Why all the fuss about
Air-sac Mites?
An Introduction
Throughout the years, I have offered most of the following information in a condensed form to numerous Canary and Lady Gouldian Finch breeders and owners. This time I have tried to be as comprehensive as possible with the limited amount of information available to us non-scientific folk. A complete print-out of most of the referenced studies and papers are available (for a price) on the internet. However the complete Tidemann and
Therefore some of the initial text below is going to be a bit technical. I have tried to insert plain language explanations wherever I could to make it easier to understand. Please do not be turned off by the technical stuff. An understanding of how our birds are infected is important to understanding what needs to be done to keep them healthy.
Avian Respiratory System
The avian ventilation/respiratory system, like the mammalian respiratory system, delivers oxygen from the air to the body tissues and it also removes carbon dioxide. But that is where the similarity ends. The avian respiratory system also plays an important role in thermoregulation in that it helps to maintain normal body temperatures despite wide fluctuations in the temperature of the surrounding air.
The avian ventilation system also serves as a storage station for oxygen because it is directly connected to the skeletal system where oxygen is stored in the semi hollow bones. This storage system is especially important during migration when birds are flying at altitudes where oxygen is in short supply. This fact was tested and proved 200 years ago in 1758 by John Hunter
The avian respiratory system is composed of a paired set of lungs and 9 air-sacs:
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1 interclavicular sac
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2 cervical sacs
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2 anterior thoracic sacs
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2 posterior thoracic sacs
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2 abdominal sacs
These 9 air sacs have very thin walls with few blood vessels, so they do not play a direct role in gas exchange to the body tissues. The gas exchange between the ventilation system and the blood which transports the oxygen to the body cells takes place in the air capillaries which rise up from the
It actually takes 2 inhalations to totally exchange the air within the avian respiratory system. During the first inhalation, air enters through either the nares or the mouth, passes through the pharynx and down the trachea directly into the posterior air sacs, while simultaneously into the lungs and all the way to the
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Oxygen Storage Pockets
A portion of the air sac system actually penetrates the skeleton at the humerus, vertebrae and femur, forming air pockets in otherwise dense bone. The exact reason that this function evolved is not known but it is theorized that it happened to lighten the bone structure, allowing dinosaurs to walk upright and the ancestor of birds to fly. These oxygen storage cavities make it possible for birds to fly long distances (during migration) at high altitudes where oxygen is in short supply.
Now that you can see just a small part of how important the ventilation/respiratory system is in your Gouldian Finches, it might be easier to understand that when they are infested with air sac mites it 
will affect everything that they do. Since the ventilation system helps to maintain their body temperature system, when it is not functioning properly your birds will become fluffed and frumpy in an attempt to control their body temperature by external means. They are attempting to create an insulation blanket around themselves like we would when we cover up with heavier clothing during the colder months of the year.
The best course of action when you see this behavior in your birds, whether the cause is air sac mites or some other illness causing the bird distress, would be to supply them with an external heat source to help maintain a normal body temperature so that the bird does not have to use what energy it is able to produce to keep itself warm, but can use that energy to help itself heal. The external heating should not come from a source that also provides light, such as an electric light bulb. You should use something that provides only heat, such as a ceramic reptile heater, an infrared heat bulb, or even a heated perch system. A warmed hospital cage can be fashioned quite inexpensively by using a heating pad under a small cage that has one perch hanging very near the bottom of the cage to facilitate the bird absorbing as much warmth as possible radiating up through the floor of the cage. Place newspaper on the floor and be sure to locate food and water near the perch. A partial covering over the cage with a cloth will keep the warmth contained where it is needed. One important note: only older versions of a heating pad can be used in this manner, because our government has taken it upon itself to “protect” us from ourselves and now require that all newly manufactured heating pads automatically shut off after 2 hours.
Air Sac Mite studies
In 1992, Sonia C. Tidemann et al. ran extensive studies on the relationship of the rhinonyssid parasite Sternostoma tracheacolum (air sac mite) and the Gouldian Finch. Her goals were to:
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Determine the prevalence and intensity of infection in the wild Gouldian Finches compared to other finch species living in the same
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Determine the earliest date of occurrence in wild birds in
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Determine the pathological effect of S. tracheacolum on individual birds.
