Abstract

Management of neonatal cetaceans in general is challenging due to the aquatic environment, deficiencies in immune defense, and physiologic adaptations.¹ Clinicopathological evaluation in the Franciscana dolphin (Pontoporia blainvillei), a small cetacean listed as “Vulnerable” according to the International Union for the Conservation of Nature, is complicated due to the lack of published normal blood value reference ranges and imaging in this species. Additionally, there are only a few reported cases of clinical management of Franciscana dolphins.^2-4

A female, calf, Franciscana dolphin estimated to be a newborn, approximately 1 week old (length: 71 cm, body weight: 4,2 kg, with umbilical cord, vibrissae on the rostrum and fetal lines), stranded alive on the coast of Florianopolis (Santa Catarina State, Brazil) in November 2023. No other animals were observed in the area, and the calf was transported to the R3 Animal Association’s rehabilitation facility for medical care. The dolphin was extremely weak and in critical condition. Clinical signs on admission included dehydration, hypoglycemia, and dyspnea, and she was unable to stay afloat unassisted. The calf was placed in a water pool at 26–28°C with a flotation device to aid in buoyancy, and she was monitored 24 hours/day. Several diagnostic tests (hematological and blood gas analysis, bacterial isolation, and antibiotic sensitivity from the blowhole) and diagnostic imaging (thoracic ultrasound and radiograph) were performed to establish the most appropriate treatment.

Initial respiratory rate was 5 breaths per minute and heart rate was 150 beats per minute. Preliminary blood analysis showed mild respiratory alkalosis (pH: 7,635 and pCO₂: 31,9 mm Hg), and hemogram values were similar to other reports.^3,4 Blood glucose level was 50 mg/dl. Radiographs of the thorax revealed a mild interstitial pattern, and thoracic ultrasound showed focal areas of moderate alveolar interstitial syndrome. During rehabilitation, antibiotic, fluid therapy and glucose were administered, and the calf was tube fed with 10 ml of fluids and milk formula hourly.⁵ On the third day, the dolphin’s condition further deteriorated, and she began to vomit and had labored breathing. Feeding was halted temporarily, and only fluids were administered, as well as injectable antibiotics and antiemetics. Nebulization with bronchodilator and oxygen was conducted QID, but the animal went into respiratory arrest and died. Postmortem investigation was carried out using endoscopy, computed tomography, and complete necropsy. Endoscopy of the upper gastrointestinal tract demonstrated the presence of milk formula and mild esophageal hyperemia. Computed tomography scan showed pneumonia in the caudal portion of both lungs and soft tissue opacity in tympanic bulla of the left ear. All additional cultures of blowhole, hemoculture, and bronchoalveolar lavage isolated pure Pseudomonas aeruginosa.

Pneumonia is one of the most common illnesses reported in dolphins, and several pathogens have been identified in respiratory infections.^6,7 Thoracic ultrasound is a valuable diagnostic method for detecting pulmonary diseases, and endoscopy and computed tomography (CT) can be used for postmortem investigation.^8-10 The diagnostic imaging, clinicopathological, and microbiological findings allowed us to diagnose the Franciscana dolphin with Pseudomonas aeruginosa pneumonia and sepsis. Immunologic dysfunction may have contributed to the otitis.

Acknowledgements

The authors thank Ana Carolina Santos Ibanez, Jenny Meegan, and Ricardo Fernandes Bernardo for their assistance. This research was supported by the Beach Monitoring Program of Santos Basin (PMP-BS), an environmental licensing, ABIO No. 640/2015 conducted by Brazilian Institute for the Environment and Renewable Natural Resources (IBAMA), which aims to assess the interference of production and flow of oil and natural gas over marine tetrapods.

*Presenting author

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