As a tsunami of stomach flu hits schools across the US, here’s how to tell the difference between the two main culprits: Shigella and norovirus

If you or a loved one has had the stomach flu in the past few weeks, you’re not alone.

Cases of norovirus – or the “stomach flu” – hit a 12-month high in February and continue to wreak havoc, particularly in schools.

At the same time, cases of bacterial Shigella infection are increasing and health officials are concerned about an antibiotic-resistant strain growing in the United States.

The two bugs—which are the leading cause of gastroenteritis in American schools—have very similar symptoms, making it difficult to tell them apart.

But there are ways to tell the difference between the two:

The graph above shows the number of reported Shigella outbreaks this year (red line) and earlier. The season started early but has since slowed down. It remained below pre-pandemic levels

This map shows the number of reported outbreaks by state. It was most common in Virginia, California, Ohio and Michigan – with pending cases. Virginia schools advise parents to keep their children home for 48 hours after symptoms resolve to stop the spread of norovirus

Dr. Marci Drees is the senior infection prevention officer at ChristianaCare in Delaware, who regularly treats patients with the diseases.

When asked how to tell the illnesses apart, she told ABC6, “Norovirus usually starts with a lot of vomiting and then progresses to diarrhea, or sometimes both start at the same time.

‘[But] Shigella is more prone to diarrhea than vomiting. You could have stomach cramps.’

Diarrhea caused by Shigella is usually more watery or bloody, health professionals say, while diarrhea caused by norovirus tends to cause vomiting.

The two can also be distinguished by their duration. Norovirus cases usually go away within three days, but Shigella usually lasts four to seven days.

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For months, a wave of respiratory and stomach viruses swept across the United States, hitting earlier and harder than usual, causing symptoms similar to the pandemic virus.

In severe cases, it can take weeks to months for the intestines of people with the bacterial infection to return to normal.

Other differences are that Shigella patients are more likely to have a fever than those with norovirus.

The diseases can also occur in different age groups.

Norovirus is also known as the “stomach bug” because it tends to peak during the cold months of November through April before being released again.

Shigella, on the other hand, reproduces at a constant rate throughout the year.

Norovirus causes up to 21 million cases annually in the United States, 109,000 hospitalizations and 900 deaths, according to statistics.

Data show that the number of cases peaked earlier than usual this year, peaking in early January with 30 outbreaks per week.

But they have since refused. They remained below the levels recorded before the pandemic between 2012 and 2020.

Data shows that Virginia, California, Ohio and Michigan have experienced the most norovirus outbreaks this year.

Earlier this month, schools in Chesterfield, outside Richmond, Virginia, urged parents to keep children home for 48 hours after their symptoms disappeared – suggesting that norovirus was behind the illness.

Shigella, on the other hand, causes fewer illnesses each year than norovirus.

Surveillance data from the Centers for Disease Control and Prevention (CDC) indicate that the bacterial infection causes approximately half a million cases each year, resulting in 5,400 hospitalizations and 38 deaths.

A “serious public health warning” was issued last month about cases where the superbug has become resistant to antibiotics across the country, making treatment more difficult.

Drug-resistant strains now account for about five percent of all cases, up from just six or seven years ago.

Medical specialists say that in most cases, the best treatment for sick children is to get enough rest and make sure they are hydrated.

Some patients may also eat small amounts of bland foods as recommended, such as soup, rice, pasta or bread.

Children only need to see a doctor if they start to show symptoms such as bloody diarrhea, persistent fever, severe stomach cramps or dehydration.

In these cases, a stool test is done to determine if infection is caused by Shigella or norovirus.

Because Shigella is caused by a bacterium, it can be treated with a range of antibiotics.

But there is no comparable treatment for norovirus, which is caused by a virus, and doctors instead focus on treating the symptoms.

CDC issues “serious public health warning” of nationwide rise in drug-resistant stomach flu

America faces a “serious public health threat” after a surge in infections from an antibiotic-resistant stomach flu, officials have warned.

The Centers for Disease Control and Prevention (CDC) warned that about 5 percent of Shigella cases are now drug-resistant, compared to none in 2015.

It is estimated that around 450,000 patients contract Shigella – the bacteria that causes shigellosis – each year. The main symptoms are diarrhoea, which is sometimes bloody, fever, abdominal pain and the urge to defecate even when the bowel is empty.

Naeemah Logan, a CDC physician, said these “superbug” cases pose a “serious threat to public health and we want to make sure providers are aware of the increased likelihood of antibiotic failure.”

Most do not need antibiotics and recover within a week with rest and hydration.

But antibiotics are offered to people who have weakened immune systems due to HIV or any chemotherapy they are receiving. This can help prevent complications and shorten the duration of the disease.

The increase in Shigella cases with superlice was particularly sharp among gay and bisexual men, travelers, the homeless and people living with HIV.