Dr Adebola Adejimi is a consultant public health physician at the University of Lagos and Lagos University Teaching Hospital. She talks about the risks of dysentery and how to prevent infection
What is dysentery?
Dysentery is an intestinal infectious disease resulting in inflammation of the intestines, especially the colon, and causing severe diarrhoea with blood or mucus in the stool. Other symptoms may include abdominal cramps or pain, nausea, vomiting, fever with temperature of about 38°C or higher and dehydration, which can become life-threatening if left untreated. This usually lasts for between three and seven days. However, the signs and symptoms can be mild and disappear within a few days in some cases. Most of the global burden of this disease is contributed by the developing countries where over 60 per cent of the fatalities are reported among children under five years old.
What are the causes of dysentery?
Dysentery is usually spread as a result of poor hygiene, as well as poor sanitation and improper sewage disposal. The infection is often spread through contact with food or water that has been contaminated with faecal matter. Good hygiene practices, such as hand washing and proper sanitation, can help prevent dysentery and keep it from spreading. Dysentery is most often caused by shigella bacteria called Shigella bacillus or an amoeba called Entamoeba histolytica (E. histolytica). Bacillary dysentery, also known as shigellosis, produces the most severe symptoms, while Amoebic dysentery, also known as amoebiasis, is more common in the tropics. Other causes of dysentery diarrhoea include parasitic worm infections, chemical irritation, or viral infections.
Can you speak more about the symptoms of dysentery?
The symptoms of dysentery range from mild to severe. A key symptom of dysentery is bloody diarrhoea. Mild symptoms include a slight abdominal pain, cramps and diarrhoea. These usually appear from one to three days of infection, and the patient recovers within a week. Often, symptoms are so mild that a doctor’s visit may not be required, and the problem resolves within a few days. Other symptoms of dysentery include intense abdominal pain, fever and chills, nausea and vomiting, watery diarrhoea, which can contain blood, mucus or pus, malaise, fatigue, painful passing of stools and intermittent constipation.
In amoebiasis, amoeba can move through the intestinal wall and spread into the bloodstream to infect other organs. Ulcers can develop in the intestines and these may bleed, causing blood in stools. Symptoms may persist for several weeks. The amoebae may continue living within the human host after symptoms have disappeared but the symptoms may recur when the person’s immune system is weaker. Treatment reduces the risk of the amoebae surviving in the human host.
Who is at risk of dysentery?
People who live in environments with poor sanitation are at risk of having dysentery. Those who come in contact with faecal matter from people who have dysentery are most at risk. This contact may be through contaminated water, food and other drinks, as well as through swimming in contaminated water, such as lakes or pools. People who come in contact with infected persons with poor hand hygiene practices are also at risk of dysentery.
Even though anyone can develop dysentery at any age, children are most at risk of shigellosis. It can easily spread by taking contaminated food or drink. Shigellosis mostly spreads from one person to another among people who are in close contact with an infected person in places such as day care centers, schools and nursing homes.
What is the difference between bacterial and amoebic dysentery?
Bacterial dysentery, also known as shigellosis, is caused by infection with bacteria from Shigella, Campylobacter, Salmonella, or enterohemorrhagic E. coli. This type produces the most severe symptoms and mostly related to poor hygiene. On the other hand, Amoebic dysentery, also known as amoebiasis, is caused by a single-celled parasite, Entamoeba histolytica (E. histolytica), an amoeba that infects the intestines. Amoebic dysentery is less common in the developed world. It is more common in the tropics with poor sanitary conditions. The amoebae group together to form a cyst, which emerges from the body in human faeces. The amoebae can contaminate food and water and infect other humans. They can survive for long periods outside the body and can also linger on people’s hands after using the bathroom.
How can dysentery be distinguished from cholera?
Dysentery is an inflammation of the intestine characterised by the frequent passage of faeces with blood and mucus. Cholera is an acute diarrhoeal infection caused by ingestion of food or water contaminated with the causative bacterium, which is known as Vibrio cholerae. The major symptom of cholera is massive watery diarrhoea that occurs because of a toxin secreted by the bacteria that stimulates the cells of the small intestine to secrete fluid. Cholera stools may contain faecal matter and bile in the early phases of the disease. The characteristic symptom of severe cholera is the passage of profuse “rice-water” stool, a watery stool with flecks of mucous. It typically has a ‘rice-water’ appearance and a fishy odour. There are several strains of V. cholerae and the severity of the disease is based on the particular infectious strain.
