Lobomycosis has been reported in the United States in coastal bottlenose dolphin populations in the Indian River Lagoon on the eastern coast of Florida, in the Gulf of Mexico off the western coast of Florida, and off the Texas Gulf coast. The Indian River Lagoon dolphin population has been assessed for temporal and spatial prevalence of lobomycosis (10). A prevalence of 6.8% was observed in that population from 1996 through 2006, and most cases were observed in the southern portion of this elongate body of water (10). The number of new cases per year, as determined from photograph identification studies, ranged from 1 to 9. Resolution of lesions has not been reported. In comparison, a prevalence of 3.9% was observed in a photograph identification study of S. guianensis from the Paranagua estuary in Brazil, a site of anthropogenic impact (5).

The cases in 2 stranded dolphins and in 1 photographed dolphin occurred in a subtropical climate of North America and involved an offshore rather than a coastal species. Information regarding unknown factors about these diseased animals, including host and pathogen range, pathogen molecular characterization, and environmental factors, could lead to a new range of organismal survival.

The offshore ecotype of bottlenose dolphins is generally found in waters >40 m deep but has been observed as close as 7.3 km from the coast at depths of 13 m (12). Bottlenose dolphins with offshore characteristics have been found as far south as the Florida Keys (12), but latitudinal movements of the offshore ecotype are not well understood. The 3 dolphins may have had a range that extended to the tropics where exposure could have occurred, rather than occurring in the region of stranding. A better understanding of movements of offshore ecotypes is needed so that potential exposure pathways can be inferred.

During preparation of this report, dorsal fin photographs from photograph identification projects along the mid-Atlantic coast identified 2 additional offshore T. truncatus that had skin lesions consistent with lobomycosis-like disease, a term used to describe gross observations that cannot be confirmed histologically (5). A more expansive study of photograph identification records could provide information on additional suspected cases. However, prevalence calculations from these studies will be negatively biased because the objective is generally to acquire photographs of the dorsal fin only. Dart biopsy of affected animals could confirm infection of dolphins with suspected cases but would require accuracy of sampling that may not be feasible in field conditions.

Because L. loboi has not been cultured, molecular techniques have been used to characterize the fungus. It is most related to the fungal order Onygenales, which includes Emmonsia spp. and Paracoccioidies spp. There are limited DNA sequences from Lacazia spp. for comparison, and PCR results for suspected Lacazia spp. are similar to those for P. brasiliensis (13), which are consistent with our findings for samples from case KLC020. The host range of P. brasiliensis, method of exposure (inhalation), and propensity for multisystemic invasion makes this fungi an unlikely causative agent of the disease in the 2 stranded T. truncatus dolphins. Histologic features of P. brasiliensis were also consistent with lobomycosis.

Decreased lymphocyte populations, which indicates decreased immune function, have been observed in animals with lobomycosis from the Indian River Lagoon (14) compared with noninfected cohorts in capture-and-release studies. Systemic disease has been reported in dolphins with lobomycosis from this lagoon (15). Of the 2 dolphins from North Carolina with lobomycosis, 1 had disseminated Toxoplasmosis spp.–like protozoal infection, and the other had suspected parasitic migration to the brain. Despite no histologic evidence of lymphoid depletion, lymphocytic function could not be determined for either animal. In stranded cetaceans such as dolphins, concurrent systemic disease is not an unexpected finding. Whether the presence of the fungus predisposes the animal to infectious processes, lowers immunity, or is a sign of decreased immunity may be best addressed in long-term capture-and-release studies in areas where the fungus is endemic and where data may be available from animals before and after infection.

Confirmation of lobomycosis in 2 stranded cetaceans off the coast of North Carolina represents a change in the northern distribution of this organism. Additional information on distribution and movements of offshore population(s) is needed to understand the prevalence and potential sources of infection.