Illustrated Articles

Infectious Diseases

  • Aspergillosis is a fungal infection that commonly causes respiratory disease in pet birds. It can cause both upper (nose, sinuses, eye, and trachea) and lower (lungs and air sacs – a specialized part of the respiratory tract that birds have) respiratory problems or more broadly distributed systemic infections. Aspergillus is normally an environmental contaminant and is not contagious from bird to bird.

  • Candida albicans is a common environmental fungus that can affect the digestive tracts of birds. It is a common cause of 'sour crop' or a crop infection (ingluvitis), especially in young birds. Candida can be a primary or secondary cause of crop infections. Often, other diseases compromise the bird's immune system and predispose a bird to secondary Candida infection (candidiasis).

  • COVID-19 is a viral respiratory disease of humans that was first discovered in late 2019. The illness is caused by the virus SARS-CoV-2, which is a new coronavirus that has not previously been identified in humans. Certain animals can be infected by the COVID-19 virus, but it appears to be an infrequent occurrence. If you contract COVID-19, you will need to remain quarantined on your property which may make caring for dogs a bit more challenging. If you suspect that you may have COVID-19 (with or without a positive test result), you should minimize contact with your pets. Just as you would quarantine yourself from the other human members of your home while sick, you should also quarantine yourself from your pets. If you are hospitalized and your pets must be cared for by a boarding kennel or pet sitter, inform the kennel or pet sitter that you are ill, allowing them to take the necessary precautions.

  • The normal lens in the eye of any animal is clear and colorless. A cataract is an increase in the density or opacity of the lens; it is often observed as whiteness within the pupil. Cataracts are often seen in canaries and less often in Amazon Parrots, African Grey Parrots, and Macaws. Cataracts decrease the visual acuity of the bird and may eventually lead to blindness.

  • Chlamydophilosis (psittacosis, chlamydiosis, parrot fever, ornithosis) is a common disease of birds caused by a bacterial organism called Chlamydophila psittaci. While this disease can occur in any bird, it is especially common in cockatiels, Amazon parrots, and budgerigars. Birds with chlamydophilosis exhibit a decreased appetite, weight loss, lethargy, diarrhea, nasal or ocular discharge, a fluffed-up appearance, and breathing difficulties. Some birds can carry C. psittaci asymptomatically, spreading it to other birds (and people) through their droppings and respiratory tract secretions. Because tests for diagnosing chlamydophilosis in birds, are not 100% reliable, veterinarians will often rely on a combination of test results to formulate a diagnosis. Treatment is usually with oral or injectable doxycycline antibiotic for 45 days. In humans, this disease often causes flu-like respiratory tract signs such as fever, sweating, headache, fatigue, muscle pain, inappetence, nausea, vomiting, diarrhea, and a dry cough. Since chlamydophilosis is a zoonotic disease, all new pet birds should be examined by a bird-savvy veterinarian and have some form of testing for this disease.

  • COVID-19 is a disease caused by the coronavirus, SARS-CoV-2. Current evidence suggests that person-to-person spread is the main source of infection. While there is evidence of transmission from humans to dogs and cats, it does not appear to be a common event at this time. If you suspect that you are ill with COVID-19, you should practice the same precautions with your pet as you would with people: wear a mask, keep your distance, wash your hands regularly, and avoid cuddling and other close contact. If your pet needs veterinary care while you are sick with COVID-19, do not take your pet to your veterinary clinic yourself.

  • Crop infections are common in pet birds, especially baby birds that are being hand fed. While not usually fatal if treated early, crop infections can be serious and result in a complete loss of appetite.

  • Feather loss occurs either because the bird is truly losing feathers or because the bird, or its cage-mate, is picking out its feathers. Feather-picking is often a behavioral problem, especially in the larger species of birds (such as cockatoos, macaws, and African gray parrots). However, feather loss and feather-picking can also be caused by diseases that result in irritation or pain for the bird, or damage to, or inappropriate growth of feathers. Your veterinarian may have to many perform several diagnostic tests to rule out potential causes. Treatment of feather loss depends on the cause. Feather loss and feather-picking are complicated problems; for specific advice, your bird should have a thorough work-up by a veterinarian familiar with birds.

  • There are four major infectious diseases seen in pet rabbits. Myxomatosis is spread by bites from mosquitoes, flies, fur mites, and fleas and can also be acquired from injuries caused by contaminated thorns or thistles. Subcutaneous swelling extends around the eyes, ears, and genital region and can progress to skin hemorrhages, breathing difficulties, decreased to no appetite, fever, generalized skin tumors, and death. Viral hemorrhagic disease is transmitted by direct contact with infected rabbits, rodents, and contaminated cages, dishes, and clothing. If signs are present, they include decreased appetite, fever, lethargy, collapse, convulsions, coma, difficulty breathing, foaming at the mouth, bloody nasal discharge, and death. Encephalitozoonosis causes a latent condition in rabbits. When signs do develop, the affected rabbit may develop dense white cataracts in one or both eyes, a head tilt, nystagmus, lack of appetite, difficulty walking, uncontrollable rolling over in one direction, tremors, and seizures. Pasteurellosis commonly causes abscesses, respiratory infections, and chronic inflammatory disease in rabbits. It can infect the nasolacrimal ducts, eyes, ears, and nose, and can cause abscesses of tooth roots, bones (particularly the jaw), skin, tissues under the skin, and internal organs.

  • While many owners believe parasites are common causes of skin disorders and feather loss in birds, this is usually not the case. However, Knemidokoptic mange, also called cere mites or scaly face is a relatively common disorder, particularly in some of the smaller species of birds.