Physiology, diagnosis, and diseases of the avian reproductive tract.

Disorders of the reproductive system represent a large portion of both large and small domestic animal medicine. Although some disorders of this system have been extensively studied in birds, this science is still in its infancy, when compared to mammalian reproductive medicine. This may be due to several reasons, but the simple fact that birds are oviparous renders knowledge of mammalian reproductive anatomy, histology, physiology, and disease process, inapplicable to avian patients. Nevertheless, several specific diseases or conditions affecting the reproductive system of birds have been described. By integrating information about the comparative anatomy and physiology of birds, reports of the most common reproductive diseases of birds and utilizing the latest diagnostic techniques, especially videoendoscopy, the avian practitioner should be able to diagnose and properly treat a high percentage of the avian reproductive diseases.     

The anatomy and physiology of the avian endocrine system.

The endocrine system of birds is comparable to that of mammals, although there are many unique aspects to consider when studying the anatomy, physiology, and biochemistry. Avian endocrinology is a field of veterinary medicine that is unfamiliar to many practitioners; however, it is important to have a comprehensive understanding when evaluating companion birds in clinical practice. This article covers the anatomy and physiology of the normal avian, and readers are referred to other articles for a more detailed explanation of altered physiology and pathology.     

Avian mycobacteriosis in companion birds: 20-year survey

The causative agents of avian mycobacteriosis in pet birds are rarely identified. The aim of this study is to add information about the etiology of avian mycobacteriosis. The identification of mycobacterium species in 27 cases of avian mycobacteriosis in pet birds was investigated by polymerase chain reaction (PCR) and sequencing of a rRNA hypervariable region. Avian mycobacteriosis appeared to be an infrequent diagnosis. Interestingly, a few cases of avian mycobacteriosis were recorded in very young birds. The most commonly affected species were the canary (Serinus canarius), the Eurasian goldfinch (Carduelis carduelis) and the red siskin (Spinus cucullatus). All but one bird were infected with Mycobacterium genavense. Mycobacterium avium was identified only in one case.     

Avian Vision: A Review of Form and Function with Special Consideration to Birds of Prey

More so than any other terrestrial vertebrate, birds rely most heavily on their ability to assess their visual environment. High visual acuity is not only necessary to find and acquire food, but also to navigate surroundings, to identify conspecifics and potential mates, and to quickly identify and escape from predators. This article aims to help the reader understand how birds, particularly birds of prey, see by reviewing pertinent anatomy and physiology of the eye, color vision, visual fields, visual acuity, accommodation, and flicker-fusion frequency. For more information on specific disease conditions of the avian eye, the reader is encouraged to review any number of avian medical and surgical texts.     

Compendium of measures to control Chlamydophila psittaci (formerly Chlamydia psittaci) infection among humans (psittacosis) and pet birds, 2005

Psittacosis, also known as parrot fever and ornithosis, is a bacterial infection of humans that can cause severe pneumonia and other serious health problems. It is caused by Chlamydophila psittaci, formerly known as Chlamydia psittaci. From 1988 through 2003, 935 human cases of psittacosis were reported to the CDC and most resulted from exposure to infected pet birds, usually cockatiels, parakeets, parrots, and macaws. In birds, C. psittaci infection is referred to as avian chlamydiosis. Infected birds shed the bacteria through feces and nasal discharges, and humans become infected from exposure to these materials. This compendium provides information about psittacosis and avian chlamydiosis to public health officials, physicians, veterinarians, the pet bird industry, and others concerned with controlling these diseases and protecting public health. The recommendations in this compendium provide standardized procedures for controlling avian chlamydiosis in birds, a vital step to protecting human health. This document will be reviewed and revised as necessary.     

Some considerations when nursing birds in veterinary premises

This paper indicates the need for, and the benefits to be gained by, better standards of avian nursing. The subject is approached by a discussion of the behaviour of birds in general and suggests ways in which stress in the hospitalized bird can be reduced to the minimum. The dangers of young birds becoming imprinted are emphasized. The contrasts between mammalian and avian anatomy, particularly of the respiratory and renal systems, are considered together with the implications when nursing birds. There is a discussion of the avian metabolic rate, the nutrition of sick birds, and some indications for physiotherapy in birds are mentioned.     

Psittacine plasma concentrations of elements: daily fluctuations and clinical implications.

During the past 2 decades, the potential for excessive exposure of pet birds to zinc has become a concern for many pet bird owners. Ideally, avian zinc toxicosis is diagnosed on the basis of history of exposure to zinc, radiographic evidence of ingested metal, occurrence of melena, detection of an elevated plasma zinc concentration, and response to treatment. However, most pet birds suspected of having zinc toxicosis present with vague signs and lack of radiographic evidence; therefore, the diagnosis relies on the presence of an elevated plasma zinc concentration. A question was, is there a significant diurnal variation in the zinc concentration in psittacine birds and could this be clinically relevant? Because studies in other species have shown that zinc is not the only element that shows a diurnal variation, the authors examined 13 other plasma elements including arsenic, cadmium, calcium, cobalt, copper, iodine, iron, magnesium, manganese, molybdenum, potassium, selenium, and total phosphorus. Fifteen adult psittacine birds housed in the same aviary were used in this study. Three blood samples, separated by 4 hours, were taken from the right jugular vein in each bird. All elements were measured in plasma. Zinc, copper, and molybdenum revealed diurnal fluctuations. The results of this study suggest that interpretation of clinical samples may be more complicated than previously believed. Furthermore, on the basis of the results of this study, it is possible that some avian reference ranges may need to be reexamined.     

