Pathology and causes of death in stranded humpback whales (<i>Megaptera novaeangliae</i>) from Brazil

<div><p>This study describes the pathologic findings of 24 humpback whales (<i>Megaptera novaeangliae)</i> found stranded along the Brazilian coast from 2004 to 2016. Eighteen (75%) animals evaluated were found stranded alive. From these, 13 died naturally on shore and five were euthanized. Six died at sea and were washed ashore. Of the 24, 19 (79.2%) were calves, four (16.7%) were juveniles, and one (4.2%) was an adult. The most probable cause of stranding and/or death (CSD) was determined in 23/24 (95.8%) individuals. In calves, CSD included neonatal respiratory distress (13/19; 68.4%), infectious disease (septicemia, omphaloarteritis and urachocystitis; 3/19; 15.8%), trauma of unknown origin (2/19; 10.5%), and vehicular trauma (vessel strike; 1/19; 5.3%). In juveniles and adult individuals, CSD was: emaciation (2/5; 40%), sunlight-thermal burn shock (1/5; 20%); and discospondylitis (1/5; 20%). In one juvenile, the CSD was undetermined (1/5; 20%). This study integrates novel findings and published case reports to delineate the pathology of a South-western Atlantic population of humpback whales. This foundation will aid in the assessment of the population health and establish a baseline for development of conservation policies.</p></div

Gross and histopathologic findings in stranded humpback whales in Brazil.

<p>A) Pulmonary edema (animal no. 21). Large amounts of white foamy fluid fill in the respiratory airways and ooze trough the blowhole. B) Pulmonary parenchyma (animal no. 18). Large amounts of intra-alveolar keratin squames. C) Fibrinosuppurative umbilical arteritis (animal no. 23). The distal end of the right umbilical artery and adjacent urachus are dark red discolored and contain fibrin cast within the lumen. D) Right ventricle (animal no. 23). A major descending branch of the right coronary artery shows a markedly narrowed, 1 cm in diameter, white segment with circumferential irregularly thickened walls. Communicating with the former is a mural arterial ramification that penetrates deep into the underlying myocardium.</p

Skin lesions in stranded humpback whales in Brazil.

<p>A) Sunlight-induced thermal burn (animal no. 3). Multiple sunburn-associated bullae and blisters along with extensive areas of dermo-epidermal clefting and ulceration throughout the left lateral peduncle and dorsal aspect of the tail fluke B) Cyamid cutaneous infestation (animal no. 8). Massive cutaneous infestation by whale lice (<i>Cyamus</i> sp.) covering more than 60% of the epidermis (partially visible). Inset: Close-up view of <i>Cyamus boopis</i> cutaneous infestation (image from left flank of the animal).</p

Individual epidemiologic stranding data and signalment of humpback whales stranded in Brazil (2004–2016).

<p>Individual epidemiologic stranding data and signalment of humpback whales stranded in Brazil (2004–2016).</p

Summary of the main histopathologic findings in 23 humpback whales^* stranded in Brazil (2004–2016).

<p>Summary of the main histopathologic findings in 23 humpback whales^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0194872#t002fn001" target="_blank">*</a>} stranded in Brazil (2004–2016).</p