The issue of bird flu has been hitting the headlines worldwide recently, with worries that a dangerous strain may pose a risk to humans. But what is bird flu, how is it spread and should we be worried about it?

As the name suggests, bird or avian flu is a type of disease that affects birds.

There are 15 different types of bird flu in existence, but the most deadliest strains are H5 and H7.

It’s very contagious and spreads rapidly through flocks of birds, often proving fatal.

Bird flu can be carried from country to country by birds as they migrate.

It can be also be carried by live birds, or bird products such as meat or feathers, that are imported to different countries.

The only strain of bird flu that can be harmful to humans is H5N1. So far, it has only infected a few people in South East Asia, who were mostly vets and poultry workers. But it is very dangerous and (as of 20 October 2005) 61 out of the 118 people who’ve caught it have died.

The first human cases of bird flu occurred in Hong Kong in 1997.

The big worry is that, if the H5N1 strain mutates, it could spread rapidly from human to human and cause a global pandemic. If this happens, millions of people could lose their lives.

The Spanish Flu of 1918-9 jumped from birds to humans in a similar way and killed 50 million people.

Experts say that there might be a small risk of catching the disease if you’re travelling in rural areas of countries where the bird flu has already been reported. This includes parts of Vietnam, China, Thailand, Mongolia, Indonesia, Russia, Romania and Turkey.

As yet, there’s not a vaccine available to use against H5N1, but scientists are working hard at developing one. Some drugs, such as the antiviral medication, Tamiflu, are available and could help reduce symptoms and the spread of the disease.

In an attempt to stop the spread of the disease amongst flocks, some countries are culling millions of birds.