||Important key words or phrases.
Important concepts or main ideas.
1. Learning Objectives
Be familiar with the diagnostic and therapeutic options
available in avian medicine
2. Pet Bird or "Individual Bird" Diagnostic and Therapeutic
The techniques described below are common practice in
pet bird medicine. These techniques are not restricted to psittacines however
and can be employed in any individual bird situation (including a chicken).
Techniques commonly used for poultry or "flock" medicine are described at the
end of this chapter.
2.1. History taking
A complete and thorough history is absolutely
essential in avian medicine as it is in small animal practice. Many of the
diseases seen are a direct result of husbandry or management practices in the
home, or due to exposure to other birds. The history should included the
following information at a minimum:
- Signalment: species, age, sex (?)
- Acquired when and where from: Pet store, breeder,
- Husbandry questions
- Dietary history
- Exposure to other birds
- Details of illness
2.2. Physical examination
The physical examination should be routine and comprehensive as in all other animals. This includes obtaining an accurate body weight in grams. The examination is usually performed in two parts:
Part I: observe the bird in the cage or carrier -evaluate respiration, posture, droppings
Part II: hands on examination from head to toe, including a thorough oral exam
Sometimes the physical examination can be very stressful for the bird. It is important to keep an eye on respiratory rate, body temperature and attitude as signs of stress. The bird may need "rest periods" if very stressed, requiring the physical examination to be performed in stages.
2.3. Routine Diagnostic Tests
2.3.1. Fecal examination
A fecal examination for parasites is important, especially in the new bird. Both a direct smear (saline) and flotation should be performed to look for protozoal and helminthic parasites. A gram stain of a fecal smear is also sometimes performed to look for abnormal bacterial flora when indicated.
Normal fecal gram stain from psittacine
2.3.2. Routine culture techniques
Bacterial diseases are very commonly encountered in pet bird medicine. Cultures and antibiotic sensitivity testing are therefore vital in correctly diagnosing and treating these conditions. Cultures in these small creatures necessarily require the use of mini-tip culture swabs which should always be on hand in an avian clinic. The following cultures are routine, while more invasive cultures can also be performed as indicated:
- Respiratory tract - choanal culture
- GI tract - cloacal culture
- Folliculitis - feather follicle culture
2.3.3. Routine blood work
188.8.131.52. Sample collection
The most commonly used sites for blood collection in birds include:
- the jugular veins (largest on the right)
- cutaneous ulnar veins
- tibiotarsal/metatarsal veins
Volumes needed rarely exceed 1 ml, and should not exceed 1% of the animal's body weight in grams.
Collection of such small volumes require the use of small needles (25g, 26g, 27g), and small receptacles (e.g. Microtainers, hematocrit tubes, unopettes). Avian blood clots very quickly and should be collected and transferred to the appropriate receptacle as quickly as possible.
184.108.40.206. Complete blood count
Avian CBCs are often performed in-house, but may be sent out to a diagnostic laboratory. To perform a CBC, you will need at least one smear (differential), one unopette (WBC count), and one hematocrit tube(PCV, TSP). Ideally a full CBC is performed on 0.2 ml EDTA blood (Microtainer).
Avian RBC's are big and nucleated!
WBC counts are accomplished using eosinophil unopettes. The Unopette comes with its own pipette and a fixed volume of diluting fluid, which allows for an accurate dilution of the blood sample. One disadvantage is that the phloxine diluent stains only granulocytes (heterophils, eosinophils, and basophils); therefore, the count obtained must be corrected, since mononuclear cells (lymphocytes and monocytes) are not included. A hemacytometer is used to produce the granulocyte count. A white blood cell differential count must then be done to accurately complete the WBCcount:
TOTAL WBC/ul EQUALS hemacytometer count (10 squares)X 32* divided by the percentage of granulocytes/100 (decimal)
*dilution factor of unopette
Differentials require practice and experience on the part of the veterinarian or technician performing the analysis. Several good references exist to help develop proficiency in identifying the various white blood cells. The following characteristics are typical of the different cell types:
Heterophils are the most common leukocyte in the peripheralblood of most avian species. They tend to be round cells with a colorless cytoplasm containing eosinophilic or basophilic rod-shaped granules (thegranules may be spherical in some species). Heterophil granules usually have adistinct central body that appears refractile. Mature heterophils have a lobed nucleus (usually two or three lobes) with a coarse, clumped chromatin that stains purple. The nucleus is often partially hidden by the cytoplasmic granules.
