Sarcoids are a type of skin tumour found in up to 12% of equids. All equids can suffer from sarcoids including donkeys, mules, horses, ponies and even zebra. Sarcoids can be very serious in some cases and when sarcoids are particularly aggressive or do not respond to treatment they can lead to the euthanasia of affected donkeys. This sad fact became very personal to me early in my career at The Donkey Sanctuary when I was involved in one of our first projects to understand these devastating tumours.
Imagine a group of 20 beautiful donkeys; all with individual characters, soft muzzles, deep brown eyes, enjoying the sunshine and playing with their friends – perfect! But when you looked a little closer it was obvious that most of these donkeys had large skin growths which in some cases were sore and bleeding. These donkeys were unlucky enough to have developed sarcoids, we are not sure what predisposes some donkeys to develop these tumours but sadly we know that some will not respond to the treatments our veterinary team have available.
Of this group of donkeys there was one that did not respond to any of the treatments that our vet team tried and whose sarcoids were deteriorating rapidly. His name was Friday. Friday was a beautiful, chocolate brown donkey with a kissable muzzle and deep brown eyes; he was just 8 years old. Sadly his sarcoids deteriorated to such an extent that they were covering much of his neck and ‘man bits’ and he could not be kept free from pain. He had no future with a good quality of life, after much heartache the decision was made to put him to sleep. I will never forget the tears and heartbreak of saying goodbye to such a young donkey who had become a real favourite. I remember hoping that in time progress could be made to prevent other donkeys developing sarcoids.
Many years on it was with sadness that I heard that we had a number of donkeys at our Italian rescue centre - Il Rifugio degli Asinelli (IRDA) suffering from aggressive sarcoids. After discussions with our veterinary team and experts in this field the sanctuary embarked on a non-invasive research project with experts at the University of Vienna to try to understand what was happening at our Italian sanctuary and whether there were measures that we could put in place to prevent other donkeys from developing sarcoids.
The research project is ongoing but has so far produced some interesting insights; it appears that the affected donkeys at our IRDA base were suffering from multiple types of sarcoids which pointed to multiple sources of infection and not one ‘super sarcoid’ outbreak; this was a relief as control would be easier. The project has also further supported the belief that sarcoids are caused by a virus called ‘bovine papilloma virus’ (BPV), the link appears similar to that between a papilloma virus and cervical cancer in humans. Understanding this link helps scientists to develop future treatment and prevention programmes; for example cervical cancer in humans is now being successfully prevented by vaccinating teenagers against HPV. Similar developments may be a very long way off for equids but they are not impossible and with understanding comes the hope of prevention. Many scientists believe that flying insects help to transfer these viruses between donkeys; this has yet to be completely proven but is the ‘best guess’ at the moment. Our ongoing research project is helping to understand these issues and develop management techniques to prevent transmission between donkeys.
We are still waiting to finalise the details of this research but in the meantime based on good practice the team at IRDA have been caring for any donkeys with sarcoids carefully in their own specific groups away from other donkeys and have been improving fly control around these donkeys. Whilst flies have not been equivocally proven to assist sarcoid transmission between equids they are at a minimum a nuisance and congregate on bleeding sarcoids. The types of flies present in the summer months at IRDA can be 1-2 inches long and bite viciously (I know, I’ve been on the receiving end!!) and cause much distress to the donkeys. Thankfully we have taken advice from people ‘in the know’ who have directed us towards some very effective traps for these specific flies, hopefully by reducing the population of these flies we can help to prevent transmission of sarcoids if there is an association – and of course prevent the donkeys from suffering from these biting, blood sucking monsters!
Whilst there are no ‘quick fixes’ for the devastating problem of sarcoids our understanding of this problem in donkeys and mules improves all the time. Through collaborative research with experts we are learning about new treatments, prevention, getting better at identifying sarcoids early on and deepening our understanding of the enemy – a tiny virus and its subsequently devastating tumour. Every time we progress this knowledge we are a step closer to stopping more donkeys like Friday suffering from this horrible disease.