Michael Pees

Research on the Anatomy and Pathology of the Psittacine Heart

Abstract Understanding the normal anatomy of psittacine birds is basic to the diagnosis and treatment of disease in these species. As a first step toward a systematic investigation of the avian cardiovascular system, we conducted a 2-part study of healthy and diseased parrots. In the first part, the normal heart shape, size, and weight were studied in budgerigars (Melopsittacus undulatus) and Australian king parrots (Alisterus s scapularis) that were euthanatized because of genetic feather abnormalities. To compare results of birds of different sizes, measurements were evaluated in relation to the length of the sternum of the individual bird. Only minor differences were found between the 2 species studied. In the second part of the study, the spectrum and the frequency of pathologic changes of the heart and the major vessels were evaluated in 107 caged psittacine birds that were presented for routine necropsy. Of the birds examined, 36% had visible gross lesions of the heart, the major vessels, or both. On histologic examination, 99% exhibited at least low-grade pathologic changes of the heart or major vessels, which frequently were associated with noninfectious diseases. The results of this study emphasize the importance of cardiovascular disease in captive parrots.

Echocardiographic examinations of 60 African grey parrots and 30 other psittacine birds

The aim of this study was to establish reference values for the assessment of cardiac function in birds by measuring structures in the heart of healthy psittacine birds; 60 grey parrots, 10 Amazon parrots, 10 cockatoos and 10 Senegal parrots were anaesthetised with isoflurane and examined echocardiographically. The heart was visualised in two planes (vertical and horizontal views). Depending on the quality of the images, several dimensions of the heart could be measured and various parameters calculated. On the basis of these values, it was possible to establish reference values for each parrot genus. Some relative parameters showed no significant difference between the genera, independent of the birds size.

Blindness as a sign of proventricular dilatation disease in a grey parrot (Psittacus erithacus erithacus).

An approximately eight-year-old female grey parrot (Psittacus erithacus erithacus) was presented with a two months history of blindness. The radiographic examination showed a dilatation of the proventriculus, ventriculus and gut. Ophthalmoscopy and electroretinography revealed degeneration of the retina. A proventricular dilatation disease was suspected. The bird was euthanased because of deteriorating condition and poor prognosis. The pathological examination showed an atrophy of the ventricular muscles and lymphoplasmacytic infiltrates of the myenteric plexus of the proventriculus, ventriculus and gut as well as moderate lymphoplasmacytic infiltrates of the cerebrum with moderate neuronophagia. Lymphoplasmacytic infiltrates in the retina, indicating proventricular dilatation disease, and subsequent retinal degeneration were found. A potential common aetiology for proventricular dilatation disease and blindness is discussed.

Prevalence of viral infections in captive collections of boid snakes in Germany

Data on viral infections in apparently healthy snake collections in Germany were obtained with respect to husbandry conditions and health status. Samples from 100 boid snakes (from 14 collections) were examined microbiologically and for the presence of paramyxoviruses (PMVs) using RT-PCR. Blood was tested for the presence of antibodies against PMV, adenovirus and reovirus and for inclusion bodies indicative of inclusion body disease. Nine snakes tested positive for PMV, and inclusion bodies were detected in six snakes. Antibodies against PMV were found in one snake, and two snakes had antibodies against an adenovirus. A significant correlation was found between the origin of the snake and the presence of PMV, and between the presence of remarkable microbiological findings and husbandry conditions.

RT-PCR diagnosis followed by sequence characterization of paramyxoviruses in clinical samples from snakes reveals concurrent infections within populations and/or individuals

Paramyxoviruses (PMV) are important causes of disease in snakes in both private and zoologic collections and have been described in many different parts of the world. We have used the described L-gene nested RT-PCR (Ahne et al., 1999) as a diagnostic tool for the detection and characterization of PMV in clinical field samples from 102 snakes from Germany and Hungary. Fifty of the tested 203 samples were positive in the RT-PCR. 38 organs or swab samples from 25 snakes were selected for sequencing. They resulted in 13 different partial L-gene sequences, eight of which were identical to earlier characterized isolates, while five were new unique sequences, but also closely related to the earlier described PMV sequences. The comparison of sequences obtained from tissues from the same animal or from different animals from the same collection indicates that snakes can be infected with several different PMV during one outbreak. This is the first report of concurrent infection in a single snake or group of snakes with several distinct PMV.

Cardiovascular Physiology and Diseases of Pet Birds

Avian cardiac disease in pet birds occurs more often than previously assumed. The article focuses on anatomic peculiarities of the avian cardiovascular system and common diseases. Diagnostic possibilities are demonstrated, and therapeutic measures are discussed.

Computed tomography for the diagnosis and treatment monitoring of bacterial pneumonia in Indian pythons (Python molurus).

Eight Indian pythons (Python molurus) with clinical and microbiological evidence of pneumonia were examined by computed tomography (ct) before and after treatment. The results were assessed subjectively and measurements were taken following a standard protocol. Changes in the lung tissue of all the pythons were diagnosed, and the extent of the disease could be assessed. ct examinations after treatment showed an improvement in the six pythons whose clinical condition had improved, but in the other two pythons they demonstrated the severity of the disease. The subjective assessments were superior to the evaluation of measurements of attenuation in regions of interest. However, the average and the maximum attenuation provided additional information on the extent of the disease. Except for one python with only mild clinical signs, the attenuation after successful treatment was still higher than in healthy pythons.