Prevalence and Intensity of Infection
These studies found air sac mites in Gouldian Finches and 6 other species living in close proximity to them. The other 6 species were Long-tailed Finches, Masked Grassfinches, Pictorella Manikins, Zebra Finches, Double-barred (Owl) Finches, and Budgerigars. But the prevalence and intensity of infection in Gouldian Finches was higher than in the other species except the Pictorella Manikins.
Timetable for Infection
The studies were unable to determine the exact date that the air sac mites arrived in
Pathological Effect
(This is the beginning of the technical stuff, so don't stop reading now) S. tracheacolum is a virulent species of nasal mite known to enter the trachea, lungs and even the body cavity of perching birds throughout the world (Baker et al. 1956; Fain and Hyland 1962). This mite causes inflammation, lesions, parasitic nodules, and hemorrhaging of the respiratory system leading to pneumonia and ultimately death of Canaries and the Gouldian Finch (Baker et al. 1956; Cumming 1959).
In the Tidemann study, the lungs of infected birds contained disintegration of the tissue lining the site of mite attachment as well as the infiltration of macrophages and lymphocytes to fight off the invading mites. The air sacs were thickened by excess fluid accumulation and infiltration of fibroblasts and lymphocytes. The trachea also had moderate epithelial lesions and lymphocyte and macrophage infiltration, again to fight off the invading parasites.
The mites were 0.2 – 0.3mm wide, 0.4 - 0.6mm long and dorso-ventrally flattened. Scanning electron micrographs indicated that individuals attached themselves by embedding their legs into connective tissue. A mucus coat, secreted by the bird’s immune system covered most of the individual mites that they found attached to the lining of the respiratory system. When mites were found in the trachea, they (plus their mucus coats) reduced the internal volume of the trachea. So you can see why it is hard for infected Gouldians to breathe once the width of the trachea is reduced and they are unable to get enough air to pass on down into their ventilation system. As the infestation of mites grows, the trachea narrows even further, and the birds will begin breathing with an open beak in an attempt to bring more air into their respiratory system. This same mucus coating will also thicken the wall of the air sac at the site of the mite attachment, thus preventing the air sac from acting as an efficient bellows to move air in and out of the lungs. The harder their breaths become the more bodily movement you will notice. This explains why “tail bobbing” is often stated as a symptom of an air sac mite infection. A healthy finch without an air sac mite infection will not noticeably move when they are breathing.
Immune System Checks
In the Tidemann study, there was a 62% infection rate in the Gouldians studied, so it does seem that it is possible to have Gouldian Finches that have never been infected with air sac mites. Through the centuries, in the face of continuous threats from parasites, birds have developed an elaborate system of preventive and controlling measures to keep themselves free of invading organisms – this elaborate system is a quality, high functioning immune system. In our captive Gouldians, air sac mite infections are a rare event when adequate nutrition is present to allow the birds to develop a strong immune system from time of hatch. So even if a few mites invade the respiratory system, the immune system will keep their numbers in check, preventing a life threatening infestation.
But stress always lowers the immune response in all living organisms. Most of our captive finches are under a constant amount of stress, if not from their molting cycle, breeding cycle or crowded living conditions then just from the fact that they are captive and living behind bars. I know what you are going to say now…”but they have always lived in a cage, they have never known anything else”. But have you ever watched your flock as you approach them on a daily basis. They see you every day of their lives. You feed them and clean up after them. Yet, if they are all down eating at their food dish, and you approach, they will fly up in unison to higher perches and a position of safety. Whenever this fight or flight mechanism is triggered, there is resulting stress, if only for a very short time period.
Transmission Biology Studies
Studies conducted in 1995 by P. J. Bell explored the parasite-host relationship and the transmission biology of the air sac mites to the Gouldian Finch. These studies found that S. tracheacolum was ovoviviparous (producing eggs that develop within the maternal body and hatch within or immediately after release from the parent body). The young are laid in the lung of the host (your birds) and molt 
without feeding. Following a blood meal the female protonymphs move to the posterior air sacs (where they are protected from the host’s immune response because there is little blood flow to the air sacs preventing any insecticide in the bloodstream during this time from reaching them) The male protonymphs tend to stay within the lungs, where there is significant blood flow, to complete development and therefore can be killed when an insecticide is present in the blood stream. Pregnant females tend to occupy the air sacs, the syrinx and trachea of the host while adult non-pregnant females are more commonly found in the upper respiratory system, particularly the mouth and nasal cavities. In vitro rearing experiments and other observations indicate that the life cycle (from egg to adult) is completed in less than 6 days.
