Other proposed virulence factors include germ tube formation and morphologic switching, as well as the production of proteases and phospholipases. The distinction between colonizer and pathogen can be problematic. Short-course azole therapy also used for vaginitis. Amphotericin B is first line therapy for severe systemic disease, or if Candida species is unknown. Aspergilli have a number of mechanisms for disease causation that affect a broad range of hosts.
Invasive disease is difficult to diagnose, and the associated mortality is high.
The primary ecological niche is decaying vegetable matter, and farms are a major source of the organism. Common sources include potted plants, pepper, spices, and marijuana. Hospital air ducts have been identified as sources of nosocomial isolates, and epidemics have been associated with building remodeling. If macrophages cannot kill the conidia, they germinate to form hyphae that can then invade tissue. Neutrophils are the predominant innate effector cell against hyphae, and defective neutrophil killing is the most common host defect in patients with invasive aspergillosis.