Aspergillosis is caused by an infection by the aspergillus fungus which is quite literally everywhere in the environment, in that the spores are so light and tiny that the smallest movement will make them airborne and they will be breathed in without being noticed. Most of the time they cause no trouble, but if they are present in particularly large numbers, or in an enclosed environment, or the bird (or any animal) is not in the best health or is immune suppressed due to medication, then the aspergillus can gain a foothold the very serious condition of aspergillosis can develop, sometimes with startling suddenness.
Where can Aspergillus be found?
The quick answer is everywhere, but of course there are some places where it is more likely to be found in problematic amounts. It is worth taking a moment whenever you buy any food or bedding for your bird to think about whether it seems to you to be damp, musty smelling, has visible mould – this will be greyish-green and powdery – or may have been stored in damp conditions, or harvested in the rain and left to dry. If the answer to this moment of pondering is either yes, it has been damp or even that you can’t be sure, then it is best not to let it get anywhere near your bird. Peanuts are particularly bad – in other ways than carriers of aspergillus but that’s another story – as they grow in the ground and aspergillus is found in most soils.
Sunflower seeds which are a late crop often begin to moulder even before harvesting, so unless you know exactly where they come from they are best left out of the diet. Corncob bedding is very prone to mould and so is best avoided. These simple examples should be enough to enable the owner of a pet bird to work out the kind of things to avoid. It sounds at first as though nothing is safe, but if the bird is in good health and the environment it lives in is dry, clean and well ventilated then there should be little or no risk.
Things to watch out for
Perhaps the first thing to say about the signs of aspergillosis is that they will almost certainly come too late. The acute form will be a sudden onset of breathing difficulties, increased drinking and therefore urination, and a bluish colour (cyanosis) of the membranes in the mouth due to lack of oxygen reaching the blood from the lungs. The bird, if vocal, will sometimes lose its voice, or the voice will change. This is often the first real sign that points specifically to aspergillosis. Sometimes the only sign of it in the acute form is sudden collapse and death. In many diseases the chronic form is easier to treat than the acute, but this is not usually the case with aspergillosis as the onset can be so gradual and generally asymptomatic that the bird is too ill to respond.
Aspergillosis and the Respiratory System
As the aspergillus is breathed in to begin the infection, the first organ to be affected is the respiratory system, where the fungus forms spores in white nodules on the walls of the airways which then migrate into the bloodstream and then can go all over the body, affecting other organs. Sometimes at this point the bird will die of respiratory failure without further organ involvement. If the infection does go further, it will sometimes reach the central nervous system and the bird may have seizures, or will develop a limp or may show signs of having balance problems. It may also have diarrhoea, loss of appetite and become lethargic and depressed. Unfortunately, these symptoms are not unique to aspergillosis and sometimes valuable time is lost whilst other avenues are explored.
Most vets will be honest with the owner and give a prognosis which will not promise a good outcome. However, treatment with a wide range of fungicides and also a lot of back up with heat treatment, feeding via a tube, oxygen administration and the treatment as needed of underlying problems such as respiratory tract infections and vitamin deficiencies may result in recovery. This has to be balanced against the obvious stress that all of these interventions must cause the bird and unless it is a very prized specimen intended for breeding or a particularly treasured companion, it is usually kinder to let the vet put it to sleep, difficult though that decision always is.
Prevention of aspergillosis
Aspergillus is a very common fungus and so the main way of preventing it from becoming a very serious problem for your pet bird is to make sure that no part of its food or bedding ever has a chance to go mouldy and certainly to take whatever steps are possible to make sure that the mould is not introduced to the environment. It is possible to take these precautions to excessive levels such as not going near the bird if you have been digging in the garden, using distilled water in its water trough, changing the water is ever the bird bathes in it, not allowing it to breathe in air that has been disturbed by building work and similar measures. Whilst these will certainly go a long way to ensuring that your bird does not develop aspergillosis, keeping to such a demanding regime may also remove any pleasure you once got from keeping a pet bird. As long as the environment is dry and clean and the food and water is also fresh daily and most importantly if the bird is maintained in the very best of health and condition, then this serious disease will almost certainly be kept at bay.