Avian case discussion: the good, bad, and ugly (Proceedings)

Bite wounds

One of the most common avian presentations at our veterinary hospital is the predator attack.  These cases often present with severe lacerations, limb amputations and crushing injuries.  Apart from stabilization and concern with blood loss, shock and pain rapid treatment with antibiotics are indicated.  With our cases we give the owners a 72 hour window for treatment response and at least a week of hospitalization before we consider the patient in good condition. Antibiotic therapy consisting of treatment for both anaerobic and aerobic bacteria is crucial to increasing the chances of a successful case outcome.  Listed below are products used to treat wounds sustained in predator attacks.

Avian Chlamydiosis

A bird becomes exposed and subsequently infected with avian chlamydiosis when the bacterium enters the host through the respiratory and/or gastrointestinal epithelium.  Depending on the specific biotype involved, dyspnea, nasal and ocular discharge, inflamed choanal and diarrhea are common signs observed in birds infected with avian chlamydiosis.2  In chronic infections cachexia, poor feather condition, depression and anorexia may be noted by the veterinarian.               

A misconception has existed for many years that “lime green” diarrhea is pathogenomic for a C. psittaci infection.  This myth has been perpetuated because the infectious organisms are associated with liver infection/inflammation.  Many disease conditions cause or aid in the development of hepatitis that results in a yellow-to-green color stool. A green-colored stool only indicated possible liver involvement; serum chemistry panel and liver bile acids should be reviewed to confirm the suspected diagnosis.

Bacterial gastroenteritis

Birds often are diagnosed with bacterial infections involving the crop, proventriculus, and/or intestinal tract.  The most common pathogenic organisms isolated are Enterococcus spp., Klebsiella spp., and Pseudomonas spp.  Although Gram negative organisms are the primary pathogens isolated Gram positive bacteria can also cause disease, primarily the hemolytic Streptococcus spp. isolates.  It is always recommended to submit a culture of the affected area for culture and sensitivity testing.

Avian respiratory diseases

Companion birds are commonly exposed to infectious bacterial and fungal organisms through the environment, handfeeding techniques, foods and contact with other birds or owners who have handled unfamiliar birds.4 Gram-negative bacteria frequently isolated from birds with upper respiratory tract infections include Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Pasteruella mutocida, Yersina pseudotuberculosis, and Salmonella spp.5  Strains of Streptococcus spp. and Staphylococcus spp., Mycobacterium tuberculosis, and Norcardia asteroides are gram-positive bacteria that have been isolated from birds exhibiting rhinitis and sinusitis.  Bacillus spp., Corynebacterium spp., and Lactobacillus spp. are common nonpathogenic bacteria isolated from the upper respiratory system. Spirochetes have been isolated from cockatiels diagnosed with upper respiratory infections, but this is uncommon.  Aspergillus spp. is a common environmental fungal pathogen that infect the respiratory system of susceptible birds. Candida spp. infections that originate in the oropharyngeal cavity may spread from the choana to the infraorbital sinus, resulting in varying degrees of dyspnea.  Candida spp. are usually opportunistic pathogens that infect birds suffering from primary infectious diseases or malnutrition, or young birds with immature immune systems.  Lesions usually appear as white plaques in the oral cavity, sometimes extending into the choana or coexisting with a primary bacterial sinusitis.  The intracellular bacteria Chlamydophila psittaci and Mycoplasma spp. are often isolated from birds with clear nasal discharge (rhinorrhea), sneezing and conjunctivitis.  Chlamydophila psittaci causes the disease avian chlamydiosis (AC) in pet bird species.  Although Mycoplasma spp. infections are not as serioius as AC in pet birds, infected birds show similar clinical signs.  There is currently a PCR antigen test available to detect Mycoplasma spp. in avian species. Mycoplasma spp.  are relatively low in infectivity but may affect high-density, poorly managed cockatiel aviaries.  Many known Mycoplasma spp. infect waterfowl, but unidentified species may be associated with psittacine infections.

