Gastroenteritis also known as, stomach flu, is an inflammation of the stomach and intestines. It is not related to influenza, but rather usually the result of infections by viruses, bacteria, or parasites. “Gastro” refers to the stomach and “enter” means intestine, “itis” refers to inflammation, usually caused by an infection.

The condition causes painful symptoms like diarrhoea, vomiting, and abdominal cramps. Most cases of the infections are mild, but if symptoms become more serious, medical attention may be needed.

Gastroenteritis is extremely contagious. You can avoid spreading and catching it through simple hygiene measures such as washing your hands.

According to the report by Centre of Disease Control and Prevention, published in May 2024, annually on average, there are 685 million total cases of gastroenteritis worldwide. Also, there are 200 million annual cases in children under 5 years old.

How does gastroenteritis (stomach flu) affect the stomach and intestines?

The infection causes irritation and inflammation of the lining of the stomach and intestines. The body tries to eliminate the infectious agents by inducing vomiting and diarrhoea but, unfortunately, can rapidly lead to dehydration, especially in young children, older adults, and those whose systems that are immunocompromised.

What are the symptoms?

Symptoms caused by gastroenteritis include: 

• Diarrhoea 
• Nausea, Vomiting 
• Decreased appetite 
• Abdominal cramps and spasms 
• Fever 
• Chills 
• Fatigue 
• Muscle aches

What is the main cause of gastroenteritis?

IMany different bacteria, parasites and viruses can infect your gastrointestinal system.

Infectious diseases lead to acute gastroenteritis. Infectious gastroenteritis is caused by infection in your gastrointestinal tract. These include:

• Viral infection

• Bacterial infection

• Parasitic infection

• Fungal infection

These infections are the leading causes of acute gastroenteritis.

Viral gastroenteritis:

Viral infections lead to viral gastroenteritis. This is the most prevalent type. The viruses responsible are:

• Norovirus 

• Rotavirus 

• Astrovirus 

• Adenovirus 

• Calicivirus 

• Sapovirus

Bacterial gastroenteritis:

There are different bacteria responsible for bacterial gastroenteritis. Some of the common bacterial gastrointestinal infections include:

• Salmonella 

• Campylobacter 

• Clostridioides difficile (C. diff) 

• Escherichia coli (E. coli) 

• Shigella 

• Staphylococci (Staph) 

Parasitic gastroenteritis:

Parasite infections give rise to parasitic gastroenteritis. The commonly occurring infections are:

• Giardiasis 

• Cryptosporidiosis 

• Cyclosporiasis 

• Amebiasis (amoebic dysentery) 

Fungal gastroenteritis:

Fungal infections cause fungal gastroenteritis. The most common fungal infections include the following:

• Candidiasis 

• Aspergillosis

Risk Factors for Gastroenteritis

Certain factors can increase the likelihood of contracting gastroenteritis or developing more severe symptoms:

Age: Young children (under 5) and older adults are more vulnerable due to weaker immune systems. 

Compromised Immune System: People with conditions like HIV/AIDS, cancer, or those on immunosuppressant medications are at higher risk. 

Living or Working in Crowded Environments: Schools, nursing homes, daycare centres, and cruise ships are hotspots for outbreaks due to close contact among individuals. 

Poor Hygiene Practices: Inadequate handwashing and unsanitary practices increase the risk of viral and bacterial infections. 

Travel to High-Risk Areas: Visiting regions with poor sanitation and unsafe drinking water raises the risk of exposure to contaminated food or water. 

Consumption of Contaminated Food or Water: Eating undercooked foods or drinking contaminated water can lead to infections. 

Close Contact with Infected Individuals: Caring for someone who is sick or sharing utensils increases the chances of catching the infection. 

Underlying Health Conditions: Patients with chronic digestive disorders like IBS (Irritable Bowel Syndrome) or other gastrointestinal issues may experience more severe symptoms. 

Understanding these risk factors helps individuals take proactive steps to prevent gastroenteritis and protect their health.

Is gastroenteritis infectious?

Infectious gastroenteritis is communicable. If you have an infection in your gut, it infects your stool. Infections can then be transferred from your stool to anyone that comes in contact with it. 
 
Minute traces of stool remain on bathroom surfaces, diaper-changing areas and peoples’ hands if they don’t clean them well. These minute traces are transferred to other people that touch them, or to their food or water.

How can the gastroenteritis be prevented?

Good hygiene may reduce your chance of getting stomach flu or passing it on to other people. This includes:

Hand washing: Good hand washing is a primary defence against stomach flu viruses since hand sanitiser is not always effective. This is particularly important after using the bathroom or after changing a diaper and before touching food.

Sanitation: Clean and disinfect any surfaces or objects you or the infected person has come into contact with. Use bleach and water with a concentration to disinfect surfaces, especially in the bathroom. Use hot temperatures in your washing machine for bed linens and clothes. 

Safe food handling: Food can become contaminated with stomach flu viruses, bacteria or other organisms. Safe food preparation helps prevent this. Those who have already been infected with stomach flu should avoid preparing food for others when possible