Acute Diarrhoeal Diseases

Causative agents

Acute diarrhoea can be caused by a number of different agents. Common infective causative agents include bacteria such as Salmonella and Vibrio parahaemolyticus, and viruses such as norovirus, rotavirus, sapovirus and astrovirus. Less common causative agents include the bacteria causing bacillary dysentery, cholera and Shiga toxin-producing Escherichia coli infection, etc. Acute diarrhoeal diseases may occur in all ages, with children being more commonly affected.

Clinical features

Patients with acute diarrhoeal diseases present with sudden onset of frequent loose or watery stools, often accompanied by vomiting and fever. The disease is usually mild with spontaneous recovery. Dehydration and shock may occur in severe cases.

Mode of transmission

Acute diarrhoeal diseases are usually transmitted by contaminated hands or ingestion of contaminated food or drinks, and occasionally by aerosol spread with contaminated droplets of splashed vomitus. Outbreaks may occur in settings like institutions and child care centres.

Incubation period

The incubation period is usually from a few hours to 5 days after exposure for bacterial diarrhoea and 1 to 3 days for viral diarrhoea.

Management

Acute diarrhoeal diseases are usually managed by fluid and electrolyte replacement. The patient should consult his/her family doctor for proper management if the diarrhoea is severe. Self-medication is not advisable.

Prevention

1. Maintain good personal hygiene

• Perform hand hygiene frequently, especially before handling food or eating, and after using the toilet.
• Wash hands with liquid soap and water, and rub for at least 20 seconds. Then rinse with water and dry with a disposable paper towel or hand dryer. If hand washing facilities are not available, or when hands are not visibly soiled, hand hygiene with 70 to 80% alcohol-based handrub may be considered. As alcohol does not effectively kill some viruses e.g. norovirus, alcohol-based handrub should not substitute hand hygiene with liquid soap and water.
• Wear gloves and a surgical mask while disposing of or handling vomitus and faeces, and wash hands thoroughly afterwards.
• Refrain from work or attending school, and seek medical advice if suffering from vomiting or diarrhoea.

2. Maintain good food hygiene

• Adopt the 5 Keys to Food Safety in handling food, i.e. Choose (Choose safe raw materials); Clean (Keep hands and utensils clean); Separate (Separate raw and cooked food); Cook (Cook thoroughly); and Safe Temperature (Keep food at safe temperature) to prevent foodborne diseases.
• Drink only boiled water from the mains or bottled drinks from reliable sources.
• Avoid drinks with ice of unknown origin.
• Purchase fresh food from hygienic and reliable sources. Do not patronise illegal hawkers.
• Wash and peel fruit by yourself and avoid eating raw vegetables.
• Cook all food thoroughly before consumption, particularly seafood and shellfish.

* Please visit the website of Centre for Food Safety for more information on food safety.

3. Maintain good environmental hygiene

• Regularly clean and disinfect frequently touched surfaces such as furniture, toys and commonly shared items with 1:99 diluted household bleach (mixing 1 part of 5.25% bleach with 99 parts of water), leave for 15 to 30 minutes, and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.
• Use absorbent disposable towels to wipe away obvious contaminant such as vomitus or faecal spillage. Then disinfect the surface and neighbouring areas with 1:49 diluted household bleach (mixing 1 part of 5.25% bleach with 49 parts of water), leave for 15 to 30 minutes and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol.
• Maintain good indoor ventilation.
• Maintain proper sanitary facilities and drainage system.
• Clean and disinfect toilet used by infected persons and soiled areas.