Thousands of birds, including quail, pigeons and chicken, have died in Hong Kong due to a flu caused by the H5N1 strain of avian influenza virus. The virus, that killed six people in 1997, has not affected any human beings till now (Read: Fowl play, Down To Earth, January 31, 1998). Local markets have been closed and all retail stalls are being disinfected. The carcasses are being disinfected, packed in bags and disposed in landfills. The process of slaughtering would take at least six weeks and cost more than us $10 million. The origin of the virus has not been found as yet, though it is suspected to have come from China, which is the main source for Hong Kong's poultry. China has denied the allegation, but it is willing to help Hong Kong to contain the outbreak. The poultry suppliers are also being compensated for losses. As a precautionary measure, Hong Kong plans to set up a central abattoir as a long-term solution against health hazards. The affected birds lose interest in food and die within a week. Though the same strain of virus cannot affect humans, mutations can occur in it and then it can be passed on to humans. Infected people show symptoms of pneumonia and inflammation of brain but can be cured if treatment is given during the early stages of infection.