Avian respiratory disease treatments

Many of the same infectious organisms and problems that affect the upper respiratory tract also cause disease of the lower respiratory system.  Unfortunately the increased surface area, environment and unique anatomy of the avian lower respiratory system allows for susceptibility to many more parasitic and viral diseases.  The bacterial species discussed as etiologic agents of upper respiratory tract infections can also casue tracheitis, laryngitis, pneumonia, respiratory abscesses and airsacculitis.  Biopsy and culture by endoscopy may reveal the causative microorganism.  Serologic antigen and antibody testing has not been perfected to the point of offering reliable results for antemortem diagnosis.  Itraconazole is the drug of choice for avian aspergillosis at 5 – 10 mg/kg.  Caution should be used when contemplating the use of this drug in grey parrots.  Terbinafine is alternative to itraconazole, dosed at 5 – 15 mg/kg.  For concurrent upper respiratory therapy or sinular upper respiratory therapy there is an effective sinus flush for parrot species.  Recommended equipment includes a nebulizer compressor (Sportneb®, model 3050, Medical Industries America, Adel, IA), infant nebulizer, nebulizing chamber.  Therapeutic agent formulation for treatment of systemic aspergillosis, 5 – 10 ml saline, 3 – 5 drops mucomyst and amphotericin B, 7 mg/ml.  Clotrimazole can be substituted for amphotericin B, 10 mg/ml for 30 – 60 minutes.  Normally nebulization intervals are 10 to 15 minutes per treatment.  Fungal hyphae of Candida spp. may extend into the proximal trachea from the oral cavity, resulting in varying degrees of dyspena.  Fungal hyphae may be seen in cytologic specimens taken from the trachea or other affected areas.  Crytococcosis, trichosporonosis, mucormycosis and nocardiosis have been isolated from the lungs and air sacs of birds showing signs of respiratory compromise. 

Feather picking

Self-induced feather loss in companion birds is one of the most common and frustrating avian case presentations.  There are a number of causes for feather loss and these cases require a thorough investigative work-up by the attending veterinarian.  Differential diagnoses for feather picking birds include hypersensitivity, environmental and nutritional causes and psychological.

Initial treatment is based on history, clinical presentation and diagnostic test results.  If a disease process is identified as a primary cause of the feather loss then it is appropriately treated.  If it is determined that the self-induced feather loss is psychological the other medications are prescribed.  We start with the anti-depressant and hope that treatment is effective.  If we decide that the bird should be treated with the anti-psychotic medication we have a conference with the owner explaining the serious side effects that may be noted with its use. We never place a patient on a concurrent anti-depressant and anti-psychotic treatment regime.

Psychological medications

• Anti-depressant: Nortriptyline HCL (Aventyl HCL, Lilly) syrup 2 mg/ml

• Dose: 1 ml/4oz drinking water

• Anti-psychotic: Haloperidol (Haldol, Henry Schein) solution 2mg/ml

• Dose: 0.2 mg/kg BID for birds < 1 kg

• 0.15 mg/kg SID-BID for birds > 1kg

• NEVER ADMINISTER TO HYACINTH MACAWS – TOXIC

If we feel the case may be the result of an environmental hypersensitivity there is another treatment protocol that we commonly use.  This treatment is listed below and is given concurrently to the patient.

• Hydroxyzine HCL (Barre-National) 10 mg/5 ml

•     Dose: 0.1 ml/100grams body weight SID

• Liquid Fatty Acid (Pfizer)

•     Dose: 0.1 ml/100 grams body weight SID

References

Gerlach H, Chlamydia. Clinical Avian Medicine and Surgery (G.J. Harrison; L.R. Harrison, eds.). W.B. Saunders, Philadelphia, PA., 1986; pp457-463.

Isaza R, Murray MJ, Vanrompay D, Yeary T, Tully TN, Fudge A, Round table discussion: use of PCR testing in diagnosing chlamydiosis. J. Avian Med. Surg. 2000;14(2):122-127.

Wyrick PB, Richmond SJ, Biology of chlamydia: reports from the symposium on avian chlamydiosis. JAVMA 1989;195 (11):1507-1512.

Gerlach, H. Bacteria. In: Ritchie, BW; Harrison, GJ; Harrison, LR. eds. Avian medicine: principles and application. Lake Worth, Florida; Wingers, 1994; 949-983.

Tully, TN; Harrison, GJ. Pneumonology. In: Ritchie, BW; Harrison, GJ; Harrison, LR. eds. Avian medicine: principles and application. Lake Worth, Florida; Wingers, 1994; 556-581.

Morrisey, JK. Diseases of the upper respiratory tract of companion birds. Seminars in Avian and Exotic Pet Medicine 1997; 6: 195-200.

Tully, TN. Avian respiratory diseases: clinical overview. Journal Avian Medicine and Surgery 1995; 9: 162-174.