Interesting avian and exotic cases (Proceedings)

A 4 year old neutered male rabbit weighing 1.98 kg presented in December of 2002 for a 1 year history of nasal discharge and violent sneezing. The rabbit's condition was unresponsive to antibiotics. Due to the violent nature of the sneezing and the unresponsiveness to antibiotics, a nasal foreign body was suspected. Endoscopy of the nasal passageways revealed a large mass. Initial biopsies of the mass revealed pyogranulomatous inflammation and possible intralesional foreign bodies. Special stains revealed no acid fast staining organisms. A culture revealed normal respiratory flora.

The rabbit was referred to The University of Georgia Veterinary Teaching Hospital for a CT scan to determine the full extent of the mass. After the CT scan, the mass was debrided aggressively via endoscopy. At this point in time nearly complete destruction of the nasal septum was noted. A preliminary culture revealed Acinetobacter and an unidentified gram negative bacillus. The preliminary histopathology report showed granulomatous inflammation that was consistent with a possible foreign body reaction or fungal infection. While culture and sensitivity were pending, the rabbit was started on ciprofloxacin at 10mg/kg PO q 12 hrs, itraconazole at 10mg/kg PO q 12 hrs and carprofen at 2.5mg PO q 12 hrs.

The rabbit experienced complete cessation of the violent sneezing within 3 days of the aggressive debridement. The final histopathology report showed the presence of acid fast staining organisms. Approximately 3 weeks later culture results verified the presence of a Mycobacterium spp, however the Mycobacterium unable to be isolated and further typed.

Within 2 months, the rabbit had begun to sneeze excessively and violently again. He presented again at the author's clinic. Endoscopy was performed and an excessive amount of crusty, scab-like material was debrided from the nasal passageway. Pieces of tissue were once again submitted for culture to identify the Mycobacterium species and to determine its sensitivities. After 7 weeks, the bacteria was identified as Mycobacterium avium complex. Sensitivity took an additional 4 months. The rabbit was started on a combination of rifampin at 75mg/kg PO q 12 hrs, azithromycin at 50mg/kg PO q 24 hrs and ciprofloxacin at 10mg/kg PO q 12 hrs.

The rabbit did well on this protocol for 8 months. He came in after 8 months for a recheck because there was an increase in sneezing again. Endoscopy showed a recurrence of the crusty dried exudates and excessive granulation tissue. The nasal passageway was debrided again and the rabbit improved. The rabbit was brought back in every 3-7 months for rechecks. Periodically the nasal passageways needed to be debrided again. Fourteen months later in January of 2005, the rabbit was doing well clinically and the medications were discontinued. After 2 weeks the rabbit stated having increased episodes of sneezing and appeared to be lethargic. Medications were resumed.

The rabbit was presented again 5 months later in June of 2005 for endoscopic debridement. The nasal conchi were improved. More defined conchi were observed. At this time, significant serum chemistry findings were an elevated ALKP 177 IU/L (ref 10-70IU/L) (1) and an elevated total bilirubin 15.3umol/L (ref 3.4-8.5umol/L) (1). The results of a complete blood count were a WBC of 4,100/uL (ref 5,000-12,000/uL)(1) consisting of 58% segmented neutrophils, 41% heterophils and1% monocytes. The RBC was 5.5 x 106 and the hematocrit was 28% (ref. 33-38%) (1). Another endoscopic debridement 5 months later in November of 2005 was peformed. A culture at that time grew a light growth of Bordetella bronchiseptica, Staphlococcus coagulase negative and no Mycobacterium species were noted.

In January of 2006 the medication regimen was changed to rifampin 6 times per week, azithromycin 3 times per week and ciprofloxacin twice daily. Meloxicam was also given at a dose of 0.2mg/kg PO q 12 hrs. Four months later in May of 2006 the rabbit presented again for endoscopic debridement. There was very little exudate and there was dramatic improvement in the appearance of the nasal conchi. Medications were discontinued at that time.

The rabbit was presented again 2 months later in July of 2006 because sneezing and mucopurulent discharge from the nose had resumed. Endoscopy revealed deterioriazation of the rabbit's nasal passageway. There were excessive crusts and mucopurulent discharge as well as blunting and swelling of the rabbit's nasal conchi. A culture was sent to Sekot Laboratories (3) which specializes in isolation and obtaining drug sensitivities to Mycobacterium species. Mycobacterium avium spp was again identified. The sensitivity panel showed resistance had developed to ciprofloxacin and rifampin. The organism was only sensitive to clarithromycin, ethambutol, and rifabutin. The rabbit was started on clarithromycin at 50mg/kg PO q 24 hrs, rifabutin at 25mg/kg PO q 12 hrs and ethambutol at 45mg/kg PO q 12 hrs (2).

It is easy to assume that all sneezing rabbits have an upper respiratory tract infection with a common organism such as Pasteurella. After all, common things happen commonly! However, it is important to look further – especially if the condition does not improve with routine antibiotic use. Violent, repetitive sneezing is a clinical sign that merits nasal endoscopy to look for a foreign body or mass. If a mass is observed via routine endoscopy, an advanced imaging technique such as MRI is necessary to determine the extent of the lesion. As with other species, mycobacteriosis can be extremely challenging to completely eliminate.

A 8 year old DNA sexed male Blue and Gold Macaw was evaluated for a behavioral issue of increased aggression and biting. The bird was hand raised by the owner starting at 5 weeks of age. The bird lives on an open bird tree in a hallway in the owner's veterinary practice. The main stressor that triggered the aggressive behavior was an associate veterinarian. A board certified behaviorist was consulted to assist in the evaluation and treatment of this behavior. The bird, Xander, was diagnosed as having mate aggression, misdirected aggression and dominance aggression.

