avian Flu

Avian flu: description

Experts actually understand avian flu to be an animal disease caused by avian influenza viruses. She is also called avian influenza or avian Influenza usually refers to chickens, turkeys, ducks but also wild birds, which they bring into the fattening farms.

It is caused by influenza A viruses. Avian flu is not actually infectious for humans. some forms do not seem to jump on humans at all, with others a contagion is possible in close contact with poultry. To date, around 1000 cases of bird flu in humans are known worldwide – most of them in Asia. Of these, however, depending on the pathogen, between 20 and 50 percent of the infected died.

In the headlines of the last years occurred in this context increasingly names such as H7N9, H5N1 or H7N2 on. This designates the triggering virus type in more detail. For influenza viruses carry certain proteins on their surface, which are characteristic of them.

These include hemagglutinase (short H) and neuraminidase (short N). These proteins can damage the organism they are infecting. So far, 16 different hemagglutinases and 9 different neuraminidases are known. After the composition of the proteins that form the viruses on their shell, they are also named.

In the bird flu subtypes experts distinguish whether they cause severe diseases in the affected birds (highly pathogenic) and or only mild symptoms cause (low pathogenic). For example, the types are harmless for humans H5N8 and H5N3, So far no diseases of humans are known on this type.

Avian flu: symptoms

If a person becomes ill with avian influenza, they will suddenly experience the following symptoms two to five days after the infection. They are mostly flu-like:

• high fever
• to cough
• difficulty in breathing
• Sore throat

In about half of the cases, patients complain of complaints of the gastrointestinal tract. These include:

• diarrhea
• stomach pain
• Vomit

Since the avian influenza viruses mainly affect the respiratory tract, it can lead to a severe pneumonia (Pneumonia), which in many cases leads to death. Often, this is a secondary infection with bacteria that exploit the body’s immune system to be weakened. The patients suffer from severe respiratory distress. In some cases, they cough up blood.

Avian influenza: causes and risk factors

Avian influenza occurs in humans when influenza viruses, which otherwise only infect poultry, are transmitted to humans. Mostly it is very close contact necessary to the animals. In many cases, it is known that patients live closely with their livestock. Actually, the highly pathogenic avian influenza viruses are not well adapted to the conditions in the human organism.

In an infection, the viruses attach mainly to superficial cells of the respiratory tract, the epithelia. These epithelia are different in humans and birds. Therefore, not every contact with the virus leads to the disease. Especially the types H7N9 and H5N1 have been transferred to humans in the past. In these cases, it can not be ruled out in individual cases that the infection has spread from person to person.

In order to minimize the risk of infection, usually the entire bird population of a poultry farm is killed as a precaution when a sick animal was discovered.

Avian influenza virus H5N1

For the first time in the 1990s, H5N1 infected people, especially in Southeast Asia and Egypt. To date, more than 668 cases are known worldwide, 393 of them died (as of October 2014). Current figures are published regularly by the World Health Organization. In Germany, no case occurred. So far, it is still unclear why exactly this virus subtype is so fatal to humans.

The major bird flu epidemic that began in Korea in mid-December 2003 was triggered by subgroup H5N1. WHO experts considered this virus very dangerous. Because it can change very quickly because it can take genes of other pathogens into its genome and thus develops new properties. So far, however, the virus has not changed so much that it can be transmitted from person to person.

Avian influenza virus H7N9

Mainly in China, H7N9 affected humans as a new subtype of bird flu. In 2013, the first cases became known here. There are 450 confirmed cases, of which 165 died (as of October 2014). The average age of onset was 58, with more men than women infected with this bird flu. China precautionarily culled a large number of birds in this context.

