Psittacosis is commonly known as parrot fever and should correctly be renamed depending on the species it affects, as it can easily cross over to affect other birds, animals both wild and domesticated and humans. This disease can cause depression, ruffled feathers, loss of weight, loss of appetite, diarrhoea and various problems with breathing.
Common Symptoms of Parrot Fever
The most commonly seen symptoms in caged birds is known as ‘sick parrot’, presenting the symptoms mentioned above: depression, ruffled feathers, loss of weight, loss of appetite, diarrhoea and various problems with breathing (which could include a ‘runny nose’ with thick discharge). The diarrhoea where present is often a rather obvious fluorescent green. In some species the symptoms are rather more specific, with parakeets and cockatiels for example tending to show eye problems rather than the gastric ones seen in other psittacines.
Prevention of Psittacosis
As always when tending animals in captivity of any kind, it is only humane to keep them in scrupulously clean surroundings. In the wild, psittacosis is kept to a minimum for several reasons. Firstly, affected birds are less likely to survive predation and harsh weather, as they will generally be too slow to avoid the predator and too weak to migrate. Also, as most birds roost fairly high above the ground, the droppings of affected animals are not redistributed by wind and foraging to reach the lungs of others.
So it is vital to keep the droppings of birds cleaned up, never allowing them to dry and become airborne. The same applies to shed feathers, which can harbour the chlamydophila and re-infect recovering birds as well as new cases. Stress is also a factor in the likelihood of a bird contracting psittacosis, so keeping the environment calm, with adequate food and warmth, is vital in keeping birds free of this disease.
The Lifecycle of Chlamydophila Psittaci
Many organisms which result in infections in birds are easy to eradicate in that they do not live outside the body and so strict hygiene policies can easily prevent their spread. However, chlamydophila psittaci is unusual in that it can live in air for many months if protected by a layer of cell debris. It can even survive if the stratum dries to dust, so if the aviary is draughty, for example, re-infection can occur as the dust swirls around, particularly as a dose of psittacosis does not confer immunity.
In fact to call chlamydophila psittaci a bacterium is to be imprecise; although it responds to antibiotics, its action in the body is more like a virus, in that it can only multiply within the cells of a living thing; the cell then ruptures, releasing toxins and this is what causes the symptoms. It is vital to disrupt the cycle with the use of ammonium or formalin based cleaners; these are extremely hazardous and should be used with great care. The advice of most COSHH (Control of substances hazardous to health) guidelines would be to employ a professional to do this.
Experts vary on the length of quarantine which will ensure that a new bird to a collection will be free from psittacosis. The incubation period is generally accepted as between 10 days and 6 weeks, with an infected bird not showing any symptoms at all already shedding the organism and possibly affecting those around it. It is also possible that a bird may be an asymptomatic carrier, until it is stressed in some way, with another illness which could be minor, a change of housing, even, in some species which mate long term, the death of a cage mate.
The disease will then emerge, making all estimates of incubation rather meaningless. Thus, it is almost impossible to know whether a bird is suffering from parrot fever until it begins to show symptoms and is diagnosed. It is generally believed that birds which contract psittacosis by breathing in the antigen eventually present with the disease, whilst those who ingest the organism by eating food tainted with faecal or feather dust go on to become carriers, at least in the short term, although no definitive tests have been carried out to prove this conclusively.
Treatment of Parrot Fever
Treatment is problematic, because whatever drugs are given, with a tetracycline based antibiotic being the best in most cases, it will only work when the organism is active. Since it can lie dormant for long periods in an infected animal, treatment should therefore be continued for at least seven weeks, which is both costly and difficult to administer. In cases where only one bird is kept alone, it might be worthwhile, but for a collection, the treatment of all birds would be extremely expensive and all but impossible to achieve.
Euthanasia of affected birds is usually recommended, partly because successful recovery from psittacosis is not a guarantee that it will not return and also that it is very easily contracted by humans, with very serious results. When the chlamydophila organism crosses to humans and is misdiagnosed as influenza, which it closely resembles, it is not uncommon that death may result, especially in the elderly or anyone who is immune-compromised. This is why it is vital that any bird-owner who presents with flu-like symptoms must be tested for the antigen; this is easily done in the laboratory. The best way to treat psittacosis and this applies to any disease which is more prevalent in the captive situation than the wild, is to be scrupulously clean, humane and vigilant.
In other birds it is called ornithosis, for example, but because the term psittacosis is widely understood by most people, the word has come to mean any infection by chlamydophila psittaci, again a blanket term, as each affected species has in its turn its own sub-species of bacteria. The bacterium even gives slightly different symptoms depending on species, the one affecting cats for example results in conjunctival problems.