Aspergillosis
Aspergillus spp. has been identified as a primary cause of death in juvenile emus and ostriches. The most susceptible individuals are young birds in enclosed facilities with exposure to dust or to hay which is alternately wet and dry. Aspergillus spp. exposure can occur through egg contamination but, under current conditions in the industry, poorly-managed intensive chick facilities seem to be the most likely place for an outbreak to occur. Affected chicks usually die suddenly, or exhibit severe dyspnoea prior to death.
Aspergillus granulomas are detected in the lungs and/or airsacs on gross post-mortem examination. In a highly intensive farming operation, treatment may not be costeffective, but itraconizole is the drug of choice. Although a ubiquitous organism, Aspergillus spp. can cause infection in humans, and face-masks must therefore be worn to reduce human exposure. Management procedures which reduce juvenile stress and exposure to dust and hay will alleviate much potential exposure to the fungal organism.
Zygomycosis
Basidia, Mucor and Rhizopus are genera of zygomycetes which affect the upper gastrointestinal system of ratites. Zygomycotic infections occur when the organism is ingested and is allowed to overwhelm the bird, due to suppressed immune status or concurrent bacterial, viral or parasitic infections.
Non-specific clinical signs accompany a zygomycotic infection, and diagnosis is usually made on post-mortem examination. Although these fungal infections have been noted in the USA and Israel, there is a real potential for exposure in other countries due to the ubiquitous nature of this organism (13). To prevent or reduce exposure to zygomycotic organisms, the producer should eliminate stress, primary viral or bacterial infections, and fungal contamination of feed and substrate.
Candidosis
Stomatitis characterized by white raised lesions in the oral cavity extending down the oesophagus is usually associated with a Candida spp. infection (27). The two main Candida organisms isolated from ratite species are C. albicans and C. mucor. Candida spp. are opportunistic organisms and usually indicate a primary bacterial, viral, parasitic or management problem which is reducing the ability of the bird to fight infection. Diagnosis can be made through Gram’s staining, direct scraping of the oral plaques and viewing the characteristic budding yeast forms. Treatment and prevention are achieved by using nystatin, fluconizole or ketoconizole, with adjunct supportive therapy. It is essential for the veterinarian to identify and treat the underlying primary immune suppressive problem affecting the individual bird or flock to ensure proper treatment of the secondary fungal infection. To provide treatment in large-scale production operations, copper sulfate may be added to the drinking water at a level of 1:2,000 in a large-scale feedlot operation .