Bird flu

Bird flu is a disease of birds caused by influenza A viruses. They are poorly suited to people: the receptors the virus latches on to in a bird's airways and gut sit, in us, deep in the lungs rather than in the nose and throat. That is why human infection is rare, and why it almost always comes down to the same scene — close contact with a live or dead bird, with its droppings, or with dust from a poultry shed. In those who do fall ill, though, the illness is often more severe than seasonal flu.

How the virus reaches people

In birds the virus multiplies both in the airways and in the gut, so droppings carry enormous amounts of it. Droppings, saliva, feathers and dust from the bedding are all infectious, not just the bird itself.

The situations in which people have most often been infected:

• keeping backyard poultry and cleaning the coop without gloves or a mask;
• slaughtering, plucking and jointing birds at home;
• markets where birds are sold alive and killed on the spot;
• picking up a dead wild bird with bare hands — gulls, ducks, swans, birds of prey;
• working on a poultry farm during an outbreak in the flock.

Since 2024 one more route has been added. H5N1 has established itself in dairy cattle, and some human infections now come not from birds but from work on dairy farms and from raw, unpasteurised milk. In most of those people the illness went no further than an inflamed eye.

Bird flu passes poorly from person to person. Isolated cases have been described within families, in people who nursed a severely ill relative without protection, but sustained chains of transmission have not developed. That is exactly what virologists watch most closely: if the virus learned to spread between people, the picture would change.

Cooked food is not a danger: ordinary cooking kills the virus. The risk lies in handling a raw carcass and in undercooked eggs.

How the illness starts

Two to five days usually pass between contact and the first signs, sometimes a little over a week. The onset resembles a heavy seasonal flu: the temperature climbs sharply, muscles and joints ache, the head hurts, a dry cough and a sore throat appear.

Two features set bird flu apart from ordinary flu.

• The eyes. Redness, stinging, watering, swollen lids. With some variants of the virus — including those that have affected dairy farm workers — this is the only sign at all, with no fever and no cough.
• The abdomen. Diarrhoea, nausea, vomiting, stomach pain. In children the digestive complaints sometimes come before the cough and blocked nose, and the illness is first taken for a gut infection.

Severe illness usually develops on the third to fifth day: breathlessness builds, breathing quickens, the oxygen level in the blood falls, and imaging shows pneumonia in both lungs. Less often the virus involves the nervous system, bringing confusion or seizures.

Of the H5N1 cases recorded over the past twenty years, roughly half ended in death. The figure is frightening, but it needs reading correctly: the statistics mostly captured people who reached hospital, that is, the most severe ones. Mild cases — such as that isolated red eye — went uncounted for a long time.

When it cannot wait until morning

Call the emergency number — 112 across Europe — if the ill person has:

• severe breathlessness, not enough breath for a whole sentence, noisy or wheezy breathing;
• blue or grey lips, face or fingertips;
• pressure or pain in the chest;
• confusion, cannot be roused, seizures;
• in a child, the ribs and the hollow above the breastbone drawing in with each breath, refusal to drink, floppiness, several hours without passing urine.

There is a separate reason to contact a doctor the same day, without waiting for things to worsen: any fever, cough or red eye appearing within ten days of contact with a sick or dead bird, of work on a dairy farm, or of drinking raw milk. Even if you feel reasonably well.

Why the doctor must be told about the bird

The usual rapid flu test will either come back negative or simply say "influenza A", without telling the variants apart. Bird flu is confirmed by a laboratory PCR test that identifies the subtype, and where there is pneumonia a sample from the lower airways is more informative than a nose swab. That test is not done for everyone — it is requested when the doctor knows there has been contact with birds or cattle. If you do not mention it, you will most likely be treated as a case of ordinary flu.

While the result is awaited, the person is asked to stay at home apart from the rest of the household or, if seriously unwell, is admitted to a single room. Those who were nearby are monitored for about ten days and asked to take their temperature. The answer usually comes back within a day or two.

What the treatment is

Antiviral medicines from the neuraminidase inhibitor group work. With them timing is everything: the greatest benefit comes from starting within the first forty-eight hours of symptoms, so where suspicion is well founded treatment is sometimes begun without waiting for the laboratory. In severe illness they are given later as well, because there is still something to gain.

Antibiotics do nothing against the virus itself. They are added only when a bacterial pneumonia has settled on top of the viral one, and that is the doctor's call, based on tests and imaging.

Severely ill people need hospital care: oxygen and, at times, mechanical ventilation. At home the usual support remains — fluids, rest, something to bring the fever down. Children and teenagers with flu are not given aspirin, because of its link with rare but dangerous damage to the liver and brain.

People in the household may be offered a short preventive course of the same antiviral. A specialist prescribes it; there is no need to work out a dose yourself.

What genuinely lowers the risk

• do not handle a dead or visibly sick wild bird; if you find several dead birds, report it to the veterinary service;
• keep children, dogs and cats away from such finds;
• wash your hands with soap and water after any contact with birds, eggs, feed or surfaces in the coop;
• keep a separate board and knife for raw poultry and wash them in hot water with detergent;
• cook poultry right through, until the juices run clear, and eggs until the white and yolk are firm;
• do not drink raw milk or eat cheeses made from unpasteurised milk of unknown origin;
• when travelling, stay away from live bird markets and farms;
• if you keep birds yourself: gloves, a close-fitting mask, and clothes and footwear used only in the yard;
• have the seasonal flu vaccine. It does not protect against bird flu, but it lowers the chance of catching two flu viruses at once, and it is precisely that overlap which lets viruses swap genes.

Online consultation

An online appointment fits the situation where contact with birds or raw milk has happened and the signs are still unclear. The doctor goes through what exactly happened and when, judges whether the symptoms fit the incubation period, says whether it is worth pressing for a test that identifies the virus subtype and how to put that at a face-to-face visit, and explains how to isolate at home and what to watch for in the rest of the family. If the account shows that breathing is already affected, the doctor will say so plainly: call for emergency help rather than wait for an appointment.

This material is for information only and does not replace medical advice.