Dozens of rabbits found dead with missing eyes and ears had a “dangerous” and “highly contagious” form of hepatitis, according to the RSPCA.
At least 100 rabbits were mysteriously discovered dead or dying by animal rescue volunteers in a wood near Chaddesley Corbett, Worcestershire, on 11 November.
Around 60 were rescued, with the bodies of up to 40 cleared up and handed to the animal welfare charity RSPCA.
After postmortem testing, the RSPCA has now said some of the dead rabbits were infected with Rabbit Viral Haemorrhagic Disease.
The disease is a form of hepatitis that causes internal bleeding, which can seep from their eyes, ears and noses, in most cases causing sudden death, according to the RSPCA.
Some rabbits bleed from the nose and back passage before death, while others die so quickly that there may be no outward sign of disease at all, according to the Rabbit Welfare Fund.
The viruses can survive for months in any environment and are “terrifyingly easy” to bring home to your pets, the fund added.
The illness does not affect humans.
Volunteer Vicky Grant told the BBC at the time: “There were so many of them we didn’t know what to do because I thought they were going to be small but they weren’t. We were all in our pyjamas trying to stop them from being eaten by foxes or badgers.”
An RSPCA spokesperson told The Independent: “We are strongly advising that anyone who has picked up a domestic rabbit/s from Chaddesley Corbett Wood to take the rabbit/s to be examined by a veterinary surgeon without delay.
“If people have picked up rabbits from that location they should keep them separated from any existing rabbits they may have.
“It’s also important for rabbit owners to vaccinate their rabbits, as this is the only way to protect them from some of the common serious and often fatal diseases.”