Is There a Fungus Among Us?
Many people have heard of black mold. There are important health concerns for us with this mold that grows in our homes. The organism is Stachybotrys chartarum. This mold is extremely dangerous to humans due to its release of a mycotoxin. This organism appears as a greenish-black mold that has a slimy appearance when wet but, when dried, appears powdery. There are other organisms that have a similar appearance. The mycotoxins that are released from these black molds can cause a number of symptoms in humans, particularly neurologic. These include brain fog and confusion, inability to concentrate and other symptoms. Respiratory symptoms are associated with a burning sensation in the back of their throat and nasal passages leading to difficulty breathing. But what about our bird companions? While we have not documented that this mold produces disease in our feathered friends, we know that birds are very susceptible to fungal infections.
Birds have a unique respiratory tract — with a large infraorbital sinus in the head to lighten the load and air sacs that move air through a fixed lung with a much greater surface area, comparably, than mammals. They can get acute, overwhelming fungal infections or more chronic infections. More commonly, Aspergillus molds are reported to cause disease in our pet birds.
Fall tends to be the time of year when we see companion bird patients with overwhelming mold spores in the lungs and air sacs. This often occurs after an owner turns on the furnace after a cold snap and mold spores are circulated through the home. This devastating problem happens very quickly and it is very difficult to save them. So it is very important to change your filters regularly — particularly in the fall — before turning on the fan to your furnace!
Molds tend to grow during periods of rainy, humid weather and then, when followed by dry periods, spores are produced and they easily become airborne. These can get sucked into the respiratory tract where they take up residence. They then grow into something that looks like mold on bread on the surfaces of air sacs or the lung tissue. When this happens acutely, there may not be time for the body to respond, particularly when there is a huge number of them, in essence, plating themselves on the lining of the respiratory tract.
So why does this happen? We know from veterinary medicine that there can be predisposing factors that can cause fungal infections, particularly when the condition is more chronic. These predisposing factors often relate to sub-optimal husbandry conditions. This would include changes in environmental temperatures and temperatures that are not in the normal optimal temperature zone of that species of bird. Low ventilation also is a factor, in that turnover of air is insufficient. High dampness or excessive dryness are often considered triggers. Poor hygiene can be an important factor, including not cleaning the cages often enough so that some areas are wet and other areas of the cage are very dry.
Good nutrition is crucial in keeping our birds healthy and free from disease. That is particularly important in prevention of fungal infections. Hypovitaminosis A occurs with birds that eat seed-only diets or other unbalanced diets. Home-cooked foods may be unbalanced, if they do not provide green and orange veggies. Nutri-Berries and Avi-Cakes while containing seeds are whole foods that are balanced like a pellet. These balanced foods should be at least 50% of the diet. Giving fruits (particularly dry fruits as they concentrate sugars) provides large amounts of sugars, which provide fuel for fungal organisms! When vitamin A levels are either too high or too low for your bird, that causes the cells of the body to turn over faster and they cannot perform their normal functions. This makes them more susceptible to infection — with bacteria, viral or fungal organisms. The respiratory system is one organ where proper levels of vitamin A are critical. Invasion with fungal spores stops normal functions and then they start multiplying in the warm environment of the lining of the respiratory tract.
Other factors that are considered changes from normal husbandry include: immunosuppression; prolonged antibiotic treatment; infections from bacteria, viruses or parasites that compromise health; trauma; and stressors that affect the immune system. Immune suppression can result from a variety of causes — nutritional, stress from putting birds in high traffic areas of the home when they don’t like it, corticosteroids which should be given in rare situations, and infections from other diseases including cancer.
One thing that I think that we do not consider enough is this: All birds come from an environment that they were designed to live in — that would be considered their optimal temperature zone. This zone has other factors besides temperature that make that species successful, including the humidity that they would normally have and the foods that they would normally eat. All of this would be normal. So for blue-fronted Amazons from Brazil to live in the Midwest is nothing like what their bodies and their immune system was designed to live in. That is a big stressor, and I commonly see blue fronts with yeast infections. And it should be no surprise that they are considered a more susceptible species for getting Aspergillus mold infections. We should predict that from the fact that we took them out of an environment of higher heat (80-110oF) and higher humidity (near 100%) and placed them in an area that gets very cold with low humidity with furnaces blowing out mold spores.
We need to be more aware of environmental factors and try to provide the temperatures and humidity levels that mimic their environment. But when we do that we must also watch for creating more fungal spores — remember that mold likes high heat and humidity. Changing papers, putting some vinegar in the water to keep it more acidic and cleaning humidifiers are all important safeguards for our wonderful birds. Feeding them healthy foods and making sure mold spores do not grow in sprouts or other foods is also important. Let’s be diligent to avoid fungus among us!
