A new norovirus strain is spreading throughout the UK as cases have increased by 16 per cent in just two weeks.

According to the UK Health Security Agency (UKHSA), 70 per cent of all cases are caused by a Japanese strain called Kawasaki.

The most recent data suggests there were 447 lab-confirmed cases in the final two weeks of October, which is 16 per cent more than in the two weeks prior. Hospitalized norovirus cases are 26 per cent higher than the five-year norm.

Only lab-confirmed cases are included in the figures; many more people may be infected with the virus but have not been tested.

To prevent the virus from spreading, patients with norovirus are admitted to separate rooms in hospitals.

The GII.17 strain was named Kawasaki after the city where it was initially discovered. The combination of the new strain and the cold weather have been blamed by the UKHSA for the spike across the country.

Gauri Godbole, deputy director of gastrointestinal infections at the UKHSA, said: “If you have diarrhoea and vomiting, do not return to work, school or nursery until 48 hours after your symptoms have stopped and don’t prepare food for others in that time either.

“If you are unwell, avoid visiting people in hospitals and care homes to prevent passing on the infection in these settings.”

Here is everything we know about norovirus, including its transmission, symptoms, and treatment.

The norovirus bug causes inflammation of the stomach and intestine, stopping the absorption of fluids from intestinal lining cells. However, unlike salmonella, these cells are not killed, hence the quicker recovery time.

The infectious virus can strike at any time and typically lasts between one to three days, but for most people, it is most common to contract this virus from November to April.

It affects millions around the world and symptoms typically develop 12 to 48 hours after being exposed to it.

According to the NHS, the main symptoms of norovirus are nausea, diarrhoea, and vomiting. You may also suffer a high temperature of 39°C or above, a headache, and aching limbs.

Symptoms usually start suddenly, within one to two days of being infected.

The virus can only be transmitted if particles from vomit or faeces are passed on and ingested.

This can happen in a number of ways. You could catch it by eating food or drinking liquids that are contaminated, for instance. Alternatively, you might touch surfaces or objects that are contaminated and later put them near your mouth or touch your face.

In humans, the incubation period usually lasts between 12 to 48 hours. Symptoms appear very suddenly but usually only last for two to three days before the bug clears.

Hygiene is a top priority to easily avoid contracting the virus.

The easiest thing is to make sure you practise proper hand hygiene, especially after using public transportation, when using the bathroom, or before touching or preparing food.

When preparing food, all fresh produce should be washed thoroughly, and all surfaces should be wiped down and disinfected before cooking.

It is highly contagious, so when cleaning contaminated surfaces, use bleach-based household cleaners and handle garments with plastic gloves. Wash these items of clothing separately on a high setting to kill the germs.

Antibiotics don’t work on norovirus, but you can take painkillers to combat any aches and pains you feel.

The best thing you can do is to drink plenty of fluids with electrolytes to balance the salts in your body and stay hydrated.

Also, make sure to get plenty of rest and eat plain foods such as bread and rice.

You should call 111 if you have diarrhoea for more than a week or continue vomiting after two days, experience bleeding from your bottom, show signs of dehydration, or the patient is a baby under 12 months.

And, if your vomit is red, dark brown, or green, you have a stiff neck and pain when you’re exposed to bright lights, or you have sudden and severe headaches and stomach aches, you’re advised to call 999 or go to the A&E.

Check out NHS guides for more details on treatments.