What is bird flu and how worried should I be about a pandemic?

Bird flu, also known as avian flu, is a disease caused by a virus that infects birds and sometimes other animals, such as foxes, seals, and otters. The major strain, H5N1, emerged in China in the late 1990s and has led to outbreaks in domestic and wild birds due to bird migration. While the virus has infected humans in very rare cases, the current risk to humans is considered low. Experts are monitoring its spread and studying how it is changing and evolving to assess the potential for triggering a pandemic. The recent rapid spread of H5N1 in dairy cow herds in the US has surprised scientists, who previously thought cows were not susceptible to it. This development comes amid another unusual occurrence where a 59-year-old man in the US was infected with a different strain of bird flu - H5N2 - which had never before been recorded in people. Health bodies such as the World Health Organization and the CDC consider the overall public health risk from bird flu to be low, but scientists emphasize the need to keep a close eye on the spread of the virus.