Causes of Gastroenteritis

Gastroenteritis is caused by an infection of the stomach and intestine. The infection is caused mainly by bacteria, viruses and parasites which interfere with one of the main functions of the intestines that is in the absorption of water and its distribution around the body.

• No absorption of water
  
• Water is still in the tract
• Body has to get rid of water
• Diarrhea(down the tract)/ vomiting(up the tract)

Types of viruses that cause viral gastroenteritis

Viruses that cause gastroenteritis are Norovirus, Rotavirus, Adenovirus and Astrovirus. The most common among all are Norovirus and Rotavirus. But we will talk more about Norovirus.

Norovirus

· Occurs at any time of the year

· In addition to diarrhea , nausea, vomiting a person may experience muscle aches, headaches, fatigue and low grade fever

· Common within environments such as hospitals, nursing homes, schools

· Illness can spread easily from person to person and the virus can survive for several days in a contaminated area

· Ways of getting infected: a) contact with surface or object that are contaminated with the virus

b) by eating or drinking contaminated food or water

c) contact with an infected person

There are many different types of norovirus and it is possible for the infection to occur several times. This is because after getting the illness, immunity to the virus only lasts for 14 days.

Other causes of Gastroenteritis

1. Food Poisoning

· Can be caused by bacteria (Salmonella, E. Coli) or virus

· Mostly it is caused by bacteria which can lead to gastroenteritis

· Food can be contaminated in several ways:

a) Meat is not cooked properly

b) Food is not properly stored and refrigerated eg: meat, eggs, dairy products

c) Food is washed in dirty water

d) Food is handled by someone with a bacterial infection who has not washed their hands after going to the toilet (indirect contact)

2. Contaminated Water

· Animal or human faeces in water can lead to gastroenteritis

· In developed countries it is less likely to happen

· In non well developed countries such as Africa and South Asia it is more likely as there isn’t good water purification equipment available

3. Antibiotics

· Certain antibiotics can kill off the so called ‘friendly bacteria’(useful bacteria) that live in the stomach and the intestines

· Therefore we are more likely to get infected by other types of bacteria that can cause gastroenteritis

· Gastroenteritis caused by taking antibiotic is known as ‘antibiotic-associated gastroenteritis”

· “antibiotic associated gastroenteritis” is usually mild and symptoms should pass within a few days

4. Travellers diarrhea

· Parasites such as Giardia lamblia and Cryptosporidium can cause diarrhea

· Get contracted when travelling in a foreign country

· Common in countries with low standards of public hygiene

· Can be caused by consuming contaminated food or water

· Most cases are usually mild and pass within a few days