Adult male mites tend to be common in small populations but uncommon and often absent in large populations, supporting an argument for parthenogenesis (biological reproduction that involves development of a female sex cell without fertilization) and an arrhenotokous (producing only males) system of sex determination.
Transmission from one bird to another is accomplished by the adult non-pregnant females as this stage was observed on the head plumage, beak and nares of infected birds. Artificial infection experiments indicated that non-pregnant females from the nares of Gouldian Finches are capable of surviving long enough to start a new infection in a naive host.
The Bell studies clearly state that they felt that the most probable modes of transfer were (1) direct from the nasal cavity of an infected bird to the nasal cavity of a recipient bird via the external nares of each bird and (2) indirect from the nasal cavity of an infected bird to the nasal cavity of a recipient bird via the external nares, but including a period of time on water, perches or nest material. This is why it is very important that you thoroughly clean and disinfect the cages and nestboxes if any are present during treatment for air sac mite infestations.
Posterior Air Sac protection
Once a bird is infected, it is next to impossible to ever completely eradicate them from a birds respiratory system because the female protonymphs migrate to the posterior air sac where they are protected from the bird’s immune system and from the insecticides that we have available to us that will kill the adult form of the air sac mite. Remember, there is little blood flow in the air sacs themselves, so it is impossible to get the insecticide that is flowing in the bird's blood stream to the protonymphs living in the air sacs. A bird with a strong, healthy immune system can keep these nymphs in dormancy for many months, but when the bird's immune system is suppressed during times of stress, like breeding and molting, the nymphs will eventually mature and begin the whole life cycle again.
When a bird has a strong, healthy immune system it is able to keep the population of nymph air sac mites from maturing. During very stressful times of the year (breeding and molting seasons), when the immune system becomes suppressed it is up to us to help them keep the adult numbers in check as the protected nymphs mature. We can do this by using either Ivermectin (S76) or Moxidectin (Scatt). If we fail to do this, before the population of mites has grown out of control, the simple act of treating the bird to kill the mites could likely also suffocate the bird itself because the high number of dead mite bodies will clump together and block the respiratory tract completely.
Treatments to kill air sac mites
Since Scatt remains in a bird's blood stream for 3 weeks, I do not like using it more than 6 times per year…immediately prior to and immediately after both the breeding season and molting cycle. S76 will only remain in the blood stream while it is available to the bird in its drinking water, so the recommendation is that during the molting cycle the treatments should be given for 2 consecutive days every 3 weeks. The rest of the year it should be administered for 2 consecutive days every month. S76 is perfectly safe for even day old chicks so do not stop the treatments during the breeding cycle.
It Could Happen to You…
Now that we have read about all that scientific stuff, I am going to tell you a not so happy story that happened to me in the fall and winter of 2009. First let me say that I have met many Gouldian and Canary breeders during the last 32 years that will deny ever finding air sac mites in their flock…or they will deny even knowing what an air sac mite is. I believe that the thought behind this is that they are afraid that no one will purchase their birds if they know that there are air sac mites present. As was stated previously in this article, in the Tidemann study they found that 62% of the birds that they checked were infected with air sac mites. So prior to 1992 there was a possibility that some wild Gouldians may never have become infected. The wild birds do hang out in flocks during certain parts of the year, but never within the close proximity that our captive birds do. They do all drink from the same water sources, but nothing as tiny as our water bottles and bowls (in relationship to the number of birds). Therefore, I believe, based upon my own experiences, and the numbers of Gouldian people with infected birds that have contacted me for help in the last 18 years, that Gouldians raised in captivity in close proximity to each other are all infected with air sac mites. If they have had good nutrition since the day that they were hatched, they were able to develop a strong immune system which will be able to keep the infection in check. So those quality breeders that claim never to have had air sac mites in their flock, while not being absolutely factual, were being truthful in their claims. They may truly never have seen any symptoms of an infestation exhibited in their birds.
What does it sound like?
