Provide three examples of fungal pathogens and a disease caused by each.

• A. Candida albicans — candidiasis
• B. Aspergillus fumigatus — cryptococcal meningitis
• C. Cryptococcus neoformans — aspergillosis
• D. Histoplasma capsulatum — candidiasis

Answer: (A)

Understanding how a fungal pathogen relates to the disease it most commonly causes helps you predict what infection a microbe is likely to produce in different patients.

Candida albicans is a yeast that normally resides on skin and mucous membranes. When the balance of the host’s defenses or microbial flora is disrupted, it overgrows and invades, leading to candidiasis. This can manifest as oral thrush, vaginal candidiasis, diaper dermatitis, or skin/other mucosal infections, and in people with weak immune systems it can progress to invasive candidiasis affecting the bloodstream and organs. This is a classic example of a common opportunistic fungus causing a familiar mucosal infection.

Aspergillus fumigatus typically causes aspergillosis, which includes allergic reactions in susceptible people, aspergillomas in preexisting lung cavities, and invasive disease in severely immunocompromised patients. Cryptococcus neoformans is the usual cause of cryptococcal meningitis, especially in people with advanced HIV/AIDS, rather than aspergillosis. Histoplasma capsulatum causes histoplasmosis, acquired from inhaling spores from soil enriched with bird or bat droppings, and can range from mild pulmonary disease to disseminated infection in those with weakened immunity, not candidiasis.

So the best-match example is Candida albicans causing candidiasis.