Abstract:
We report on the epidemiology of lobomycosis-like disease (LLD), a cutaneous disorder
evoking lobomycosis, in 658 common bottlenose dolphins Tursiops truncatus from South America
and 94 Indo-Pacific bottlenose dolphins T. aduncus from southern Africa. Photographs and stranding
records of 387 inshore residents, 60 inshore non-residents and 305 specimens of undetermined origin
(inshore and offshore) were examined for the presence of LLD lesions from 2004 to 2015. Seventeen
residents, 3 non-residents and 1 inshore dolphin of unknown residence status were positive.
LLD lesions appeared as single or multiple, light grey to whitish nodules and plaques that may ulcerate
and increase in size over time. Among resident dolphins, prevalence varied significantly
among 4 communities, being low in Posorja (2.35%, n = 85), Ecuador, and high in Salinas, Ecuador
(16.7%, n = 18), and Laguna, Brazil (14.3%, n = 42). LLD prevalence increased in 36 T. truncatus
from Laguna from 5.6% in 2007−2009 to 13.9% in 2013−2014, albeit not significantly. The disease
has persisted for years in dolphins from Mayotte, Laguna, Salinas, the Sanquianga National Park
and Bahía Málaga (Colombia) but vanished from the Tramandaí Estuary and the Mampituba River
(Brazil). The geographical range of LLD has expanded in Brazil, South Africa and Ecuador, in areas
that have been regularly surveyed for 10 to 35 yr. Two of the 21 LLD-affected dolphins were found
dead with extensive lesions in southern Brazil, and 2 others disappeared, and presumably died, in
Ecuador. These observations stress the need for targeted epidemiological, histological and
molecular studies of LLD in dolphins, especially in the Southern Hemisphere.
