Olympic champion Jessica von Bredow-Werndl has spoken of her grief following the death of Diallo BB aged 11, following a sudden illness yesterday (6 January).
“No words feel big enough for what’s broken inside me right now,” Jessica said. “Just over the weekend, we danced together, it all felt so easy.
“And then this disease came like a storm, silent, merciless and unstoppable, ate through your body in hours and ripped my heart out of my chest.”
In his short career with Jessica, the Dancier x Floriscount gelding had already established himself as a serious prospect for future championship teams.
Bred in Germany by Margaret and Herrmann Hasseler, Diallo was produced as a young horse by Jasmin Schaudt, who competed him in 2019 and 2020. He later moved to Annette Göbelsmann-Schweitzer, who allocated the ride to Roxana Noack (née Mohr) in 2021.
That year, Diallo BB finished 16th at the Bundeschampionate for six-year-olds. Diallo returned to Schaudt in 2022 before progressing to grand prix with Uta Gräf, who competed with him in the Louisdor Cup qualifiers in 2024.
Jessica and Diallo BB first competed together in April 2025, after an ownership group including Göbelsmann-Schweitzer and long-time Werndl supporter Beatrice A Buerchler-Keller secured the ride. The partnership made an immediate impact. From just nine international starts, they recorded seven wins.
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Jessica added: “You have been fighting. We fought together. We had to let you go with a broken heart because yours couldn’t any more. It’s quiet now, and I know you’re out of pain, that you’re free.
“Thank you, Diallo. For your love. For your strength. For your trust. For every moment that we were together. You’ve been a great gift. I carry you in my heart. In all I am.”
What is bornavirus, suspected cause of Diallo BB’s death?
Jessica said that investigations into the illness are still ongoing, but the suspected cause is bornavirus.
Bornavirus, more specifically Borna disease virus 1 (BoDV-1), is a rare viral infection that affects the brain and central nervous system. In horses, infection is associated with severe neurological disease and carries a poor prognosis.
The virus is thought to be carried by small mammals, particularly shrews, which can shed it without showing signs of illness. Horses are considered accidental hosts, and although transmission is believed to occur through contact with contaminated environments or secretions, the exact route of infection is not fully understood.
Clinical signs can develop suddenly and may include behavioural changes, loss of coordination, lethargy, difficulty swallowing and rapid neurological deterioration. Once symptoms appear, the disease typically progresses quickly.
There is currently no effective treatment or vaccine. Diagnosis is difficult, and most commonly confirmed through post-mortem examination, which contributes to the challenge of recognising cases early.
Cases of bornavirus infection in horses are considered extremely rare. When they do occur, the disease is devastating owing to its aggressive course and poor outcome.
At present, prevention relies on standard biosecurity and stable hygiene measures, with particular emphasis on limiting contact between horses and wildlife that may act as carriers.
Oscar joined Horse & Hound in October 2023 and is the magazine’s dressage editor and sports manager, overseeing coverage of equestrian sport. After studying equine science at Myerscough College, he spent four years working for leading dressage rider Emile Faurie, competing at the 2015 National Dressage Championships and travelling with the yard to CDIs including Aachen and Saumur. He holds a master’s degree in Literature from York St John University (2021).
