How dangerous is bird flu for humans?
The symptoms of avian influenza in humans were generally relatively similar to that of ordinary flu in the case of the infections previously detected, but they were often significantly more severe and those affected were more prone to complications, such as pneumonia. Avian flu, caused by certain influenza viruses, is usually only a danger to birds. In the past, however, influenza viruses have passed from birds to humans several times and have caused serious, often fatal infections.
Transmission of bird flu to humans
Avian influenza that has been shown to have infected humans includes the influenza virus of the H5N1 subtype, the highly pathogenic Asian variant of which was first detected in China in 2003 and which experts have estimated has infected millions of people worldwide since then. Later on, a human-pathogenic variant of the bird flu virus H7N9 appeared in China, which claimed the lives of several people within a short period of time. It has not yet been conclusively clarified whether this variant can be transmitted from person to person. Many of the infected had close contact with poultry, but this does not apply to all patients. The development of a bird flu virus that can be transmitted from person to person is one of the most feared scenarios among epidemiologists worldwide.
Flu-like symptoms at the beginning of bird flu
The World Health Organization (WHO) assumes a relatively high death rate for both H5N1 infections and H7N9 infections, although possible statistical biases should be considered here, since as a rule only infections with an already severe course are recorded. Logically, many of these subsequently end up being particularly lethal. The typical symptoms of avian flu initially resemble those of conventional flu and usually include high fever, cough, sore throat and occasional shortness of breath. In rare cases, those affected also suffer from diarrhea, abdominal pain, nausea and vomiting. According to the WHO, the first signs of the disease can be seen in an H5N1 infection after two to eight days of incubation. Under certain circumstances, however, it can take more than two weeks between contact with the viruses and the appearance of the first symptoms.
Severe course of bird flu disease
As the disease progresses, those infected with avian flu often develop further symptoms such as conjunctivitis, pneumonia, a deficiency in white blood cells, a condition known as anemia (anemia) or thrombocytopenia (lack of platelets in the blood). The kidneys of those affected are sometimes affected and they suffer from renal insufficiency - in the worst case, up to kidney failure. Pneumonia can also lead to acute lung failure. Since the bird flu pathogens cause a significantly more drastic defense reaction of the organism than conventional flu viruses, a relatively large number of infected people experience a so-called toxic shock. In the end, bird flu disease often results in fatal multi-organ failure. This can be initiated by kidney failure as well as thrombocytopenia or lung failure. (fp)
Author and source information
This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.
Dipl. Geogr. Fabian Peters
- Craig R. Pringle: Avian Influenza, MSD Manual, (accessed October 8, 2019), MSD
- Bernhard R. Ruf et al .: Human and avian influenza - "bird flu", Dtsch Arztebl 2005; 102 (47): A-3254 / B-2749 / C-2570, (accessed October 8, 2019), aerzteblatt.de
- Walter Haas: Influenza, Urban & Fischer Verlag / Elsevier GmbH, 2009
ICD-Codes for this illness: J10, U69.21! ICD-Codes are internationally valid encodings for medical diagnoses. You can find yourself e.g. in doctor's letters or on disability certificates.