Index of Bird Diseases ... Symptoms and Potential Causes ... Bird Species and Diseases They are Most Susceptible to
Below are several resources that should be of interest to any owner who is concerned that his pet might, or actually has been diagnosed with, aspergillosis. Corn cob, which may be used to line a nest box or cage bottom, is most often associated with causing this infection, peanuts (especially those with black spots on the outside) in addition to nutritional deficiencies can predispose birds to infections. In-depth information on this fungal condition is below ...
Beginning with a bird owner, Katrina, who reiterates her own experiences and advice by her veterinarians, followed by medical research / publications on this topic. All areas -- from prevention, symptoms, diagnosis and treatment options-- are covered.
The Silent Parrot Killer
By Katrina Coleman
Baby was nine years old and already a master of disguise. He was a blue and gold macaw and loved by everyone. He had a wonderful sense of humor and an insatiable appetite and never even gave a hint of his illness until seven weeks before his death. Louise Bauck, DVM writes, “The first signs are subtle and often missed.” If there were signs, Baby’s were missed. By the time I realized something was wrong it was much too late to save him. Baby was very affectionate and always had a kiss in store for me. He never stopped playing with and tormenting his brother Sammy. He loved hanging around by his toe nails exposing his belly tempting the next passerby to get it.
But his most admirable characteristic was his electric personality and it was present even until the end. I could have never guessed he was so sick. What I wouldn’t give to know then what I know now. I pray that by sharing with you some of what I have learned I might be able to save at least one bird and Baby’s death will not have been in vain.
Most of the following information was learned over the last six weeks of Baby’s life. He was being treated and monitored on a daily basis under the careful and watchful eye of his veterinarian Dr. Sam Vaughn. Dr. Vaughn also made a believer out of me of the importance of an uncontaminated, nutritional diet and clean environment.
The single most memorable piece of advice I was given that I will pass along to you is to never, ever give a parrot a peanut. Every single source of information I have found on this subject is in total agreement. Virginia Caputo, author of Aspergillosis and Jardine’s Parrots says: “Peanuts grow in the ground and are considered to be a common source of aspergillus which can sicken birds."
Peanuts are also often contaminated with aflatoxin, a fungal toxin. Aflatoxin is carcinogenic and causes liver damage in birds and other animals. Roasting reduces aflatoxin but does not eliminate it entirely. North American peanut producers are currently working on eliminating contaminated peanuts from their products. Caution is advised when feeding peanuts. Some bird owners, opting to be on the safe side, are eliminating peanuts from their pets' diet.
Be aware of the possibility of mold growing in all seeds and nuts.”
Aspergillosis is a respiratory fungal infection caused by aspergillus spores that become airborne. Through Dr. Vaughn I also learned spores can be ingested and spread throughout the gastrointestinal tract, and that is how aspergillosis killed Baby. His reluctance to talk was the only sign he presented but I didn’t know it was something I should have been concerned about. Without the silence I may have had a chance to save him. A little known fact to the average bird owner is that acute (sudden and severe) infections often cause a voice to change or disappear completely and aspergillosis is usually not diagnosed until after death. So please, I beg of you, do not wait until you see clinical signs, by then it is usually too late. Take your bird into a qualified avian veterinarian every six (6) months for a check-up. Researchers at The University of Miami have developed a test allowing us to screen parrots for early or mild infections. Subtle changes in bloodwork will tell your vet to investigate further. If I had I wouldn’t be writing this now.
The chronic cases (long term) are somewhat easier to spot. There are symptoms to be seen but they are often associated with other illnesses. A well informed and observant parrot owner has a much better chance of stopping this disease before it consumes your parrot. Some symptoms that can catch your attention are:
- Nasal discharge
- Weight loss (especially if the bird appears to be eating well)
- Flakey or delaminating beak
- Unstructured or frayed feathers
- Black edged feathers on the outside of the wings and
- Extreme itchiness and possible mutilation (digging at the skin with beak)
- Loss of or changes in voice
- Neurological problems (including seizures)
Aspergillus is everywhere; it can grow on bread, in rotting vegetation, in materials used to line cages and on living tissue. Every speck of dust and dirt and every batch of corncob bedding have spores of at least one species of Aspergillus. A parrot does not usually succumb to the disease when it has a strong immune system. Over time it has built up antibodies strong enough to wage a proper war against the spores. But, a weakened immune system or ingestion of a huge amount of spores is what causes this disease. Every animal with lungs breathes in thousands of Aspergillus spores every day. The spores cannot grow in the lungs of a healthy body, but a diseased lung can easily become a host. Aspergillosis can consume a parrot with a weakened immune system. Poor nutrition, another illness, anxiety, loneliness, old age, unsanitary conditions or disturbed soil can also bring on this illness. Always keep your parrot’s immune system as healthy as possible. A constant and gradual exposure can create a chronic (long term) infection and the causes are all too commonly found in places you would never expect. Many parrot foods even have the potential to cause a parrot to ingest spores.
