A bad experience with fungus.
I've recently had a long ordeal during which I nursed & lost two beloved pigeons, despite my best efforts and more money that I can afford to spend on vet care, and I wanted to share the experience with others who may be interested and benefit.
As a brief background, in August of 2007 I brought 3 young birds home from a fellow fancier, who were kept in quarantine 3 weeks and then moved into the main loft. About 2 weeks after they moved in one bird became ill and I separated him, bringing him indoors to watch and care for him. Although he was eating well enough, he was listless and he wasn't keeping any of his food down. He ended up being injected twice daily with Baytril and getting multiple small volume tube feedings daily, but less than a week after bringing him inside he was gone. Immediate cause of death was aspiration of vomit, which happened because he'd become too weak to actually execute vomiting.
While that bird was being cared for indoors I became suspicious that a 2nd pigeon was becoming ill. Her symptoms included listlessness and apparent pain or discomfort in her crop. This was evidenced by her sitting very erect with head stretched up high, and an inability or unwillingness to sit in a relaxed position. Subsequently she stopped eating and I ended up medicating and feeding her as well, but she also expired quickly, within days.
Fecal and crop swabs showed only a high # of gram positive rod bacteria, hence the baytril they were both treated with. I'd also collected stool specimens from the entire loft and sent that off for testing, which returned only haemophilus bacteria (I have a suspicion that one turns up in those mail tests a lot just because it survives the shipping time frame, so not a lot of confidence there really). That pathogen should succumb readily to antibiotic treatment, so the entire loft was treated with baytril (tablets) as a precaution.
During the course of the illness as it progressed in the two birds who died, respiratory congestion developed and became severe, so Tylan was also delivered via any available means, which pretty much in this case meant via tube to the crop.
I decided that despite the expense, I had to know what was happening to my birds because at this point, it seemed contagious but not bacterial, or possibly due to some kind of toxicity, and I had to find out what was going on to try and keep it from wiping out my birds.
I took one of the deceased birds (Beauty) to Michigan State University's Diagnostic Center for Population and Animal Health (http://animalhealth.msu.edu) for necropsy. It's an excellent resource and many veterinary colleges have something similar so always do your best to see what similar services are in your area.
[I want to stress how thorough and complete this organization is, and I would encourage everyone to contact them for such services if ever needed. You can ship animals to them and they will provide you with complete instructions. The cost for this service was $150.00 which is very reasonable given that it included complete necropsy, all indicated cultures, histological examination, and any other procedure deemed indicated by the pathologist. The only additional charges are for individual toxicological tests, and those are handled ala carte as indicated by other results. My avian vet was willing to do a necropsy and send tissue samples out, but it would have cost far more to do it that way as they charge for the tests, then in turn pass on the lab's charges, and most likely MSU would be doing the actual tests anyway. In all my experiences with the Veterinary hospital at MSU they have exceeded expectations and I am very impressed with them. I have to include that recommendation of them as a resource!]
Beauty's necropsy did indicate some tissue damage and possible rupture in her crop, however it was only the microscopic histology which revealed what had really happened to her. She had developed a severe fungal infection of the crop and surrounding tissues, something known to experts as a 'mucor' class infection of a type most often seen in young cattle. The organism indicated was 'Zygomyces' which is a normal environmental fungus (found everywhere) and which is not normally pathogenic, however it can invade tissues and become dangerous if ingested in large amounts or if the host is debilitated. This is one of the types of things that can cause life-threatening problems in diabetics and immune compromised patients.
The most likely source of exposure would be through feed, and of course we're told time and again not to feed damp, wet, or moldy seeds and to keep our lofts dry, etc. Well I live by this advice and my loft is kept very clean and dry. During the weeks it took for this situation to evolve I drove myself insane trying to figure out what I was doing wrong and how 'whatever-it-was' got into my birds. We went through bedding (sawdust, straw) being a culprit to the birds ingesting too much grass, to something in the soil, to contemplating possible vandalism (deliberate poisoning) and the list went on. I couldn't sleep at night wondering if there was anything more I could or should be doing.
As for food, I buy it in small amounts, mix in my legumes and other supplements, and store it in a closed container. It is dry and I have never had a problem with any mildew, mold, fungus, or damp feed. I threw all out anyway and replaced it with food from a different source, just trying to cover every possible avenue.
On the day that Beauty passed, I happened to find a large amount of mold/fungus growing in, of all places, their bag of grit.
I had been purchasing (note the past tense!) my grit from a local feed/farm supply, in 5 lb packages, which they bag up and sell pre-measured out of bulk gravel. The best explanation I can come up with is that the bags were damp, or the grit itself was damp or wet and dirty when bagged, and the mold grew up and through the material. It was not visible at all through the plastic, which makes sense since molds and mildews avoid the light, and not grossly apparent until I'd used up about half the grit material and exposed the fungus. Bits of it that might have been scooped up or come loose would just have looked like dusty gray bits of dry grass or something else innocuous. Once I saw the large mass of it in there, I immediately threw it away but later retrieved it and took it along with the pigeon remains to the lab. When the pathologist completed her tests, she was convinced this was the source given the appearance of the material and her other findings. I regret that I did not take a picture of it to share. It's indicative of how stressed I was at the time that I didn't even think about doing that!
I guess I should also share that this is not a topical sort of fungus (like yeast) and that drugs like Nystatin are useless against it. In fact, drugs such as ketoconozole, in a class the pathologist referred to as 'big guns' anti-fungals, should be used sparingly if at all as they pose health risks in the form of tissue and organ damage that can be more dangerous than the pathogens they are used against. I have since confirmed this opinion with 2 other vets and also web research, even on human patients being treated for fungal infections. Administration of drugs like ketoconozole and the like must be done carefully and certainly never given to any patient 'just in case' they might have some sort of fungal infection, and at the very least should be used knowing and accepting the associated risks. Despite my knowing with 100% certainty that my birds were exposed to this potential fungal pathogen, I have elected NOT to treat the rest of them with an anti-fungal as I feel the risks outweigh the benefits. It is best to trust to their own immune systems and on getting/keeping them in top shape with good diet and supplements.
This type of fungus is commonly found in the environment and we are all exposed to such things regularly but normally our immune systems are not overwhelmed.
I also wanted to stress how easy it is to become distracted by one set of circumstances or symptoms and fail to see a bigger picture. Making an assumption such as blaming a newly introduced bird for bringing something contagious into the loft was an obvious early mistake. And finally...and most scary, there is no way to test for illnesses like these. The only available way to test would be through histological examination of biopsied tissue from the crop.
Believe it or not that's the short version, and I apologize for the length of it but I wanted to share it because dangers like this lurk in such unexpected places. In this case the most likely chain of events involved the two birds who perished consuming a large quantity of material that overwhelmed their body's defenses.
I am happy to share a copy of the official report with anyone who's interested, but use the email link from the member's page, as my PM box is always full and I'm lazy about cleaning it out. Just send me a note requesting it and I'll send a copy.