Opportunistic Infections of Avians

Abstract

Opportunistic infection is an infection by a microorganism that normally does not cause disease but becomes pathogenic when the body's immune system is impaired and unable to fight off infection. A compromised immune system presents an ``opportunity{''} for the pathogens (bacteria, virus, fungus, or protozoa) to infect. Immunosuppression can be caused by malnutrition, fatigue, coinfections, recurrent infections, immunosuppressing agents for organ transplant recipients, genetic predisposition, skin damage, and long-term antibiotic treatment, among others. This chapter describes opportunistic mycotic, bacterial, protozoal, and viral infections that do not infect the avian species under normal circumstances but do so when the body's immune system is compromised or there is some predisposing factor.