Which of the following is considered one of the big 5 associate illnesses?

Norovirus is recognized as one of the "big 5" associate illnesses primarily because of its highly contagious nature and its significant impact on food safety. This virus can cause severe gastroenteritis, leading to symptoms like vomiting and diarrhea, which can be easily transmitted in a food service environment. It poses a high risk of foodborne illness outbreaks, especially when infected food handlers prepare food for the public.

In contrast, the other options typically present lower hazards in food service settings. Sore throat, seasonal flu, and headache may hinder an employee's ability to work but do not have the same level of direct transmission risk associated with food handling that norovirus does. Understanding these distinctions is crucial for maintaining food safety and public health standards in the workplace, especially in the context of food handling and service.