Avian eosinophils are typically round but have a greater tendency toward irregularity than do heterophils. The cytoplasm stains a clear, pale blue (in contrast to the colorless cytoplasm of heterophils) and contains round eosinophilic granules (or rod-shaped in some species). In most birds, the granules of eosinophils have different staining qualities from heterophil granules from the same blood smear. The eosinophil granules may appear duller or brighter than the heterophil granules. Eosinophil granules tend to lack the central body found in heterophil granules. Eosinophil nuclei are lobed with coarse, clumped chromatin that stains purple, and the eosinophil nucleus often stains bluer and is usually more noticeable than the heterophil nucleus.
Avian basophils tend to be round cells with a round, centrally located nucleus. The nucleus stains a light blue and is often hidden by the cytoplasmic granules. The cytoplasmic granules are deeply basophilic and may dissolve or coalesce in Wrights stain (or other alcohol-solubilized stains). We rarely see basophils because they may dissolve or coalesce in Wright's stain(or other alcohol-solubilized stains like Hema 3).
Lymphocytes are the most common leukocyte found in the peripheral blood of some avian species. They can be classified into three groups according to cell size (small, medium, and large). Most normal mature lymphocytes in the peripheral blood are small or medium. Lymphocytes aretypically round cells but often show irregularity due to molding around adjacent cells in the smear. The nucleus is usually round (occasionallyindented slightly) and centrally located. The nuclear chromatin is densely clumped or reticulated. The nucleoplasm is often colorless in lymphocytes witha reticular chromatin, and dark in those with dense chromatin clumping. The amount of cytoplasm varies from a narrow band surrounding the nucleus in small lymphocytes to a moderately wide band in medium and large lymphocytes. A high nuclear to cytoplasmic ratio is typical of lymphocytes. The cytoplasm is homogenous and weakly basophilic. Occasionally, lymphocytes have irregular cytoplasmic projections or blebs.
Monocytes are large leukocytes that are irregular in shape. Thenuclei vary from round to bi-lobed and often have a delicate, lacelikereticular chromatin. Chromatin clumps may be present but are few in number. The cytoplasm of monocytes stains blue-gray with a finely granular appearance andoccasionally contains vacuoles. The cytoplasm may contain two distinct zones; a light-staining area and a more deeply stained area. Monocytes occasionally contain fine (dustlike) eosinophilic cytoplasmic granulation.
These cells can be confused with lymphocytes, so care must be taken not to count them as part of the WBC differential count. Mature thrombocytes are oval cells that are smaller and more rounded than mature erythrocytes. The thrombocyte nuclei are larger in relation to the amount of cytoplasm and more rounded than erythrocyte nuclei. The nuclear chromatin isdense and clumped. The cytoplasm is clear but not homogenous and often has a reticulated appearance. Avian thrombocytes frequently contain one or more red granules at the poles of the cell. Thrombocytes tend to clump in peripheralblood smears, which aids in their identification.
(Descriptions courtesy of Carolyn Corsiglia; Good reference: Campbell, Avian Hematology)
220.127.116.11. Chemistry analysis
Remember that micro-chemistry techniques preferred. Some suggested laboratories can be found in the supplementary material Avian/Wildlife Diagnostic Laboratories.
18.104.22.168. Chemistry analysis
Micro chemistry techniques are required for such small volumes and are available, but not with every diagnostic pathology laboratory. You must locate a lab that can perform the tests you want on the volumes you want. There are no special "avian" requirements for general chemistry tests (including thyroid), and tests can be performed as they would on dog or cat serum. Individual tests using dry chemistry techniques can often be run on 10弮l (0.01 ml) of serum. At Tufts a multiple test panel usually requires at least 0.3 ml of serum.
