Parasitic diseases

Parasites are among the most common health problems in birds, both pet and wild. They are divided into internal parasites, which live in the digestive tract and other organs, and external parasites, which live on the skin, in the feathers or in the bird's surroundings. Many birds carry a few parasites without signs of disease, but in young, weakened or overcrowded birds parasites can cause serious illness.

Nematodes (roundworms and hairworms) are common in poultry, pigeons and parrots that spend time on the ground or in aviaries. A bird becomes infected by swallowing eggs from droppings, soil or litter.

Tapeworms are transmitted via intermediate hosts such as insects, snails or earthworms, so they are more common in birds that eat these.

Signs of intestinal parasites:

• weight loss despite a good appetite, and later loss of appetite;
• diarrhoea and untidy feathers;
• lethargy and weakness, stunted growth in young birds;
• sometimes visible worms or tapeworm segments in the droppings.

With a heavy infestation, roundworms can block the intestine, which is life-threatening.

Trichomoniasis, which pigeon fanciers call “canker”, is caused by the single-celled parasite Trichomonas gallinae. It affects pigeons and doves, and in recent years also wild finches, especially greenfinches and chaffinches. It is transmitted through water and food and when parents feed their young crop milk, so it spreads easily at garden feeders and bird baths. Birds of prey can become infected by eating sick birds.

Signs of trichomoniasis:

• yellowish, cheesy deposits in the beak and throat;
• difficulty swallowing – the bird picks up food and drops it;
• saliva or wet feathers around the beak;
• difficulty breathing when the deposits narrow the airway;
• ruffled feathers, weakness and weight loss.

Giardia is an intestinal parasite found more often in cockatiels and budgerigars. It can cause diarrhoea, loose, foul-smelling droppings and weight loss, and in cockatiels it is also linked to dry skin and scratching.

The red poultry mite (Dermanyssus gallinae) hides by day in cracks in cages, nests and hen houses, and comes out at night to suck blood. You will hardly ever see it on the bird during the day. Signs: birds are restless at night, do not want to go into the nest, are pale and weak, and a heavy infestation can cause anaemia and the death of the young. You can detect the mites at night with a torch or with a white cloth draped over the cage.

Lice live in the plumage and feed on parts of the feathers. They cause itching, restlessness, damaged and ruffled feathers and increased feather loss.

Scaly face and leg mites (Knemidocoptes) burrow into the skin. In budgerigars they cause greyish, spongy crusts on the cere, beak, around the eyes and on the legs. Over time the beak can become deformed. In chickens a related mite causes thickened, scaly legs.

External parasites generally cause excessive scratching and feather plucking, skin changes, scabs and restlessness, and the bird can injure itself.

• the bird cannot swallow food or has yellow deposits in its beak;
• it has difficulty breathing or breathes with its beak open;
• it is very pale, weak or sitting on the cage floor;
• it has seizures, is trembling or losing its balance;
• it is losing weight quickly or has not eaten for more than a day;
• crusts are deforming the beak or the bird is bleeding from self-injury;
• several birds in the flock are dying.

The vet examines the droppings under a microscope, takes a swab from the beak if trichomoniasis is suspected, and a skin scraping for skin changes. Bring a fresh droppings sample.

Treatment depends on the type of parasite and is always decided by the vet. Antiparasitic drugs are used against intestinal worms, for example fenbendazole, and praziquantel against tapeworms. Trichomoniasis and giardia are treated with drugs from the nitroimidazole group. For mites and lice the vet prescribes products that are safe for birds, and with red mite the whole area must also be treated.

Do not use products for dogs and cats or shop-bought insecticides without a vet's advice. Small birds are very sensitive and the dose must be precise.

• Separate the sick bird and place it in a warm, dark and quiet place.
• Do not force-feed it or pour water into its beak.
• Clean cages, perches and nests regularly and wash them with hot water, paying special attention to cracks.
• Wash drinkers and feeders every day and make sure droppings do not fall into them.
• Keep new birds in quarantine and have their droppings and feathers checked.
• If you see sick finches or pigeons at a garden feeder, remove the feeders and bird baths for a few weeks, clean them and only then put them back.

Hand over a sick wild bird to a rescue centre or a vet. Wild birds are protected in Croatia and may not be kept at home for long periods.

Most bird parasites are adapted to birds. The red poultry mite can, however, also bite people and cause itching and small red spots on the skin, especially in people who clean infested hen houses. Wear gloves when working with sick birds and droppings, do not raise dust from droppings, and wash your hands thoroughly afterwards.

Parasites are a common but mostly curable problem in birds. Weight loss, diarrhoea, yellow deposits in the beak, scratching and crusts are reasons to see a vet, who will determine which parasite is involved. A clean, dry environment, quarantine and regular washing of feeders are the best protection.