Recommendations made were to provide visual barriers to prevent the bird from constantly seeing the associate. A tension rod was used to hang a shower curtain in the hallway blocking his view of her travelling between her office and the treatment room. A full window decal was used to prevent him seeing her in her office from his perching tree. She was also instructed to start providing the bird with his favorite treats, sunflower seeds, on a regular basis. She was essentially to become the walking treat dispenser. The treats were to be administered very quickly – i.e., tossed into his food cup as she causally walked past. The object was for him to start seeing her as a bearer of positive feedback. Another technique that was utilized was for the owner to stand next to the perching tree and allow the bird unlimited access to sunflower seeds in her hand. The associate was to slowly approach them from down the hallway. As soon as the bird showed any signs of agitation, the owner denied the bird access to her and the sunflower seeds by stepping away and behind the curtain. Clicker training was also introduced to the bird to provide structured sessions of interaction with the owner. The most difficult part of this process was getting compliance from the associate and making time for the desensitisation training sessions. The most valuable part of working on this case was coming to an appreciation for just how difficult it is to properly address behavioral problems in pet psittacines. The boarded behaviorist's input and frequent feedback on training progress was absolutely invaluable.

A 5 year old male neutered rabbit was presented for a routine wellness exam. Upon palpation of the abdomen, an approximately 4 cm, hard mass was palpable in the caudal abdomen in the region of the bladder. Radiographs revealed a radio-opaque stone in the urinary bladder. Routine cystotomy was performed and the rabbit recovered without complications. This case illustrates the importance of routine wellness exams. This rabbit was completely asymptomatic for this urinary bladder stone at the time of presentation.

A 9 month old African Grey Parrot was presented for a 2 month history of feather picking. The feather picking had started after the bird was boarded at another facility while the owner was on vacation. The bird had had its wings trimmed while boarding. The picked areas included the neck, chest, under the wings and the legs. The referring veterinarian cultured MRSA and treated the bird with tribrissen.

This case illustrates a very common presentation of young African Grey Parrots. It can be challenging to identify the antecedent or the "trigger" that started the feather destructive behavior. A very detailed history needs to be taken in these cases to try to evaluate the bird's environment, nutrition and lifestyle. This bird was already on a very good plane of nutrition. The treatment plan for this bird focused on initially limiting the birds ability to get at its feathers by using a collar. The other main focus was on getting the bird on a very predictable schedule and introducing a captive foraging tree to the bird's environment. The owners were extremely devoted to this bird and were very compliant in providing the foraging tree and finding ways to enrich this intelligent bird's life. The bird was very receptive to the toys and foraging tree. The concept of captive foraging has been greatly advanced in the field of avian medicine by Dr. Scott Echols. He has made a DVD available for retail sale to clients that explains the needs and benefits for captive foraging opportunities for pet birds.

The significance of the positive MRSA culture was never determined. Both owners worked at a local Veteran's Hospital and had been tested negative for MRSA. There was no obvious skin lesions on this bird other than the areas of feather loss.

The bird made excellent progress and was able to live without the collar on after a few months. Another aspect of care that seemed to influence and encourage the owner's compliance was frequent communications to the owner via email. The bird will occasionally pick a few feathers, but not produce any significant areas of alopecia. Clicker training has also been introduced to this bird to provide more periods of structured interaction with the owner.

A 4 year old spayed female ferret presented for progressive generalized alopecia and development of mammary glands. Results of serum biochemistry profile revealed a significant hyperglycemia – 429mg/dl. The ferret was not experiencing any polydipsia or polyuria and was negative for ketones in the urine. The author had previously seen a case of an employee's ferret also having very significant hyperglycemia that required 6 units of NPH insulin every 6 hrs to barely keep the ferret's blood sugar under 200mg/dl. While trying to control the ferret's hyperglycemia secondary to suspected diabetes melitis, the ferret started exhibiting increasing generalized alopecia. It was assumed that the ferret was showing signs of adrenal disease and the ferret was treated with 200ug of lupron. Within two weeks of receiving the lupron injection, the ferret's blood sugar level started coming down and less and less insulin, and eventually no insulin was needed to control the blood sugar level. Towards the end of the four week interval between lupron doses, the ferret's blood sugar level started to rise again. Since initially there was such an extremely high dose of insulin needed to try to control the ferret's blood sugar level and there was clinical signs consistent with adrenal disease it was suspected that the sex hormones that the adrenal glands were producing were antagonizing the insulin. A similar scenario was suspected in this case. Blood was collected for an adrenal panel, insulin and cortisol levels. The results were:

• Estradiol 133pmol (30-180)

• 17 OH progesterone 25.1nmol (0-0.8)

• Androstendione 30 nmol (0-15)

• Cortisol 14.4 (6-140)

• Insulin 44.1 (5-30)

The ferret was treated with 200ug of lupron. The owners were had very limited finances. They returned 3 weeks later for for lethargy. Her hematocrit was 19% and a CBC showed a non-regnerative anemia. The ferret's condition declined and the owners elected euthanasia.

References

1 Harcourt-Brown, Frances; Textbook of Rabbit Medicine; Butterworth-Heinemann, Oxford, 2002.

2 Harrenstien, Lisa et al, "Mycobacterium avium pygmy rabbits (Brachylagus idahoensis): 28 cases"; Journal of Zoo and Wildlife Medicine; Dec 2006 (in press).

3 Sekot Laboratory, 800-330-4377, 8181 NW 154th ST Ste 290, Miami Lakes, FL 33016