The most basic chemistry panel is suggested below (however a full chemistry is more desirable if possible ):
Avian Mini Panel
- Uric acid
- Total protein
- Aspartate transaminase (AST)
Note that uric acid is used as an indicator of renal function, and AST is most predictive of hepatic insult although still not a very specific indicator of hepatocellular damage. Bile acids are now being used more and more in the diagnosis of liver disease in birds.
"Big 3" - A quick and easy emergency monitoring test using only 2 hematocrit tubes of blood can predict PCV, TSP, and blood glucose. Note that the azostick test has been dropped from the usual "Big 4".
22.214.171.124. Normal Hematologic and Biochemical Parameters of some species of birds
|WBC (x 103)
| Eosinophils (%)
|RBC (x 106)
|Total Protein (g/dl)
| Potassium (mEq/L)
| Sodium (mEq/L)
|Uric Acid (mg/dl)
|Alkaline Phos (U/L)
| AST (U/L)
| Cholesterol (mg/dl)
126.96.36.199. Serology, protein electrophoresis and other specific diagnostic tests
Various serology tests are available for chlamydia, giardia, aspergillus and many viral diseases. These tests will be discussed in sections dealing with the specific disease. Use of protein electrophoresis in conjunction with serologic tests and other diagnostic parameters has proved to be useful in reaching a diagnosis. This test is routinely offered in conjunction with other chemistries or serology by the University of Miami diagnostic laboratory.
188.8.131.52. Sex determination
Most psittacine species (especially South American) are sexually monomorphic. Individual owners as well as breeders often want to know the sex of their bird. The traditional method for sexing has been surgica l(laparoscopy, discussed later), however less invasive techniques are now available.
DNA sexing through a blood sample is the technique which has been most successful. This technique requires only a drop of blood providing sufficient DNA to perform the test with a specially developed DNA probe. The laboratory that originated this test (ZOOGEN) is also now keeping DNA records on every bird as a method of identification (DNA fingerprinting) for future reference.
Laparoscopy is still performed as a reproductive tool to better evaluate the exact condition of the reproductive organs and to predict breeding readiness, problems, etc.
Radiology is an essential diagnostic tool in pet bird medicine practice. It is often part of a routine workup, along with cultures and blood work. Radiographs provide supplemental information often missing from physical examination and allows more accurate assessment of the skeletal system (fractures etc.), respiratory system (lungs and air sacs), gastrointestinal system (size and position of esophagus, proventriculus,ventriculus, intestine, cloaca), and assessment of other internal organs -liver, spleen, kidneys, gonads and uterus.
Details of avian radiography will be covered in an upcoming lecture.
2.4. Basic therapeutic choices - General medications
Most medications needed for avian practice are readily available and are often routinely kept in any veterinary practice. Each individual veterinarian will develop their own preferences for antibiotics and treatments of commonly encountered diseases. One should design a pharmacy based on the most commonly encountered diseases, bacterial spectrum, and the most convenient preparations available.
Basic Avian Pharmacy List
- Tube feeding formula
- Parenteral fluid solutions - lactated Ringers, 5% dextrose, saline
- Parenteral vitamin/mineral solutions - Vitamin A and D3, B complex, Vitamin K1, Vitamin E/selenium, calcium, iron dextran
- Antibiotics - Trimethoprim-sulfa, oxytetracycline, doxycycline, enrofloxacin
- Glucose, 50%
- Calcium disodium edetate
- Isoflurane anesthetic gas
2.4.1. Fluid therapy
As in general medicine, fluid therapy is the
backbone of good medical technique. The principles in avian medicine are
basically the same as in other animals with few exceptions.