Furthermore, individual cases are known in which people are affected by the virus-influenza subtypes H5N6, H7N2 and H3N2.

disease risk

Germany is so far free from bird flu in humans. Due to the globalization and the many journeys that people make today, however, there is a risk that bird flu viruses are introduced to Germany. Basically, the following groups of persons are considered endangered:

• People who work in the poultry or meat processing industry
• Veterinarians and employees of special laboratories
• Normal population, when handling dead wild birds or when poultry is not properly cooked before eating
• As with the “normal” flu, the elderly, the chronically ill and pregnant women

Theoretically, there is the possibility that a human is contemporaneously infected with a “normal” flu virus and an avian influenza virus. The viruses sometimes exchange their genetic material with each other. So it could happen that the avian influenza virus can adapt better to humans through an exchange of genetic information. This would create a highly contagious, highly dangerous bird flu virus. So far there are no indications that this scenario has already taken place.

Avian flu: examinations and diagnosis

To diagnose bird flu, your doctor will first ask you about yours medical history (Anamnese). He asks you under other questions:

• Have you been on vacation lately?
• Did you touch wild birds?
• Did you come into contact with raw poultry meat?
• Since when do you feel sick?
• Did the symptoms come on suddenly?
• Do you suffer from shortness of breath?

He then examines you physically, He listens to lungs and abdomen, measures your temperature and looks at your throat.

To prove an avian influenza disease, the patient may take a nasal or throat swab. This is then examined in a laboratory for the genetic material of the pathogen.

Avian flu: treatment

If bird flu is suspected, the patient is first isolated to prevent possible transmission to other people and hence spread. The medicines that are directed against the flu viruses (antiviral drugs) are only effective within a short time after infection. Neuraminidase inhibitors are used, for example zanamivir or oseltamivir. They prevent the viruses from spreading in the body.

If the infection is too long ago, the bird flu can be exclusively treated symptomatically become. This means that one tries to relieve the symptoms. The cause itself, in this case the bird flu viruses, you can not fight directly. The symptomatic treatment of bird flu includes:

• adequate fluid and salt intake
• oxygenation
• antipyretic measures (for example administration of paracetamol, calf wrap)

Children should not be given acetylsalicylic acid for the purpose of reducing their temperature because it can lead to a life-threatening illness, the Reye syndrome, in connection with the bird flu virus.

It is possible that bacteria cause additional pneumonia, as the body’s defense system is severely weakened by bird flu. In this case, antibiotics which are exclusively effective against bacteria are used for the treatment. These include the antibiotic classes beta-lactamase inhibitors, cephalosporins and macrolides.

Avian Influenza: Prevention

It is still very unlikely that you will be infected with bird flu. Basically, however, applies to the bird flu as well as other diseases: To prevent it, the contact with the pathogen should be avoided. For this applies:

• Do not touch sick and dead wild birds (especially water or migratory birds), inform the authorities (veterinary office, municipality, district).
• Roast or cook poultry meat and eggs; the virus dies quickly on heat, but it survives at low temperatures in the freezer.
• Wash hands after handling raw poultry meat (e.g., while cooking)
• In holiday destinations where acute infections are known, do not record live birds or areas that the animals were in contact with.

Already suspected bird flu disease is notifiableso that disease control measures can be taken in good time and prevent their spread.

The vaccine, which is offered annually against the “normal” flu, does not protect against bird flu. Nevertheless, it is advisable that people who belong to the endangered groups of people (such as poultry breeders) be vaccinated against the flu. This prevents the “normal” and the bird flu virus from simultaneously infecting the same human and exchanging their genetic material. In this way, you protect yourself and your fellow human beings from the development of a highly dangerous bird flu virus.

Avian influenza: disease course and prognosis

The time after infection with the bird flu virus and the onset of the disease (incubation period) is two to five days on average. It can also take up to 14 days. Then suddenly appear flu-like symptoms. Avian influenza patients often develop pneumonia during the course of the disease.

This can be so severe that patients die from respiratory failure. On average, six days after the onset of the disease, there is severe respiratory distress. More than half of the patients die from the disease, usually between the ninth and tenth day after the first bird flu symptoms appear. In the 1990s, the disease was more often fatal in older people, while at the end of the 1990s the disease was more severe avian Flu 2013 many children died.