Mucormycosis - Epidemiology

Epidemiology

Mucormycosis is a very rare infection, and as such it is hard to note histories of patients and incidence of the infection. However, one American oncology center revealed that mucormycosis was found in 0.7% of autopsies and roughly 20 patients per every 100,000 admissions to that center. In the United States, mucormycosis was most commonly found in rhinocerebral form, almost always with hyperglycemia and metabolic acidosis. In most cases the patient is immunocompromised, although rare cases have occurred in which the subject was not; these are usually due to a traumatic inoculation of fungal spores. Internationally, mucormycosis was found in 1% of patients with acute leukemia in an Italian review.

A cluster of infections occurred in the wake of the 2011 Joplin tornado. As of July 19, a total of 18 suspected cases of cutaneous mucormycosis had been identified, of which 13 were confirmed. A confirmed case was defined as 1) necrotizing soft-tissue infection requiring antifungal treatment or surgical debridement in a person injured in the tornado, 2) with illness onset on or after May 22, and 3) positive fungal culture or histopathology and genetic sequencing consistent with a Mucormycete. No additional cases have been reported since June 17. Ten patients required admission to an intensive-care unit, and five died.

Cutaneous mucormycosis has been reported after previous natural disasters; however, this is the first known cluster occurring after a tornado. None of the infections were found in persons cleaning up debris; instead it is believed transmission occurred through penetrating injuries inflicted by contaminated objects (e.g. splinters from a woodpile). Health-care providers should consider environmental fungi as potential causes of necrotizing soft-tissue infections in patients injured during tornados and initiate early treatment for suspected infections.

Predisposing factors for mucormycosis include AIDS, diabetes, malignancies such as lymphomas, renal failure, organ transplant, long term corticosteroid and immunosuppressive therapy, cirrhosis energy malnutrition, and Deferoxamine therapy. Despite this, however, there have been cases of mucormycosis reported with no apparent predisposing factors present.