An orphaned 156 cm., 58 kg. female pygmy sperm whale calf (Kogia breviceps) was treated for 147 days at Mote Marine Laboratory, Sarasota, Florida from 18 August 1994 until her death on 11 January 1995. Care and monitoring were provided by staff and numerous volunteers 24 hours/day. The age estimate of the calf at stranding was initially placed at 3-6 months, but was later reduced to approximately one month. Therapy goals were to provide adequate nutrition for growth, and to treat for a possible pulmonary infection, a gastric yeast (Torulopsis glabrata)infection, and a regenerative anemia.
Several unusual, transitory behaviors were observed at different times within the first 2 months of treatment including: a "ballistic aerial behavior", "shrimping", and "SB arching". The only overlap of behaviors was between the last 1-2 days of "shrimping" and the start of "SB arching". None of the above behaviors were seen during the 2 months prior to her acute death. In addition to the T. glabrata, post mortem histopathology revealed disseminated mycolic gastritis (Mucor sp.) and sepsis as the cause of death. The previously undiagnosed mucormycosis was found in the colon and mesenteric lymph nodes, and there was mild subarachnoid meningitis of possible fungal etiology. It was unclear whether the mucormycosis was present during the time of the unusual behaviors. In addition, serum electrophoresis on samples taken during rehabilitation demonstrated a severely depressed humoral immune system.
"Ballistic Aerial Behavior"
On 12 September, after 18 days of treatment with Enrofloxacin (Baytril), a series of unusual behaviors were noted. (The Enrofloxacin dosage was 5.7 mg/kg PO bid, but was reduced temporarily to 2.7 mg/kg for five days in response to a prerenal azotemia.) Her initial change in behavior was an abrupt, dramatic decrease in her interactions with people. A few days later extended bouts of stereotypic swimming and rubbing of her back, chest, and dorsal fin were first recorded. This behavior of slowly swimming around the circumference of the circular pool was observed off and on throughout the time she was treated, but not always as a presumed response to pruritis. At other times, when the calf had her eyes closed and was less responsive to external stimuli, the behavior seemed to be more associated with resting. Finally, a probable CNS disturbance resulting in seemingly uncontrolled aerial behavior, hyperesthesia, and sound hypersensitivity was observed. The aerial behavior often resulted in repeated collisions with the sides of the pool, requiring physical restraint to protect the whale from potential trauma. The whale calf "startled" at even light human touch, and at any sound above a whisper.
In addition to enrofloxacin, other concurrent medications included amoxicillin/clavulanate potassium (Augmentin) at 10 mg/kg PO bid, fluconazole (Diflucan) at 1.7 mg/kg PO sic, nystatin (Nilstat), 650,000 IU PO tic, Cimetidine (Tagamet) at 3.2 mg/kg PO tic, and sucralfate (Carafate), lg PO tic. All medications were discontinued when the aerial behaviors appeared, and symptoms gradually tapered off to undetectable levels approximately 12 days later. Amoxicillin/clavulanate potassium, which has a human half-life of <2 hours, had been discontinued 3 days prior to the onset of the aerial behaviors, and all of the other medications except Cimetidine were given at other times during the 4.5 months of treatment without adverse effects.
Possible etiologies for the "ballistic aerial behavior" included: a drug sensitivity reaction, an infectious agent, or an autoimmune condition. Chest skin biopsies taken on 21 September from an area she had been rubbing showed a diffuse, severe, necrotizing dermatitis with eosinophilic and neutrophilic infiltration. Special staining and electron microscopy failed to identify an infectious etiology.
"Shrimping" Behavior
Thirty seven days into care (23 September) another unusual behavior suddenly developed. The calf would briefly assume a crescent shaped posture with her head, peduncle, and sometimes flukes, flexed towards the abdomen. This behavior was referred to as "shrimping" in the log books because of the similarity to the shape of a curled shrimp. The degree of flexing and her orientation varied, but most commonly the calf gently assumed this posture with her dorsal peduncle and dorsal fin against the pool bottom, and her flukes and head curled upward towards the surface in a "C" (Figure 1). She remained stationary in this position for a few seconds to a minute, drifting with the current. Other times she would lie on her side or hang at the surface with her ventrem towards the pool bottom in the same crescent shape. Although her eyes were most often open she seemed unresponsive to external stimuli during these bouts. Following each episode, which sometimes occurred in series, she would resume normal swimming activity.
