Section: Information In-depth
Causes
There are many causes of ataxia in birds. Ataxia can be caused by diseases of the nervous systems (brain and spinal cord) and can occur due to toxicities, metabolic diseases or systemic weakness. There are many contagious diseases that cause ataxia, so it is important to inform your veterinarian of any potential contact – direct or indirect – with other birds. Possible causes of ataxia in birds include:
Trauma. Trauma to the brain or spinal cord commonly occurs when birds fly into objects such as windows or mirrors.
Toxins. Heavy metal toxicity, caused by ingestion of objects containing lead or zinc, is one of the most common diseases seen in pet birds. Other toxins, such as insecticides, mycotoxins (from mold) and salt poisoning can also cause ataxia.
Nutritional deficiencies. Thiamine (Vitamin B1), vitamin E, selenium and calcium are all nutrients required for proper functioning of the nervous system.
Bacterial infection. Bacteria may infect the brain, causing encephalitis or abscesses or may infect the inner ear. Bacterial septicemia will also cause severe weakness and ataxia.
Viral infection. Several different avian viruses may cause neurologic signs, especially ataxia. Proventricular dilatation disease is caused by a virus that tends to target the nervous system. Many of these birds will also have symptoms of intestinal tract disease. Other viruses, such as Newcastle's disease virus (paramyxovirus), reovirus, togaviruses (eastern and western equine encephalomyelitis) and polyoma virus may also cause ataxia. With these viruses, however, ataxia is usually only one of several symptoms. Viruses can be transmitted by direct exposure to another bird, shared food or water dishes, or on your hands or clothing, depending on the type of virus.
Chlamydiosis. Chlamydia may affect the nervous system in addition to other organ systems. Generally, birds will have other symptoms in addition to ataxia.
Fungal infection. Aspergillus or cryptococcus may invade the brain or spinal cord.
Neoplasia (cancer). These include tumors in the brain or spinal cord.
Parasites. Toxoplasma and sarcocystis are microscopic parasites that can form cysts in the brain. These parasites are acquired by ingestion of cat, raccoon or opossum feces or by eating cockroaches.
Metabolic disorders. These include liver disease, diabetes mellitus and renal disease.
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