Avian Medicine 101
World Small Animal Veterinary Association World Congress Proceedings, 2013
Laurel Degernes, DVM, MPH, DABVP (Avian)
College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA

With approximately 10,000 species of birds, the topic of avian medicine cannot be taught in a few short sessions! This presentation will focus on basic skills and knowledge necessary to work with companion birds presented for veterinary care, with an emphasis on Psittacines (parrots).

History

Collecting a complete history for avian patients is critically important for developing a set of differential diagnoses and initial diagnostic and treatment plans for sick or injured birds. One should ask about the length of ownership and origin of the bird (pet store, breeder, rescue organization, etc.), and whether or not that bird was exposed to any other birds in the home or elsewhere in the previous few months. Are any other birds in the home sick? Also important are questions related to the onset, progression and possible treatments for the presenting problem, diet, caging and husbandry issues, and possible exposure to toxins (is the bird supervised while outside the cage?).

Handling/Restraint

A fundamental challenge associated with incorporating bird patients into a small animal practice is learning the basic skills needed to handle, examine, collect diagnostic samples, and treat these patients. There is no substitute for learning handling skills except by practicing on actual live birds. Docile birds such as pigeons or doves can be used to learn basic handling, treatment and diagnostic skills. Competence and confidence develops with practice. Gentle but firm handling of parrots includes: 1) restraint of the bird using a towel to remove from the cage or carrier; 2) restraint of the head and neck using an encircling grip of the thumb and index finger at the base of the skull, initially through the towel, and then switched to direct handling of the head and neck without the towel; and 3) restraint of the lower legs just proximal to the feet. Remember to use slight upward pressure to stretch the neck to prevent being bitten, and avoid pressure over the keel, which can impair normal respirations. Fine-tune control of the head for oral exams or other procedures that require head restraint, can be accomplished using a "side-to-side" grip with thumb and forefinger on the masseter muscles.

Handling, physical examination, and diagnostic/treatment procedures can be quite stressful for most birds. Therefore, it is important to anticipate all diagnostic and treatment procedures in advance to minimize handling time, especially for sick birds. Abbreviating some parts of the exam for sick birds may be necessary to prevent excessive stress and potential death.

Equipment needed for handling and PE include a towel, a bird net (may be useful for errant patients!), a platform scale capable of weighing up to 5 kg (+/- 1 g; it is easiest to weigh the bird in its cage or carrier prior to the exam, and subtracting the weight of the empty cage), and all of the typical items found in a small animal practice (stethoscope, pen light, and gauze strips to open the beak for oral exam).

"Sick Bird Symptoms"

It is important to know that most avian patients are "prey" species, and have evolved survival strategies to hide clinical signs of illness to avoid being "picked off" by predators and/or ostracized from the flock. Therefore, it is critical that veterinarians know subtle signs of "sick bird symptoms" since many sick birds will try to mask their illness until they are critically ill. Many signs of illness are non-specific for any one disease problem, and can include changes in behavior (increased sleeping, decreased activity, fluffed feathers, sitting on bottom of cage), changes in vocalization, changes in appetite (selective appetite to anorexia), changes in droppings (volume, consistency, color), vomiting, increased respiratory effort, etc. Obviously, the time to learn how to handle and treat these critically ill patients is not when one of these patients presents on emergency! Learning the basic skills is best done on stable and healthy normal birds.

Causes for Admission

Parrots are presented for veterinary care for a variety of reasons including well-bird exams, grooming (wing, nail and beak trims), behavioral issues (feather destructive behavior, self-mutilation, aggression, excessive screaming, etc.), trauma, and a multitude of infectious and non-infectious diseases. Common infectious diseases are caused by: 1) gram-negative bacteria (e.g., E. coli, Pseudomonas spp, Klebsiella spp., Pasteurella spp); 2) gram-positive bacteria (most gram-positive bacteria are considered part of the normal flora of parrots; however, hemolytic Streptococcus and Staphylococcus aureus are considered pathogens); 3) Mycobacteria spp; 4) Chlamydophila psittaci; 5) fungal organisms (Candida spp, Avian gastric yeast, Aspergillosis spp); and 6) viruses (e.g., polyoma virus, circovirus, Pachecos disease (herpes virus), and avian borna virus (cause of proventricular dilation disease). Parasitic diseases in psittacines are generally uncommon due to the fact that most parrots in the pet trade are hand raised with limited exposure to parasites. Giardia is one common exception to this general rule. Common non-infectious diseases include neoplasia, toxins (e.g., lead and zinc toxicosis), and reproductive tract disease (e.g., egg binding, egg yolk peritonitis, salpingitis, etc.). Disease descriptions and diagnostic and treatment options are provided in the references1,3-6 and will be partially covered in other presentations by this author.

