By Laura Wade, DVM, DIP. ABVP — Avian Practice
Excerpt from BIRD TALK Magazine, February 2011 issue, with permission from its publisher, BowTie Magazines, a division of BowTie Inc. To purchase digital back issues of BIRD TALK Magazine, click here.
African parrots are popular pets in the United States. They are characterized by a stocky build, short, blunt tail and a relatively large, sharp beak. The more commonly kept African parrots are the African grey parrots, several members of the Poicephalus parrot genus and several species of lovebird. As a veterinarian who is also the owner of two Meyer’s parrots, I have come to really enjoy the personalities of African parrots.
Common Diseases of African Parrot Species
As a geographic group, Old World parrots (those from Africa and Australasia) have some increased susceptibility to certain infectious diseases— most notably circovirus, the cause of psittacine beak and feather disease — as compared to New World parrots (those from Central and South America). Likewise, Old World parrots have increased resistance to certain infectious diseases, such as herpesvirus (the cause of gastrointestinal papillomas).
A common medical concern for Poicephalus parrots, like this red-bellied parrot, is avian bornavirus/proventricular dilatation disease.
In veterinary practice, we see certain diseases more commonly in African species, and this article discusses seven major problems based on the organ system affected.
African Parrots: Dermatologic Concerns
African grey parrots and lovebirds are predisposed to feather destructive behavior (FDB). FDB comes in many forms, and typically involves the bird chewing or plucking its own feathers. Self-mutilation usually starts with the breast feathers and may involve leg, wing and tail feathers. Head feathers are spared, and the condition may progress to self-trauma of the skin.
There can be a multitude of causes associated with feather destructive behavior. Wild parrots are programmed to be constantly with their flockmates and spend considerable time and energy searching for food, water, and roosting and nesting sites. A captive parrot may become frustrated to the point of picking its own feathers if it does not receive adequate satisfaction of these innate desires. Pain causes the release of endorphin, a chemical in the brain, which has pain-killing, euphoric and habit-forming effects. Although the condition is complex, often the cause is multi-factorial.
Medical causes include organ dysfunction, malnutrition, infections, trauma and possibly allergic reactions. Environmental causes include dry skin/low humidity, molt-associated itchiness, pollutants (cigarette smoke), improper amount of light, lack of sleep, changes in weather patterns, cage concerns, boredom, lack of stimulation and/or a change in the bird’s daily routine.
Separation from an owner, emotional stress in the owner’s life, undesired contact with strangers or family pets and extremely heavy activity/noise in the bird’s environment can also contribute to feather destructive behavior.
Behavioral causes include lack of basic training or it can be a learned behavior (a young bird observing a feather-picker). Feather destructive behavior can also be an attention-seeking behavior or related to sexual/hormonal problems.
Diagnosis involves a complete behavioral history and physical examination. To rule out medical causes, a basic laboratory workup is important. It is also important to rule out aggression or over-grooming by other birds.
Treatment for FDB includes addressing any medical problems, including nutritional optimization. Also, any necessary environmental modifications should be made, including providing bathing opportunities or misting with water; alterations in the amount of light exposure, use of full-spectrum lighting; increasing exposure to fresh air, exercise; and adequate sleep.
A radio or television set on a timer while the owner is away offers entertainment and distraction from feather destructive behaviors. Encourage your bird to work for food via foraging opportunities, and rotate intellectually stimulating and destructible (chew) toys to teach the bird to be independent, yet interactive. Avoid situations that may increase sex-hormone production (excessive cuddling, stroking near tail/vent, etc.), and reward the bird for chewing on toys instead of its feathers.
Avoid inadvertently reinforcing feather-picking behavior, such as yelling at your bird when it feather picks or having a visible reaction. Serious cases involving mutilation may require a temporary restraint collar. For severe cases, anti-anxiety medications may be prescribed in conjunction with altered behavioral therapy.
