Racing Victoria (RV) would like to alert trainers to an increased number of horses presenting with skin lesions on raceday and being treated for ringworm in training stables and on spelling properties.
The higher frequency of ringworm cases is most likely a result of recent weather conditions and excessive moisture in the environment.
Cause of Infection
Ringworm (dermatophytosis) is a highly contagious fungal infection of the skin which can be transmitted by direct contact between horses, tack, grooming equipment, clothing, infested stables or floats.
The disease is usually apparent within 9-15 days of exposure. Characteristic skin lesions are areas of hair loss (alopecia) with variable crusting and scaling and affected horses can be very pruritic (itchy). Lesions are most common where tack contacts the skin but can also occur on distal limbs and rarely, coronary bands.
Your Permitted Veterinarian will be able to confirm a ringworm diagnosis through:
- Direct microscopic examination of the hair shafts for fungal elements (rapid results)
- Fungal culture of hair plucks, skin scrapes or skin biopsies (results in up to 4 weeks)
- Polymerase chain reaction (qPCR) of hair plucks and skin crusts (available at IDEXX) (results in 1-3 days)
Prevention & Control
Infected horses should be isolated to prevent direct or indirect contact with other horses. Isolation within a main barn is acceptable as long as there is no potential for horse-horse contact.
Personal protective equipment should be worn whenever the horse is handled or when the stall is entered. Separate tack and grooming gear should be used on affected horses.
Treatment
Although most cases of ringworm can heal spontaneously, this can take up to four months. Treatment is advised to accelerate recovery and reduce the risk of subsequent animal or human infection and should be continued for 2-4 weeks after resolution of clinical signs.
RV recommends the use of products registered for the treatment of ringworm in horses, including:
- Application of 0.2% enilconazole e.g. Imaverol, Austrazole at a 1:50 dilution - It is important to follow the manufacturer’s instructions when using these products
- Bathing with antifungal medicated shampoos e.g. Malaseb (chlorhexidine + 2% miconazole) and use of topical creams/ointments e.g.Fungazol, Fungafite
- Decontamination of the environment including brushes, tack, blankets, leg wraps and riding apparel, particularly the rider’s boots
- Dermatophyte spores will be destroyed by most disinfectants (bleach, benzalkonium chloride and Virkon)
- Enilconazole can be used for disinfecting tack
Anti-fungal treatments registered for use in cattle are not recommended. Trainer Obligations
Pursuant to AR90 in the Australian Rules of Racing: “a person must not permit a horse suffering from an infectious disease to be brought on to a racecourse or training track”.
Trainers are required to notify Stewards if a horse is suffering from a condition causing multiple/diffuse skin lesions or if the horse has recently had Ringworm and inactive/healing lesions are still present. A veterinary clearance (including detailed assessment/description of the skin condition and any diagnostic procedures performed, results and treatment) with accompanying photographs (before and after treatment) is required prior to the horse participating in a race, jump-out or official trial.
Due to the contagious nature of ringworm, if a horse presents at a raceday, jump-out or official trial with skin lesions consistent with a ringworm infection without prior notification to Stewards, the Chairman of Stewards, in consultation with Official Raceday Veterinarians, may elect to prevent the horse from participating in the race, jump-out or official trial.
A veterinary clearance will be required with accompanying photographs (before and after treatment) prior to future nominations for that horse.
Figure 1. Common ringworm lesions consist of a circular area of alopecia (hair loss) and scaling, with centripetal spreading and resolution of infection in central areas with new hair growth, while active disease continues to extend outward.
A) 
B) 
C) 
Figures 2. Characteristic papules with tufted hairs (a) and more progressed alopecic and scaling areas in horses with typical ringworm infections (b, c) Durham A, (2020) Diagnosing and treating ringworm in horses.
Human Infection
It is possible but rare for ringworm to be transmitted from horses to humans. Infection usually causes round flat patches of itchy and/or scaly skin (may be red, brown or grey). Please consult your general practitioner should you have any concerns.
Conclusion
If you seek further information in relation to ringworm, be that now or in the future, please feel free to email: veterinaryadmin@racingvictoria.net.au.