Key points
- Shigella is a serious gut infection causing severe, prolonged diarrhoea and stomach cramps. It is transmitted by contact with very small amounts of human faeces.
- Shigella can be successfully treated with antibiotics.
- Using condoms for anal sex and latex gloves for fisting, as well as washing hands frequently, can help prevent transmission of shigella.
Shigella is an infectious disease caused by a group of bacteria called Shigella, the most common of which in the UK are Shigella sonnei and Shigella flexneri.
In the UK, most cases of shigella used to be associated with foreign travel. However, since 2011, there has been a significant increase in UK-acquired cases associated with sexual transmission, predominantly among men who have sex with men. Many of the men being diagnosed with shigella also have other sexually transmitted infections such as LGV, syphilis and HIV. The increase in shigella cases has been linked to high numbers of sexual partners and chemsex (sex under the influence of drugs).
Transmission
Shigella bacteria are found in faeces (poo) and can also be present in contaminated food. It is highly infectious, regardless of whether or not a person has HIV.
Shigella is transmitted by contact with very small amounts of human faeces. This can occur as a consequence of poor hygiene; for example, by not washing your hands after going to the toilet, especially if you have diarrhoea. It can also be passed on during certain sexual activities. Rimming, fingering, fisting, anal sex, handling sex toys after use in the anus, and occasionally oral sex can all carry a risk. The bacteria may pass from fingers to the mouth.
Prevention
Basic hygiene and handwashing habits reduce the risk of transmission. Wash your hands, with warm water and soap, after sex, after using the toilet and before preparing food.
Use a condom for anal sex, latex gloves for fingering and fisting, and a latex square for rimming. Don’t share sex toys unless they’re washed or covered by a new condom each time they are used.
It is best not to prepare food for other people while you have symptoms, and for a week afterwards. Don’t share towels or flannels. Wash any dirty clothing, towels or bedding on the hottest cycle of the washing machine. Clean taps, door handles, the toilet seat and the flush with hot soapy water frequently. Do not use spas, Jacuzzis or hot tubs, or go swimming.
Symptoms
Occasionally, people will have no symptoms, but usually they start within a day or two of exposure and last about a week. Shigella can cause stomach pain and watery diarrhoea. More serious cases can involve severe diarrhoea, which can contain blood or mucus, stomach cramps, nausea, vomiting and a fever. Symptoms can be worse in people living with HIV who have a low CD4 cell count.
If you have symptoms, see your GP (family doctor) or a sexual health clinic to be tested for shigella.
Treatment
Many people recover from shigella without the need for treatment, although it can take several months for bowel habits to return completely to normal. You may be infectious for up to a month.
Shigella can be successfully treated with antibiotics. Treatment can also reduce the risk of passing the infection on. Shigella bacteria can be resistant to some antibiotics, so a drug will be chosen based on the particular strain’s resistance profile.
Drink plenty of fluids to replace the salts and water you will have lost; you could also use oral rehydration drinks. Do not use over-the-counter anti-diarrhoea medicines such as loperamide, as these can make your illness worse. You can take painkillers, such as paracetamol, to treat pain and fever, if you have these symptoms. Eat if you feel able.
Once you have had shigella, you are not likely to get infected with that specific type again for at least several years. However, you can still be infected with other types of Shigella.
Stay away from work, college, etc. for at least 48 hours after the last episode of diarrhoea or vomiting. Avoid contact with other people as much as possible during this time.
If your job involves handling or serving food, or working with patients, and you develop symptoms, you must tell your employer and leave work immediately. If you have tested positive for Shigella, you should tell your employer and stay away from work until your doctor or a public health official advises you it is safe to return.
Do not have sex for a week after your symptoms have stopped.
If you think you were infected through sexual activity, it may be a good idea to have a full sexual health check-up. Sexual health clinics offer confidential and free treatment. You don't need to be referred by your GP or your HIV doctor.