The Canadian Food Inspection Agency confirmed Tuesday the country's sixth case of mad cow disease and said it will investigate where the cow was born and what other animals may have eaten the same feed.

It is believed cows contract mad cow disease when they eat feed contaminated by the tissue of other cattle. Humans can get a related disease, variant Creutzfeldt-Jakob Disease, from eating meat contaminated with mad cow. Over 150 people infected with Creutzfeltd-Jakob worldwide have died from the disease.

The infected cow was at least 15 years old and was born before 1997 -- the year Canada banned the use of cattle parts in feed for cows.

The agency says the country's food supply is safe for consumption, and the number of cattle infected with mad cow disease in Canada is very low.