zoonoses and communicable diseases common to ... - PAHO/WHO

RHINOSPORIDIOSIS 351The disease is seen mostly in children and young people, predominantly in males(Mahapatra, 1984).Rhinosporidiosis in animals occurs in cattle, horses, dogs, cats, and geese. Morethan 90% of the cases occur in males (Carter and Chengappa, 1991). The diseaseoccurs sporadically, as it does in humans. An unusual case occurred in a province innorthern Argentina where an outbreak was described in a herd of cattle that was keptin a flooded field for two years. Twenty-four percent of the animals examined hadpolyps (Luciani and Toledo, 1989).The Disease in Man and Animals: Rhinosporidiosis is characterized by pedunculatedor sessile polyps on the mucous membranes, particularly of the nose andeyes. The polyps are soft, lobular, and reddish with small white spots (the sporangia).These excrescences are not painful but they do bleed easily. In humans, thesegranulomatous formations can also be found in the pharynx, larynx, ear, vagina,penis, rectum, and on the skin. Cases of dissemination to internal organs are rare.The clinical picture in animals consists of a chronic polypoid inflammation thatmay cause respiratory difficulty and sneezing if the disease lodges in the nasalmucosa and if the lesion is sufficiently large. Another common symptom is epistaxis.Treatment for humans and animals consists of surgical excision of the polyp.Recurrence is rare. Successful treatment with dapsone has been described in threepatients (Job et al., 1993).Source of Infection and Mode of Transmission: The natural habitat of the agentis unknown. It is suspected that the infection enters the body with soil particlesthrough lesions of the mucous membranes. Those affected almost always live inrural areas, thus the assumption that the agent lives in the soil. In India and SriLanka, where most cases have been recorded, the source of infection has been associatedwith stagnant waters, but it has not yet been possible to demonstrate the presenceof the fungus in such waters or in aquatic animals. The route of infection andthe mode of transmission are also unknown.Role of Animals in the Epidemiology of the Disease: Rhinosporidiosis is a diseasecommon to humans and animals, contracted from an as yet unknown environmentalsource. It is not transmitted from one individual to another.Diagnosis: Since the fungus cannot be cultured, diagnosis depends on the clinicalappearance of the lesions and demonstration of the agent’s presence in tissues.Best results are obtained by using stained histological preparations.Control: No practical control measures are available.BibliographyAjello, L., L.K. Georg, W. Kaplan, L. Kaufman. Laboratory Manual for MedicalMycology. Washington, D.C.: U.S. Government Printing Office; 1963. (Public Health ServicePublication 994).Carter, G.R., M.M. Chengappa. Essentials of Veterinary Bacteriology and Mycology. 4thed. Philadelphia: Lea & Febiger; 1991.Job, A., S. VanKateswaran, M. Mathan, et al. Medical therapy of rhinosporidiosis with dapsone.J Laryngol Otol 107:809–812, 1993.