African Parrots: Cardiovascular Concerns
It has recently been found that up to 30 percent of birds that die suffered from heart disease. In the early stages, heart disease is often difficult to detect, and it is one of the most common causes of sudden death. There are many causes of heart disease, but one of the most common is atherosclerosis.
In 2007, the avian community lost Alex, the famous African grey, to
atherosclerosis. Alex was Dr. Irene Pepperberg’s feathered colleague and research subject for more than 30 years and was an ambassador for parrot intelligence and communication.
Research has shown that up to 25 percent of birds that die have lesions of atherosclerosis. Atherosclerosis involves abnormal cholesterol deposits and calcification of major heart arteries. Essentially, these hardened, narrowed blood vessels cause altered blood flow to the heart and brain. Over time, birds may suffer fainting spells, seizures, difficulty breathing and sudden death.
The disease is quite common and more prevalent in middle-aged to older parrots. Although several parrot species are predisposed, atherosclerosis seems especially common in African grey parrots in their 20s and 30s.
The cause is not clearly known, but similar to arteriosclerosis in people, age, diet, activity level and body condition may play a role. Female birds appear to be affected more often, and this may have to do with problems with fat metabolism, especially during egg laying. Many birds often have liver problems, which can also be traced to altered fat metabolism. Lack of exercise and a high-fat diet (high amounts of fatty seeds, red meat and eggs) may be risk factors also.
Unfortunately, atherosclerosis is challenging to diagnose in the living patient. Sometimes, a heart murmur may be detected on physical examination and X-rays may show opacification of the aorta. Birds with atherosclerosis that are not feeling well may exhibit FDB. Many birds present with neurologic signs. African greys with blue discoloration of the skin around the eyes may be suffering from low blood-oxygen levels. As the disease progresses, it becomes more difficult for the heart to pump blood to the vital organs, and sometimes the heart fails.
There is a considerable amount of research being done on avian atherosclerosis in recent years and, although treatment options are currently limited, we hope this improves in the future. Because heart disease often does not manifest clinical signs until greatly advanced, wellness exams and early treatment of heart disease is critical.
African Parrots: Gastrointestinal Concerns
Common in lovebirds, avian gastric yeast (AGY) infection was formerly thought to be caused by a bacterium (previously called “Megabacteria”). Now, it is known to be a fungus that lives in the proventriculus (stomach) and is called Macrorhabdus ornithogaster (meaning “large rod of the bird stomach”). It affects finches, canaries, budgerigars, lovebirds and cockatiels, and it may be a risk for lovebirds sharing cages with other species.
Although many birds that carry AGY do not become ill (one third of affected birds fail to show signs), the yeast can cause the stomach to dilate and reduce its ability to grind food. Birds more likely to become sick with AGY are under increased stress from molting, egg laying or other problems, such as poor nutrition. Birds that are affected lose weight, often vomit and may pass undigested seed in stool.
Diagnosis is fairly straightforward, as the organism may be detected on microscopic evaluation of moist feces. But since the yeast is shed intermittently, samples may need to be done over several days. DNA testing is also available.
Treatment of sick birds with the antifungal Amphotericin B is needed, as well as nutritional support.
African Parrots: Neurologic Concerns
Previously unknown, avian bornavirus has been recently identified in parrots suffering from
proventricular dilatation disease (PDD). This novel virus is currently being studied intensively by a number of experts in the field and is thought to be the most common virus affecting companion parrots today. It is common in African grey parrots and Poicephalus and is not uncommon in lovebirds.
PDD was first recognized in 1977 and found to be the cause of macaw-wasting syndrome. Since then, it has been known by other names, such as Lymphoplasmacytic Ganglioneuritis and Encephalomyelitis (LPGE) and Neuropathic Gastric Dilatation (NGD), which have been used to describe the unique pathologic abnormalities seen. Although adult birds are more commonly affected (the average age is 4 to 5 years old), it has been described in birds of all ages, and in birds as young as 10 weeks old.