184.108.40.206. Evaluation of hydration status
- History: anorexia, diarrhea, polyuria,
dyspnea/hyperventilation, heat stress
- Physical appearance: dull sunken eyes, tacky oral
mucous membranes, increased skin turgor
- PCV, TSP - may be helpful and/or misleading
- Body weight monitoring (once or twice daily)
220.127.116.11. Estimation of hydration needs
18.104.22.168. Choice of fluids
Choice of fluids to use for maintenance and
supplementation is made based on the same principles used in mammals and include
normal saline, 5% dextrose, lactated Ringers, and the various colloidal
solutions such as dextrans and hetastarch.
22.214.171.124. Methods of fluid administration
Methods of administration can involve any of the
following, depending on the situation at hand. The colloidal solutions must be
given intravenously or through an intraosseous catheter.
- Oral fluids - gavage
- Subcutaneous fluids - inguinal, lumbar, patagium
(wing). The use of subcutaneous fluids is the most common technique and
is very successful unless rapid fluid delivery is required (shock,
severe dehydration, acute blood loss, hypovolemia).
- Intravenous fluids - cutaneous ulnar/brachial v.
jugular vein, medial metatarsal vein; a 24 ga. catheter may be placed in most
sites in any bird larger than a cockatiel
- Intraosseous fluids - distal ulna or proximal
Intraosseous catheter placement in the
2.4.2. Therapeutic administration
The condition of the patient, and the formulation of
medication required, will often dictate the method of therapeutic
administration. The following techniques are commonly used:
- Oral administration: Substances are administered
either via crop gavage or directly per os, if the substance is palatable and
the patient is cooperative. Oral administration should not be used in
severely depressed or weak individuals, or in cases of vomiting or GI
- Subcutaneous administration - inguinal, lumbar,
- Intramuscular administration: Intramuscular is the
most commonly used method of administration and is often easier than
oral administration, especially in hospitalized patients. The preferred site is
in the pectoral muscles either side of the sternum. Injections in the legs
should be avoided.
- Intravenous administration - cutaneous ulnar/brachial
v., jugular vein, medial metatarsal vein.
- Intraosseous administration - distal ulna or
proximal tibiotarsal bone.
- Nebulization: This technique delivers medications
and moisture to the respiratory tract, targeting the sinuses and the air sacs.
Both of the sites are poorly vascularized and may not receive adequate levels
of parenterally administered medications. Consequently nebulization is often
a helpful adjunctive therapy in respiratory diseases.
3. Poultry or "Flock" Diagnostic and Therapeutic
Although pet bird medicine often utilizes hematology
and clinical chemistry to help establish a diagnosis, such tests are almost
never employed with poultry. An autopsy is the diagnostic procedure most often
used in establishing a diagnosis when a disease outbreak occurs in a poultry
flock. (To be somewhat facetious, a poultry flock is the essence of communism -
the individual is less important than the flock.) The most import diagnostic
material that one can submit to a diagnostic laboratory are one or two live
birds showing representative clinical signs of disease in addition to a few
recently dead birds that have also shown typical disease signs prior to death.
Physical examination of a live bird is usually helpful
in establishing a diagnosis. The feather cover should be examined and chickens
should be assessed to determine if molting is in progress. The feathers should
also be examined for presence of external parasites. Ataxia, tremors,
paralysis, abnormal gait or leg weakness should be evaluated. Respiratory
difficulty, depression or blindness should also be determined. It is sometimes
helpful to examine poultry while they are confined to a cage and accustomed to
their surroundings. Sometimes it is also important to observe birds 24 - 48
hours after they have been removed from the flock to determine if signs of
recovery have occurred. This is especially helpful in the diagnosis of
transient paralysis, respiratory infection, chemical toxicity, feed or water
deprivation and overheating.
3.1. Collecting Blood samples in poultry
Blood samples are sometimes collected for serologic
tests in order to confirm the diagnosis of some of the common viral diseases.
These samples are usually drawn from one of the following sites:
- Brachial (wing) vein - least traumatic
- Heart puncture - usually at the thoracic inlet. This site
is less favorable as it is associated with a variable number of fatalities
depending on the skill of the bleeder.