Chlamydiae and atherosclerosis: can psittacine cases support the link?

Atherosclerosis is a common disease in pet birds, particularly in psittacines. Little is known about the role of risk factors predisposing birds to this disease. In our study, we tried to detect chlamydiae in formalin-fixed and paraffin-embedded atherosclerotic tissue from 103 pet birds to clarify their role in atherosclerosis. Methods used were polymerase chain reaction (PCR), sequencing, and immunohistochemistry. Histopathologic examination served to classify the extent of atherosclerotic lesions. In the PCR, 4 (3.9%) of 103 cases, all of them with advanced stages of atherosclerosis, were positive. Subsequent sequence analysis revealed high identities (94%-100%) with Chlamydophila psittaci in three cases. Interestingly, two of these birds came from C. psittaci-infected populations. Because of the low incidence (3.9%), the occurrence only in advanced stages, and the association with C psittaci-infected avian populations, a causal relationship between chlamydiae and atherosclerosis in pet birds is rather improbable.     

Emergency and critical care of pet birds.

Critically ill birds must be assessed accurately and provided with immediate supportive care. This article reviews the assessment and diagnostics required for evaluating the critical avian patient. The most common emergencies seen in pet birds are discussed. Diagnostics and treatments protocols are provided to help direct the practitioner toward a complete recovery.     

TRANSCUTANEOUS ULTRASONOGRAPHY OF THE AVIAN UROGENITAL TRACT

The purpose of this article is to provide a survey of the diagnostic use of transcutaneous sonographic examination of the urogenital tract of pet birds. Possibilities and limitations in imaging normal and altered components of this organ system are discussed. Ultrasonographic examination of the avian urogenital tract was evaluated in 386 pet birds. Abnormal clinical signs were present in 289 birds; 97 birds were normal. Transcutaneous ultrasonography proved to be a useful, noninvasive, and fast diagnostic tool, especially in imaging laminated eggs and changes of the oviduct. Until now, these pathologic changes were not diagnosable in birds with other common noninvasive methods (e.g. radiography). The imaging of low-grade changes of the oviduct, disorders of the kidney without enlargement of the organ, as well as roughening of the egg shell proved to be difficult. Sonographic imaging of neither the normal kidney nor the inactive gonads was possible.     

Arterial Catheterization,Interpretation, and Treatment of Arterial Blood Pressures and Blood Gases in Birds

Blood pressure monitoring of patients has become increasingly common in companion animal veterinary hospitals, especially during anesthesia, surgical procedures, critical care, and general health assessments. Determining an animal’s blood pressure has become a standard part of the routine diagnostic evaluation for monitoring hypertension in geriatric patients or patients affected with renal insufficiency, cardiac disease, vision loss, or endocrine disorders. To increase the standard of care in exotic and zoological medicine, new diagnostic techniques must be identified and implemented. Blood pressure measurements in avian species are more challenging because only direct blood pressure techniques have been reported to be accurate. Arterial catheterization and interpretation can be daunting without the knowledge of avian physiology and anatomy; however, techniques for placing arterial catheters are not difficult once clinicians have gained sufficient experience. This article describes the techniques, anatomy, and appropriate interpretation of blood pressure results obtained through arterial catheterization in birds.     

Current Trends in Avian Pediatrics

This article is a current overview of the common presentations of avian pediatric cases. The number of avian pediatric cases as well as the sources of the birds has changed dramatically in the last 5 years. The number of pediatric avian cases has substantially decreased and the source has changed from aviculturists to major pet store chains. Four of the more common avian pediatric disease conditions that are treated in veterinary hospitals are reviewed as well as lesser-identified presenting complaints. Behavior as an important aspect of avian pediatrics is also discussed.     

中国基干鸟类综述

"基于鸟类(basal birds)"为一种类数量相对较少的化石鸟类,基干鸟类较另一鸟类群--"鸟胸类(Ornithothoraces)"原始;鸟胸类(包括现生鸟类和反鸟类)为一类种类数量很大、具有同一祖先、且来源于基干鸟类的鸟类群.在过去的15年里,共有产自中国的8个属、12个有效种基干鸟类发表,而产自的德国的始祖鸟为唯一的非中国产基干鸟类;当然,孔子鸟化石也发现于朝鲜.本文对产自中国的基干鸟类的形态学、系统发生和生态学进行了简单的综述.中国的化石材料对科学地了解鸟类的早期演化具有重要意义,揭示了基干鸟类个体相对较大、形态特征和生态环境变异也相对较大等特点.尽管有些明显的不确定因素的存在(例如热河鸟、会鸟和中鸟的相对系统关系存有争议),但是由于中国化石材料的存在,鸟类早期演化的真实场景已经愈加清晰.     

