Photodermatitis and Photokeratoconjunctivitis in a Ball Python (Python regius) and a Blue-Tongue Skink (Tiliqua spp.)

Abstract

A male ball python (Python regius) and a female blue tongue skink (Tiliqua spp.) of unknown age were evaluated for anorexia, lethargy, excessive shedding, corneal opacity (python), and weight loss (skink) of approximately three weeks' duration. These animals represented the worst affected animals from a private herpetarium where many animals exhibited similar signs. At necropsy, the python had bilateral corneal opacity and scattered moderate dysecdysis. The skink had mild dysecdysis, poor body condition, moderate intestinal nematodiasis, and mild liver atrophy. Microscopic evaluation revealed epidermal erosion and ulceration, with severe epidermal basal cell degeneration and necrosis, and superficial dermatitis (python and skink). Severe bilateral ulcerative keratoconjunctivitis with bacterial colonization was noted in the ball python. Microscopic findings within the skin and eyes were suggestive of ultraviolet (UV) radiation damage or of photodermatitis and photokeratoconjunctivitis. Removal of the recently installed new lamps from the terrariums of the surviving reptiles resulted in resolution of clinical signs. Evaluation of a sample lamp of the type associated with these cases revealed an extremely high UV output, including very-short-wavelength UVB, neither found in natural sunlight nor emitted by several other UVB lamps unassociated with photokeratoconjunctivitis. Exposure to high-intensity and/or inappropriate wavelengths of UV radiation may be associated with significant morbidity, and even mortality, in reptiles. Veterinarians who are presented with reptiles with ocular and/or cutaneous disease of unapparent cause should fully evaluate the specifics of the vivarium light sources. Further research is needed to determine the characteristics of appropriate and of toxic UV light for reptiles kept in captivity.

Biology and Diseases of Reptiles

“…Several species of active, diurnal lizards and turtles will develop metabolic bone disease (MBD) if deprived of ultraviolet light (Harcourt-Brown, 1996), particularly if an inappropriate diet (low in calcium or improper calcium-phosphorus ratio) is being fed. Conversely, too much light exposure can induce pathology (Gardiner et al, 2009). Information on specific species requirements are available (Barten and LABORATORY ANIMAL MEDICINE Fleming, 2014;http://www.uvguide.co.uk/index.htm).…”

The effects of UV light on calcium metabolism in ball pythons (Python regius)

“…Photokeratoconjunctivitis and photodermatitis have been reported in a ball python associated with exposure to a UV bulb (Gardiner and others 2009). That bulb, however, had a much higher UV-b output than the bulbs tested in this study, and a disproportionately high output of UV-b below 300 nm which is within the action spectra for photokeratoconjunctivitis, photodermatitis and DNA damage (Setlow 1974).…”

Plasma 25-hydroxyvitamin D3 concentrations in Hermann's tortoises (Testudo hermanni) exposed to natural sunlight and two artificial ultraviolet radiation sources

“…12,36 Theoretically, ingested vitamin D and vitamin D produced in animals via exposure to UV radiation can be differentiated via chromatographic separation of 25hydroxyvitamin D 2 and 25-hydroxyvitamin D 3 . However, exposure to UVB radiation can cause adverse effects in reptiles 50 ; therefore, use of appropriate UVB lamps and careful adherence to the manufacturer' s instructions are suggested. Results of other studies 13,24 indicate certain reptiles (eg, red-eared sliders [Trachemys scripta elegans] and veiled chameleons) meet their need for vitamin D via both dietary sources and production in skin.…”

“…50 Although minimum adequate circulating concentrations of 25-hydroxyvitamin D 3 have not been determined for tortoises, the manufacturer' s recommendations for safe use of lamps may not allow adequate 25-hydroxyvitamin D 3 synthesis in tortoises. 50 Although minimum adequate circulating concentrations of 25-hydroxyvitamin D 3 have not been determined for tortoises, the manufacturer' s recommendations for safe use of lamps may not allow adequate 25-hydroxyvitamin D 3 synthesis in tortoises.…”