A preliminary overview of skin and skeletal diseases and traumata in small cetaceans from South American waters

Abstract

ABSTRACT:We succinctly review and document new cases of diseases of the skin and the skeletal system and external traumata in cetaceans from Ecuador, Colombia, Peru, Chile, Argentina, Uruguay, Brazil, and Venezuela. The survey revealed 590 cases diagnosed with a significant pathology, injury or malformation on a total of 7635 specimens of 12 odontocete species examined or observed in . Tattoo skin disease (TSD), lobomycosis-like disease (LLD) and cutaneous diseases of unknown aetiology seem to be emerging in several populations. TSD was confirmed in eight species from the SE Pacific and SW Atlantic. LLD affected only inshore Tursiops truncatus but was found in four tropical countries, namely Colombia, Ecuador, Peru and Brazil. Lobomycosis was confirmed by histology in one male from the Tramandaí estuary, southern Brazil. All LLD-affected specimens were encountered in the vicinity of major ports and cities and a possible association with chemical or organic water pollution is suspected. Whitish velvety cutaneous marks associated with scars occurred in inshore T. truncatus, Sotalia guianensis and Pseudorca crassidens. Large, rounded lesions were seen in a Cephalorhynchus eutropia calf and a C. commersonii. Cutaneous wounds and scars as well as body traumata possibly related to net entanglements and boat collisions were observed in 73 delphinids and Phocoena spinipinnis. Traumatic injuries resulted in the partial or complete amputation and other disfiguring scars of appendages in 17 cases. Fractures of the skull, ribs and vertebrae thought to be caused by fisheries-related interactions or boat collisions were seen in single individuals of Delphinus capensis, Lagenorhynchus obscurus, T. truncatus, S. guianensis and Ziphius cavirostris. Prevalence of osteopathology in small cetaceans from Peru, Brazil and Venezuela ranged widely, from 5.4% to 69.1%. In four species from Peru, lytic cranial lesions were the most frequently observed disease (5.4%-42.9%), followed by hyperostosis and ankylosing spondylitis in offshore (31%, n=42) and inshore (15.4%, n=26) T. truncatus. Fractures and other bone traumata were present in 47.2% of 53 axial skeletons of S. guianensis from the northern Rio de Janeiro state (Brazil) in 1987-1998. A high prevalence (48.4%, n=31) of, apparently congenital, malformations of cervical vertebrae, observed in a 2001-2006 sample, may be explained by a hypothetical genetic bottleneck in this population. Malformations with deficient ossification would clearly increase susceptibility for fractures. This study demonstrates the utility of a continent-wide analysis to discern epizootiological trends more readily than any local study could provide. Secondly, it underscores the need for focussed research on the effects of human activities on the spread of diseases in cetaceans, particularly in near-shore populations that utilize highly degraded coastal habitats. RESUMEN:En este trabajo revisamos y documentamos brevemente nuevos casos de enfermedades de piel y de esqueleto, y traumas externos en cetáceos de Ec...

Osteological alterations in the tucuxi Sotalia fluviatilis (cetacea, delphinidae)

“…However, observations of the cervical vertebrae in specimens of S. guianensis from other locations in South America confirm that an open neural process may also occur in the Ce7 in 19 to 30% of all individuals of this species (n = 222) (unpublished data) and as much as 20% of S. fluviatilis individuals (n = 31). Thus, the open neural canal in Ce3, Ce4, and Ce7 observed here is interpreted as a commonly observed feature in the two species of Sotalia, rather than a congenital malformation as suggested by van Bressem et al (2007) and Laeta et al (2010).…”

“…1 DISCUSSION Osteomyelitis is a condition whereby some bacterial agent causes the inflammation of connective tissues and bone marrow .The occurrence of osteomyelitis in dental alveoli changes is the most common infectious nature in the skeletons of dolphins and occurs secondary to dental infections (Sweeney, 1978). There are reports of osteomyelitis occurring in the oral region and the spine of Sotalia guianensis (van Bressem et al, 2007;Simões-Lopes et al, 2008), Orcinus orca (Linnaeus, 1758) (Kompanje, 1995c), Lagenorhynchus albirostris (Gray, 1846) (Kompanje, 1995b), Phocoena spinipinis Burmeister, 1865 (Montes et al, 2004), Globicephala melas (Traill, 1809) (Sweeney et al, 2005), Pontoporia blainvillei (Gervais & d'Orbigny, 1844) (Gerholdt, 2006), Delphinus capensis Gray, 1828 (Loch et al, 2011;van Bressem et al, 2007), Tursiops truncatus (Montagu, 1821) and Pseudorca crassidens (Owen, 1846) (van Bressem et al, 2007); Megaptera novaengliae (Borowski, 1781) (Felix et al, 2007). Kompange (1995c) suggested that dental injuries can function as a "gate" for infectious agents, since these infections are usually followed by penetrating wounds or fractures , or simply by normal wear and tear of the teeth that may eventually expose the pulp cavity, creating a mean of entry for infectious agents (Drehmer et al, 1998).…”

“…We analyzed specimens representing all age groups, determined according to the degree of fusion in cranial sutures and vertebral epiphysis (Dawbin et al, 1970;Perrin, 1975;Ito & Miyazaki, 1990). Diagnoses and descriptions were realized according to the methods of Kompanje (1995a,b, 1999), van Bressem et al (2007 and Simões-Lopes et al (2008).…”

“…Different events can leave permanent marks on the bones and reveal important aspects of the life history of a particular animal, but it is not always a simple matter to recognize which processes are involved (Simões-Lopes et al, 2008). Bone fractures, pathological processes, malformations, deformities or alterations related to senescence in cetaceans have been noted in the literature by various authors (Purves & van Bree, 1972;de Smet, 1977;Odgen et al, 1981;Kompanje, 1995a;Berghan & Visser, 2000;Montes et al, 2004;Félix et al, 2007;van Bressem et al, 2007;Oremland et al, 2010, Hellier et al, 2011Groch et al, 2012;Marigo et al, 2013), however, there is persistent confusion regarding certain terminology, the causes and biomechanical consequences of such incidents, sometimes leading to the use of the same term for different osteological features (Simões-Lopes et al, 2008).…”

“…Fractures in different regions of the skeleton, deformities, adaptive changes in response to aging of the spine and diseases of exogenous origin have been previously recorded for Guiana Dolphins Sotalia guianensis (Van Bénéden, 1864) (Furtado & Simões-Lopes, 1999;van Bressem et al, 2007;Simões-Lopes et al, 2008), but until now this subject has not been addressed in its congener, the tucuxi [Sotalia fluviatilis (Gervais, 1853)]. The current study aims to detail some of the osteological alterations that have been observed for the first time in S. fluviatilis individuals from different areas of the Amazon basin.…”