Atherosclerosis is a common disease in companion parrots – one we must all take seriously. If you have ever heard of an older parrot who died suddenly, without apparent cause, there is a good chance that this progressive disease was a primary factor in the demise.
What is Atherosclerosis?
Atherosclerosis is one type of arteriosclerosis. The word atherosclerosis derives from the Greek words athero, which means “gruel or porridge,” and sclerosis, which means “hardness.” This is a fairly descriptive term for the disease itself, in which cholesterol is deposited onto the sides of arteries, creating hard plaques. Once build-up is great enough, plaques can dislodge; these cause blockages, which lead to heart attack.
It is primarily a disease of inflammation. The more inflammation, the greater the risk of atherosclerosis.
Birds are more susceptible to atherosclerosis than any mammal, with the exception of humans. “The reported incidence rates in avian species range widely from 1.9% to 91.9%.”(Powers, 2015)
A Confusion of Information
While much is known about atherosclerosis in humans, this information cannot be readily transferred with reliability to birds. Reading through scientific papers about the disease causes consternation and befuddlement. Undeniable conclusions are lacking, although more recent research does point to strong correlations.
Much of the research has been done on bird species other than parrots, such as quail, waterfowl, and chickens. Diagnosis on parrot species who have succumbed to this illness has been conducted on a very mixed population, particularly those kept previously in zoos, who have been maintained under a variety of conditions and fed a mix of diets.
Moreover, the studies that are being done on risk factors that exist for parrots are being performed on the known risk factors for humans and other mammals. There may, however, be other risk factors specific to avian species that may take longer to uncover, such as individual species’ genetics.
Thus, I will warn you that what I write today may well be something I will edit extensively in another five years. The danger is significant and real for our parrots, so an examination now of what we know is important. However, I have every expectation that some of what you read below may be proved wrong in the future, while additional details will in turn come to light.
Which Parrots Are At Risk?
While we have a very good understanding of risk factors in mammals, this is not so with parrots. But, a few things we do know.
Species
It is currently agreed that Amazon parrots, African Grey parrots, quaker parakeets, and cockatiels appear to be at greatest risk. While the disease has been seen in cockatoos and macaws, they are not believed to be quite as susceptible. Many avian species, though not all, have been found to develop atherosclerosis in captivity.
Age
Increased age is a significant risk factor. However, while more common in older parrots, Nemeth states that atherosclerosis has been found in birds aged 1 to 42 years. (Nemeth at al, 2016) It is most common in companion parrots over the age of 10.
Gender
Female parrots have been proven statistically to be at greater risk. Female birds in reproductive mode generally have elevated levels of cholesterol, triglycerides and lipoproteins, as well as calcium, creating greater susceptibility.
Diet and Nutrition
“The inclusion of cholesterol in the diet of birds that consume non-animal protein, even as low as 0.25% of the diet, dramatically increases plasma and serum cholesterol levels.” (Petzinger and Bauer, 2013).
Petzinger also mentions a 2003 paper by Bavelaar and Beynen that found that African grey parrots fed a high-fat diet containing palm kernel oil (saturated fatty acids) had increased cholesterol levels.
Petzinger also reports on the findings of yet another study from 2012. In this research, a total of 47 cockatiels who were supplemented with fish oil had lower plasma cholesterol than cockatiels fed flaxseed oil. The conclusion? “Thus, dietary fish oil (and possibly dried algae products) may be more beneficial than oils high in A-linolenic acid on reducing risk factors and prevalence of atherosclerosis in avian species.” (Petzinger and Bauer, 2013)
Another nutrient capable of lowering cholesterol levels in birds is pectin. Pectin is the soluble fiber contained in fruit and some vegetables.
The overall amount of food eaten may also contribute to the development of atherosclerosis. Overeating and obesity are proven risk factors for mammals. This correlation has been studied in birds with varying conclusions.
Physical Inactivity
Every research paper I read reported a presumed link between inactivity and the development of atherosclerosis. However, I could find no evidence that any link between exercise and this illness had actually been researched in avian species.
Since such a strong link exists between the two in mammals, including humans, it would be foolish to ignore it here and the papers I read did include recommendations for exercise in companion parrots.
