A Case of Meconium Aspiration Syndrome in a Bottlenose Dolphin (<i>Tursiops truncatus</i>) Calf

Abstract

Stillbirth and neonatal mortality are significant problems in captive breeding of dolphins, however, the causes of these problems are not fully understood. Here, we report a case of meconium aspiration syndrome (MAS) in a male neonate of bottlenose dolphin (Tursiops truncates) who died immediately after birth. At necropsy, a true knot was found in the umbilical cord. The lungs showed diffuse intraalveolar edema, hyperemic congestion and atelectasis due to meconium aspiration with mild inflammatory cell infiltration. Although the exact cause of MAS in this case was unknown, fetal hypoxia due possibly to the umbilical knot might have been associated with MAS, which is the first report in dolphins. MAS due to perinatal asphyxia should be taken into account as a possible cause of neonatal mortality and stillbirth of dolphin calves.

Retrospective pathological survey of pulmonary disease in free-ranging Amazon river dolphin Inia geoffrensis and tucuxi Sotalia fluviatilis

“…The microscopic features -i.e. abundant aspirated intrabronchial, -bronchiolar and -alveolar individual squames and/or aggregates of keratinized stratified epithelium with retained nuclei (pulmonary vernix caseosa), along with brown granular particles or aggregates -coincide with previous descriptions in humans and other animals, including odontocetes and mysticetes (Tanaka et al 2014). MAS is a neonatal pathology associated with serious respiratory disorder caused by aspiration of meconium-stained amniotic fluid in the airways during intrauterine gasping or during the first few breaths (Srinivasan & Vidyasagar 1999).…”

Ultrasonographic findings associated with normal pregnancy and fetal well‐being in the bottlenose dolphin (Tursiops truncatus)

“…The finding of a ball-shaped umbilical coil in three of 203 exams in our study was surprising, given the focally convoluted appearance of the cord and the clinical concern warranted for antenatal diagnosis of true umbilical knots in humans 39 and neonatal dolphins. 44 The lack of correlation between fetal fluid depth and gestational age in dolphins has also been found in horses. 31 Clinically, it may be of most value to note the fluid characteristics reported and maximum fluid depths seen in these successful pregnancies.…”

Pathology and causes of death in stranded humpback whales (Megaptera novaeangliae) from Brazil

“…Concentric hyaline membranes have been seen occluding the bronchioles of newborn harbor porpoises[ 50 ] and a striped dolphin ( Stenella coeruleoalba ) [ 45 ]. Recently, a case compatible with meconium aspiration syndrome was described in an Atlantic bottlenose dolphin [ 51 ] that died immediately after birth and a newborn harbour porpoise ( Phocoena phocoena ) [ 50 ]. In the former, a knot in the umbilical cord might had led to hypoxia [ 51 ].…”

“…Recently, a case compatible with meconium aspiration syndrome was described in an Atlantic bottlenose dolphin [ 51 ] that died immediately after birth and a newborn harbour porpoise ( Phocoena phocoena ) [ 50 ]. In the former, a knot in the umbilical cord might had led to hypoxia [ 51 ]. Our results suggest that perinatal asphyxia or respiratory distress appears to occur quite frequently and should be taken into account as a possible cause of neonatal mortality in this humpback whale population.…”