Dysentery

Good hygiene can reduce the risk

Dysentery is general term for a group of diseases which trigger inflammation of the lining of the large intestines, leading to stomach pains, and diarrhoea, and possibly vomiting and fever.

Untreated dysentery can be a killer.

What causes it?

The condition is caused by bacteria which usually enter the body through the mouth in contaminated food or water, or by physical contact with a person who has already been infected.

The bacterium Shigella dysenteriae type 1 (Sd1) causes a particularly severe form of the disease known as epidemic dysentery.

Three other types of of bacteria from the Shigella family - Shigella flexneri, Shigella sonnei and Shigella boydii - can also cause dysentery, but usually these forms are less dangerous, and do not cause large epidemics.

The disease may also be caused by other types of bacteria, including Campylobacter jejuni, Escherichia coli, and some strains of Salmonella.

What are the symptoms?

The main symptom of epidemic dysentery is bloody diarrhoea.

Other common symptoms include abdominal cramps, fever and rectal pain.

Less frequent complications can include a form of blood poisoning known as sepsis, seizure and kidney failure.

Approximately 5-15% of epidemic dysentery cases are fatal. It tends to be more common in infants, and elderly and malnourished people. Mortality is also highest in these groups.

Are there other forms of dysentery?

Yes. Amoebic dysentery is caused by a tiny parasitic creature called an amoeba.

Once in the digestive system they take up residence in the intestine and cause infection.

The most dangerous form of the disease is caused by an amoeba called Entamoeba histolytica, which lives predominantly in tropical areas.

This creature is able to burrow through the intestinal wall and spread through the bloodstream to infect other organs, such as the liver, lungs and brain.

Why is dysentery dangerous?

The diarrhoea associated with dysentery means that people suffering from the condition are likely to lose a large amount of important salts and fluids from the body.

This dehydration can be fatal if untreated as vital organs like the kidneys, brain, and heart cannot function without a certain minimum of water and salt.

Dysentery is highly contagious. Only a few bacteria need to be swallowed to trigger disease.

Who is at risk?

Dysentery often poses a major threat in crowded areas with inadequate sanitation, poor hygiene and limited supplies of safe water.

For instance, it was a major problem among soldiers in the trenches of the first world war, where sanitation was, at best, rudimentary.

The disease is more likely to thrive in hot, humid and rainy conditions.

How is it treated?

In adults, dysentery caused by bacteria usually subsides spontaneously.

But in children, and other vulnerable groups, the condition can be treated with antibiotics. However, Sd1 has, in recent years, become increasingly resistant to drug treatments.

The key among people who have become dehydrated as a result of the disease is to replenish their fluid stocks as quickly as possible. This can be done using oral rehydration salts or intravenous fluids.

Amoebic dysentey is usually treated with a combination of drugs. These include an amoebicide to kill the parasite, an antibiotic to treat any associated bacterial infection, and a drug to combat infection of the liver and other tissues.