During the 14 days that "shrimping" was observed, the calf's appetite remained good to excellent, and she continued to show an average weight gain of 0.5-1 kg/day. There were occasional reports of vomiting episodes, but they did not occur any more frequently than at earlier periods prior to the onset of the "shrimping" behavior. At the onset of these behaviors she had a 15,000 WBC with neutrophilia (10,000), and the gastric yeast, Torulopsis glabrata, was still present. Treatment consisted of clindamycin hydrochloride (Cleocin HCL) at 8.8 mg/kg PO bid, fluconazole (Diflucan) at 1.5 mg/kg PO bid, Cimetidine (Tagamet) at 1.5 mg/kg PO tic, and diphenhydramine hydrochloride (Benadryl) at 1.8 mg/kg PO tic. Amikacin sulfate (Amikin) at 6.8 mg/kg IM bid had been given for 3 days, but was discontinued approximately 12 hours before the onset of the "shrimping" behavior. Clindamycin had been given two weeks previously for a 36 hour period without any adverse effects; however, symptoms began a few hours after restarting clindamycin. Clindamycin alone was discontinued that afternoon. "Shrimping" was recorded 6080 times in the first two days, then dropped dramatically in frequency, being recorded only occasionally over the next week. Another week passed with no recorded "shrimping" when the behavior abruptly appeared again occasionally for 12 days in conjunction with episodes of a new behavior, "SB arching". The possible etiologies for the "shrimping behavior" included: a drug sensitivity reaction, abdominal pain, or a CNS disturbance of unknown etiology.
"SB Arching"
On 12 October, fifty-six days after arriving at Mote, the animal exhibited a new stationary, arched posture with her dorsum flexed, her lower abdomen resting on the pool bottom, her rostrum above water, and her pectoral flippers generally held extended, nearly perpendicular to her body (Figure 2). Occasionally the fluke tips would also be raised from the pool surface several inches. Since this posture involved her body extending from above the water to the pool bottom it was logged as a "surface to bottom arch" or "SB arch". This behavior was described over 14 days and was strongly correlated with certain areas of the pool. Once the calf had begun the "SB arch" posture, changes in external stimuli (people, toys, feeding) did not result in the termination of the current bout. The act of forming the "SB arch" appeared always to be controlled and relaxed without an obvious pain component. Initially, this behavior increased in frequency and duration varying from several seconds to 45 seconds. The peak activity period for "SB arching" was from 12 October to 15 October (137, 177, 313, 214 episodes/day respectively), at which time the bouts slowly started declining in frequency and duration, ranging from 1-10 seconds in length over the next 10 days.
Her health status during the course of this behavior included the previously diagnosed gastric Torulopsis glabrata, a possible virus of unknown etiology, phlebitis of the fluke vessels, and an excoriation type wound located on her ventral abdomen. The wound was first examined on 14 October and originally extended from her anus along the peduncle to the fluke, and eventually spread to encompass both the genital and mammary slits, 2/3 of the ventrum and small patches in each axilla. The wound is best described as patchy, white, slightly elevated lesions over pink tissue surrounded by a bright red fringe. These conditions were being treated with the following: trimethoprim/sulfadiazine (Di-Trim) at 23 mg/kg PO sid for 5 days prior to the onset of this behavior, azithromycin (Zithromax) at 3.1 mg/kg PO sid for 6 days prior to the onset of this behavior, Itraconazole (Sporanox) at 3.6 mg/kg PO bid, dirnethyl sulfoxide gel (DMSO) applied topically to the flukes approximately every 1-3 days, when the animal was restrained for exams, (DMSO was administered 4 consecutive days prior to the onset of symptoms), and Folic Acid 2000 mcg sic. Azithromycin, an antibiotic which has been documented in humans to exhibit full systemic benefits even several days after discontinuation from an oral course lasting approximately 3 days, was stopped secondary to this behavior under concerns of a possible drug reaction. The dosage of Itraconazole was based upon antifungal drug levels performed at the University of Texas, Fungus Testing Laboratory. Her appetite, which was good, showed little variation over the 14 day period. Other health indicators included a 7.2 kg weight gain, a steadily declining WBC count (from 10.4 to 7.9), a newly learned behavior to voluntarily position for and allow tube feeding at a designated station, and interest in solid food (squid).