Unfortunately, almost all caged birds are eating poor diets, deficient in important vitamins, minerals, amino acids and ample supplies of protein. Stress runs a close race with poor nutrition as being the most common cause of a weakened immune system allowing the Aspergillus spores to grow.;
In every chronic case the slow growing fungus is also very slow to die and recovery can take time. The treatments often last for months or even years. Aspergillosis will never go away on its own.
I’ve listed a few stressors you should be concerned about:
- Spending much of the day in restricted isolation.
- Smoke inhalation
- Prolonged antibiotic therapy
- Being a breeder (laying eggs and caring for the young)
A list of possible contaminates that I never would have expected follows. I hope it brings to your attention just how careful you must be.
- PEANUTS, never give a bird a peanut
- Sunflower seeds if their growing season was really wet or the seeds weren’t harvested on time (in essence avoid sunflower seeds since there is no way to detect their history)
- corn cob bedding and other organic matter
- walnut shells
- wood bark (mulch)
- the air during spring planting and fall harvesting on farms
- construction sites where soil is being moved
- damp nesting materials
- potting soil and peat moss, don’t transplant or plant when your birds are around
- wet shavings or other litter
- dried corn
- moldy parrot seed
- fresh fruits and vegetables, if they are not human grade produce and have not been washed with soap and water and a scrub brush
- A warm humid environment, this can speed up the deterioration of nutrients in a parrot’s food and increase the possibility of spores becoming rampant
Remember; “an ounce of prevention is worth a pound of cure.” Once this disease has set in it is very hard to conquer. I have also listed a few simple but critical preventative measures to include in your daily routine.
- Change their water twice a day and any time they have bathed in it or contaminated it.
- Give your parrot fresh food every day.
- Fresh air and exercise are very important, a lack of them can compromise the immune system.
- Remove fresh produce within four hours
- Wash and disinfect cages, toys and perches weekly.
- Boil their water, even bottled or spring water since it is not guaranteed that it doesn’t contain harmful bacteria. A gallon of boiled water kept in the refrigerator will last for days. Just save it for the birds their immune systems are much more delicate than ours.
- Provide good ventilation.
- Provide clean bowls, stainless steel is preferable.
- Provide extra nutrition to your breeders.
- Make sure their nesting materials are clean and dry. Spores can penetrate fresh or incubating eggs and will kill the embryos.
- Eliminate poor ventilation, poor sanitation, dusty conditions and close confinement, these can all increase the chance spores will be inhaled.
My appreciation and thanks are given to Sam Vaughn, BS, DVM, ABVP (AVIAN) of Veterinary Associates Stonefield Louisville KY for taking the time to answer questions about spergillosis, to give advice about preventative measurers and to give me a better chance of giving Sammy a long and healthy life.
Aspergillosis in Birds
Veterinary and Aquatic Services Department, Drs. Foster and Smith, Inc.
What is aspergillosis and what causes it?
Aspergillosis is a respiratory disease of birds caused by the fungus Aspergillus, which is found almost everywhere in the environment.
A. fumigatus is the most common species of the fungus to cause disease, although A. flavus, A. niger, and others can also cause problems. Aspergillus grows readily in warm and moist environments. The microscopic spores of the fungus become airborne, and poor ventilation, poor sanitation, dusty conditions, and close confinement increase the chance the spores will be inhaled.
Usually, the fungus does not cause disease, however, if a bird does not have a healthy immune system, it can cause illness. Predisposing factors include other illnesses, stress, poor nutrition, poor husbandry or unsanitary conditions, another injury to the respiratory system (e.g.; smoke inhalation), and prolonged use of certain medications such as antibiotics or corticosteroids.
The combination of the number of spores in the environment and the presence of predisposing factors determine which birds are most at risk of disease. Aspergillosis appears to be more common in parrots and mynahs than other pet birds.
What are the signs of aspergillosis?
