‘We’re determined to get answers’: new campaign launched after increase in grass sickness cases and fatalities
It has been a “pretty bad year” for grass sickness but it is thought there have been far more cases than have been reported
A major appeal has been launched for funding to help in the ongoing battle against equine grass sickness (EGS) after a recent increase in cases – including the death of five ponies in a herd of eight.
The Equine Grass Sickness Fund, a charity that is part of the Moredun Foundation, had recorded 74 cases of EGS by 11 September 2026, compared to 67 in 2025. The condition, which causes degenerative changes to the central and autonomic (involuntary) nervous systems, is fatal in some 80% of cases.
Research scientist Beth Wells of the foundation told H&H it had been a “pretty bad year” for reported cases.
“But I think we only get the tip of the iceberg,” she said. “We think there are far more cases than are reported. But without that, we just don’t know where they’re occurring, what time of year, how many cases, what type of horses, whether they survive or not.”
Dr Wells said it is thought the increase is owing to the atypical weather conditions this year.
“Cases are springing up where we wouldn’t necessarily expect them,” she said. “We’re getting them on the usual east coast, Scotland, right down England to Kent, and quite a few further west.
“It’s not to say there’s never grass sickness in the west because there are sporadic cases. But we seem to be getting clusters of acute cases where the horses are all dying. A lady in the south-west of Scotland had a horrible experience. She’s a breeder, she’d never had it before and she lost five over a weekend.”
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The foundation has, with a climatologist, modelled weather conditions that can increase the risk of EGS; high temperatures during the day followed by cold nights, and prolonged drought followed by a sudden change and flush of grass.
Dr Wells said owners can sign up to weather alerts on the Equine Grass Sickness Fund website, which means they will be sent a WhatsApp message if the conditions are risky, and if cases are reported in the area – another highlight of the importance of reporting.
The fundraising campaign is on now
She said she keeps her Highlands in a high-risk area so she keeps an eye on the weather but also feeds hay in the field all year round.
“Anything that keeps the microbiome stable,” she said. “The hypothesis is that the weather causes a flush of grass, which potentially upsets the microbiome. That could interfere with the tight junctions of the gut, potentially letting through anything into the ‘inner workings’ of the horse, where it has access to the nervous system, the neurons, circulatory system.
“That’s my gut feeling so the biggest thing the owner can do is keep the microbiome stable.”
Dr Wells gets as many ponies in as she can every day for a break from grass with hay. She feeds the minerals key to smooth muscle function and ensures her horses have a balanced diet, making no sudden changes. She said a link between ivermectin and EGS has been shown, so if worming with this is needed, as shown by testing, she advises delaying worming until high-risk conditions have settled.
All the 38 reported cases between April and June died, which Dr Wells said shows “the devastation of the disease”.
“And we can’t treat it,” she said. “That’s why research is so important.”
The fund set up a biobank, funded by the British Horse Society, of tissue samples from affected horses to be studied and compared with those from healthy horses. They also grow “organoids”, versions of equine organs grown in a lab from stem cells, which can be used to model the disease and carry out tests – but this is hugely expensive.
“The fund is a charity and relies on donations,” she said. “We’re really pushing the research and doing massive fundraising campaigns. We appreciate any support from horse owners, and it’s all about the funding; we need equine research properly funded but we are absolutely determined. We will get answers but it’s really not simple.”
The campaign, launched on 11 September, asks owners to donate anything they can.
“We hear regularly from owners whose lives have been changed forever by grass sickness,” a fund spokesperson said. “For those who have lost beloved horses and ponies, the impact can be devastating. We also celebrate the small number of chronic cases that survive through intensive nursing and dedicated veterinary care, offering hope that improved understanding and treatment can make a real difference.”
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Eleanor is an experienced journalist who spent over eight years working for local and national newspapers before joining H&H as news editor in March 2016. Passionate about equine welfare and exposing the truth, Eleanor has reported on all aspects of the industry, from Brexit to anti-bullying campaigns, and from dressage rules to mules. Her sport of choice is showjumping, in which she competes her own horses, and she also enjoys reporting at local jumping shows through to international championships.