Prevalence of Epidermal Conditions in California Coastal Bottlenose Dolphins (Tursiops truncatus) in Monterey Bay

Abstract

The prevalence of epidermal conditions in a small population of coastal bottlenose dolphins (Tursiops truncatus) in Monterey Bay was evaluated between 2006 and 2008. Five different skin condition categories were considered, including Pox-Like Lesions, Discoloration, Orange Film, Polygon Lesions, and Miscellaneous Markings. Of 147 adults and 42 calves photographically examined, at least 90 and 71%, respectively, were affected by at least one or multiple conditions. Pox-Like Lesions were the most prevalent, affecting 80% of the population, including adults and calves. This condition warrants the most urgent investigation being possibly indicative of the widespread presence of poxvirus or a similar pathogen in the population. In view of the high number of individuals affected, standard monitoring of the health status of Monterey Bay bottlenose dolphins is considered imperative. Discoloration was strongly associated with Pox-Like lesions. Orange Films were likely an epifaunal infestation caused by diatoms, which have been documented in other cetacean species. Polygon Lesions, a newly described category, could be the result of infestation by barnacles of the genus Cryptolepas. Miscellaneous Markings were variable in appearance and may not have the same causative factor. Although none of the proposed etiologies can be confirmed without appropriate clinical tests, recognizing common visible characteristics of the conditions could aid in preliminary comparisons across populations and individuals.

Epidemiological characteristics of skin disorders in cetaceans from South American waters

“…However, the fact that phenotypically recognizable clinical symptoms occurred in photo-identified individuals, allowing assessment of disease progression and survival of several dolphins, deserved their documentation. Photographic examination has proven useful to classify skin disorders and study their epidemiological features in cetaceans worldwide (Wilson et al, 1997;Van Bressem et al, 2003;2009b, c;Maldini et al, 2010;Daura-Jorge and Simões-Lopes, 2011;Bertulli et al, 2012). Time series of the affected VBS fraction provides a safe and practical tool for monitoring the evolution and severity of skin conditions (Van Bressem et al, 2003;Murdoch et al, 2008;Kiszka et al, 2009;Riggin and Maldini, 2010; Daura-Jorge and Simões-Lopes, 2011; this paper).…”

“…Intense shrimp-farming and fishing plants in this area also produce large quantities of sludge and organic material 14 . The exponential increase in reports of, often severe, skin disorders in cetaceans worldwide (Van Bressem et al, 1993;2009c;Wilson et al, 1999;Reif et al, 2006;Barry et al, 2008;Maldini et al, 2010;Riggin and Maldini, 2010;Daura-Jorge and Simões-Lopes, 2011;Bertulli et al, 2012;Fury and Reif, 2012) cannot alone be explained by intensified field research, and suggests a causal link with markedly deteriorating coastal environments. Climate change may also play a role in the emergence of skin diseases by increasing pathogen survival through higher water temperatures and by changing pathogen and host interaction dynamics (Burek et al, 2008).…”

“…These and similar conditions are also increasingly reported worldwide, may be severe and are sometimes associated with the death or disappearance of affected individuals 4 (Wilson et al, 1997;Riggin and Maldini, 2010;Maldini et al, 2010;Van Bressem et al, 2007;. However, general knowledge of their aetiology, epidemiology, pathogenesis and prognosis is still patchy.…”

Cutaneous Lesions in Cetaceans: An Indicator of Ecosystem Status?

“…Maldini and co-workers [46] reported on bottlenose dolphins living in Monterey Bay, California. Their research, conducted between 2006 and 2008, showed that approximately 90% of these cetaceans were characterized by skin lesions.…”

Mucocutaneous lesions in free-ranging Atlantic bottlenose dolphins Tursiops truncatus from the southeastern USA

“…Mucocutaneous lesions in Atlantic bottlenose dolphins Tursiops truncatus have been described in stranded and managed-care animals, but little information is available regarding the etiopathogenesis of these conditions in free-ranging populations. Photo-identification studies have been used to document the gross appearance of cutaneous lesions in free-ranging dolphin populations (Wilson et al 1999, Van Bressem et al 2003, 2007b, Bearzi et al 2009, Maldini et al 2010, Hart et al 2012). However, photo-identification studies do not provide a definitive morphologic or etiologic diagnosis of cutaneous lesions and are of limited use for documenting the presence of mucosal lesions.…”