Aspergillosis can follow one of two courses
- acute or chronic. Birds with acute aspergillosis have severe difficulty breathing, decreased or loss of appetite, frequent drinking and urination, cyanosis (a bluish coloration of mucous membranes and/or skin), and even sudden death. The fungus generally affects the trachea, syrinx (= sound-producing vocal organ), and air sacs. The lungs may also be involved. Diagnosis is generally made through a post-mortem examination.
Chronic aspergillosis is much more common, and unfortunately, much more deadly due to its insidious nature. The bird may not become symptomatic until the disease has progressed too far for a cure. The respiratory system is the primary location of infection. White nodules appear and ultimately erode through the tissue, and large numbers of spores enter the bloodstream. The spores then travel throughout the body, infecting multiple organs including kidneys, skin, muscle, gastrointestinal tract, liver, eyes, and brain.
Respiratory symptoms will be the first to occur but will depend on the location of the greatest areas of colonization. Difficulty breathing, rapid breathing and/or exercise intolerance are common. If the syrinx (voice box) is involved, a change in voice, reluctance to talk, or a "click" may occur. Nares may become plugged or you may see a discharge. Eventually, severe respiratory compromise may kill the bird.
Other signs and symptoms will vary, depending on the other organs involved. If any portion of the central nervous system has become involved, the bird may have tremors, an uneven or wobbly gait, seizures, or paralysis. With liver involvement, a green discoloration to the urates may be seen, and the veterinarian may feel an enlarged liver. Generalized, non-specific symptoms can include loss of appetite leading to weight loss, muscle wasting, gout (painful, inflamed joints due to urate deposits), regurgitation, abnormal feces or diarrhea, excessive urination, depression, and lethargy.
Spores can penetrate fresh or incubating eggs and will kill the embryos.
How is aspergillosis diagnosed?
Aspergillosis can be very difficult to diagnose since the signs of disease mimic those of many other illnesses, especially in the chronic form. The veterinarian will need a detailed history of the course of the illness, and an accurate description of the diet and husbandry of the bird. Radiographs, a complete blood count, and a chemistry panel may help support a diagnosis. Endoscopy can be used to view lesions in the syrinx (= sound-producing vocal organ) or trachea, and a sample can be taken for culture and microscopic examination, either of which can confirm a diagnosis. A diagnosis can also be made based on a specific blood test used to detect antibodies to Aspergillus in the blood. Sometimes, however, the test can be falsely negative, especially if the bird's immune system is suppressed.
How is aspergillosis treated
Surgery may be performed to remove accessible lesions. Antifungal drugs, such as itraconazole, ketoconazole, terbinafine, flucytosine, and amphotericin B, may be administered orally, topically, by injection, or nebulizing, depending upon the drug. Therapy needs to be continued for weeks to months and more than one antifungal drug may be used. Supportive care such as oxygen, supplemental heat, tube feeding, and treatment of underlying conditions are often needed. Unfortunately, the prognosis is always guarded.
How can aspergillosis be prevented?
The importance of good husbandry to prevent outbreaks of aspergillosis cannot be overstated. Keep your bird in a well-ventilated environment. Clean food and water dishes every day. Replace substrate (material lining the cage bottom) regularly. Remove your bird and thoroughly clean cages, toys, perches, etc., at least once a month. Pay attention to good nutrition, offering the right combination of fruits, vegetables, grains and seeds with variety, and only a sprinkling of "treats." Essentially, you want to do everything you can to alleviate stress in your bird's life and provide a scrupulously clean environment.
A susceptible bird that has been exposed to Aspergillus may be treated with flucytosine and itraconazole in an attempt to prevent infection.
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References and Further Reading
Rupley, AE. Manual of Avian Practice. W.B. Saunders Co. Philadelphia, PA; 1997.
Oglesbee, BL. Mycotic Diseases. Altman, RB; Clubb, SL; Dorrestein, GM; Quesenberry, K. (eds.). Avian Medicine and Surgery. W.B. Saunders Co. Philadelphia, PA; 1997.
Olsen, GH; Orosz, SE. Manual of Avian Medicine. Mosby, Inc. St. Louis, MO; 2000.
Aspergillosis in birds
Aspergillosis is a major cause of morbidity and mortality in birds. It affects birds whether in captive or free-ranging environments, young, mature or geriatric, and whether immunocompetent or immunosuppressed.
Predisposing factors include
- species predilection (turkeys, penguins, raptors, and waterfowl)
- environmental conditions (limited air exchange, exposure to aerosolized toxins resulting in mucosal irritation, and improper temperature and humidity),
- immunosuppression secondary to forced production
- physical exertion (migration), and
- administration of exogenous corticosteroids.
