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

304 MYCOSESThe disease is generally asymptomatic, but resection of the affected tissue may benecessary if it persists and symptoms appear.In 7 out of 25 skunks (Mephitis mephitis) captured and autopsied in Alberta,Canada, lesions were found that varied from slight and only visible microscopicallyto severe with grayish-white nodules in the pulmonary parenchyma that spread tothe bronchotracheal and mediastinal lymphatic ganglia. Histologically, the lesionswere characterized by a centrally located spherule surrounded by granulomatousinflammation (Albassam et al., 1986).Source of Infection and Mode of Transmission: The great preponderance ofpulmonary localizations indicates that the infection is contracted through inhalation.C. crescens has been isolated from the soil. Differences in the infection ratesfor three very similar species of squirrels indicate that the fungus may be presentin certain habitats (Leighton and Wobeser, 1978), possibly linked to the rootmicroflora of certain plants. Other authors (cited by Mason and Gauhwin, 1982)suggest that predator-prey interactions affect its distribution: upon ingestinginfected animals, carnivores eliminate adiaspores in their feces, where the sporesgerminate and develop. This was demonstrated in cats, in a mustelid (Mustelanivalis), and in birds of prey. Thus, predators could play a role in disseminating theetiologic agent.Under very windy conditions, both animals and humans may inhale airborne conidiareleased from the soil.Role of Animals: The soil is the reservoir for the fungus and the source of infectionin humans and other animals. It is believed that some animals may play a rolein disseminating the agent.Diagnosis: Diagnosis may be made by observation of spherules in lung tissue, bystained histological preparations, and by culture and inoculation into laboratory animals.The most effective method for detecting adiaspores in the lungs of animals istissue digestion with a 2% sodium hydroxide solution (Leighton and Wobeser,1978). The spherules are stained with acid-Schiff and Gomori methenamine silvernitrate reagents (Englund and Hochholzer, 1993).BibliographyAinsworth, G.C., P.K.C. Austwick. Fungal Diseases of Animals. 2nd ed. Farnham Royal,Slough, United Kingdom: Commonwealth Agricultural Bureau; 1973.Albassam, M.A., R. Bhatnagar, L.E. Lillie, L. Roy. Adiaspiromycosis in striped skunks inAlberta, Canada. J Wildl Dis 22:13–18, 1986.Cueva, J.A., M.D. Little. Emmonsia crescens infection (adiaspiromycosis) in man inHonduras. Am J Trop Med Hyg 20:282–287, 1971.Echevarría, E., E.L. Cano, A. Restrepo. Disseminated adiaspiromycosis in a patient withAIDS. J Med Vet Mycol 31:91–97, 1993.England, D.M., L. Hochholzer. Adiaspiromycosis: An unusual fungal infection of the lung.Report of 11 cases. Am J Surg Pathol 17:876–886, 1993.Jellison, W.L. Adiaspiromycosis. In: Davis, J.W., L.H. Karstad, D.O. Trainer, eds.Infectious Diseases of Wild Mammals. Ames: Iowa State University Press; 1970.Leighton, F.A., G. Wobeser. The prevalence of adiaspiromycosis in three sympatric speciesof ground squirrels. J Wildl Dis 14:362–365, 1978.