Gastroenteritis - shigellosis

Shigellosis is a bowel infection caused by bacteria from the Shigella family. It is also known as Shigella infection, Shigella enteritis or bacillary dysentery.

To cause infection, the bacteria have to be swallowed, either through direct physical contact with an infected person or indirectly through contaminated food and water. After incubating in the body for around one to three days, the infection produces its characteristic symptoms, which usually last about four to seven days.

Symptoms#

Common symptoms of shigellosis include:

• diarrhea, which may contain traces of blood, mucus or pus
• fever
• abdominal cramps
• nausea
• vomiting
• dizziness, especially when standing up

Seek prompt medical advice#

In very rare cases, shigellosis can be life threatening, so it is important to seek medical advice early.

Anyone can catch the infection, but children are particularly prone to it (although infection in babies under six months is unusual). The illness tends to be more severe in young children and in older people.

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

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

Outbreaks can occur in group settings, particularly where children are still in nappies, such as childcare centres, or where adults may be incontinent, such as residential aged care.

How shigellosis spreads#

The bacteria are passed in the feces of an infected person. If someone does not wash their hands after going to the toilet, the bacteria can spread when they touch objects and surfaces that others will touch, or handle food that others will eat. A person changing the nappy of a baby with Shigella may contaminate their hands with the bacteria.

Shigella 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 contaminated with human feces containing Shigella.

Infection can persist after symptoms stop#

The symptoms of shigellosis may clear up after a week or so, but a person can continue to carry and excrete the bacteria for months afterwards. These carriers may feel well but can still pass the infection on to others.

Diagnosis and treatment#

Shigellosis is diagnosed by testing stool samples or rectal swabs. Treatment is mostly supportive and may include:

• plenty of fluids
• oral rehydration drinks
• intravenous fluids in severe cases
• returning to solid foods as tolerated
• avoiding anti-vomiting or anti-diarrhea medicines unless prescribed or recommended by your doctor

Antibiotics can kill the bacteria within a few days. Because of increasing antibiotic resistance, however, these medicines are now generally reserved for people who are very sick, or to reduce the spread of infection to vulnerable people and those in residential facilities.

Preventing the spread of shigellosis#

Good personal hygiene is the most important way to reduce the risk of shigellosis. General suggestions include:

• Wash hands thoroughly with soap and hot water after going to the toilet or changing nappies, and before preparing food or eating.
• Dry your hands with disposable paper towels rather than cloth towels, as the bacteria can survive for some time on cloth.
• Keep cold food cold (below 5°C (41°F)) and hot food hot (above 60°C (140°F)) to discourage bacterial growth.
• Make sure foods are thoroughly cooked, and reheat food until the internal temperature reaches at least 75°C (167°F).
• Thoroughly wash raw vegetables before eating.
• Clean toilets and bathrooms regularly, including the toilet seat, door handles and taps, using a product that kills bacteria, such as one containing chlorine.
• Clean baby change tables regularly.
• Boil water from rivers and lakes before drinking, as it may be contaminated by human feces.

If someone in the household is infected, additional steps can reduce the risk of passing it on:

• Don’t share towels or linen with the infected person.
• The infected person should not prepare meals for other family members.
• The infected person should stay home until the diarrhea has stopped, to avoid infecting others at work, school or childcare. It is especially important not to visit vulnerable people, such as those in aged care facilities and hospitals.
• People in high-risk occupations, such as food workers, healthcare workers, childcare workers and those in residential facilities, should stay away from work while awaiting advice from public health authorities.
• Children should not attend childcare, kindergarten or school until 24 hours after their symptoms have stopped.

Do not have sex with anyone who currently has, or has recently recovered from, diarrhea of any cause; this is particularly important for oro-anal contact. Avoid sex for a week after diarrhea has stopped. For a further two weeks, wash hands before and after sex, avoid higher-risk activities such as oral and oro-anal sex, or use barrier methods such as condoms and dental dams.

Travel advice#

When travelling to areas with poor sanitation:

• Only drink bottled or boiled water, and use it to brush your teeth as well.
• Avoid food buffets, uncooked foods, peeled fruit and vegetables, and ice in drinks.

Key points#

• Shigellosis is a bowel infection caused by Shigella bacteria, spread through contaminated food, water, hands and sexual contact.
• Symptoms usually last about four to seven days; seek prompt medical advice as severe illness can occur, especially in young children and older people.
• Men who have sex with men are at particular risk through oral and oro-anal contact.
• Infection can still be passed on after symptoms have stopped.
• Thorough hand washing, food safety and good hygiene are the best ways to prevent its spread.

Where to get help#