ABSTRACT
CASE REPORT: A 2-month-old Standardbred filly was presented for examination and treatment of extensive congenital skin lesions that had a linear distribution on the left front leg extending from the dorsal midline to the metacarpal region. The lesions were surgically excised under general anaesthesia. Surgical excision was curative and there were no signs of recurrence 6 weeks after surgery. The number and distribution of lesions were more extensive than in previously reported cases of congenital papillomas, which have also been described as epidermal growth abnormalities (naevi or hamartomas). Early reports of congenital papillomas suggest in-utero infection with papillomavirus may be responsible, despite a lack of histological features associated with papillomavirus infection. Papillomavirus immunohistochemistry has subsequently proven negative in tested cases. CONCLUSIONS: The presence at birth, their appearance and the extensive distribution of lesions in this case is similar to verrucous epidermal naevus of humans. A name change from congenital papilloma to epidermal naevus is proposed for this condition in horses.
ABSTRACT
OBJECTIVE: Review 103 cases of presumed tick envenomation in horses. DESIGN: Retrospective study. METHOD: Variables, including date of presentation, age, breed, weight, presence of ticks, gait and respiration scores, duration of recumbency, treatment, outcome and complications were recorded. A series of univariable screening tests were performed and used in a multivariable logistic regression model. RESULTS: There were a total of 103 cases affecting 10 breeds, aged between 1 week and 18 years of age. Horses >6 months old and weighing >100 kg had a higher odds of death than those <6 months old and <100 kg. Cases were seen from North Queensland to the central coast of New South Wales and were more likely to present in the warmer months. There was no association between the number of ticks found on an animal and death. Horses with a higher respiratory score had higher odds of dying, but there was no association between gait score and survival. Horses recumbent >120 h after presentation had higher odds of dying. Complications were reported in 35% of horses. The odds ratio for survival was higher for horses receiving >0.5 mL/kg of tick antiserum. Overall, 74% of horses survived. Multivariable modelling was limited by the small sample size. CONCLUSION: In general, tick envenomation in horses follows the geographic distribution of Ixodes holocyclus. Tick antiserum administered at >0.5 mL/kg increases the odds of survival. It would appear that the complications associated with managing a recumbent horse increase the odds of death.
