Diseases spread by rats: the risks and how to stay safe

Rats are more than an unpleasant thing to find in the garden or the loft. They can carry bacteria that cause illness in people, mostly through their urine and droppings. Serious infections are uncommon in the UK, but the risk is real enough to take sensible precautions and to deal with rats promptly.

01How rats spread disease

The brown rat lives close to people and moves between drains, bins, compost heaps and buildings. As it goes, it leaves urine and droppings behind. People are usually exposed in one of these ways:

• through cuts, grazes or the eyes, nose and mouth, after contact with rat urine or water and soil contaminated by it
• by eating food, or using surfaces or utensils, that rats have contaminated
• through a bite or scratch, or by handling a live or dead rat

Rats can also carry fleas, mites and ticks, which bring problems of their own.

02Leptospirosis and Weil's disease

Leptospirosis is a bacterial infection spread mainly through the urine of infected animals, and rats are one of the most common sources. It enters the body through cuts and broken skin or through the eyes, nose and mouth, often after contact with contaminated water, such as rivers, canals, flood water or standing water in drains.

Many people have mild flu-like symptoms or none at all. Common symptoms include a high temperature, headache, chills, aching muscles, feeling or being sick, red eyes and loss of appetite. In a small number of people it becomes more serious. The severe form is known as Weil's disease, and it can affect the liver, kidneys and lungs. Warning signs include yellowing of the skin or the whites of the eyes (jaundice), swollen ankles, feet or hands, chest pain, shortness of breath and coughing up blood. These need urgent medical attention.

Leptospirosis is rare in the UK, but it is treatable with antibiotics, so early diagnosis matters.

03Salmonella

Salmonella bacteria can be carried in rat droppings. People catch it by eating food or drinking water that has been contaminated, or from contaminated kitchen surfaces. It causes food poisoning: diarrhoea, stomach cramps, fever, nausea and vomiting, usually starting within a few days. Most people recover at home with rest and plenty of fluids, but it can be more serious for babies, older people, pregnant women and anyone with a weakened immune system. This is why droppings in a kitchen or food cupboard always mean throwing away anything that may have been touched and disinfecting the area.

04Rat-bite fever

Rat-bite fever is a bacterial infection usually passed on by a bite or scratch from an infected rat, or by handling one. Less often, it comes from food or water contaminated by rats. It is rare, but it can be serious if it is not treated. Symptoms can include fever, headache, vomiting, muscle and joint pain or swelling, and a rash, and the bite wound may become swollen or ulcerated. Anyone bitten by a rat, wild or pet, should clean the wound well and get medical advice.

05Other infections

Rats can carry other organisms too, including listeria and, much more rarely in the UK, hantavirus. The precautions are the same: avoid contact with rats, their droppings and their urine, and keep them away from food.

06How to protect yourself

• Do not handle rats, live or dead, with bare hands.
• Cover cuts and grazes with waterproof plasters before gardening, clearing out sheds or working near drains and water.
• Wear gloves when cleaning areas rats have used, and never sweep or vacuum droppings dry. Dampen them with disinfectant first. Our clean-up guide explains how.
• Wash your hands after being outdoors, handling bins or compost, or touching anything rats may have reached.
• Protect food. Store it in sealed containers and throw away anything rats may have got into.
• If you feel unwell after contact with rats or water they may have contaminated, see your GP or call NHS 111 and mention the contact.