At the present time, it is not entirely clear how birds acquire bornavirus. Since it has been found in feces, the fecal-oral route is suspected. It is suspected that infection may even occur in the egg while still in the hen’s body, because young birds have been found to be positive.
Bornavirus is an RNA virus and is highly unstable in the environment. Therefore, routine disinfection (including 1:20 bleach and water solution) and good hygiene is likely to reduce risk of infection. It appears that avian bornavirus does not grow in mammalian cells, so transmission to people is thought to not occur.
Birds with PDD have gastrointestinal or neurologic signs or a combination of both. The virus destroys nerves of the gastrointestinal tract, brain and spinal cord. Various portions of the gastrointestinal tract, most often the stomachs (proventriculus and ventriculus), are severely dilated and non-functional.
There appear to be three strains of bornavirus. New World parrots exhibit primarily gastrointestinal signs, while Old World parrots exhibit primarily central nervous system signs. However, Congo African greys may develop either syndrome.
Birds with PDD show progressive weight loss despite a good appetite. They may develop passage of poorly digested food and regurgitation/vomiting. Weakness (decreased perching ability, unsteady walking), head tremors, and seizures are seen in some individuals. Sometimes birds may become blind or develop heart disease. Many exposed birds remain asymptomatic. Some birds can be in direct contact with PDD-positive birds for prolonged periods without developing disease.
The most definitive diagnosis is microscopic pathology, which is done on the bird’s tissues (usually on birds that have died). Only 70 percent of affected birds have a dilated proventriculus, so it is important to evaluate other organs, including the brain. This is especially important in birds with central nervous system signs. Surgical crop biopsy may be performed on living birds, but is only about 70 percent accurate. X-ray findings (may include barium study) and fluoroscopy may suggest PDD, but it is important to note that “PDD Syndrome” could be caused by other infections, lead toxicosis, tumors and foreign-body obstruction. Newer diagnostics, including blood testing, are being used to screen potentially affected individuals.
Birds that develop PDD should receive veterinary care. There are several treatments that have been shown to improve the quality of life of (and in some circumstances, cure) affected individuals. One of these includes the anti-inflammatory drug Celebrex.
African Parrots: Respiratory Concerns
Aspergillosis is the most frequently occurring fungal disease in birds. Aspergillus (usually Aspergillus fumigatus) is an opportunist and is not directly infectious (contagious) to other birds. In birds, aspergillosis is primarily a disease of the lower respiratory tract. Although the lungs and air sacs are usually involved, the trachea may be affected as well.
In some cases, infection may occur in the upper respiratory system, including the nasal cavity and infraorbital sinuses. African grey parrots and Poicephalus (especially Jardine’s parrots) are commonly affected.
The fungi are ubiquitous in the environment and flourish in rotting vegetation and decaying organic material. Disease occurs primarily from inhalation of fungal spores. Since Aspergillosis is a disease of captivity and close confinement, predisposing factors include a humid environment with poor air quality. Immunocompromised and malnourished birds are at increased risk. Hand-fed chicks that aspirate feeding formula can also develop aspergillosis.
In the acute form, which primarily occurs in young birds and newly shipped birds, it is the result of exposure to a large number of spores. It is characterized by the growth of fungus in the lower respiratory tract, as well as in the intestinal tract and other organs. Birds exhibit decreased appetite, labored breathing, severe depression and are generally very ill. Unfortunately, the mortality rate is exceptionally high in this form.
The chronic form is more likely to occur in older birds. Fungal spores are widespread in the environment, and many birds may carry them in their lungs and air sacs until the immune system weakens or stress triggers clinical disease. These birds tend to develop granulomas (pockets of fungal infection) called aspergillomas.
A tentative diagnosis can be made by clinical signs, physical findings, including a history of environmental conditions suitable for fungal growth, and recent stress. Suspicion rises for fungal infection when a patient’s condition worsens on antibiotics. Blood work may reveal an elevated white-blood-cell count, anemia and elevated inflammatory proteins. Antibody levels are inconsistent but may be elevated in some individuals. X-rays show loss of air sac definition, nodular densities in air sacs and lungs, and hyperinflation of air sacs.
