Introduction
Protozoa are difficult to define, as they share characteristics with animals, but they are not really animals in any other way except that they can move independently, usually with whip-like tails called flagellae, but sometimes with a sliding or rolling movement. The whip like ones can be found in garden ponds if you have a lens and the sliding ones include the slime moulds which most people have seen – not individually, but as a colony – if they are keen gardeners. But no matter what they are or how they move, protozoa can cause some very unpleasant symptoms in birds and for a young, old or immune suppressed individual they can often be fatal.
Signs that your bird has a protozoal infection
There are many protozoa which can infect birds but the general symptoms are the same. Protozoa basically make a bird ill by colonizing the gut and interfering with the absorption of fats and other nutrients. This will make the bird lethargic and it may also cause diarrhoea, which will be sticky rather than loose. If the absorption problem has been fairly long-term, with a subclinical dose of protozoal infection, then the vitamin deficiency can result in poor condition, feather problems, itching and dermatitis. Unfortunately, not all birds suffering with a protozoal infection with look unwell. Many are asymptomatic permanently, others only for some of the time and others are ill straight away. All of these can shed the protozoa in their faeces, though, so if a bird appears to spontaneously improve it is still a very good idea to have a lab report on its faeces, to make sure there are no protozoa present. Protozoa can encyst themselves, in other words take on a protective coat to enable them to survive outside the body and so they can live in dried faeces on the cage floor or perches so it is important to keep on checking if you have had an outbreak that the protozoa have been eradicated properly.
Spotting protozoal infections
Protozoa are very small, but with a lens with reasonable magnification – although a microscope is better – you can check for protozoa in the faeces of your birds. Because they move about, they are easy to identify as they will be bumbling around under the lens; they are the only things you will find in the bird’s faeces which will do this so although this is not diagnosis in the proper sense, it will give you an idea what you are dealing with before you take the bird to the vet. Different protozoa move in different ways – giardia roll along, for example, trichomonas are random movers – and in skilled hands this is diagnostic of the species. The treatment tends to be the same for all protozoa so this will not change the choice of medication, but if you are interested in birds you might like to know what is causing their condition; it isn’t many things you can investigate in this way. That said, it is vital to follow strict hygiene rules when doing this kind of thing; almost all protozoa can be passed to humans and many can cause quite unpleasant symptoms.
Prevention of protozoal infections
Because protozoa can encyst – although different species can survive for differing lengths of time outside of the host – it is absolutely vital to disinfect the environment if a bird has had a protozoal infection. Bleach will eradicate any remaining cysts, but it is very important to let the cage or aviary dry out properly after cleaning, as damp conditions can promote the survival of the parasite. Also, damp conditions are not good for birds in general and keeping them in tip top condition is the best way of all to prevent a devastating outbreak. Any surface which is porous should be discarded – this will include wooden perches, floors and any toys the birds may have. This is because bleach is an irritant to birds and the fumes from the porous surfaces could be quite damaging to them. Keeping drinking water clean, either by changing it regularly or using a drinker which prevents soiling will make a huge difference to re-infection rates. Because birds can be asymptomatic it is essential to treat all of them not just the one who shows symptoms as it may well be the apparently unaffected bird which is shedding the cysts in its faeces and infecting all of the others. Any infected bird must be isolated from the others and it is also good practice, after an outbreak, to set a regime of regular testing to make sure that there are no asymptomatic birds shedding protozoa.
Treatment of protozoal infections
Treatment is quite straightforward and consists of one of several anti-parasitic medicines available to the vet. It is never a good idea to medicate an animal yourself – even if you have found the protozoa for yourself under a lens. All medicines should be given at the advised dosage and it is particularly important to complete the course – the life cycle of the protozoa will have been taken into account by the vet when prescribing and stopping too soon will probably mean that the next generation of protozoa are not killed. The most important part of the treatment is to remember to give the medicine to apparently unaffected birds as well, and to test their faeces after the course has finished, along with the affected bird. Finally, some protozoal infections can be quite serious in people who are immune compromised in some way, so a visit to the doctor for anyone in this category who has come into contact with an affected bird would probably be a very good idea.
