International Notes - Avian influenza, Thailand - Update

On 4 October 2004, the Ministry of Public Health in Thailand confirmed a further case of human infection with H5N1 avian influenza. The case, which was fatal, was a 9-year-old girl from the northern province of Phetchabun. She developed symptoms on 23 September, was hospitalized on 27 September, and died of severe respiratory disease on 3 October.

Investigation of the case has identified exposure to diseased chickens as the most likely cause of infection. Following the death of chickens in the child's household, she assisted in the preparation of the birds for cooking, including the plucking of feathers.

WHO stresses the importance of educating populations in affected countries, especially those living in remote rural areas, about the danger of contact with diseased birds.

Since the beginning of this year, Thailand has reported 16 laboratory-confirmed cases of H5N1 infection, of which 11 have been fatal. Four of these cases occurred during the past 5 weeks.

Two weeks ago, Thai officials announced a probable case of human-to-human transmission in a family cluster of cases. Analysis of specimens from this cluster is presently under way at a WHO collaborating laboratory to determine whether the virus has changed its genetic make-up. Heightened surveillance for further cases has provided no evidence that efficient and sustained human-to-human transmission is presently occurring in Thailand.

Source: WHO Weekly Epidemiological Record, Vol 79, No 42, 2004.