Definitive diagnosis involves endoscopic examination of the respiratory tract on stable birds and necropsy evaluation. Samples may be obtained for culture, cytology and DNA testing.
Treatment includes mechanical removal of any lesions restricting air flow via endoscopic surgery and killing fungal organisms with antifungal medication, which can be given topically (via endoscope), intravenously (in critical cases), orally or through inhalation (nebulization). Nebulization is usually done initially in the hospital, and oral medication is given once the bird is stable and may need to be continued for three to six months.
Prevention of aspergillosis includes minimizing stress and overcrowding, ensuring proper diet, food storage, ventilation and reducing contact with contaminated nesting materials.
African Parrots: Reproductive Concerns
Lovebirds are often predisposed to chronic egg laying. An egg may fail to pass through the reproductive tract at a normal rate, leading to egg binding. Causes of egg binding include: low calcium stores (associated with soft, thin eggshells), obesity, poor diet, environmental stress, overproduction of eggs (especially in older hens), lack of exercise, a large egg, reproductive tract infections and genetic predisposition.
Signs of egg binding include: straining, tail wagging, drooping wings, lethargy, depression, standing on bottom of cage and leaning back on tail, difficulty perching, abdominal enlargement, difficulty breathing and lameness.
Diagnosis is often made by a history of recent egg laying, physical examination and X-rays. Treatment includes a warm, humid environment, supplemental fluid support, pain medication, lubrication of the egg and cloaca and calcium injections. In many cases, the bird will lay the egg unassisted within several hours. Sometimes, however, manual or surgical removal of the egg is needed.
Complications of egg binding include: prolapsed oviduct, egg-yolk peritonitis, pressure on nerves of legs, and kidneys and death.
African Parrots: Nutritional Deficiencies
African grey parrots are subject to a condition characterized by low blood-calcium levels and intermittent convulsions, known as hypocalcemia syndrome (calcium deficiency). Mature Congo and Timneh African greys between the ages of 2 to 5 years of age are most commonly affected.
This syndrome is not completely understood, but it is suspected that abnormalities in vitamin-D metabolism may be involved. Not all calcium-deficient African greys show symptoms and not all African greys are calcium-deficient. Females that are producing eggs can develop calcium deficiencies if they are on a poor diet. With no skeletal reserves, a diet low in calcium may result in low blood-calcium levels, leading to incoordination, seizures and, possibly, death.
Diana May of The Alex Foundation has studied the feeding habits of greys in Africa. She observed elephant herds stomping out large depressions in the ground that collect water. The grasses that grow in and around these water holes where greys feed are evidently rich in calcium. Finding adequate food sources for calcium can be a difficult task, as it is present in significant amounts in few foods. Nutritionally balanced pelleted diets can greatly enhance the calcium content of a bird’s diet and work well as a portion of a varied diet.
Milk and dairy products are the most dependable sources for people. However, birds lack the enzyme lactose, which is needed to digest milk sugar. Because of this, milk should avoided or given only in small amounts (Lactaid milk preferable). Fermented milk products, such as yogurt, cottage cheese and cheese in which the lactase has been converted to lactic acid by bacteria in the fermentation process make these dairy foods better tolerated as a good source of calcium.
Broccoli, kale and leafy greens, such as collard, turnip and mustard, have an appreciable amount of calcium and good calcium:phosphorus ratio. Other foods that can contribute calcium to the diet are cabbage, pumpkin, sweet potatoes, dried figs, pitted dates, oranges, almonds, tofu, oats, kelp, cooked beans and peas, sunflower and sesame seeds, brewer's yeast, cooked lima beans, alfalfa and occasional hard-boiled eggs (with the shell), salmon and tofu. Herbs, which are known to be high in calcium (dandelion, parsley, comfrey, alfalfa, horsetail, oat straw and chamomile) may be served fresh, dried or sprinkled over fresh food by capsule powder.