The route of inoculation is inhalation and the lower respiratory tract is the location where Aspergillus spp. tend to initially colonize. A. fumigatus accounts for approximately 95% of the cases and A. flavus is the second most common organism associated with avian infections. – 2005 ISHAM, Medical Mycology, 43, S71/S73 S72 Tell Downloaded At: 18:33 26 August 2007 Clinical signs are usually non-specific (lethargy, inappetance, and anorexia) or can be related to compromise of the respiratory system (rhinitis, change in vocalization, dyspnea).
Diagnostic testing includes:
- Hematologic testing, cytology, fungal culture, histopathology, radiography, and computed tomography.
- Antigen and antibody tests have been reported for use in birds, however their success in properly diagnosing the disease are relatively poor.
The forms of the disease that have been reported in birds include focal aspergilloma, multifocal lesions, and disseminated infections. The target tissues are lungs and air sacs, gross pathologic lesions include caseous nodules or plaques, and massive granulomas with necrotic cores can be appreciated on histopathology. The susceptibility of birds to Aspergillus spp. may be attributed to differences in innate and acquired immunity against this pathogen when compared to mammals.
Anatomic characteristics that might predispose birds to this disease include a lack of an epiglottis for preventing particulate matter from entering the lower respiratory tract, lack of a diaphragm resulting in the inability to produce a strong cough reflex and a limited distribution of pseudostratified ciliated columnar cells through the respiratory tract. Cellular characteristics that might predispose birds to respiratory aspergillosis include a lack of surface macrophages for phagocytizing Aspergillus spp. conidia and dependence on heterophils that use cationic proteins, hydrolases, and lysosymes rather than myeloperoxidase and oxidative mechanisms for killing fungal hyphae [6,7].
The majority of the avian cytokine genes for the Th-1 response have been molecularly characterized; however, cytokines of the Th-2 response still remain elusive despite research efforts. Protective immunity following vaccination for aspergillosis appears promising in turkeys as experimental infections simulating natural disease have been performed and birds appear to confer immunity following vaccination. A unique feature of avian aspergillosis is the presence of reproductive phases of Aspergillus spp. in tissues. This has been reported for the asexual phase of A. fumigatus  and both the asexual and sexual phases of A. nidulans . Potential reasons for this finding include the presence of cavernous air sacs, the warm core body temperature of birds (range/38/458C) that might promote conidial germination, and birds’ sensitivity to gliotoxin that might result in tissue necrosis and thus provide a nutrient rich environment.
Given all of these unique characteristics of birds, these animals should no longer be considered as a taxon for which numerous case reports exist, but rather as an interesting and potential experimental animal model for studying this disease. Conclusion Treatment options for resolving Aspergillus infections in animals (i.e. dogs, horses, dolphins, and birds) are still of great need and importance in veterinary medicine. Given the growing population of humans infected with aspergillosis, opportunities to study this disease have significantly increased over the past two decades. These opportunities could benefit both human and veterinary medicine and allow experimental animal models to provide alternative treatment regimens for minimizing morbidity and mortality in the future
On: 26 August 2007
Access Details: Free Access
Publisher: Informa Healthcare
Informa Ltd Registered in England and Wales Registered Number: 1072954
Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Aspergillus and Aspergillosis
by Marilu Anderson, Bird Nutrition and Behavior Consultant
You've probably hears of Aspergillus and Aspergillosis, but may not be clear on what these terms mean. First, "Aspergillus" is the name of a common fungus that is naturally present in the environment. For most birds (and people) it causes no problems, but if too many aspergillus organisms are around and your bird has a poor immune system, then the illness "Aspergillosis" sets in. It is often fatal, causing severe respiratory problems. It can be transmitted from birds to humans and vice versa.
Aspergillus spores can be airborne, and are often abundant in corn cob litter. In a damp environment, like we have here in the Northwest, the problem is even worse. I always advise against using this type of litter since it is such a breeding ground for all types of fungus, molds, and bacteria.
Once Aspergillosis has taken hold, the lungs and air sacs fill with large white masses, causing serious breathing problems and further sapping the bird's energy and immunity. The bird will wheeze, or you'll hear a clicking sound and often see tail bobbing when the bird's at rest. Sometimes there is discharge or crustiness around the nostrils. A low grade infection can show as itchiness, frayed feathers, peeling beak or black feather edging onthe wings. There is a blood test for Aspergillosis and it should be part of your bird's annual checkup.