Since serum is used for most of these tests
anticoagulants are not required. If unclotted blood is required the same
anti-coagulants commonly used for mammalian blood can be employed for avian
blood (EDTA, heparin, oxalate).
Serology is frequently used to establish a diagnosis
for the following diseases:
- Pullorum disease
- Newcastle disease
- Infectious bronchitis
- Avian influenza
- Infectious bursal disease
3.2. Antibiotic use in poultry
Antibiotics used in the treatment of bacterial
diseases in poultry that produce eggs or meat for human consumption needs
careful consideration. Residues in human and animal food products has been a
long debated issue in the veterinary profession. These residues can potentially
result in antibiotic resistant strains of bacteria that cause human
The following antibiotics are currently approved for
use in egg laying hens.
- Bacitracin (oral)
- Lincomycin (oral)
- Virginiamycin (oral)
For more information on drugs approved for poultry, and withdrawal times go to the FARAD website at http://www.farad.org/
4. Ancillary Material
4.1.1. Texts and Articles
Altman, Robert B., et al. Avian Medicine and Surgery.
Philadelphia. W.B. Saunders Co., 1997. Chapters 9, 10, 11, 12, 17.
Campbell, Terry W. Avian Hematology and Cytology.
2nd ed. Ames: Iowa State University Press, 1995.
Cray, Carolyn, Gregory Bossart, and Don Harris. Plasma
protein electrophoresis: principles and diagnosis of infectious disease. 1995
Main Conference Proceedings of the Association of Avian Veterinarians, August
28 - September 22, 1995.
Hoefer, Heidi L. et al. The use of bile acids in the
diagnosis of hepatobiliary disease in the parrot. Proceedings of the 1991
Annual Conference of the AAV, Chicago, Illinois, September 23-28, 1991,
Oglesbee, Barbara L., Hamlin, Robert L., Klingaman, Heather, Cianciola, Janin, Hartman, Stephen P. Electrocardiographic Reference
Values for Macaws (Ara species) and Cockatoos (Cacatua species) Journal of
Avian Medicine and Surgery 2001 15: 17-22
Ritchie, Branson W., et al. Avian Medicine: Principles
and Application. Lake Worth, Fla.: Wingers Publishing, c1994: Chapters 8, 9,
10, 11, 15.
Steinhort, Lani A. Avian fluid therapy. Journal of
Avian Medicine and Surgery, 13(2), 1999:83-91.
Stone, E.G. and P.T. Redig. Preliminary evaluation of
hetastarch for the management of hypoproteinemia and hypovolemia. Proceedings
of the Annual Conference of the Association for Avian Veterinarians, 1994.
Tatum, Lisa M., et al. Protein electrophoresis as a diagnostic and prognostic tool in raptor medicine. Journal of Zoo and Wildlife Medicine 31(4), 200: 497-502.
VIDEOTAPES: Techniques in Avian Medicine, Part I and
II. Veterinary Learning Systems, 1993. Available in the Webster Library
and the Wildlife Library for review.
4.1.3. Products mentioned in the text
Microtainer, Becton-Dickson,1 Becton Drive Franklin Lakes, NJ USA 07417 201.847.6800 http://www.bd.com/
Eosinophil Determination kit Test 5877 from Becton-Dickinson, 1 Becton Drive Franklin Lakes, NJ USA 07417 201.847.6800 http://www.bd.com/
Zoogen Inc., 1756 Picasso Ave., Davis, CA 95616. http://www.zoogen.biz/
BioServ,One 8th St. Suite 1,Frenchtown, NJ 08825908-996-2155 http://www.bio-serv.com
Hopkinton Drug,52 Main StreetHopkinton, MA 01748(508) 435-4441
Island Pharmacy Service, Inc.,PO Box 1412Woodruff, WI 54568(715) 358-7712
Mortar & Pestle Pharmacy,PO Box 12124Des Moines, Iowa 50312(800)-279-7054