Vet Nick Graham of Severn Edge Equine Vets explains all about the common fungal skin infection known as ringworm.
Not caused by a worm – as its name suggests – but rather a type of fungus, ringworm is a highly contagious condition that can be easily spread from horse to human. Largely to blame are the microsporum and trichophyton species of fungi, which are expert in spreading their spores via direct horse-to-horse contact, or through shared tack, grooming brushes, bedding and other surfaces including stable doors and fencing.
As with most diseases of this type, very young and very old horses are more likely to develop ringworm as their immune systems are generally less effective, though if a horse does catch it he’ll develop a natural immunity that will protect him. This doesn’t mean he’s necessarily protected for life, but he will be less likely to get it again in future.
Mildly affected horses will usually be well in themselves, though some may attempt to rub the ringworm patches and the condition can make them sore and itchy. Left untreated it can start to damage the coat, can take up to several months to ‘self-cure’ and occasionally develop into a serious health problem.
However most cases soon recover with correct treatment and good stable management, and the hair will grow back within a month or so.
As the disease is often spread via infected tack, it’s common to see ringworm patches in the saddle or girth region, though it can affect any part of the horse’s body.
Symptoms and diagnosis
The condition may develop in a characteristic ‘ring’, but ringworm patches can be any shape and size, often starting as a raised tuft of hair. It’s common to see the spots in a cluster, with the affected skin becoming scurfy and scabby, leading to patchy hair loss. The area may be sore and itchy, and if left untreated it can spread to cover quite a wide area.
Just to confuse matters ringworm symptoms can mimic other skin conditions and your vet may suggest a skin scrape to confirm the diagnosis. This can then be examined under a microscope to look for any ringworm spores, and cultured (which is more sensitive in picking up the disease).
However, as the fungi that cause ringworm are slow-growing, treatment is usually started on suspicion before the results are available.
As the condition is so easily passed between horses and people, good stable management is the key to both preventing ringworm, and limiting its spread.
The funghi responsible are hugely resistant to heat, cold and other environmental factors, which means they can stick to stable doors, fencing, tack and grooming brushes for weeks or even months. Added to this is the fact that they can survive on a horse’s skin for up to three weeks before signs of ringworm start to show, allowing the disease quite a lengthy period of time to spread its wings – or at least its spores.
Disinfecting a new stable before your horse moves in is a wise precaution. Look for a product that specifically targets ringworm, such as Virkon S, which is available in tablet, sachet or powder form, priced around £19.99 for 1kg from amazon.co.uk
It’s also a sensible precaution to isolate any new horses that come on to the yard for a sensible amount of time – between two and three weeks – and avoid sharing your grooming equipment and rugs, etc with other horses, especially if you don’t know their history.
If your horse is diagnosed with ringworm, your vet will prescribe treatment in the form of an antifungal wash and/or as an oral medication (grieiofulvin).
They may also suggest you use one of a number of fungicidal shampoos on the market, such as Aqueos’ range of horse shampoos and disinfectant tack cleaners (see www.aqueos.co.uk). Whatever is prescribed, areas covered in thick scabs will need removing gently with a nylon brush that will need disinfecting afterwards. Some vets will advise clipping affected areas, but blades must be carefully disinfected afterwards.
As the fungus loves moist areas of skin, it’s wise to towel your horse dry where necessary and help prevent the condition taking hold further. Everything he touches, and all of his gear, must be kept well disinfected.
Your horse should be kept in a paddock or stable where he can’t make direct contact with other horses. Anyone who handles him should wear gloves, and they should change their clothes before handling any other horses on the yard. If you become itchy or have any red sore patches, go and see your GP and tell them your horse is being treated for ringworm.