A six-year-old Holstein cow from the northern Japanese Island of Hokkaido was found to be the fourth cow in the country infected with BSE, after test results were revealed on Saturday by the health ministry.

The Japanese government responded to the news by narrowing the focus of its investigation for the source of the BSE infections, as all four cases were noted to be born in the March or April of 1996.

The tests were conducted at the Obihiro University of Agriculture and Veterinary Medicine, on the northern island of Hokkaido.

The news, and its expected impact on consumer confidence and demand for beef products, has dampened the hopes of countries such as Australia that they could promote imports of beef into Japan. Beef consumption in Japan has fallen by 50% since the discovery of the disease last September.