Treatment is tough - the fungus is hard to kill and because of the weak immune system, there's often secondary infections as well. Birds on poor diets and living in unsanitary conditions are much more prone to this disease. In dealing with the disease, it's important to improve the diet, feeding lots of fresh veggies, fruit and using whole food supplements.
Cleanliness also needs to be a top priority, with daily cage cleaning and scrubbing of food and water dishes, as well as perches and toys. Birds on antibiotics for bacterial infections are much more susceptible to Aspergillosis, as well as other fungal and yeast infections. I advise supplying probiotics to birds who are on antibiotics, as well as feeding yogurt and acidophilus. In addition, feed foods rich in Beta Carotene, as Vitamin A is important for good health of the respiratory tract and skin. Yams, carrots, broccoli, red peppers and apricots are all great, as are supplements like wheat grass and spirulina. Many birds really enjoy fresh carrot juice, which is an excellent NATURAL source of Vitamin A. Natural sources are preferable over synthetically produced nutrients, which may not be absorbable and could easily be overdosed).
Boosting your bird's immune system by supplying a diverse, broad spectrum diet, ensuring adequate rest and daily exercise, and keeping your bird's cage and supplies scrupulously clean will all help prevent this widespread fungus from grabbing hold in your bird. Don't forget the importance of regular "well bird" checkups every year, to catch any disease as early as possible, for the best success in treatment. Treating Aspergillosis with antifungal medications needs to be done under direction of an avian vet - it's not something to try and cure on your own!
Aspergillosis is commonly found in decaying vegetable matter. A bird becomes infected by the ingestion or inhalation of mold spores from contaminated foods. The infection causes lesions in the lungs and air sacs and has been reported in many species of birds. Occasionally, outbreaks of the disease cause significant mortality in certain species.
To reduce the risk of this disease:
- Store seed in a dry place to discourage the growth of mold and fungus. Discard any seed that has become wet or moldy.
- Aspergillus fungi are most likely to grow on corn and peanuts. If you live in a warm, humid environment, you may want to avoid feeding these foods.
- It is crucial to not overcrowd birds and to remove fresh foods after a few hours; never leave overnight. No damp, organic matter should be allowed to accumulate in the area the patient(s) is in. Cleanliness is key in both preventing and treating aspergillosis.
Medications: The vet may prescribe Nystatin, Amphotericin B, Ketoconazole or other medications.Many disease-causing organisms / toxins are transmitted via air and water. If you suspect a disease problem (or if you would like to prevent one), please investigate the possibility of filtering your air and purifying / treating your birds' drinking water.
Holistic Treatment: Options:
Please note: There is little information available on holistically treating birds and my research took me to resources that pertain to HUMAN patients. The safety for and application to birds has not been ascertained. However, my recommendation is to collect the information and discuss your options with your vet -- try to find a vet with additional training in holistic medicine, as regular vets obviously don't have the knowledge to recommend for or against such treatments.
Remove any possible sources: Moldy food items. Also humidifiers have been mentioned by veterinarians and others as a possible source of mold spores that can cause aspergillosis in birds. Humidifiers need to be properly maintained (as mentioned above). Vets suggest that parrot owners use warm mist humidifiers or vaporizers that boil water prior to releasing it into the air.
Goldenseal Herb: Strong antibiotic properties. It has a long history of use in infections including bacterial, viral, fungal, and parasitic. Staph, strep, E. coli, Vibrio cholera, Giardia lamblia, and even tuberculosis bacterium have proven sensitive to this herb.
Echinacea Herb: Kills a broad range of disease-causing pathogens, including: viruses, bacteria, fungi and protazoa.
Cinnamon Leaf - Essential Oil: Used as an insecticide, emmenagogue, antispasmodic, antibacterial, aphrodisiac and antifungal particularly against Candida and Aspergillis. Indicated for tooth care, blends for vaginitis, respiratory blends for the lungs. Eases colds and breathing difficulties. As an inhalation, it is excellent for exhaustion, feelings of depression and weakness. It is a very effective antiseptic, digestive and anti-rheumatic and is regarded as one of the strongest antiseptic oils. Useful for preventing infectious and contagious diseases. Not recommended for skin care. Traditionally used in clearing warts (I cleared up several warts with this -- it worked! Although my skin was sore for a few days. I preferred that to having them cut or frozen off). The leaf oil is relatively non-toxic. Very powerful, should be used with extreme care, could be a skin irritant for certain persons.
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