Abstract
Pododermatitis is a common problem in many captive avian species.1,2 This disorder is widespread in captive flamingos.3 A comprehensive study investigated the lesions in multiple Swiss facilities and included gross appearance, histology, bacteriology, virology, electron microscopy and immunohistochemistry. Important husbandry factors (pond type, nutrition, water) as well as influences of sex, weight, age, origin, breeding status and flight ability were also evaluated. The present study focuses on the macroscopic and histologic features observed in captive flamingos compared with those from free-ranging wild flamingos from the Camargue (southern France).
Macroscopic lesions were divided into three different groups: cracks (superficial/deep), nodules (without/with ulceration) and papillomatous proliferations (finger-like/cauliflower-like). Macroscopic lesions were first seen in a 4-week-old chick while histologic changings were already seen in a 3-week-old chick without evident macroscopic lesions. Early histologic lesions were hyperkeratosis, epidermal hyperplasia, hydropic swelling and degeneration and heterophilic infiltration of the dermis with exocytosis. Different stages (zoospores, hyphae) of Dermatophilus-like bacteria were infiltrating the epidermis and are considered to be an important co-factor in the progression of the disease. Therefore, further work will be carried out to identify these bacteria. In comparison with wild animals, feet from zoo flamingos showed a marked hyperplasia of the epidermis and especially of the stratum corneum, keratinization of immature keratinocytes and an increase in matrix and fibroplasia in the dermis. These changes were considered to be mechanically induced (due to standing on hard and rough substrate). Flamingos kept in ponds with concrete showed more severe lesions than animals in zoos with natural ponds, confirming our hypothesis of a primary mechanical problem.
Acknowledgments
The authors acknowledge the staff of the Zoo Basel, especially the responsible keeper, Bruno Gardelli, the staff from all participating zoos for their valuable cooperation, Antoine Arnaud for organising import permits and Prof. Monika Welle for her advice concerning skin pathology. The study was partly funded by the Swiss Association of Zoo-, Wild- and Pet animal medicine (SVWZH).
Literature Cited
1. Halliwell, H. H. 1975. Bumblefoot infections in birds of prey. J. Zoo Anim. Med. 6 (4) 8–10.
2. Harcourt-Brown, N. H. 2008. Bumblefoot. In: Samour, J. (ed). Avian Medicine. Mosby Elsevier. Pp. 126–131.
3. Nielsen, A. W., S. S. Nielsen, C. E. King, M. F. Bertelsen. 2010. Classification and prevalence of foot lesions in captive flamingos (Phoenicopteridae). J. Zoo Wildl. Med. 41: 44–49.