1 An average of 110 cases of botulism is reported annually in the US. 2  About twenty-five percent of these cases are foodborne botulism. 3  Mean age of infected people is 46 years, with a range from 3 to 78 years. 4  Men and women are affected equally. An average of 110 cases of botulism is reported annually in the US. 2  Over the past few years the number of cases of wound botulism has been between thirty and forty percent. 3  The median age of affected patients is 41 years with a range of 23-58 years.