Sources of Mucormycosis

The fungi that cause mucormycosis live in the environment

Microscopy of Apophysomyces
Photomicrograph of Apophysomyces trapeziformis

Mucormycetes, the group of fungi that cause mucormycosis, are present throughout the environment, particularly in soil and in association with decaying organic matter, such as leaves, compost piles, and animal dung.1  They are more common in soil than in air, and in summer and fall than in winter or spring.2-4 Most people come in contact with microscopic fungal spores every day, so it’s probably impossible to completely avoid coming in contact with mucormycetes. These fungi aren’t harmful to most people. However, for people who have weakened immune systems, breathing in mucormycete spores can cause an infection in the lungs or sinuses which can spread to other parts of the body.

Types of fungi that cause mucormycosis

Several different types of fungi can cause mucormycosis. These fungi are called mucormycetes and belong to the scientific order Mucorales. The most common types that cause mucormycosis are Rhizopus species and Mucor species.5 Other examples include Rhizomucor species, Syncephalastrum species, Cunninghamella bertholletiae, Apophysomyces, Lichtheimia (formerly Absidia), Saksenaea, and Rhizomucor.2 

References
  1. Richardson M. The ecology of the Zygomycetes and its impact on environmental exposure. Clin Microbiol Infect. 2009 Oct;15 Suppl 5:2-9.
  2. Al-Ajam, MR, Bizri, AR, Mokhbat, J, Weedon, J, Lutwick, L. Mucormycosis in the Eastern Mediterranean: a seasonal disease. Epidemiol Infect. 2006 Apr 134(2):341-6.
  3. Talmi, YP, Goldschmied-Reouven, A, Bakon, M, Barshack, I, Wolf, M, Horowitz, Z, et al. Rhino-Orbital and Rhino-Orbito-Cerebral Mucormycosis. Otolaryngology-Head and Neck Surgery, 2002 July 1;127(1):22–31.
  4. Sivagnanam, S, Sengupta, DJ, Hoogestraat, D, Jain, R, Stednick, Z, Fredricks, DN, et al. Seasonal clustering of sinopulmonary mucormycosis in patients with hematologic malignancies at a large comprehensive cancer center. Antimicrobial Resistance & Infection Control. 2017 November;6(1).
  5. Roden MM, Zaoutis TE, Buchanan WL, Knudsen TA, Sarkisova TA, Schaufele RL, et al. Epidemiology and outcome of zygomycosis: a review of 929 reported cases. Clin Infect Dis. 2005 Sep 1;41(5):634-53.