The virus that causes the flu may look pretty under a microscope, but it is dangerous. That's why you know it's there when you come down with a fever that causes cold chills, body aches and a cough. But the virus is little more than a protein coat and a small strand of genetic material.
Not every flu-like infection is the flu. Strictly speaking, the flu only comes from certain viruses, be it Type A or Type B influenza. The Rhinovirus is usually responsible for the common cold. That infection is harmless when compared to influenza.
Flu viruses like the cold, and that's why the flu season is always in winter. In January, a violent flu virus circulated the US, especially New York. So experts from the Robert Koch Institute also fear the 2012 flu season will be worse than last year's in Germany.
The Spanish flu (1918-1920) killed more than 25 million people - many aged between 20 and 40 years. Normally, newborns and the elderly are affected when it comes to flu strains. Many die of pneumonia. Those affected often suffer from a deadly cerebral bacteria and myocardial inflammation.
When it comes to the flu virus, doctors usually fight symptoms with prescription medication: cough and pain medication, and antipyretics, which reduce fever and allow patients to sleep. In severe cases, doctors are able to prescribe antiviral drugs to stop the virus from reproducing in the body.
Tamiflu, made by Swiss pharmaceutical Roche, is an antiviral drug used to fight influenza. Many German states hoard large amounts of the expensive drug, in case of a flu outbreak. But most of the drugs expire and have to be disposed of. The drug's effectiveness has been brought into question - Roche has been keeping the results from clinical trials secret.
You can be vaccinated against the flu, but the virus that causes it mutates rapidly, so there are new strains every year. So a new vaccine has to be developed - under strict sterile conditions. It is made up of inactive virus particles of the three virus strains that are particularly prevalent that year.
Some vaccine manufacturers use fertilized chicken eggs to replicate the virus. Because flu viruses also infect birds, incubated eggs act as a replacement for birds. The vaccination is extracted from the developing chicken embryo. One egg is enough for about one dose of a vaccine.
When the influenza virus affects birds, such as Avian flu, the epidemic must be registered with the authorities. This influenza type is known as the H5N1 flu virus, commonly called bird flu. The virus is transmitted between birds, but can sometines infect humans.
Under current German law, an outbreak of avian flu would mean all the birds would be killed. The H5N1 virus, which becomes stronger when it is passed between humans, could cause a flu pandemic. It is thought to be a new variant of the virus.
The flu virus also infects pigs, as a respiratory disease. A specific virus subtype, H1N1 infects many mammal species, including humans. An H1N1 virus was responsible for the Spanish flu. In 2009, there was another swine flu outbreak.
In 2009, swine flu spread from Mexico and the US to more than 200 countries. People were especially affected in South Asia, East Africa and South America. According to the World Health Organization, more than 18,000 people died as a result of the swine flu pandemic.
Hand washing is the best way to prevent colds. Above all, you shouldn't touch your eyes or nose with unwashed hands - that's how you infect yourself with with the flu virus.
The flu isn't a dangerous viral illness. What helps to fight it. How are vaccines made? And what is the difference between bird flu and swine flu?