Lobomycosis: risk of zoonotic transmission from dolphins to humans

Abstract

Lobomycosis, a fungal disease of the skin and subcutaneous tissues caused by Lacazia loboi, is sometimes referred to as a zoonotic disease because it affects only specific delphinidae and humans; however, the evidence that it can be transferred directly to humans from dolphins is weak. Dolphins have also been postulated to be responsible for an apparent geographic expansion of the disease in humans. Morphological and molecular differences between the human and dolphin organisms, differences in geographic distribution of the diseases between dolphins and humans, the existence of only a single documented case of presumed zoonotic transmission, and anecdotal evidence of lack of transmission to humans following accidental inoculation of tissue from infected dolphins do not support the hypothesis that dolphins infected with L. loboi represent a zoonotic hazard for humans. In addition, the lack of human cases in communities adjacent to coastal estuaries with a high prevalence of lobomycosis in dolphins, such as the Indian River Lagoon in Florida (IRL), suggests that direct or indirect transmission of L. loboi from dolphins to humans occurs rarely, if at all. Nonetheless, attention to personal hygiene and general principals of infection control are always appropriate when handling tissues from an animal with a presumptive diagnosis of a mycotic or fungal disease.

FIG. 1.

Dolphin with extensive lesions of lobomycosis from the Indian River Lagoon, Florida. Photograph courtesy of E. Howells, Harbor Branch Oceanographic Institution at Florida Atlantic University, 2007. Reprinted with permission.

FIG. 2.

Photomicrograph of dermal tissue from a dolphin with lobomycosis. The yeast-like cells are seen singly and in chains connected by tube-like bridges, characteristic of Lacazia loboi. Gomori methenamine silver stain. Magnification, 400×.