitiosis. Because infected cattle frequently show no clinical signs, newly introduced animals originating from endemic areas should always undergo serological testing before or during quarantine, for example by means of an ELISA test. In the Netherlands, this test is offered by Wageningen Bioveterinary Research. Whenever possible, importing cattle from endemic areas should be avoided.
Together we make a difference
Do you have questions about besnoitiose or the diagnostic test for the detectiona of antibodies? Contact our expert.
