Bird flu

Bird flu (avian influenza) is a viral disease that affects poultry and wild birds, and in its severe form it can wipe out an entire flock within a few days. The virus is most often spread by wild waterbirds. In Croatia bird flu is a notifiable disease, and sick or dead wild birds must not be touched with bare hands.

The cause is influenza A virus. There are two forms:

• low pathogenic avian influenza (LPAI) causes mild problems, such as reduced egg laying or milder respiratory signs, and often goes unnoticed;
• highly pathogenic avian influenza (HPAI) causes severe disease and sudden deaths, especially in chickens and turkeys.

Wild waterbirds such as ducks, geese, swans and gulls are natural carriers of the virus. Some of them carry the virus without visible signs and spread it during migration, which is why the disease most often occurs in autumn and winter.

The virus spreads:

• through the droppings and discharges of infected birds;
• through contaminated water, food and litter;
• via footwear, clothing, equipment and vehicles;
• through direct contact between domestic poultry and wild birds, for example at a shared pond or feeding site.

In poultry (highly pathogenic form):

• sudden deaths, often without any previous signs;
• marked lethargy and apathy, the bird does not eat and sits with ruffled feathers;
• a sudden drop in egg laying, eggs with thin shells or none at all;
• swollen head, eyes and wattles, a bluish or dark comb;
• redness and haemorrhages on the legs and skin;
• difficulty breathing, sneezing, coughing and discharge from the eyes;
• diarrhoea, green or bloody droppings, soiled feathers around the vent.

In wild birds, especially swans, ducks and geese:

• disorientation, circling, the bird does not flee from people;
• a twisted neck, head tremors, unsteady gait;
• inability to fly, drooping wings;
• cloudy eyes and poor sight.

The low pathogenic form may cause only mild respiratory signs and a small drop in egg laying, so it is hard to recognise without a laboratory test.

Inform a vet or the veterinary inspectorate immediately if you notice:

• sudden deaths of several birds in the flock within a short time;
• a sudden drop in egg laying together with lower food and water consumption;
• a swollen head and bluish comb in hens;
• difficulty breathing, bloody diarrhoea or neurological signs in several birds;
• several dead or obviously sick wild waterbirds or birds of prey in the same place.

Until the vet arrives, do not move the birds, do not give away or sell eggs or meat, and do not let visitors into the yard.

• Do not touch dead or sick wild birds with bare hands.
• Keep children, dogs and cats away, as mammals can also become infected.
• Note the exact location and the number of birds and, if you can, photograph them from a distance.
• Report the find to the veterinary service or the veterinary inspectorate, who will arrange safe collection and testing.
• Do not take a sick wild waterbird home on your own initiative; first call a vet or a wildlife rescue centre. Wild birds are protected in Croatia and may not be kept at home for long periods.
• If you have nevertheless been in contact with the bird, wash your hands with soap and clean your footwear and clothing before going near your own poultry.

Bird flu can only be confirmed in the laboratory, from swabs or samples from dead birds, which are taken and sent by the veterinary service. Newcastle disease, infectious coryza or poisoning can produce a similar picture, which is why testing is essential.

There is no treatment for bird flu in birds. When the disease is confirmed, the measures are decided by the competent authorities and may include euthanasia of the infected flock, cleaning and disinfection, and restrictions on the movement of poultry in the surrounding area. Do not try to treat the disease yourself with medicines or home remedies, as this only delays reporting and increases the risk of spread.

• Keep food and water under a roof, where wild birds cannot get to them.
• Do not let poultry onto lakes, ponds and streams visited by wild ducks and geese.
• When the authorities order measures, keep poultry indoors or under netting.
• Have separate footwear and clothing for working in the hen house.
• Limit visits and do not lend equipment to other breeders.
• Keep new birds separate before adding them to the flock.
• Monitor egg laying and food and water consumption; a sudden change is an early sign of disease.

Some subtypes of the bird flu virus can rarely infect humans, mainly after close contact with sick or dead poultry. Such infections can be severe, so caution is essential:

• do not touch sick or dead birds with bare hands; if you must, wear gloves and a protective mask;
• wash your hands thoroughly with soap after every contact with birds;
• do not sweep droppings dry – dampen them before cleaning so that no dust is raised;
• do not eat the meat or eggs of sick birds.

If within about ten days of contact with sick birds you develop a temperature, cough, muscle pain or red eyes, see a doctor and tell them you have been in contact with birds.

Bird flu is a severe and highly contagious disease for which there is no cure, so prevention and prompt reporting are the most important things. Do not touch dead wild birds, report them to the veterinary service and protect your poultry from contact with wild birds.