In 2004, Laos, along with a number of other Southeast Asian countries, reported an outbreak of Avian influenza (bird flu). The strain in question, known as 'Influenza A HSNV or simply 'the H5N1 virus', was a highly contagious form of Avian influenza that has since spread as far as Turkey to the west. Throughout the region, government officials scrambled to contain the spread of the disease, which wreaks havoc with domesticated bird populations.

While the Avian influenza virus usually poses little risk to humans, there have been several recorded cases of the H5N1 virus spreading from birds to humans. Since 1997, there have been about 250 reported cases of human infection, with a fatality rate of about 30%. The main risk is to people who directly handle infected birds or come into contact with contaminated bird faeces or carcasses. Because heat kills the virus, there is no risk of infection from properly cooked poultry. In February 2007 Laos reported its first human case of the H5N1 virus, no other human cases have been reported since this book went to print.

There is no clear evidence that the H5N1 virus can be transmitted between humans. However, the main fear is that this highly adaptable virus may mutate and be passed between humans, perhaps leading to a worldwide influenza pandemic.

Thus far, however, infection rates are limited and the risk to travellers is low. Travellers to Laos should avoid contact with any birds and should ensure that any poultry is thoroughly cooked before consumption.