Salmonella infections can be life-threatening, especially for infants, the frail or elderly, and persons with chronic disease, HIV infection, or persons taking chemotherapy. The most common manifestations of salmonellosis are diarrhea, abdominal cramps, and fever within eight to 72 hours. Additional symptoms may be chills, headache, nausea, and vomiting that can last up to seven days. Consumption of food contaminated with Listeria monocytogenes can cause listeriosis, an uncommon but potentially fatal disease. Healthy people rarely contract listeriosis.
Listeriosis can cause high fever, severe headache, neck stiffness, and nausea.