An outbreak of mycotic dermatitis in horses in south-eastern Queensland.

This research paper details an outbreak of mycotic dermatitis in horses in the South-Eastern region of Queensland, a disease caused by the Dermatophilus bacterium and its effects.

History of Dermatophilus Infections

• The Dermatophilus infections were originally identified in the cattle by Van Sacegham in South Africa in 1915.
• The ailment was later identified as the cause of a skin disease in sheep in South Africa by Bekker and in Australia by Seddon in 1928.
• In the context of Australia, Bull in 1929 described a condition, labeled mycotic dermatitis, in sheep and proposed the name Actinomyces dermatonomus for the causal organism.
• Albiston, in 1933, identified a similar or possibly the same organism from a calf skin and labelled it as mycotic dermatitis.

Dermatophilus Infections in Horses

• The first isolation from a natural infection in horses was reportedly made by Hudson in Kenya and Stableforth in England in 1937.
• In New South Wales, a condition was documented in draught horses, by Edgar and Keast in 1940, with lesions only in the facial skin, focusing around the eyes and nose. The horses showed no sign of irritation due to the lesions.
• Recently, Scarnell in England and Bentinck-Smith et al. reported about the disease, who described an exudative dermatitis in North American horses. This was the first “cutaneous streptothricosis” cases recorded in the United States, caused by Dermatophilus sp.
• Subsequently, Macadam in 1964 identified the organism from lesions in Nigerian horses as Dermatophilus congolensis. He also hypothesized that biting flies may act as mechanical vectors under natural conditions.
• In 1967, the disease was documented in four horses in New Zealand by Smith and colleagues.
• However, as Seddon stated in 1953, the conditions that encourage the growth of mycotic dermatitis in horses remain unknown.

Outbreak of Mycotic Dermatitis in Queensland

• In the current paper, the focus is specifically on an outbreak of mycotic dermatitis in horses in South-Eastern Queensland.