Inflammation
The literature on human health names inflammation in the body as a primary cause for the development of atherosclerosis. In fact, inflammation is currently being discussed in what is being called “a unifying theory of disease.” (Harvard Health, 2006) In other words, inflammation is now considered as a significant factor in the development of many chronic human illnesses.
Nevertheless, inflammation as a process “remains a mystery.” (Anft, 2016) However, scientists are beginning to agree that lifestyle choices like diet and exercise may increase (or reduce) inflammation.
Common foods that cause inflammation, which are often fed to parrots, are fried foods and those containing refined carbohydrates (white flours and sugars).
Co-Infection with Psittacosis
The disease Psittacosis, also known as Parrot Fever, is more accurately referred to as Chlamydia psittaci. This disease is still relatively common among companion parrots, especially those who have come from large collections. While researchers disagree about whether there is a conclusive correlation between infection with Chlamydia and atherosclerosis, some studies appear to agree on this.
Signs and Symptoms
Sadly, the most common sign of atherosclerosis is sudden death. In the late stages, there may be symptoms such as weakness, lethargy, neurological signs (including seizure-like activity), trouble breathing and exercise intolerance. However, these may be less observable due to parrots spending long hours in cages. It is easier to identify exercise intolerance, for example, in parrots who fly.
At this point in time, diagnosis is extremely difficult. Most people will never imagine that their parrots are ill until they lose them unexpectedly, well before their time. With better imaging techniques, as well as a better understanding of identifying factors in serum chemistries, this may change in the future.
What Can We Do?
Atherosclerosis in companion parrots is still not well-understood. Direct and specific correlations from the human health field may only be suggestive. Thus, we do not have well-defined risk factors that would allow us to target flawless measures for prevention.
Suggested lifestyle changes reported in the literature include “increasing physical activity by providing more opportunities for locomotion and foraging behaviors and decreasing the stress level in their captive environment. Limiting dietary excess and obesity also seem to be a reasonable strategy, but species-specific dietary needs should be considered.”(Beaufrere, 2013)
“Birds should be provided ample opportunities for exercise and activities such as foraging, and even flight, if considered safe for the bird. Excessive energy content in the food should be avoided, such as excess carbohydrates and fats. Birds should receive regular preventative veterinary care with periodic bloodwork monitoring.” (Powers, 2015)
Diets that contain relatively high levels of Omega-3 fatty acids reduce the prevalence of the disease. (Petzinger and Bauer, 2013) 
Newer research indicates that fish oil may be more effective in this than alpha-linolenic acid, the type of omega-3 found in plants, such as in flax seed oil. Supplementation with fish oil may be an excellent addition to the diets of many companion parrots, but this should not be undertaken without the advice of your veterinarian.
Pectin in the diet has also decreased the occurrence of atherosclerosis. (Petzinger and Bauer, 2013) Pectin is the soluble fiber found in fruit. Too much pectin can result in a decrease in the absorption of nutrients from the intestine, however. Thus, fruit should be fed in moderation for most species.
Reducing the overall amount of food, i.e. not over-feeding, can also decrease the prevalence of atherosclerosis. This information too, however, could be harmful if implemented to the extreme. Hunger and malnutrition do nothing to improve overall health. It is best to consult with your veterinarian about the quantity of foods to offer.
Suggested Action Steps:
After as thorough a review as I could muster with the research I was able to access, I think the following steps are prudent:
- Identify an avian vet who specializes in birds and schedule annual visits.
- If your veterinarian tells you your bird is fat, take this seriously and formulate a plan for gradual weight reduction.
- Discuss with your veterinarian supplementation with fish oil. (The correct dose is important and should be obtained from your vet.) Nordic Naturals is an excellent choice.
- If you have a female parrot, do everything you can to minimize triggers for the increased production of reproductive hormones. (You should do this for males too.)
- Discourage a pair bond
- Avoid cuddling and other highly affectionate interactions
- Prevent cavity seeking (getting into closets, boxes, etc.)
- Feed a low-fat, low-carbohydrate diet
- Do not feed foods high in saturated fat (fatty meats, butter, margarine, cheese, coconut oil, palm oil, fried food, or snack foods).
