Avian influenza or avian flu is a viral disease that is prevalent worldwide. It predominantly affects birds or poultry. However, several hundred people have also been infected with avian influenza, especially in Asia.
What is bird flu?
Avian influenza is also known as avian influenza and has been known for over 100 years. Thereby, only a few but very pathogenic avian influenza viruses exist. Especially the viruses of the subtype Influenza A/H5N1 can cause severe damage in farm poultry. Many animals can die as a result of this infection. For this reason, this severe form of avian influenza in animals is also called avian influenza. If there is very close contact between infected animals and humans, there is also a possibility that humans may become infected.
Causes
The cause is based on a specific pathogen, namely the avian influenza virus. This belongs to the so-called influenza A viruses, which also occur in a normal person with flu viruses. The influenza A virus occurs in the H and N subtypes. Thus, the letters denote the proteins of the viral envelope hemagglutinin and neuraminidase. If influenza A viruses occur in a human, they usually belong to subtypes H1, H2, and H3. Often, subtypes H5 and H7 are responsible for outbreaks of avian influenza. Migratory birds, such as ducks, chickens and turkeys, are mainly affected. Much less frequently, pigs, horses, cats, or even humans become infected.
Symptoms, complaints and signs
Bird flu primarily affects chickens, turkeys and ducks. In the animals, the disease manifests itself in the form of fever, reluctance to eat, diarrhea and a black coloration of the comb. Through mutation, humans can also become infected with avian flu. The H5N1 and H7N9 viruses are particularly dangerous. In most cases, avian influenza is harmless in humans, but in some cases it can be severe. The incubation period is a few hours to several days. The first symptoms in humans occur in a flash and resemble flu. The affected person experiences a high fever and severe headache, sore throat and muscle pain. Coughing and shortness of breath also occur. Less commonly, the disease is initiated by nosebleeds or mucosal bleeding. As the disease progresses, avian influenza concentrates on the respiratory tract. Pneumonia and even respiratory failure are the result. An increase in liver enzymes can be observed in patients. The white and red blood cells decrease and anemia occurs. Furthermore, disturbances in kidney function occur and the patient suffers cardiac arrhythmias. Nearly half of all patients hospitalized with avian influenza die of respiratory failure. This can be attributed to the fact that it is a pathogen previously unknown to our defense system.
Diagnosis and course
Avian influenza manifests itself in humans by symptoms that also occur in severe influenza. The first sign is usually a high fever accompanied by coughing and shortness of breath. In addition, diarrhea may also occur. Rather rarely, abdominal pain, vomiting and nausea occur. Pain in the limbs, headache and sore throat, on the other hand, do not occur in all cases. In very severe cases, pneumonia may even develop. If avian influenza is suspected, the diagnosis is made by detecting the pathogen. Reliable test methods are available that can detect avian influenza viruses within a few hours. A throat or nasal swab and a coughed-up bronchial secretion can also serve as further material for tests. The suspicion of avian influenza arises when the person in question shows flu-like symptoms after contact with an already infected animal. The course of avian flu in a person can be very different. There may be no symptoms at all, mild cold symptoms to severe pneumonia. In this case, a fatal course of bird flu is also possible. Often, avian influenza takes a very severe course in humans. The simultaneous illness of a person from a normal flu and an avian flu can lead to a mixture as well as a change in the genetic material of the different viruses. This poses a high risk because these mixed viruses would be more easily transmissible from person to person than the avian flu viruses.Thus, an epidemic can be triggered in the further course.
Complications
Among the possible sequelae of avian influenza is the so-called cytokine storm (hypercytokinemia). This is a life-threatening immune system derailment. As a result, there is a feedback between immune cells and cytokines. The adaptive immune response fails and an overreaction of the defense system occurs. Thus, defense system cells such as macrophages or T-cells release substantial amounts of cytokines, resulting in pronounced inflammation. In the further course, severe pneumonia (influenza pneumonia) is imminent. Organ failure and acute lung failure are also conceivable. In such cases, the patient requires intensive medical therapy and artificial respiration. In the context of avian influenza, there is a risk of additional symptoms such as a lack of white blood cells, a lack of blood platelets (thrombocytopenia), septic shock or anemia (anemia). Some patients also experience renal insufficiency (kidney weakness). In extreme cases, the kidneys fail completely. Toxic shock is one of the most severe sequelae of avian influenza. The reason for this is the body’s much more radical defense reaction to bird flu viruses in contrast to ordinary flu viruses. In the worst case, multi-organ failure occurs, resulting in the death of the patient. In this case, death occurs either through lung failure or kidney failure. Bird flu is considered particularly dangerous when bird flu viruses and common flu viruses meet. Thus, these virus hybrids are more easily transmitted from one person to another.
