Gastroenteritis - shigellosis

Shigellosis is a bowel infection caused by bacteria from the Shigella family. Other names for shigellosis include Shigella infection, Shigella enteritis and bacillary dysentery. Common symptoms include diarrhoea that may contain blood, mucus or pus, abdominal cramps, nausea and vomiting.

To cause infection, the bacteria have to be eaten, either directly through physical contact with a person with the illness, or indirectly by contaminated food and water. After incubating (bacteria multiplying) in the body for around one to three days, the infection causes the characteristic symptoms. These symptoms last for about four to seven days.

It is important to seek prompt medical advice. In very rare cases, shigellosis can be life threatening.

Children are particularly prone to shigellosis

Anyone can contract the infection, but children are particularly prone (although infection in babies under six months is unusual). The infection tends to be more severe in young children and the elderly. Outbreaks can occur in institutional settings, particularly where children are still in nappies (such as childcare centres) or adults are incontinent (such as nursing homes).

Symptoms of shigellosis

The symptoms of shigellosis include:

• diarrhoea (which may contain traces of pus, mucus or blood)
• fever
• abdominal cramps
• nausea
• vomiting
• dizziness when standing up.

Complications of shigellosis

Young children are more susceptible to complications, which may include:

• seizures caused by fever
• dehydration
• headache
• lethargy
• stiff neck
• confusion.

Causes of shigellosis

Shigella bacteria are excreted (passed) in faeces (poo). If an infected person doesn’t wash their hands after going to the toilet, the bacteria can be spread if they touch objects and surfaces that will be touched by other people, or handle food that may be eaten by other people.

A person changing the nappy of a baby with shigella gastroenteritis may contaminate their hands with the bacteria.

Shigella bacteria can also be spread through sexual contact, especially during oral or oro-anal sex. Men who have sex with men are at particular risk.

It is also possible to get shigellosis from drinking water that is contaminated with human faeces containing Shigella bacteria.

Infection can still occur after symptoms have stopped.

The symptoms of shigellosis may clear up after a week or so, but the person can have Shigella bacteria in their faeces for at least four weeks after the symptoms stop. Occasionally, a person may excrete the bacteria for months after the symptoms have stopped.

Some people are carriers of Shigella, which means that they have the bacteria in their body, but don’t feel sick. These people can still pass the disease on to others.

Diagnosis of shigellosis

Stool samples or rectal swabs are tested to diagnose shigellosis.

Treatment for shigellosis

Treatment options for shigellosis are mostly supportive and may include:

• plenty of fluids
• oral rehydration drinks, available from your chemist
• intravenous fluids (in severe cases)
• eating solid foods
• avoiding anti-vomiting or anti-diarrhoea drugs unless prescribed or recommended by your doctor

Sometimes, taking appropriate antibiotics to kill the bacteria within a matter of days. Due to increasing levels of antibiotic resistance, these medications are now saved for the very sick or to reduce the spread of infection to vulnerable people or those in residential facilities.

Prevention of shigellosis

General suggestions on how to reduce the risk of shigellosis include:

• Wash hands thoroughly with soap and hot water after going to the toilet or changing nappies, and before preparing food or eating.
• Use disposable paper towels to dry your hands rather than cloth towels, since the bacteria can survive for some time on cloth.
• Keep cold food cold (below 5 °C) and hot foot hot (above 60 °C) to discourage the growth of bacteria.
• Make sure foods are thoroughly cooked.
• Thoroughly wash raw vegetables before eating.
• Reheat food until the internal temperature of the food reaches at least 75 °C.
• Clean the toilet and bathroom regularly, including the toilet seat, door handles and taps, by using a cleaning product that is able to kill bacteria, such as a product containing chlorine.
• Clean baby change tables regularly.
• Water from rivers and lakes may be contaminated by human faeces. Boil water from these sources before drinking.
• Do not have sex with anyone who currently has or who has recently recovered from diarrhoea of any cause – this is particularly important for oro-anal contact.

Preventing the spread of shigellosis

Good personal hygiene should be practised at all times. In addition to the above precautions, suggestions to reduce the risk of transmission include:

• Don’t share towels or linen with the infected person.
• The infected person shouldn’t prepare any meals at home for other family members.
• The infected person should stay at home until the diarrhoea has stopped, to prevent infecting others at work, school, kindergarten or childcare. It is especially important not to visit vulnerable people such as people in aged care facilities and hospitals.
• If the infected person works in a high-risk occupation, such as a food worker, healthcare worker, childcare worker or in a residential facility; it is important that they stay away from work while awaiting advice from the Department of Health.
• Children must not attend childcare centres, kindergartens or school until 24 hours after their symptoms have stopped.
• When travelling overseas to countries with poor sanitation conditions, only drink bottled water. Don’t forget to brush your teeth in bottled water too. Avoid food buffets, uncooked foods or peeled fruits and vegetables, and ice in drinks.
• Avoid having sex for a week after diarrhoea has stopped. For a further two weeks wash hands before and after sex, avoid high risk activities such as oral and oro-anal sex or use barrier methods (such as condoms and dental dams).

Information for contacts

Shigella factsheet for contacts

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Where to get help

• Your GP (doctor)
• Pharmacist
• Your local community health service
• Melbourne Sexual Health Centre Tel. (03) 9341 6200 or 1800 032 017 or TTY (for the hearing impaired) (03) 9347 8619
• Thorne Harbour Health (formerly Victorian AIDS Council) Tel. (03) 9865 6700 or 1800 134 840
• Sexual Health Victoria (SHV). To book an appointment call SHV Melbourne CBD Clinic: (03) 9660 4700 or call SHV Box Hill Clinic: (03) 9257 0100 or (free call): 1800 013 952. These services are youth friendly