Aspergillosis in Birds and Mammals: Considerations for Veterinary Medicine

Aspergillosis continues to be a significant infection resulting in morbidity and mortality in a variety of animal hosts, ranging from sea fans to elephants. Infections with this ubiquitous saprophytic mold have a significant impact on our domestic pets, livestock, commercial poultry, captive birds, as well as a variety of wildlife species. In mammals and birds, infection is usually acquired after inhalation of conidia (spores). Infection often results from invasion by the opportunistic Aspergillus spp., as a secondary invader or when immune defenses wane. However, Aspergillus spp. can also act as primary pathogens in some animals, such as birds, dogs, or horses. Clinical presentation and site of infection in the various animal species are varied due to unique anatomopathological characteristics (e.g., air sac in birds, guttural pouch in horses, sinus cavity in dogs, etc.) which also require varied methods of diagnosis and treatment (e.g., lavage treatment of dogs with sinus cavity disease versus oral or parenteral therapy of pulmonary infections). Aspergillus fumigatus is the most common pathogenic species identified in the animal kingdom; however, other Aspergillus spp. have also been implicated in disease. Early antemortem diagnosis remains challenging even with the variety of test modalities. Evaluation of environmental fungal loads and newer molecular tools such as microsatellites have helped identify risks and origin of infection. Animals also serve as useful models for human infection and treatment, so understanding the pathogenesis in these models may provide insight into human prevention, diagnosis, and treatment. The broad health and economic impacts of aspergillosis to veterinary medicine across so many animal species makes additional studies crucial.