Vomiting & Diarrhoea

Causes and Spread

Vomiting and diarrhoea can be caused by many conditions – viral or bacterial infections of the gastrointestinal tract are often to blame.

Other names for these infections include – food poisoning, travellers’ diarrhoea, gastro, gastro flu, Bali belly etc.

Other causes of vomiting & diarrhoea:

  • Vomiting associated with pregnancy
  • Some medications (such as antibiotics)
  • Other stomach conditions

Viral Infections

The most common viral (gastro) infections to cause vomiting and diarrhoea in the first world are rotavirus and norovirus. These viruses usually spread rapidly through the community.

How do viral infections spread?

Viruses commonly spread from one infected person to another. Outbreaks of viral gastro often occur when people are in close living spaces, such as: Aged-care facilities, Hospitals, Cruise ships and Community sporting events.

Beyond person to person spread, there are different ways in which people become infected with a gastro virus:

  • Eating food or drink that is contaminated with a virus. This can occur in two ways:
    • When the food may become contaminated during growing or processing, especially oysters.
    • When a person who is ill prepares food for other people.
  • Touching surfaces or objects contaminated with the virus and then putting their hands in their mouth.
  • Contaminated objects e.g. improper hand washing following a bowel movement or nappy change.
  • Particles in the air when people vomit e.g. parents and carers often contract the infection when assisting others.

Small particles of vomit settle on people or food in the same room and result in infection.

Viral Pathogen Information Incubation Period Average Illness Duration

Norovirus is a highly contagious virus, and the leading cause of acute gastroenteritis worldwide.

18-48 hours 24-48 hours

Rotavirus is a common cause of vomiting and diarrhoea, especially in young infants and children.

< 48 hours Up to 5 days

Bacterial Infections

Common bacterial infections that can cause vomiting and diarrhoea are E.coli and Salmonella. These are usually isolated to one person and are the result of ingesting contaminated food or water.

Bacterial Pathogen Information Incubation Period Average Illness Duration
Escherichia coli

Otherwise known as E.Coli is a common bacterial infection that can cause vomiting and diarrhoea.  You may be exposed to E. coli from contaminated water or food — especially raw vegetables and undercooked ground beef.

12 hours to 3 days 1 week
Salmonella spp.

Salmonella is a bacterial pathogen and a major public health problem in the developing world that can cause vomiting and diarrhoea.  Transmission is usually by ingestion of contaminated food (the particles survive freezing at -20 ?C!).

24-48 hours (up to 72 hours) Days to weeks depending on the amount ingested
Shigella spp.

Shigella is a bacterial infection which can cause a severe form of vomiting and diarrhoea.

1-3 days 3 days
Campylobacter jejuni

Campylobacter jejuni is a bacterial pathogen which is a major cause of food poisoning in Australia

1-7 days 1-7 days
Giardia duodenalis

Giardiasis is an infection in the bowel caused by a parasite. This infection is very common amongst travellers to under-developed countries, such as Bali and India.

12-15 days Weeks to months


Recommended Hydralyte products for Vomiting & Diarrhoea: