Dermatophytosis is more prevalent when horses share equipment such as tack & blankets. Younger horses, poor nutrition & , crowded conditions can also predispose. The condition presents as multiple dry, itchy, circular, scaly areas of alopecia with a pronounced, slightly raised border around the lesions. Diagnosis is through clinical signs and symptoms as well as a fungal culture from skin & hair scrapings. Ringworm is self-limiting, meaning the condition will clear up on its own within 1-4 months. To speed recovery treatment usually involves the application of topical antifungal ointments or shampoos. Symptomatic treatment includes away infected hair and keeping the areas clean & dry. Prognosis is good. Dermatophytosis can be prevented by quarantine, proper hygiene & disinfection.
Equine Pythiosis (Phycomyosis, Leeches, Swamp Cancer)
Equine pythiosis is caused by an
fungus-like organism called Pythium insidiosum, or
‘water mould’.
Transmission is environmental, but inhalation or ingestion of spores can occur.
The organism gains entry through a wound, nasal or oral cavity, spreads quickly to cause a deep infection of the skin and may also spread to regional lymph nodes, respiratory system, GI system & abdomen. Predisposition is low prairie land, tropical & subtropical regions such as Florida, Costa Rica & Australia. Due to the nature of the organism any horses that live/travel in lands can also be predisposed. The lower limbs are most commonly predisposed, but the chest and abdomen are also common sites for infection. Signs & symptoms include gray/yellow swollen necrotic eosinophilic tumor-like masses with drainage tracts of foul-smelling weeping exudate. In the centre of the lesion is a hard mass known as . The lesions may ulcerate & bleed easily. The lesions can grow up to 25cm in diameter and surround an entire limb. The lesions may be pruritic so the horse may itch and rub opening the lesions predisposing for secondary bacterial infection. If the respiratory system is affected, a dry cough and serous nasal discharge is noted.
Diagnosis is skin biopsy, exudate culture and an ELISA blood test for antigen detection.
Treatment is betadine soaks to decrease risk of bacterial infection, immunotherapy which involves a set of vaccinations with the organism to trigger a greater immune response and possible surgery to remove masses if they are large or interfere. It is important to treat early or this condition has a prognosis.
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