This is the VOA Special English Agriculture Report.

In late May, Canada reported that one cow in the province of Alberta had been infected with a deadly disease that can infect humans. It is called bovine spongiform encephalopathy, or B-S-E. The media often call it "mad cow disease."

B-S-E affects the brain and nervous system of cattle. A form of the disease, Cruetzfeldt-Jakob disease, infects people. Currently, Canadian officials are investigating the incident. It is only the second case of B-S-E in Canada. The first was in1993.

B-S-E was first observed in Britain in1986. It spread to other countries in Europe. Millions of cattle were destroyed because of the disease. Cruetzfeldt-Jakob disease is believed to have killed more than one hundred people in Europe. The victims may have eaten infected meat.

B-S-E is cause by a protein called a prion. The protein is made by a gene. However, sometimes the gene produces a deformed kind of prion. This deformed protein appears to be infectious. The disease-causing prions can spread when an animal eats the infected tissue of another animal. The brain or nervous system becomes infected. It may take two to eight years for the disease to appear, but the result is always death. Expert say the best way to prevent B-S-E is to keep animal parts out of farm animal food.

The infected cow had been killed January thirty-first. Someone thought it looked sick. Officials said the cow was not processed as food for people. Its head was taken for tests.

Months later tissue from the cow was sent to Britain for more testing. B-S-E was then found. The Canadian government announced the findings on May twentieth.

Meat from the cow had been used to make pet food for dogs. Officials have ordered a recall of that pet food. Also, cattle on a total of seventeen farms are being observed. Already, more than one-hundred cattle have been destroyed and tested. Hundreds more may be killed.

The effects of B-S-E on the cattle industry can be severe. The United States, Japan and other countries have all banned Canadian beef. Canada is the world's tenth largest beef producer. Economic affects do not stop at the border of a country where B-S-E appears. The stocks of companies that use beef also lose value. This can affect investors in many countries.

This VOA Special English Agriculture Report was written by Mario Ritter.