Diagnosis and long-term therapy of right-sided heart failure in a yellow- crowned amazon (Amazona ochrocephala)

CARDIAC disease in psittacine birds occurs more often than previously assumed. Although reference values for the echocardiographic assessment of the avian heart exist, experiences with long-term therapy of diseased birds are still lacking. A 22-year-old, female yellow-crowned amazon (Amazona ochrocephala) was presented because of a history of weakness, incoordination and dyspnoea. The bird had previously been found to be positive for circovirus (psittacine beak and feather disease) by PCR testing of a feather. Clinical examination revealed the bird to be in a poor general condition with a reduced nutritional status (bodyweight 430 g, reference value 500 g [Flemmer and Clubb 1994]). The abdominal region appeared slightly swollen. Respiration was forced and accompanied by slight squealing sounds, which were stronger when the bird was handled during examination; this was considered to be stress-induced. On radiography (ventrodorsal and laterolateral views), the shadow of the heart and the liver were noticeably enlarged, and the airsacs were displaced. The bird collapsed during the examination, and was placed in a quiet, darkened area and oxygen was administered; etilefrine (Effortil; Boehringer Ingelheim) was administered orally dropwise to effect, and 10 ml lactated Ringer’s solution with 5 per cent dextrose was given subcutaneously. After the bird had been stabilised, echocardiography was performed with the bird held in an upright position, using a 7·5 MHz microcurved convex scanner (Sonoace 8800; Kretztechnik). The scanner was placed on the medial abdominal area directly behind the sternum, using the ventromedian approach (Krautwald-Junghanns and others 1995, Pees and others 2004). Measurements of the left ventricle revealed a reduced length (systolic 14·7 mm, reference values mean [sd] 21·1 [2·3] mm) and width (systolic 4·5 mm, reference values 6·7 [1·2] mm); fractional shortening was slightly greater than reference values (29·7 mm, reference values 20·7 [6·8] mm). The right ventricle was enlarged (systolic length 13·5 mm, reference values 9·4 [1·8] mm; systolic width 5·2 mm, reference values 3·1 [0·7] mm). The outer wall of the right ventricle was thickened (no reference values exist for the outer walls of the heart, since differentiation from surrounding tissue is difficult in healthy birds [Pees and others 2004]), and the interventricular septum was also thickened (4·3 mm, reference values 2·4 [0·2] mm) (Fig 1); furthermore, the contractility of the right ventricle was reduced (26·8 per cent, reference values 34·1 [3·7] per cent) (Table 1). An anechoic area could be seen between the heart and liver tissue, and the liver vessels were subjectively considered to be dilated. On the basis of these findings, a diagnosis of right-sided heart failure (hypertrophy and dilation), left-sided hypertrophy, hydropericardium and congestion of the liver was made. Swabs were taken from the choana, crop and cloaca for microbiological examination; a heavy growth of Enterobacter cloacae was obtained on culture from both the choana and the crop. The bird was hospitalised in the clinic and initial cardiac therapy was started using 2·5 ml/kg enalapril (Enacard; Merial) orally, every 12 hours, as described by Straub and others 2003). The bird also received 20 mg/kg of a mixture of Ringer’s solution (50 per cent), 5 per cent glucose (25 per cent) and amino acids (25 per cent) (Amynin; Merial) subcutaneously, every 12 hours. Since the isolation of E cloacae in pure culture was assessed to be an accompanying problem, the bird was treated with 12 mg/kg enrofloxacin (Baytril 2·5 per cent; Bayer) intramuscularly, every 24 hours, following antibiotic sensitivity testing of the isolate. Since amazons kept in captivity often suffer from respiratory mycosis, a preventive antifungal therapy was started using 10 mg/kg itraconazole (Sempera Liquid; Janssen-Cilag) orally, every 24 hours, and 8000 iu/kg vitamin A (Stress-Vitam-N; Selectavet) was administered intramuscularly every five days, to support epithelial regeneration of the air sac walls. Additionally, a vitamin B complex (Vitamin B-komplex; cp-pharma) with a dosage of vitamin B1 of 5 mg/kg, was administered intramuscularly every 24 hours because of the central nervous signs of incoordination. Echocardiographic examination was repeated every two days during the period of hospitalisation. On day 8 after the start of therapy, the pericardial effusion was no longer visible, and congestion of the liver vessels was subjectively assessed to be reduced. Although the bird’s body mass had only increased slightly, to 452 g, its general condition had improved significantly. Enalapril therapy was then continued by the owner, at a dosage of 2·5 mg/kg administered every 12 hours, with the bird as an outpatient. It was possible to administer the drug directly via a syringe, and the bird accepted the treatment well. Treatment was monitored by examining the bird in the clinic approximately every three weeks. On day 98 after starting the cardiac therapy, the bird was slightly depressed and showed difficulties in sitting on its perch. The owners reported no changes in the application or the bird’s acceptance of the treatment, or in its environment. Echocardiography revealed no deterioration of cardiac function, but haematological examination revealed an increased haematocrit of 68 per cent (reference range 41 to 53 per cent) Short Communications

Effect of handling-induced stress on the results of spectral Doppler echocardiography in falcons

In order to evaluate the effects of habituation to handling on the Doppler-derived velocity of diastolic ventricular inflow and systolic aortic outflow, falcons that were accustomed to regular handling were compared with falcons that had been handled very little. The mean heart rate of the frequently handled birds was 111 beats per minute less than the non-habituated birds. All the mean blood flow velocities recorded were much higher in the non-habituated birds than those accustomed to handling. Taking into account the difficulty of objectively quantifying the level of stress suffered by any individual bird, the question is, if meaningful clinical or reference values for Doppler-derived blood flow velocities may be obtained in unsedated or non-anaesthetized birds?

Pericardiocentesis and the use of enalapril in a Fischer's lovebird (Agapornis fischeri)

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