Both rats and mice carry a number of potentially dangerous diseases, viruses and parasites. These cause a range of illnesses many of which can have serious consequences, most commonly food poisoning.

• Hantavirus pulmonary syndrome (HPS) is a deadly disease transmitted by infected rodents through urine, droppings, or saliva. Humans can contract the disease when they inhale aerosolized virus.
• Murine typhus occurs worldwide and is transmitted to humans by the bite of rat fleas.
• Rat-bite fever (RBF) is a systemic bacterial illness caused by Streptobacillus moniliformis that can be acquired through the bite or scratch of a rodent or the ingestion of food or water contaminated with rat feces.
• Salmonella causes a typhoid-like disease in mice. In humans S. Typhimurium causes severe disease. The disease is characterized by diarrhea, abdominal cramps, vomiting and nausea, and generally lasts up to 7 days.
• Leptospirosis is a bacterial disease that affects humans and animals. Humans become infected through contact with water, food, or soil containing urine from these infected animals.
• Eosinophilic meningitis is an infection of the brain. In a complex life cycle between rats, slugs and snails, humans become infected by accident when they eat an infected snail or food that has been contaminated by slugs or snails, particularly salads.