- Do not feed pasta, white rice, or any foods that contain white flour or sugar and other sweeteners.
- If your bird eats a seed mix as a dietary staple, convert him to a pelleted diet with supplementation of fresh foods.
- Avoid overfeeding. Remember the size of the creature you are feeding.
- Encourage foraging and try to incorporate some physical activity into this.
- Encourage exercise.
- Determine whether you and your bird might be a candidate for flight in the home.
- If not, work to discover ways to encourage as much movement as possible.
- Do feed foods high in pectin, in moderation (apples, pears, plums, peaches, apricots, cherries, strawberries, guava, carrots and peas). Apples are especially high.
- Do feed foods high in omega-3 fatty acids or that are otherwise known to reduce cholesterol (oats, barley and other grains, walnuts, flax seeds, chia seeds, hemp seeds, edamame, almonds, beans, tofu, salmon)
- Do feed foods that fight inflammation (green leafy vegetables, blueberries, salmon, broccoli, cauliflower, kale, peppers, grapes, celery, ginger, tumeric)
Atherosclerosis is a scary prospect, given what we now know about the susceptibility of our companion parrots. However, I suspect that we have in our hands the tools for prevention, just as people do. Granted, risk factors outside of our control exist, such as age and gender. However, we do have enough information to take action and keep our parrots as healthy as absolutely possible.
Thank you for reading my blog. I am Pamela Clark, an IAABC Certified Parrot Behavior Consultant. My passion is helping people with parrots by offering behavior consultations and publishing information you can trust. To access free resources, schedule a consultation, or subscribe to my newsletter (which is a different publication from this blog), please visit me at http://www.pamelaclarkonline.com. Until next time!
References:
Anft, M. 2016. “Understanding Inflammation.” Johns Hopkins Health Review. Volume 3, Issue 1. https://www.johnshopkinshealthreview.com/issues/spring-summer-2016/articles/understanding-inflammation
Beaufrere, H. Dr. Med Vet, PhD, Dip. ECZM, Dip. ABVP. 2013. “Avian Atherosclerosis: Parrots and Beyond. Topics in Medicine and Surgery.” http://dx.doi.org/10.1053/j.jepm.2013.10.015. https://www.sciencedirect.com/science/article/abs/pii/S1557506313001754?via%3Dihub
Bavelaar F. J. & Beynen, A.C. (2004) “Atherosclerosis in Parrots: A Review. Veterinary Quarterly, 26:2, 50-60. https://doi.org/10.1080/01652176.2004.9695168
Nemeth, N.M. , Gonzaliz-Astudillo, V., Oesterle, P.T. Howerth. E. W. “A 5-Year Retrospective Review of Avian Diseases Diagnosed at the Department of Pathology, University of Georgia”. Journal of Comparative Pathology. Volume 155, Issues 2–3, August–October 2016, Pages 105-120. https://doi.org/10.1016/j.jcpa.2016.05.006
Harvard Health Publishing. April 2006. Harvard Medical School. “Inflammation: A Unifying Theory of Disease. https://www.health.harvard.edu/newsletter_article/Inflammation_A_unifying_theory_of_disease
Petzinger, C. PhD, Bauer, J, DVM, PhD, Dip. ACVN. 2013. Journal of Exotic Pet Medicine. Volume 22, Issue 4, October 2013, Pages 358-365. “Dietary Considerations for Atherosclerosis in Common Companion Avian Species. https://doi.org/10.1053/j.jepm.2013.10.013
Petzinger,C BS, Heatley, J DVM, MS, DABVP, DACZM, Cornejo,J BS, Brightsmith, D. PhD; Bauer, J DVM, PhD, DACVN. Journal of the American Veterinary Medical Association. March 1, 2010, Vol. 236, No. 5, Pages 523-528. https://doi.org/10.2460/javma.236.5.523
Powers, L. DVM, DABVP. 2015. “The Silent Killer: Atherosclerosis in Pet Birds.” CVC in Washington, D.C. Proceedings. Published on DVM 360. http://veterinarycalendar.dvm360.com/silent-killer-atherosclerosis-pet-birds-proceedings.