As per the Centers for Disease Control and Prevention (CDC), there are 685 million cases of norovirus (a contagious virus) infection annually causing stomach flu. They are prevalent in both low and high-income countries, costing $60 billion worldwide due to healthcare costs.
Usually contracted through contaminated food, water and surface and close contact or sharing utensils, towels and food, norovirus also spreads through unwashed hands after going to the washroom or changing a diaper.
An interesting 2012 case study published in the Journal of Infectious Diseases reveals how a grocery bag and its contents caused a norovirus outbreak in a group of 17 girls in King County, Washington. Although the girl who first showed symptoms was not in contact with her other teammates, the other girls started showing symptoms a few days later. The researchers concluded that the infection had passed via a bag of snacks that was stored in the bathroom where the first girl was sick. Airborne norovirus within the bathroom had most likely settled on the open grocery bag and its contents. The girl initially showed symptoms of nausea and abdominal pain. After a few hours, she began vomiting and had diarrhoea all night. Stool samples collected from three sick girls tested positive for norovirus.
Stomach flu and norovirus
The CDC says that one out of every five cases of acute gastroenteritis (inflammation of the stomach or intestines) is caused by norovirus.
Professor Altaf Patel, director, department of medicine, Jaslok Hospital Mumbai, points out that viral cultures aren’t routinely conducted in India for the diagnosis of viral infections.
“Stomach flu is characterised by watery diarrhoea, stomach cramps, nausea, vomiting and fever,” says Dr Rohith M, consultant surgical gastroenterologist, Prakriya hospitals, Bengaluru. He also points out that viral cultures may not be necessary for the treatment of stomach flu. He explains that although it is difficult to differentiate between viral and bacterial gastroenteritis, watery diarrhoea is usually viral in origin and stools with blood and mucous are caused by a bacterial infection.
National Institutes of Health (NIH), a part of the US Department of Health and Human Services, states that the isolation of viruses in culture is slow, time-consuming, labour-intensive and lacks the sensitivity needed to have an appreciable impact on clinical decision making. The agency further concludes that Polymerase Chain Reaction (PCR) is more sensitive than viral culture or antigen or serologic testing for the detection of viruses, and it offers the possibility for early, more rapid diagnosis.
How to sleep with stomach flu
A 2009 study published in the journal, Neurogastroenterology & Motility revealed that poor sleep too was an indicator of gastrointestinal problems. Among 3,228 respondents, 874 (27 percent) reported trouble staying asleep. There was a significant correlation between overall sleep scores with overall gastrointestinal (GI) symptom scores. Waking up once at night at least four times a month was significantly associated with pain, nausea, dysphagia (difficulty in swallowing), diarrhoea, loose stools, urgency and a feeling of anal blockage. Trouble falling asleep was significantly associated with rectal urgency. Associations were independent of gender, age, lifestyle factors and body Mass Index (BMI).
Dr Rohith says, “Viral gastroenteritis shows pronounced symptoms at night due to the circadian rhythm (a natural 24-hour, sleep-wake cycle in the body). It decreases the cortisol levels that have anti-inflammatory action. Hence inflammation increases at the site of infection, leading to discomfort.”
Treatment of stomach flu
“With the absence of anti-viral drugs, usually gastroenteritis cases are bucketed as infectious gastroenteritis and treated with antibiotics,” says Prof Patel. But he warns about the use of over-the-counter (OTC) drugs such as loperamide to stop diarrhoea as they paralyse the gut. “If intestinal movement stops, the bacteria from the gastrointestinal tract enters the blood and start circulating throughout the body, increasing the chances of infection,” he says.
According to Dr Rohith, antibiotics are advised only when a bacterial infection is suspected. The treatment is based on the signs and symptoms and is aimed at hydration as well as managing nausea and vomiting. He points out that untreated stomach flu can lead to severe dehydration, acute kidney injury and electrolyte imbalances which may be fatal for the heart.
Samyukta Raju, head nutritionist at Nourish With Sim (NWS), an online training and nutrition platform in Bengaluru, says that dietary intervention is symptom-based depending on whether the patient has stomach pain and/or vomiting. “The goal is to soothe the gut with prebiotics and probiotics and rehydrate the body with water or electrolytes. In the recovery phase, there is a need to stabilise and replenish the gut which is very weak after washout and aid recovery of muscle loss. A soft diet rich in vitamins and minerals yet low in fibre, dairy products and citrus foods is advised,” says Raju.
Prevention can play a key role in the management of stomach flu. Since norovirus can be contracted from contaminated food or water, maintaining hygiene in the cooking area, avoiding eating raw or undercooked meat and consuming pasteurised dairy products are advisable. Washing of hands after bathroom use and changing diapers is important to keep the infection at bay.
Is the flu vaccine effective against norovirus?
As per the National Institute of Diabetic and Digestive and Kidney Diseases (NIDDK), although some people call viral gastroenteritis ‘stomach flu,’ influenza (flu) viruses do not cause viral gastroenteritis and hence the flu vaccine does not protect against viral gastroenteritis. However, rotavirus vaccines can prevent viral gastroenteritis caused by rotavirus in children.