According to "Circular (2002) 74 Concerning the Issuance of Seven Major Technical Regulations on Prevention and Treatment of Animal Epidemics", which includes those for HPAI, promulgated by the Ministry of Agriculture, an occurrence of HPAI can be substantiated by the presence of:

1) typical clinical manifestations and pathological changes, sudden morbidity and high mortality with Newcastle disease and toxicopathic diseases eliminated from the diagnosis together with positive serological testing

2) positive serological tests for subtype H5 and H7 bird flu among poultry in a farm that has not been quarantined

3) strains of subtype H5 and H7 avian influenza or other subtype bird flu strains are extracted from the bird flocks.

(China.org.cn February 13, 2004)