Its name derived from the Greek word for parrot (Psittakos), Psittacosis is a disease found in many bird species including, but not limited to, parrots. The correct term is psittacosis if it infects psittacine birds (parrots, parakeets, cockatoos, etc.), but the same illness is called ornithosis if it infects other types of birds (turkeys, chickens, etc.) The causative agent in either case is Chlamydia Psittaci, which is known as a "microvarmit", due to the fact that it posesses characteristics of both virsues and bacteria.
Chlamydia Psittaci is also able to infect humans, although it is a fairly rare occurance. Psittacosis is transmissible through the secretions of an infected bird (bird snot and poo, to use the highly technical terms), yet symptoms are different in nearly every case. Some birds show signs of infection almost immediately, while others can carry the disease for up to ten years, while showing no outward sign of infection.
Symptoms exhibited by the bird after exposure generally depends on the virulence of the strain that it has been exposed to. Some birds are genetically more resistant to the disease, and are thus more likely to become carriers of the disease. An example of this resistance is seen in pigeons (one study suggested that 70 to 90 percent of all wild pigeons are carriers), doves, budgerigars, cockatiels, cockatoos, herons, gulls, hawks, and approximately 100 additional sylvatic species. Other species, such as rosellas, lorikeets, neophemas, mynahs, canaries and some parrots have low natural resistance and are thus highly susceptible to infection by the disease.
When symptoms do appear, they tend to range quite a bit. Generally, an infected bird will shiver, appear drowsy, may have difficultly breathing or experience weight loss, or suffer from bad diarrhea. While lime-green or yellow poo is indicative that the bird is suffering from some sort of disease, the disease isn't necessarily psittacosis. In some rare cases, a bird may develop tremors, convulsions, or paralysis. C. Psittaci can kill a bird within 48 hours, but it can also appear without causing any symptoms at all for a number of years.
When C. Psittaci is passed onto humans, symptoms of infection usually appear about 6 to 15 days after exposure. Symptoms generally include:
and in rarer cases:
Psittacosis in humans can be fatal, although this is rarely the case. Generally, a mild case of psittacosis will hang around for no less than three weeks. As one would expect, people such as veterinarians and pet store employees are most suceptible to the disease. Human-to-human transmission is extremely rare, although not impossible. Psittacosis in humans is generally treated with antibiotics, with tetracycline being most the one used most frequently (Psittacosis is resistant to penicillin). Since 1996, fewer than 50 confirmed cases were reported in the United States during any given year, although experts believe many more cases may occur that are incorrectly diagnosed or reported.