Possible etiologies for the "SB arching" included: a drug reaction, pruritis secondary to an unidentified dermatitis, or other. Biopsies from the periphery of the abdominal skin lesion, taken on 28 October, were described as exhibiting a moderate, diffuse, subacute, proliferative dermatitis. Electron microscopy failed to reveal the cause of the lesion which resolved within six weeks.
Discussion
Unfortunately, there is no clearly defined etiology for any of the above unusual behaviors. All three behaviors exhibited a sudden onset of symptoms, initially occurring at high frequency, then gradually disappearing within 12-14 days following changes in drug therapy. However, this information alone does not prove a causal relationship. In addition, complicating factors include the very young age of the calf, her humoral immune suppression, the multiple changes in her treatment regimen, and the lack of basic knowledge about Kogia species.
It seems most likely that the CNS nature of the "ballistic aerial behavior", and the fact that symptoms gradually abated following discontinuance of all medications favors a drug reaction etiology, perhaps to enrofloxacin, but we have not heard of similar adverse effects reported previously in any of the many marine mammals who have been treated with this antibiotic.
Perhaps the "shrimping" behavior was a sensitivity reaction to the second regimen of clindamycin (the calf having been previously sensitized to it), or it may have been a response to abdominal pain. The calf's posture appeared subjectively different, however, from the more classic "abdominal cramping" posture (also previously seen in this case) where the upper body was straight, and the peduncle and flukes were strongly tucked either ventrally or laterally. The abdominal muscles seemed more relaxed during the "shrimping" behavior, and the posture involved the whole body, often in the unusual orientation of the abdomen facing towards the water surface. If this behavior was a drug reaction, then it is interesting that the only other time when "shrimping" occurred was following 6 days of azithromycin therapy.
It is difficult to determine whether the "SB arching" behavior resulted in the ulcerative abdominal dermatitis or whether this behavior was in response to a pruritic condition. This behavior was strongly associated with particular areas of the pool. A raised central fiberglass seam was rougher in texture than the rest of the bottom of the tank. The calf's feed station was located at one end of this seam, and above the other end was the observer's area. Both areas were normally high use areas by the calf. A third high use area was the overflow skimmer for the pool. These three areas were the location of nearly all of the "SB arching". Whether the behavior was seen in these areas because that is where she spent most of her time anyway, or whether she consciously chose these areas because the roughened surface or skimmer suction served to relieve a pruritic dermatitis is uncertain. The odd posture and the lack of movement exhibited during "SB arches" would, however, seem to be a less efficient method to relieve itching than simply swimming or gliding in a normal orientation with the abdomen in contact with the pool surface. Water depth at this time remained at approximately 4.5 feet. A dense dinoflagellate bloom ("red tide") in the bay prevented us from raising the water level in the pool to test whether this behavior might disappear if the whale was intentionally using the weight of her rostrum above water to press her abdomen towards the pool bottom. The red tide itself is not suspected as a cause of the unusual behaviors since the pool was on a closed, recirculating water system, with red tide counts at or near zero cells/liter.
Although great strides in marine mammal medicine have been made in recent years, there is still much to learn. This is particularly true when dealing with the more uncommon species, new medications, and the very young. We recommend that any unusual behaviors be well documented and reported in journals and conferences such as this. A narrative account as well as still photos and video graphic documentation is necessary. In the future we intend to keep a still camera and a video camera near the pool at all times along with a log book to describe what behaviors have been recorded.