Since 23 August 2005, 21 additional outbreaks have been detected and now the number of infected farms is 31 in total.
The surveillance for all chicken farms holding over 1,000 chickens (excluding broiler farms) in Ibaraki prefecture was completed on 12 September.
Furthermore, surveillance conducted at the national level, targeting commercial poultry farms (excluding broiler farms) in each prefecture, is due to be completed on 22 September.
Ibaraki Prefecture was previously known as Hitachi Province, until the abolition of the han system in 1871.
Ibaraki Prefecture is the northeastern part of the Kanto region, stretching between Tochigi Prefecture and the Pacific Ocean and bounded on the north and south by Fukushima Prefecture and Chiba Prefecture.
The city of Mito and the town of Ibaraki from Higashiibaraki District are scheduled to merge between April 1, 2007 to March 31, 2008.