Birds are susceptible to many types of parasites. Birds that are kept indoors and have minimal contact with the outside world are less likely to be infested with parasites than birds that are kept in an outdoor aviary. There can be many parasites present in or on a bird without you being able to detect any visible signs. Problems are often only noticed if the bird is feeling under the weather for some reason (associated illness, dietary deficiencies, etc.). This is when they can suffer from the presence of parasites.
Tapeworms or cestodes reside in the intestines. They can be found in finches and members of the parrot family. If infected, the birds can lose weight and have diarrhoea. Infection can also take place without showing any signs. Because tapeworms require an intermediate host, they hardly ever occur in birds that don't come into contact with the ground or the earth. This is much more common with imported birds.
Roundworms or nematodes are found in the small intestine. The bird is infested when it ingests eggs with larvae inside. These then bury themselves in the mucous membrane of the intestine. There may not be any problems, but if heavily infested it can cause diarrhoea, loss of weight and poor growth. If there are large numbers of worms, they can in fact block the intestines entirely. Eggs are spread with the bird faeces. They can remain contagious in the environment for a long time. Birds that don't come into contact with faecal material of other birds or infected earth have very little chance of being affected.
Threadworms / Capillaria
These are thin worms that are found in the small intestine. They bury themselves in the inner lining of the intestine. Birds with Capillaria can have diarrhoea (sometimes with blood) or can vomit. Because of the damage to the mucosa caused by the Capillaria, the blood loss can also result in anaemia. The birds become pale and have very little energy.
Gapeworms (Syngamus trachea)
This worm nestles itself in the windpipe. It is most common in species of poultry and ducks. Young birds are most susceptible to this worm. Infection causes shortness of breath; the birds start breathing with an open beak and shake the head. If the inside of the windpipe is severely damaged, the blood that the animals shake out can appear around the beak. They can suffocate to death if the windpipe becomes blocked by infected dead tissue.
Diagnosing a worm infection is performed by means of an examination of the bird stool. The With the aid of a microscope parasite eggs can be identified. If animals have died, the worms can be seen directly in the intestines during an autopsy (or in the windpipe if it concerns gapeworms).
Worms can best be treated by using anti-worm medication specifically for birds. If the worms are killed, they can be seen in the stool.
In addition, it is very important to prevent further contamination. Birds have the best chance of avoiding infection if they do not come into contact with faecal material. Worm eggs also stay contagious for a long time in the ground or soil. Another good method to minimise the risk of contamination is to clean the bird enclosure regularly.
Lice cause itchiness and poor condition of the plumage. The lice nestle themselves on the feathers, with their eggs (nits) stuck to them.
Diagnosis can be made by closely examining the bird, if necessary a microscope can be used for more precise examination.
Scaly leg mite / Knemidokoptes
This type of mite mostly causes problems in budgerigars, which often results in a so-called 'scaly face'. The bird's beak can become very large and deformed, the skin surrounding the beak (eyes and nostrils) can become thick and irregular. In other parrot species, the symptoms are usually limited to the head. The skin becomes thick and flaky and scars can remain after the bird has healed.
With other bird species, such as chickens, it's the malformed legs that are most noticeable. Scaly grey lesions cause large flakes and the legs become thicker (scaly legs). Canaries can also have abnormalities on the legs as a result of infection. Large amounts of thickened skin build up, making it very difficult for the bird to walk.
If multiple birds are kept in the same enclosure, it is possible some birds are severely affected, while other show no signs of disease. One possibility is that certain inbred lines of birds are more susceptible than others.
It is also more common to see birds that show the symptoms after stressful periods.
The diagnosis is often made based on the clinical signs. The mite can also be seen under the microscope. The mite is too small to be detected with the naked eye.
Tracheal mites / Sternostoma tracheacolum
These occur in canaries, finches and parakeets. The mite lives in the windpipe (trachea) and the air sacs. Depending on the severity of the infestation, birds can become short of breath, cough or sneeze, or even die of suffocation if very severely infected.
In some cases, the mites can be seen in the windpipe by holding a bright source of light directly behind the bird's neck. The light shines through the tissue and the mites can be seen as small black dots at the level of the trachea. The eggs can also be identified when examining the faeces.
These usually cause few problems with the natural host. Problems start occurring when they infect a bird that has never been in contact with this mite before. Feather mites can also give problems when located on the skin, instead of the feathers, this is seen in cases of severe infestation. The birds start to itch and the quality of its feathers deteriorates.
Red mites / Dermanyssus gallinae
Are sometimes also known as chicken mite or poultry mite. These mites feed on blood and can cause anaemia with birds. During the day, the mites hide in the nooks and crannies of the enclosure. At night, when the birds are resting, they begin their attack. For this reason, diagnosis can't be made by examining the birds during the day. The mites can only be found on the birds at night and you can in fact see them with the naked eye.
Therapy against infections caused by insects
An antiparasitic medicine for birds can be used in treating insect infestation. One (or more) drops on the skin in the neck is often sufficient to rid the bird of parasites. In addition, the area the bird lives in must be treated. Using an effective anti-parasite spray is a proven method.
Flagellates (Trichomonas, Giardia, Hexamites)
Trichomonas: see trichomonas / canker
This parasite lives in the intestines. Birds do not necessarily show any symptoms. Infected birds excrete giardia parasite with their droppings. This means they can pass on the parasite to other birds. Birds showing signs of infection can have a rather smelly stool, slimy diarrhoea and can become very thin. Eventually, they can be very lethargic and stop eating. Because their physical condition deteriorates, it makes them susceptible to other diseases. If heavily infested, young birds can have poor growth or even die.
These parasites resemble Giardia, but are smaller. They also reside in the intestines. If infected, the bird can show mild diarrhoea that will not improve.
The parasite can be found in the intestines of healthy pigeons. They can cause problems if the pigeon becomes ill for another reason.
The active stage of the parasite can best be seen in a very fresh stool sample (Hexamites and Giardia) or a fresh crop smear (Trichomonas). The moving parasites can be seen under a microscope. Once the stool sample/smear has cooled down, the parasites stop moving and are difficult to recognise.
The dormant stage of the parasites can also be found in the faecal material. These are called cysts.
There are several anti-parasitic medicines available to treat birds that have these parasites. Unfortunately, resistance is a phenomenon that occurs more and more, especially in the case of Trichomonas. The medication can be given straight into the beak or crop, or it can be mixed into the drinking water.
Coccidia (Eimeria, Isospora, Atoxoplasma)
Eimeria and Isospora
A bird can be infected by these single-celled parasites without showing any symptoms. Other birds will have blood in the stool, listlessness, diarrhoea, will stop eating and, if severely infested, may even die.
Eimeria parasites are usually found in songbirds and the parrot family. Isospora parasites are mainly found in galliformes (fowl) and pigeons. It is a major cause of inflammatory bowel disease in these birds.
Animals become infected when ingesting water or feed that has been infected by faeces of other birds.
The dormant stage of the parasite (oocysts) can be seen in the stool under a microscope.
This can be done by giving the bird an anti-parasitic medicine in its drinking water or directly into the beak. It is also very important to prevent recontamination and to minimise the number of oocysts in the direct vicinity. The dormant stages of unicellular parasites (the oocysyts) are very resistant to most cleaning products. The surest way to kill as many cysts as possible is by using a high-pressure hose. Small parts of the cage or aviary, such as feeding trays and perches, can be put in boiling water for 15-30 minutes. This also kills the oocysts.