My first experience with air sac mites was in my flock of Canaries back in 1984. When I walked through the house at night, I began to hear noises while the birds slept that sounded like a child, after a crying spell, who was trying to catch their breath. I’m sure that everyone reading this has probably heard what I am referring to. I would not know how to spell out the sound, but to me it sounded like the birds were trying to catch their breath…by inhaling quickly multiple times in a row. It wasn’t a loud sound, as I only heard it at night when the house was completely quite. My vet gave me Ivermectin to treat them, and since that time, I had never, ever heard that or any other respiratory sound coming from either my Canaries or Gouldians. But since that day, I have ALWAYS treated my birds, on a very regular schedule with either Ivermectin or Moxidectin. And I would never think to claim that there were absolutely no air sac mites in my flock. Personally I don’t think that you could make that claim, once you had known for a fact that there were air sac mites found in even one bird. Since the protonymphs migrate to the posterior airsac where they are protected from the immune system of their host, AND they are untouched by the insecticides that kill the adult air sac mites, unless you were going to do a necropsy on each bird, in which case you would not have any birds, you can never be sure that you do not have air sac mites in your flock!
It all began with the flood…
My not so happy story began at 2:30AM on September 21st, 2009 when the
Our basement took on 4 inches of water, and my husband and I spent 18 hours with shop vacs and mops attempting to clean up the mess. When the lights came on in my aviary at 7:30 AM, I could see that it too had 4 inches of water on the floor. At that time, I was one week from setting my birds up for the 2009-2010 breeding season. The breeders were primed and ready to go. I spent that day catching them from the flights filled with floating bedding and moving them to smaller holding cages, above the water, in very crowded conditions. The humidity in the aviary had gone from a constant 35% to over 90% in less than 5 hours. And the humidity would unfortunately remain that high for almost 10 days. My dehumidifier was ruined by the flooding water and buying another was impossible for another 10 days, because literally, the entire city was going thru the exact same problem that we were. Dehumidifiers just weren’t to be found. Once I got one, it took 3 days to dry everything out and bring the humidity levels back to 35%.
I should have known better…
It took about a month to get everything cleaned up and back to the way it had been. And at this point, I should have known better than to set the birds up to breed. My 18 years of experience should have told me that they had been under too much stress over the last month. But looking at them, they did not appear to be out of condition. The hen’s beaks were still dark and the cocks were still singing their little hearts out. So I went ahead and set them up.
The breeding did not start off with a bang the way it had the year before. That should have been my first sign as many of these were experienced, bonded pairs. Of the 26 pairs set up to breed, a few went right to work, but when the babies hatched they began pitching or just abandoning the nests. I had not had pitched babies in years, and these were experienced pairs, not newbies. Because I have about 100 birds in my aviary, it took a while before I heard the noise…a loud, wet, raspy, wheezing sound coming from 3 birds. I knew that I had been treating for air sac mites every month with S76, so it couldn’t be that. I figured that because of the wet conditions they had been exposed to for a month, the problem might be a protozoa infection like Trichomonas, so the entire flock was treated with Ronivet-S for a week. The 3 birds continued to make that same wet, raspy noise although I never heard it in any of the other birds. So then I treated those 3 with Amoxicillin and Tylan for another week thinking that it was a bacterial respiratory infection, but still the noise persisted. The rest of the flock appeared to be just fine but the breeding had gotten only slightly better. So as a last resort, I applied the air sac mite treatment directly to the skin of those 3 noisemakers, and one bird stopped the noise.
This is scary stuff…
I kept the other 2 isolated from the rest of the flock, but I found one of them… a beautiful, red headed, normal hen dead the next morning. I immediately placed her in a plastic bag and refrigerated her. I e-mailed a friend that has done necropsies of her own birds and asked if she would be willing to necropsy this hen if I Express Mailed her that same day. She agreed and so off the poor girl went. As the Post Office so often does, they took 2 days to deliver the one day package, so by the time my friend receive it, the bird was already dead for 3 days. It was late in the day when the package arrived, so she planned to do the necropsy the very next morning.
She reported that when she opened her up, every organ looked perfect, She was not under weight, just a bit dried out since she was now 4 days dead! Since we suspected something respiratory, she took some goo that she found in the upper respiratory tract, prepared a slide and looked at it under the microscope. Shock!…Horror!…she found air sac mites. As she rushed to the phone to call me, her college age daughter took a look at the microscope slide and I could hear her in the background on my voice mail asking her Mom…”should these things be moving?”
“No, heavens NO…NO WAY!” I hear my friend shouting back to her daughter.
