Granulomatous and neoplastic diseases of the skin of horses.

This research article discusses the findings of a study that examined various skin diseases in horses in North Queensland, with particular emphasis on conditions resembling ‘swamp cancer.’ The most commonly diagnosed condition was subcutaneous phycomycosis, a fungal infection that resulted in extensive, rapidly growing lesions. This disease was found to be more prevalent in younger horses and more common during the wetter season.

Overview of Skin Diseases Studied

• Subcutaneous phycomycosis: This was the most common disease with 37 cases reported. It was found to produce extensive and rapidly growing lesions, making for the poorest prognosis among all conditions studied. It was more prevalent in young horses and during the wetter seasons.
• Primary cutaneous habronemiasis: This disease was reported in nine cases. It is caused by the larvae of the Habronema fly.
• Sarcoids: Next to subcutaneous phycomycosis, sarcoids were the second most common disease with 58 cases reported. Sarcoids are skin tumors that occur in horses.
• Fibromas, fibrosarcomas, squamous cell carcinomas, haemangiomas, melanomas, palpebral adenocarcinoma: These are all different types of skin cancers that were detected in the horse sample. They varied in frequency from 12 cases of fibromas to a single case of palpebral adenocarcinoma.
• Simple granulation: This was diagnosed in seven cases. It refers to the formation of granular tissue during the healing of wounds or ulcers.

Prevalence and Prognosis of Subcutaneous Phycomycosis

• The report found that the incidence of subcutaneous phycomycosis was high in North Queensland, compared to more temperate areas, suggesting a link with environmental factors such as increased rainfall and humidity.
• Parasitical and fungal diseases such as subcutaneous phycomycosis and cutaneous habronemiasis were found to be particularly prevalent, possibly due to the wetter climate in North Queensland providing ideal conditions for the spread of these diseases.
• In addition to this, a fungus tentatively identified as Hyphomyces destruens was isolated in three cases of phycomycosis, although no sporulation was observed. This indicates the potential presence of a specific fungal strain that could be responsible for the prevalence of phycomycosis in the area.

Implications for Horse Health and Veterinary Practice

• This research sheds light on the distribution and prevalence of different skin diseases in horses located in North Queensland, thereby contributing to a broader understanding of equine health in this region.
• The identification of environmental factors and age-related trends can inform target preventive measures and treatment options, allowing for better health management of horses in the area.
• The findings may prompt further investigation into the specific etiology of subcutaneous phycomycosis, potentially leading to improved diagnostic techniques and treatment strategies for this condition.