Grooming Procedures

Most common grooming procedures include wing and toe nail trims, and less often, beak trims. Parrots typically need 1–3 wing trims per year to keep them de-flighted. There are numerous descriptions of wing trims and two common methods will be shown in the presentation. After any wing trim, it is important to warn the owner against taking their bird outside without a harness or other method of restraint, because most wing trim methods do not guarantee flightlessness. Toe nail trims are done in a similar manner to techniques used in small animals, although 100% avoidance of cutting the quick is difficult with black toenails. The author uses Kwik Stop powder packed tightly into the tip of a 1 ml syringe with the luer tip cut off, which provides a convenient, non-messy method of powder application. Lastly, beak trims are rarely required for most normal parrots if they are provided with wood and other toys for chewing, and also, provided there are no beak malocclusion problems such as "scissors beak".

Common Diagnostic Tests

These tests include complete blood count (CBC), biochemistry panel, fecal Gram stain, cloacal culture, heavy metal toxin screens (lead or zinc), plasma electrophoresis, radiographs, and PCR tests (e.g., for Chlamydophila, polyoma virus, circovirus, etc.). One can safely collect approximately 1% of a bird's body weight as a blood sample from an otherwise healthy bird (equivalent to 1 ml per 100 g body weight; in sick birds, blood collection should be limited to 0.5–0.75% of a bird's body weight). Venipuncture sites include the jugular vein, basilic vein on the ventral surface of the humerus and the medial metatarsal vein on the lower leg. Careful patient restraint and a steady, braced hand, are necessary to prevent hematoma formation or more seriously, a lacerated vein. A 25–26 ga. needle is used and the venipuncture site is held off for 30–60 seconds. This author generally pre-heparinizes the syringe to minimize sample clotting. If a bench-top chemistry analyzer is used, approximately 0.1 ml of whole blood is sufficient for an avian biochemistry panel. Diagnostic information from a CBC and biochemistry panel can provide useful information for the "jigsaw puzzle", when trying to make a diagnosis of underlying disease, or at least, narrow down the list of possible differential diagnoses and treatment considerations. For example, one can gather information about presence of acute and chronic infectious diseases based upon the CBC white blood cell count and differential,2 and internal organ function (i.e., hepatic, renal disease) from a biochemistry panel. The author commonly saves a dried blood slide to review while the official CBC is waiting analysis, because a lot of useful information can be obtained about a patient's status from a quick evaluation of the number and types of leukocytes present.

Less invasive, but equally useful diagnostic tests, include cloacal culture (provides specific aerobic bacterial flora and antibiotic sensitivity information) and fecal Gram stain (quickly provides information about the relative ratio of gram-positive versus gram-negative bacterial flora and presence of yeast and spore-forming bacteria). Both tests provide useful information about normal and abnormal GI flora, and may help guide treatment decisions. Fecal floats are less commonly done in hand-raised parrots due to the reduced likelihood of GI parasites. Birds that are flock-housed, or housed outdoors with access to the soil, however, should be checked for GI parasites. Whole body survey radiographs are commonly used as part of a diagnostic evaluation for birds, unlike in other areas of small animal practice. Useful information can include presence of metal or other foreign bodies in the GI tract, organ enlargement or displacement, presence and size of retained eggs, and orthopedic traumatic injuries.

Common Treatment Procedures

Treatments include fluid administration (IV, oral, sub- cutaneous, and intraosseous [IO]), oral tube feeding, oral and parenteral antimicrobial agents, chelation drugs, and nutritional supplementation (i.e., iron dextran, vitamin supplementation, etc.). Housing considerations for sick birds include isolation from other birds, supplemental heat and oxygen as needed, and housing in a quiet (i.e., no cats or dogs) patient area. As previously emphasized, having all anticipated treatments ready before the bird is handled, can help minimize the time and stress of examining and treating a debilitated patient. Further discussion of treatment protocols will be covered by the author in another presentation.

References

1.  Carpenter J. Exotic Animal Formulary. 4th ed. Philadelphia, PA: Elsevier; 2012.

2.  Clark P, Boardman W, Raidal S. Atlas of Clinical Avian Hematology. Ames, IA: Wiley-Blackwell; 2009.

3.  Harcourt-Brown N, Chitty J, eds. BSAVA Manual of Psittacine Birds. Quedgeley, Gloucester, UK: British Small Animal Veterinary Association; 2005.

4.  Harrison G, Lightfoot T. Clinical Avian Medicine I, II. Palm Beach, FL: Spix Publishing; 2006.

5.  Samour J. Avian Medicine. 2nd ed. Philadelphia, PA: Mosby/Elsevier; 2008.

6.  Tully TN, Dorrestein GM, Jones AK. Handbook of Avian Medicine. 2nd ed. Philadelphia, PA: Saunders/Elsevier; 2009.

  

Speaker Information
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Laurel Degernes, DVM, MPH, DABVP (Avian)
College of Veterinary Medicine
North Carolina State University
Raleigh, NC, USA


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