Questions and answers about the swine flu

What is the swine flu, how deadly is it and what can we do about it?

1. What is swine flu and why is it called that?

The Mexican flu virus was rather quickly - and incorrectly - given the name swine flu. The virus has never been found in pigs, and it is not certain if it can even infect pigs or make them sick. It is in fact a new type of the human influenza virus. The name swine flu was probably adopted to distinguish it from the avian flu or H5N1, which is a genuine bird flu virus.

There are many different strains of influenza and they are constantly mutating. Occasionally strains that usually infect only animals mutate enough to start infecting humans. This is what has happened here: a virus that normally infects pigs (hence the name "swine flu") has mutated in a way that allowed it to jump to humans and to then be infectious by person-to-person contact. Such a virus can be particularly dangerous to humans because it is new and we have not been able to build up resistance against it.

Influenza viruses are common among birds and to a lesser extent among pigs, humans and other mammals like horses and dogs. Viruses quickly adapt to their hosts. Influenza viruses tend to grow in cells in the mucous membrane in the throat and nose. The virus's genetic material hijacks the cell's normal RNA/DNA and tells the cell to create copies of the virus. Then the cell bursts, and hundreds of virus particles are released to repeat the cycle, giving the host a soar throat.

2. How deadly is the virus? How much more dangerous is it than the regular flu?

This is still largely unknown. Normally, a person's immune system kicks in and destroys the virus. Then it takes some time for the body to replace all the damaged cells. But if left unchecked the virus can kill so many cells so quickly that the infected person can die.

In Mexico, 159 deaths have been reported but the number of confirmed swine flu deaths has been downgraded from twenty to seven through stricter tests. In the US, the same virus caused only mild illness. It is possible that hundred of thousands of people in Mexico were infected with the virus but only developed a regular flu. And that the doctors only saw people who developed a pneumonia as a result of the virus. The question then is what the death ratio is: one in a thousand, ten thousand, a hundred thousand of a million people?

The Mexican flu virus is of the H1N1 variety, which has long been common among humans. Some experts think most people will have some kind of resistanceagainst this new strand of H1N1, which could mean that the pandemic is less serious than first expected.

3. Is there a vaccine? Does a face mask help?

There is no vaccine just yet. There are two medications, Tamiflu and Relenza, that reduce the flu somewhat if you take them early enough - as soon as you notice the first symptoms. This can kill the virus in less than a day. But the first symptoms are those of the common cold, which means that many people will miss them.

Massive distribution of the two medications among the population is not the answer either, because it will make the virus resistant against them. The Dutch government has bought nearly five million doses of the medications; they have been stored in secret locations to be used in case of an outbreak. Many people will want to buy their own, from a local pharmacy or the internet. They are prescription drugs.

Other measures are: stay away from infected people, stay home if you have the symptoms, and wash your hands often, especially if you've been sneezing. These simple measures are actually more effective than wearing a face mask. Face masks, as the Center for Disease Control and Prevention reports, are actually not very effective.

4. What happened with the last flu scare, the avian flu?

The avian flu still exists and still claims victims in Asia. Relatively few people are infected now, but if you are infected you have a fifty percent chance to die. The World Health Organisation has identified 421 people with the avian flu, 257 of whom died. The avian flu never succeeded in mutating to the point were it can be transmitted from human to human.