When should you go to the doctor?
If general health deteriorates within a few hours or several days, this should be interpreted as a warning signal. There is a need for action, since a severe course of the disease is possible with avian flu. A physician is needed to clarify the cause of the condition and make a diagnosis. Headache, irregularity of the neck or discomfort of the muscles are the first signs of a present disease. If the affected person complains of sudden nosebleeds or disturbances of the mucous membranes, he should discuss the perceived changes with a physician. If there is impairment of respiratory activity, general malaise or a feeling of illness, clarification by a physician is advisable. An internal heaviness, sleep disturbances, diarrhea, abdominal pain, faintness or fatigue are other complaints that should be examined more closely by a physician. Coughing, sputum or sweating should also be examined by a physician. If shortness of breath, panic or anxiety occurs, immediate action should be taken. In an acute situation, an emergency physician should be alerted. To avoid complications and reduce further risks, the instructions of the emergency medical services should be implemented until the arrival of the physician. Because avian influenza is a highly contagious disease, people who have been in the immediate vicinity of an ill person should have their own health checked as a precaution.
Treatment and therapy
The therapy for avian influenza aims to ensure that the viruses are combated and the symptoms are alleviated. Appropriate virus-killing drugs are then used against the viruses. These are also known as antivirals. Painkillers and fever-reducing drugs are suitable for alleviating the symptoms.
Prevention
By avoiding all contact with infected animals, avian influenza can be prevented. However, the risk of infection is very low even with contact with infected animals. Worldwide, approximately 200 million animals have died from avian influenza. Only about 500 people have been infected with the virus. Despite the low risk, appropriate precautions should be observed. These include, above all, avoiding contact with infected animals. If contact is nevertheless made, care should be taken to ensure thorough hand hygiene. Furthermore, poultry and eggs should be cooked or fried for a long time. Heating at 70 degrees Celsius kills the viruses. The consumption of raw or half-cooked poultry meat should be avoided. Anyone who finds sick or dead wild birds should not touch them in any case, but inform the competent veterinary office.A normal flu vaccination does not help against the bird flu viruses. No vaccination against bird flu exists yet.
Follow-up
In most cases, those affected by bird flu are dependent on rapid and, above all, early treatment by a physician. In this context, the measures of an aftercare are usually significantly limited and almost not available to the affected person. Therefore, a doctor should be consulted already at the first symptoms and signs of this disease, so that no complications or other complaints can occur in the further course. As a rule, there is no self-cure for bird flu disease. The disease itself is usually treated by taking various medications. The affected person should pay attention to a regular intake and also to a correct dosage, in order to counteract the complaints correctly and permanently. If there are any uncertainties or questions, a doctor should be consulted first. Furthermore, bed rest is recommended to avoid unnecessary strain on the body. In some cases, therefore, the support and help of one’s family with this disease is also very important, which can also alleviate depression and other psychological upsets. With proper treatment, avian influenza does not reduce or otherwise limit the life expectancy of the affected individual.
Here’s what you can do yourself
If typical bird flu symptoms such as coughing, shortness of breath or malaise occur after contact with possibly sick animals, a physician should be consulted. The medical professional should be informed of the suspicion so that the necessary quarantine measures can be initiated. Patients who are ill with avian influenza must comply with the doctor’s instructions. Hospital treatment is usually required. After discharge, rest and bed rest apply. Symptoms such as fever and gastrointestinal discomfort may persist for several days. The usual general measures apply, such as a sparing diet, plenty of sleep and avoidance of stress. The physical warning signs must be observed. If in doubt, inform the doctor, as there is a risk of spreading the disease. Avian flu should be completely resolved after one to two weeks. Any residues of the H5N1 pathogen can be detected during the medical check-up. If the pathogen has been completely killed by medical treatment, no further action is necessary. The trigger of the disease should be identified so that other people are prevented from becoming infected. Accompanying measures must also be taken to involve the public health department and the epidemic protection authority.
