Associations of age, sex and region with presence of various lesions in <i>T. aduncus</i>: results of multivariable exact logistic regression models.

1<p>OR =  Odds ratio.</p>2<p>95% C.I.  = 95% confidence interval.</p><p>*statistically significant results (p<0.100) in bold.</p><p>Associations of age, sex and region with presence of various lesions in <i>T. aduncus</i>: results of multivariable exact logistic regression models.</p

A Systematic Health Assessment of Indian Ocean Bottlenose (<i>Tursiops aduncus</i>) and Indo-Pacific Humpback (<i>Sousa plumbea</i>) Dolphins Incidentally Caught in Shark Nets off the KwaZulu-Natal Coast, South Africa

<div><p>Coastal dolphins are regarded as indicators of changes in coastal marine ecosystem health that could impact humans utilizing the marine environment for food or recreation. Necropsy and histology examinations were performed on 35 Indian Ocean bottlenose dolphins (<i>Tursiops aduncus</i>) and five Indo-Pacific humpback dolphins (<i>Sousa plumbea</i>) incidentally caught in shark nets off the KwaZulu-Natal coast, South Africa, between 2010 and 2012. Parasitic lesions included pneumonia (85%), abdominal and thoracic serositis (75%), gastroenteritis (70%), hepatitis (62%), and endometritis (42%). Parasitic species identified were <i>Halocercus</i> sp. (lung), <i>Crassicauda</i> sp. (skeletal muscle) and <i>Xenobalanus globicipitis</i> (skin). Additional findings included bronchiolar epithelial mineralisation (83%), splenic filamentous tags (45%), non-suppurative meningoencephalitis (39%), and myocardial fibrosis (26%). No immunohistochemically positive reaction was present in lesions suggestive of dolphin morbillivirus, <i>Toxoplasma gondii</i> and <i>Brucella</i> spp. The first confirmed cases of lobomycosis and sarcocystosis in South African dolphins were documented. Most lesions were mild, and all animals were considered to be in good nutritional condition, based on blubber thickness and muscle mass. Apparent temporal changes in parasitic disease prevalence may indicate a change in the host/parasite interface. This study provided valuable baseline information on conditions affecting coastal dolphin populations in South Africa and, to our knowledge, constitutes the first reported systematic health assessment in incidentally caught dolphins in the Southern Hemisphere. Further research on temporal disease trends as well as disease pathophysiology and anthropogenic factors affecting these populations is needed.</p></div

Gastric trematode associated lesions.

<p>A: Firm, round parasitic nodules (<1 cm diameter) with a small pore opening to the gastric lumen (arrow). Bar  = 0.4 cm. B: Adult trematode (arrow) in the center of a focus of extensive fibrosis (HE, bar  = 0.5 mm). C: Embryonated trematode eggs (280×160 µm, HE, bar  = 150 µm). D: Parasitic nodule with adult trematode blocking the pore and irregular mineralized foci (arrow) in the adjacent superficial gastric epithelium (HE, bar  = 500 µm).</p

Splenic filamentous peritonitis.

<p>A: Fine long filamentous tags (1×2×30 mm) on the splenic capsule. Bar  = 10 mm. B: Splenic tag consisting of mature fibrovascular connective tissue (HE, bar  = 500 µm).</p

Location (beach name), number of shark nets per beach (in parenthesis) and number of <i>T. aduncus</i> (red) and <i>S. plumbea</i> (blue) sampled along the KwaZulu-Natal coast, South Africa.

<p>Gill nets are 110 m long and 10 m deep. Adapted from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107038#pone.0107038-KwaZuluNatal1" target="_blank">[87]</a>.</p

Abdominal serositis.

<p>A: Peritoneum overlying the testis contains multiple, slightly raised, firm white nodules, some of which contain depressed red centers (arrows). Bar  = 5 mm. B: Eosinophil aggregate (arrow) and lymphoplasmacytic serositis in the testicular capsule (c). Note the seminiferous tubule in the upper left corner (HE, bar  = 100 µm). C: Mesenteric lymph node serositis with intra-lesional nematode larvae in the capsule (60 µm diameter, arrows) (HE, bar  = 30 µm). D: Severe focal granulomatous testicular serositis in the testicular capsule (c) with a central area of necrosis (arrow) resembling a helminth migration tract. Note seminiferous tubules at bottom right (HE, bar  = 500 µm).</p

Hepatic lesions in <i>T. aduncus</i>.

<p>A: Mild proliferation (hyperplasia) of small portal bile ductules (arrow) (HE, bar  = 100 µm): B: Severe hepatic periportal fibrosis associated with a trematode egg (arrow, 100 µm diameter). Note the bile ductules with hyperplastic epithelium (arrowheads, HE, bar  = 100 µm).</p

Myocardial lesions.

<p>A: Mild focal lymphoplasmacytic myocarditis (arrow) (HE, bar  = 50 µm). B: Mild focal myocardial fibrosis (arrows) (HE, bar  = 120 µm).</p

Parasitic pneumonia.

<p>A: Ectatic bronchus (b) containing thin (1–2 mm diameter), long, white helminths identified as <i>Halocercus</i> sp. (arrow). Bar  = 5 mm. B: Pulmonary helminths (arrow) in an ectatic bronchiole (b) with eosinophilic and lymphoplasmacytic interstitial pneumonia (*) and an adjacent follicle of mildly hyperplastic bronchiolar-associated lymphoid tissue (HE, bar  = 250 µm).</p

Lingual Sarcocystis.

<p>Sarcocyst containing myriad metrocytes in a muscle fiber of the tongue (HE, bar  = 150 µm).</p