I am so curious. About those diseases…. I thought it was pretty rare…. IS it? Could you briefly explain what these diseases are like for humans ….. and how they are transmitted?

I'll try to answer your questions… but keep in mind I'm not a vet or an expert.. and I'm not infallible!

Because our systems are gram opposite (one gram positive, one negative) most bacterial diseases and even most viruses can not pass from human to bird or vice versa. One exception that most everybody knows about is Salmonella, but it is very rare in birds. There are, as I found out to my chagrin, a few nasty bacteria that can "mutate" and cross from human to bird…I just happened to have a sinus infection with one of those and lost some birds to it, but those also are very rare.

Of more concern is the bacteria which is "friendly" to humans, being part of our normal digestive flora and present even in our saliva, which can sometimes make a bird very ill or even cause death. This is why some vets and "experts" will warn you not to let your bird in your mouth or let it eat after you.

As far as the other way around, avian chlamydia, also called psittacosis, is the one that causes the most concern. It is a nasty little organism related to, but not the same as, the STD chlamydia that occurs in humans. It is part virus and part bacteria, which is why it is so hard to kill. It is airborne, and very hardy, capable of living outside the body for long periods of time. Many common disinfectants don't even kill it.

Fortunately, in humans it is self-limiting and usually affects the elderly, the weak, or children with flu-like symptoms that clear up after a few days with or without treatment. It is NOT really dangerous to humans, although I suppose it could possibly kill a very weak infant or infirm elderly person…but then, so does everyday influenza, now and then.

In an aviary, it can spread like wildfire and has very high mortality rates, often 100% of chicks die before they are even old enough to pull. The symptoms can vary, but most often are reddened, inflamed eyes and/or sinuses, nasal discharge, wheezy breathing, crop stasis in babies, weight loss, and general malaise with listlessness and loss of appetite. In severe cases the urates (the white or creamy part of the dropping) may turn green or yellow indicating that the liver and/or kidneys are affected. More alarming is the fact that it is believed to be present subclinically (dormant) in almost one third of the pet bird and domestic breeding population, and is extremely difficult to detect in the dormant state.

A breeder can do everything right, quarantine, testing, etc., and still get hit with it from a carrier who tests negative and appears perfectly healthy, then becomes clinical and starts to shed the organism after being stressed. Worse, there's no 100% cure for it - our best treatment is 45 days of injected compounded doxycycline, which usually gets it, but even this is not a guaranteed cure - a few birds may still carry it afterwards. Nasty stuff, huh? It is mostly of concern to breeders, however, and will seldom affect the pet bird owner. In any case, all we can do is the best we can and hope there will be a vaccine or a cure for it soon.

Aspergillus, a fungal type of infection that affects the air sacs and lungs, is sometimes found in parrots that are kept in damp and/or dirty conditions. Humans can get it too, but generally they get it from the same conditions that the birds do, not directly from the birds. Symptoms generally are respiratory difficulties, poor condition, and sometimes discharge from the nostrils.

Polyoma, a virus that is also deadly to baby parrots, is not transmittable to humans and there is now a vaccination available. I encourage you all to get your birds vaccinated against it.

PBFD, or Psittacine Beak & Feather Disease, is incurable and also not transmittable to humans. It attacks the feather follicles, resulting in stunted and deformed feather growth, and eventually the loss of the feathers altogether. It is most common in cockatoos at present, altho many other species are susceptible to it.

Macaw Wasting Syndrome, also called Proventricular Dilation syndrome, is not exclusive to macaws and also can not be transmitted to humans. The symptom is unexplained weight loss and death. The enlarged proventriculus, part of the digestive system, is most often found on necropsy..too late for the bird.

Candida, or yeast, which is a fungus familiar to most women, is fairly common in parrots and is the same one that humans get, but since it has to live in the bird's crop or digestive tract I can't imagine how you could get it from your bird. Trying desperately not to be crude, I'll say that you would have to ingest something that had been in your bird's mouth, crop, or digestive tract in order to acquire it that way!

Most other bird "diseases" that we hear about, such as fatty liver syndrome, are actually nutritional and husbandry problems, not really diseases, and are therefore not contagious at all, even to other birds.