Birds that do not readily accept a wide variety of foods or are not on a nutritionally balanced formulated diet can benefit from a calcium supplement. A quality mineral block or cuttlebone is a good place to start. Avoid calcium sources, such as bone meal, dolomite and oyster shell that may be contaminated with heavy metals.
With any supplement, be careful not to overdo it. Megadoses of calcium can impair the absorption of other nutrients, such as iron, zinc and manganese.
Note: avoid calcium supplements containing additional vitamin D. They may have the potential to be toxic and could cause high calcium blood levels resulting in seizures, calcification of soft tissues, kidney stones and increased lead absorption.
Michael Stanford, a veterinarian in the United Kingdom, has found that African greys exposed to ultraviolet (UV) light showed higher blood-calcium levels. This is because UV-B rays are essential for vitamin D metabolism. So exposure to natural and safe synthetic UV light is likely to be very beneficial for all birds, including African greys, especially those that are egg laying or on a deficient diet.
African greys appear to be especially sensitive to low vitamin A in the diet, or hypovitaminosis A (vitamin-A deficiency).
Beta carotene is a precursor to vitamin A and is a fat-soluble vitamin found in many fruits and vegetables but missing in most seeds. Necessary for growth, vision and epithelial cell maintenance, vitamin A is especially important for the skin and linings of the respiratory tracts and kidneys.
Birds on a poor diet develop lethargy, weight loss, poor feathering, thickening of the skin on beak, legs and feet, sinus infections, discharge from eyes and nose, small white plaques in mouth, swollen salivary glands and recurring bacterial infections. Sometimes, kidney dysfunction can occur.
Treatment in the acute phase may include vitamin-A injections/supplements. Ultimately, improving the diet through supplementation of fresh fruits and vegetables and ensuring the diet contains at least 50-percent pellets is also in order.
Excellent natural sources of vitamin A include: orange and yellow fruits and vegetables (carrots, sweet potato, apricots, squash and cantaloupe), greens (spinach, parsley, kale, dandelion greens, turnip greens and broccoli) and red peppers.
Bird Health Concerns: Lovebirds
The smallest African parrots are the lovebirds, which are from the genus Agapornis. (Agape is Greek for “love” and ornis, means“bird”).
Eight species of Agapornis are native to the African continent, and one is native to Madagascar. The most common species in captivity include the peach-faced, or rosy-faced lovebird, (A. roseicollis) from northern Tanzania; the masked, or yellow-collared, lovebird (A. personatus) from northeast Tanzania, and the Fischer’s lovebird (A. fischeri) from Namibia, South Africa and Angola.
Common medical concerns: Feather-destructive behavior; avian gastric yeast (AGY) infection (previously called “Megabacteria”); chronic egg laying.
Bird Health Concerns: Poicephalus
The medium-sized African parrots are members of the Poicephalus genus, which comprises nine species native to sub-Saharan Africa, ranging from Senegal in the west, to Ethiopia in the east, and to Cape Horn in the south. These stocky birds have relatively large heads and beaks for their size (Poicephalus, from Greek, literally means “made of head”).
Several of the species exist in slightly different forms (or subspecies). The most common species in captivity include the Senegal parrot (P. senegalus), the Meyer’s parrot, (P. meyeri), the Jardine’s parrot (P. gulielmi) the brown-headed parrot (P. cryptoxanthus) and red-bellied parrot (P. rufiventris).
Common medical concerns: Bornavirus/PDD; Aspergillosis (especially in Jardine’s)
Bird Health Concerns: African Grey Parrots
The medium-to-large African parrots are the African grey (Psittacus erithacus), which occurs in two subspecies: Congo (P. e. erithacus) and Timneh (P. e. timneh), which originate from the primary and secondary rainforest of west and central Africa. Psittacus is derived from the Greek, psittakos, meaning “parrot.”
Common medical concerns: Feather-destructive behavior; atherosclerosis; Bornavirus/PDD; Aspergillosis: hypocalcemia syndrome (calcium deficiency)