Stomatitis in a Harris’ hawk

14 Stomatitis in a Harris’ hawk




INITIAL PRESENTATION


Reduced appetite and oral lesions in a Harris’ hawk.



Introduction


Clinical signs are often not pathognomonic in veterinary medicine, with similar signs often emanating from several aetiologies. This case highlights the need for laboratory investigation to make a diagnosis before treatment can proceed.



CASE PRESENTING SIGNS


The 4-year-old female Harris’ hawk (Parabuteo unicinctus) presented with reduced appetite, which was suspected to be due to oral lesions that the owner had seen.



Husbandry


The Harris’ hawk was tethered on a bow perch outdoors during the day, and housed in a bay overnight. A sand substrate was provided; this was spot-cleaned daily and replaced twice yearly. The bow perch was covered with leather padding. A shallow water bowl was provided for drinking and bathing. The bird was moved to an aviary during moulting. The aviary had solid timber walls, and was part-covered with netting across part of the roof and along one side; a sheltered area was included at one end. Branches were present for perching in the aviary.


The bird was flown on 5 days each week. She was weighed daily. The diet consisted mainly of day-old chicks, with occasional quail and rabbit. The quantity fed once daily varied depending on the morning weight, keeping the bird slightly lighter during the flying season and allowing her to put on body condition in preparation for moulting. Adult female Harris’ hawks usually weigh 825–1200 g (see Harris’ hawk ecology in Ch. 11).



Case History


The Harris’ hawk had been flying well through the season, and her appetite was usually good. The owner had noticed some changes over the previous week:


• Appetite reduced; willing to eat, but slower and not finishing the food offered

• Seen flicking head while eating, which was thought to suggest oral discomfort

• Weight reduction which the owner thought correlated with the reduced appetite

• Cream/yellow material had been seen in the oral cavity

• Still willing to fly

• Normal appearance to mutes (droppings) and casting (regurgitated indigestible part of diet).


Clinical Examination


After observation of the bird on the owner’s fist, the Harris’ hawk was cast with a towel for examination. Clinical findings were as follows:


• Moderate body condition, keel palpable but not prominent, weight 950 g

• No oculo-nasal discharges externally

• Oral examination revealed caseous off-white material covering the tongue, extending to the oral mucous membranes. The material appeared to be restricting movement of the tongue

• Integument and feathers unremarkable

• Auscultation dorsally and ventrally unremarkable

• Coelomic palpation unremarkable

• No lameness noted when perching on the fist, and no limb laxities or fractures palpated

• No bumblefoot lesions present.


DIFFERENTIAL DIAGNOSES


The differentials for white/cream caseous oropharyngeal lesions in a raptor were:


• Candidiasis (Candida albicans): often pinpoint lesions

• Trichomoniasis (Trichomonas spp): usually causes a diphtheritic membrane covering the oropharynx (called ‘canker’ by pigeon owners and ‘frounce’ by falconers)

• Capillariasis (Capillaria spp)

• Bacterial stomatitis, e.g. Pseudomonas spp, Pasteurella spp

• Viral infection, e.g. avian pox virus (wet version, particularly seen at the commissures of the beak), owl herpesvirus

• Fungal infection, e.g. Aspergillus

• Hypovitaminosis A, may predispose to other conditions: for example abscesses particularly in parrots, candidiasis, and trichomoniasis

• Infection may be secondary to trauma

• Insectivorous birds may suffer from infection with the Syngamus trachea nematode

• Visceral gout

• Neoplasia

• Exudate from sinusitis (e.g. due to mycoplasma infection).


Case Work-Up



Examination under general anaesthesia


This allowed a comprehensive assessment of the oral cavity (Fig. 14.1a) including the base of the tongue, as well as permitting sample collection for further tests. Anaesthesia was induced via a close-fitting facemask. The hawk was not intubated for two reasons: the procedure was rapid, and there was a risk of introducing infection into the lower respiratory tract if an endotracheal tube was passed via the oral cavity. The lesions extended over the tongue, making it slightly rigid, and laterally in the oropharynx (Fig. 14.1b). Lesions did not extend into the oesophagus.


image

Figure 14.1 (a) Normal raptor oral cavity (in a common buzzard, Buteo buteo). (b) Harris’ hawk (Parabuteo unicinctus) with oral lesions, predominantly over the tongue.



NURSING ASPECT



Fasting before anaesthesia



• Raptors should be fasted before general anaesthesia, to reduce the risk of regurgitation and aspiration.

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Sep 3, 2016 | Posted by in SMALL ANIMAL | Comments Off on Stomatitis in a Harris’ hawk

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