How is dysentery diagnosed?
Dysentery can be diagnosed by taking adequate history, physical examination and laboratory investigations, including testing of the stool sample to determine which bacteria are present. Laboratory results will reveal whether the infection is due to Shigella or Entamoeba histolyca infection. Other tests to decide whether an antibiotic will help can be performed. If you notice the symptoms of dysentery, please see your doctor because it can lead to severe dehydration and become life-threatening, if left untreated.
How is it treated?
Prompt medical care is required for bloody diarrhoea. Treatment may include increased fluid intake, oral rehydration solutions, IV (intravenous) fluids and antibiotics. Mild shigellosis can be treated just by resting and taking plenty of fluids. If treatment is necessary, it will depend on the results of the investigations. However, any patient with diarrhoea or vomiting should drink plenty of fluids.
Severe shigellosis can be treated with antibiotics, but the bacteria that cause it are often resistant. If your doctor prescribes an antibiotic and you don’t see improvement after a couple of days, let the doctor know. The strain of Shigella bacteria may be resistant, and your doctor may need to adjust your treatment plan.
Amoebic dysentery can be treated with metronidazole, tinidazole or secnidazole which should be based on doctor’s prescription.. These drugs kill the parasites. In some cases, a follow-up drug is given to make sure all the parasites are gone. In severe cases, your doctor may recommend an IV drip to replace fluids and prevent dehydration.
What are the repercussions of not treating dysentery?
Complications of dysentery are few, but some of them can be severe. Frequent diarrhoea and vomiting can quickly lead to dehydration. In infants and young children, this can quickly become life-threatening.
If amoebae spread to the liver, an abscess can form there. In some cases, complications of dysentery can include post-infectious arthritis, which affects about two per cent of people who get a particular strain of the Shigella bacteria called S. flexneri. These people can develop joint pain, eye irritation, and painful urination. Post-infectious arthritis can last for months or years.
There are also blood stream infections, which are rare and most likely to affect people with weak immune systems, such as people with human immunodeficiency virus or cancer. Shigella dysenteriae can also cause the red blood cells to block the entrance to the kidneys, leading to Hemolytic uremic syndrome, characterised by anaemia, low platelet count, and kidney failure. Patients have also experienced seizures after infection. Sometimes, young children can have generalised seizures.
How deadly is dysentery?
Dysentery can be fatal without adequate hydration. It is an infection of the intestinal tract and many people have mild symptoms. It is important to practise good hygiene to reduce the risk of spreading the infection.
How long does dysentery last?
Shigellosis usually goes away within a week and may not require prescription medications. It is important to practise good hand hygiene always. If you have shigellosis, avoid preparing food for other people and swimming in public places. People who have shigellosis should avoid working with children, preparing food, or having intimate contacts with others until the diarrhoea has stopped. Most people with amoebic dysentery are sick for a few days to several weeks. If you suspect amoebic dysentery, it is important to get immediate medical attention. Your doctor will prescribe medication to get rid of the parasite that causes this type of dysentery.
What preventive measures can be taken against dysentery?
Dysentery mostly stems from poor hygiene and it can be prevented through good sanitation practices. To reduce the risk of infection, people should wash their hands regularly with soap and water, and especially after using the toilet and before preparing or touching food. Make sure you eat food from reliable sources. Make sure your food is properly cooked and your fruit is properly washed before eating.
Avoid water from unknown sources and only drink water from reliable sources. It is important to make sure you drink bottled and sealed water and clean the top of the rim of drinks before drinking it. Safe sources of water include bottled water with unbroken seal, tap water that has been boiled for at least one minute; tap water that has been filtered through a one-micron filter and treated with chlorine or iodine tablets. It is best to use purified water to clean the teeth. This can reduce the frequency of dysentery by up to 35 per cent.
To prevent dysentery, it is important to be careful when changing a sick baby’s diaper, and not to swallow water when swimming. When travelling or going to these areas where dysentery is common, you should avoid drinks with ice cubes; drinks that are not bottled and sealed; food and beverages sold by street vendors; peeled fruit or vegetables, and unpasteurised milk, cheese or dairy foods.
In our communities, it is important to provide adequate potable water as well as improved water and sanitation facilities for proper hygiene. Household water should be properly treated and stored. Lack of access to safe and clean drinking water, as well as basic sanitation can promote the spread of dysentery. Adequate sanitation and toilet facilities for proper sewage disposal should be provided in homes and public places.