Feeding recommendations for the house rabbit.

The feeding recommendations for the pet or house rabbit include grass hay fed ad libitum, dark leafy green vegetables fed at one cup per 5 pounds of body weight, and a maximum of 1 cup of high fiber pellets per 5 pounds of body weight. These recommendations are based on the feeding behavior, anatomy, and gastrointestinal physiology of the rabbit. Feeding this diet reduces the occurrence of common gastrointestinal tract disease in the house rabbit. This article reviews the feeding behavior, anatomy, and gastrointestinal physiology of the rabbit.     

Adrenal steroid metabolism in birds: anatomy, physiology, and clinical considerations.

The hypothalamo-pituitary-adrenal system in birds is anatomically and functionally different from that in mammals. The adrenal gland structure and corticosteroid hormone physiology of birds will be reviewed. The anatomy and physiology sections of this article will be important for better understanding the pathogenesis, diagnosis, and possible treatment of primary or secondary adrenal gland disease. Causes of hyper- and hypoadrenocorticism in birds also will be reviewed. The article will conclude with current indications and complications to the clinical use of glucocorticoids in birds.     

Ante mortem diagnosis of mycobacterial infection by liver biopsy in a budgerigar (Melopsittacus undulatus)

Avian mycobacteriosis is an important disease which affects exotic, wild and domestic birds. The disease is most commonly caused by the ubiquitous soil and water organisms Mycobacterium avium sp. avium and Mycobacterium genavense. Mycobacteriosis should be considered in the differential diagnosis of any pet bird with chronic disease characterized by weight loss, an inflammatory leukogram and abdominal enlargement.Ante mortem diagnosis of avian mycobacteriosis in birds remains difficult. The present case report describes that even in very small species such as a budgerigar the investigating of a biopsy sample is an efficient way to rule out or confirm the disease in cases where other methods fail to be conclusive.     

Avian Reproductive Disorders

Avian reproductive disorders are commonly diagnosed in pet birds, backyard flocks, and commercial aviaries. Birds that are diagnosed with reproductive disorders can present with a variety of clinical signs that range from benign disorders to life-threatening emergencies. In many cases there are underlying husbandry and management issues that need to be addressed. This article will address the presenting signs of common reproductive disorders in avian species and the best approaches to determine appropriate diagnostic and treatment plans.     

PET AND CAPTIVE BIRDS AS POTENTIAL RESERVOIRS OF ZOONOTIC BACTERIA

Thermophilic Campylobacter spp. and Salmonella spp. are zoonotic bacteria, commonly harbored in the enteric tract of avian species. This survey aimed at verifying the presence of these microorganisms in a heterogeneous Italian population of pet birds and captive birds of prey (e.g., Passeriformes, Psittaciformes, Accipitriformes, Falconiformes, and Strigiformes) that live in close contact with humans. A total of 151 individuals were tested for thermophilic Campylobacter spp. and 444 for Salmonella spp. Six C. jejuni and one S. Livingstone were isolated from birds of prey: 4 Accipitriformes (2 Buteo regalis, 2 Parabuteo unicinctus), 1 Falconiformes (Falco peregrinus) and 1 Strigiformes (Strix aluco) were positive for C. jejuni, and 1 Falconiformes (Falco peregrinus) for S. Livingstone. Five C. jejuni strains were genotyped by Multilocus Sequence Typing (MLST) and identified as ST 2116, assigned to ST-353 CC. Results of this study suggest that these microorganisms are not common inhabitants of the digestive tract of pet birds and captive birds of prey, but occasional findings. However, as potential reservoirs of zoonotic bacteria, pet birds should be monitored in order to preserve human health.     

Avian renal disease: pathogenesis, diagnosis, and therapy.

Avian renal diseases are common in practice but are often undetected or misdiagnosed. Polyuria can be interpreted as diarrhea leading to inappropriate investigation and therapy. The avian urinary system differs from the mammalian. This article explains the anatomy and physiology of the avian kidney and focuses on the diagnosis of renal disorders. In particular, blood chemistry, urinalysis, radiography, urography, ultrasonography, computed tomography, and endoscopy (including biopsy) are explained and illustrated. Specific avian renal disorders and treatment possibilities are discussed.     

Common infectious diseases of psittacine birds seen in practice.

The "average" small animal practitioner who sees pet birds in practice comes across a variety of bacterial, fungal, protozoal, viral, and chlamydial diseases. Diagnosis and treatment of some are relatively uncomplicated, but many psittacine diseases remain enigmatic. Ante-mortem diagnosis of some diseases is extremely difficult. The clinician must often rely on combinations of clinical signs, clinical pathology, and experience to diagnose many bird diseases correctly. Many viral diseases are devastating to collections and have no cure, preventive program, or even well-documented modes of transmission. Some psittacine syndromes have yet to be definitively associated with a particular infectious agent. Get to know your local federal, state, and private diagnostic laboratories. Good relationships with other avian practitioners, both locally and through the Association of Avian Veterinarians can be extremely helpful. (See the article on sources of information.)