By the time we spoke later that day, things had settled down in their household, but she had found LIVE, MOVING AIR SAC MITES in a bird that had been dead for 4 days! How could this be possible? How could they survive that long? I still don’t have an answer for you on that, but I’m sure that you’ve heard the joke about the fact that cockroaches would probably be the only survivors if we ever had a nuclear disaster? Well my bet is that air sac mites would still be around too!
This is a photo of a gravid (pregnant) female air sac mite that was still living inside of my 4 day dead bird. It was reported in the Bell study from 1995, that “Ivermectin is known to kill S. tracheacolum (e.g. Grimm and Centufier, 1986; Kummerfeld and Schafer-Nolte, 1987) When Ivomec® (i.e. 0.8g Ivermectin) is administered orally to captive Gouldian Finches Erythrura gouldiae the egg in utero of the killed female mite does not die but continues to develop (Bell, 1995).”
This is scary stuff folks! You can kill the female mite and yet her egg does not die, but continues to grow and be born!
Reviewing the facts…
After the shock settled into my brain, I began to look for a pattern. To my horror, I discovered 3 more birds that were displaying similar raspy symptoms, but not nearly as pronounced or loud as the 3 original birds. Then, all of a sudden I saw that every bird with these symptoms had the same “family colored leg-band”. All but one of these symptomatic birds came from the same parents. This fact alleviated most of my concern. What I was seeing in these related birds was what will happen when a bird does not have a strong, vibrant, healthy immune system. These birds “looked” fine, but it was evident that none of them had an immune system strong enough to keep the air sac mite population in check during the stress caused by the flooding, being confined to crowded holding cages for a month, and then being placed into a breeding situation to top it all off.
All but one of these birds, coming from the same parents, were “weak gened” and unable to build a strong, healthy immune system, even though they were provided the best diet possible. Their parents are unrelated and show no sign of an air sac mite problem, however this particular pairing is not a good one and therefore will not be paired together again in the future. This is the type of decision making that must be made if we are going to keep improving our captive populations of Gouldians. We must be able to selectively pair and breed only the BEST birds, and not just whatever we can find to purchase, that is the exact color that we have been looking for.
As luck would have it, I kept all but one of their offspring as this was a new bloodline that I was developing. Unfortunately every one of those offspring died within 3 months of the flood. The one bird that I gave to a friend before the floods and the resulting stress is showing no sign of a problem. But I have advised him not to breed this bird and to keep it in as stress free an environment as possible, keep up the regular air sac mite treatments and just enjoy his lovely bird as a pet.
Looks can be deceiving…
I hope that you can now see that just because a bird “looks” fine, you can not just assume that it will be fine when placed under the stresses that life throws at it. I hope that you will learn from my mistake in thinking that everything was just fine after such a stressful period for my flock.
It has been said that everything happens for a reason. Back on September 21st, I could not think of anything good coming from that day. But it is now my opinion that what happened on that day, lead me down a path that will help to enlighten all of you Lady Gouldian lovers. Air sac mites are real! Air sac mites can be a real killer for your birds and therefore you need to be vigilant in keeping these mites in check with regular treatments to kill the adult mite population living in your birds.
Follow Up
I remember back in those early years when the only thing available to us to treat our birds for air sac mites was 5% Sevin Dust via the “shake ‘n bake” method. I never want to go back to that again! I can also remember when Ivermectin was discovered, unless you had a local avian vet who could give your birds liquid Ivermectin by mouth, we had only the horse paste and later the injectible Ivomec and then the Pour-On Ivomec all made for horses, sheep and cattle. It seemed that we always had to use products made for other animals, and in so doing lost numerous birds due to calculation errors in amounts to administer on such small birds.
Now we have 2 products, Scatt and S76, made specifically for our birds and both of these products, when used correctly and following label directions, will allow our captive birds to live long happy, healthy lives. I know that some of you reading this article feel that I only offer this information because I sell both products. I want to assure you that your perception of my motives is not correct.
I want to assure the rest of you that I offer this information and sell both of these products because I want all of you to have strong healthy birds. It does not matter to me whether you purchase the products from me or not. What does matter is that now that we can so easily eliminate the possibility of death from these parasites, I think that it is a shame to allow one single Canary or Lady Gouldian to die from them.
Laraine
I wish to extend a special THANKS to my friend Kristen Reeves for the wonderful air sac mite photos she took when she did the necropsy on my Gouldian hen!
