Chlamydia - What is it?

Chlamydia is an infection that you can get when you have sex. If you have chlamydia, you probably won't feel ill and may not know you've got it. That's why it's often called the 'silent disease'.

Chlamydia is sometimes called the 'silent disease' because you can have it without knowing it. Chlamydia is an infection caused by bacteria (germs) called Chlamydia trachomatis. The bacteria can be passed from person to person during sex.

If you're a man, it can affect the tube (urethra) that carries urine down from your bladder to the outside.
If you're a woman, it can affect the neck of your womb (cervix) or your urethra, or both.
The infection can be passed on by oral sex or anal sex as well as vaginal sex. So it can also affect your throat and your back passage (rectum).
If you touch your eyes after touching infected fluid from your genitals you can get eye infection.[1]

Newborn babies can also be affected by chlamydia. This is because women who have the infection can pass it on during childbirth. If you're pregnant and you have chlamydia, your baby may be born with eye infections or pneumonia. But both of these problems can be treated with antibiotics.[2]

Here we've looked at treatments for uncomplicated chlamydia. This is when the infection hasn't spread beyond your urethra if you're a man or the neck of your womb if you're a woman.[3]

You're most likely to get chlamydia if:[4]

You're younger than 25
You have a new sex partner or more than one sex partner
You don't use condoms during sex.

If you're a woman, you are also more likely to get chlamydia if you're taking the contraceptive pill.

Chlamydia is sometimes called the 'silent disease' because you can have it without knowing it. Up to 8 in 10 women with chlamydia and 5 in 10 men don't have any obvious signs of infection.[2] This is a problem for two reasons.

People who don't know they are infected can carry on infecting other people.
If chlamydia isn't diagnosed and treated, it can cause more serious health problems. (See What will happen to me?)

References

Association of Medical Microbiologists. The facts about Chlamydia trachomatis. Available at http://www.amm.co.uk/files/factsabout/fa_chlam.htm (accessed on 29 October 2007).
British Association of Sexual Health and HIV. 2006 UK national guideline for the management of genital tract infection with Chlamydia trachomatis. British Association of Sexual Health and HIV. Available at http://www.bashh.org/guidelines/2006/chlamydia_0706.pdf (accessed 29 October 2007).
Low N. Chlamydia (uncomplicated, genital). May 2006. Clinical Evidence. (Based on January 2006 search.) http://clinicalevidence.bmj.com/ceweb/conditions/seh/1607/1607.jsp (accessed on 29 October 2007).
Health Protection Agency. Chlamydia (Chlamydia trachomatis). Available at http://www.hpa.org.uk/infections (accessed on 29 October 2007).

Glossary

infection: You get an infection when an organism, such as a bacterium, a fungus or a virus gets into a part of your body where it shouldn't be. For example, an infection in your nose and airways causes the common cold. An infection in your skin can cause rashes such as athlete's foot. The organisms that cause infections are so tiny that you can't see them without a microscope.
bacteria: Bacteria are tiny organisms. There are lots of different types. Some are harmful and can cause disease. But some bacteria live in your body without causing any harm.
urethra: Your urethra is the tube that carries urine from your bladder out of your body. In a man, the urethra runs through the inside of the penis. In a woman, the urethra is shorter and opens onto the top of the vagina.
bladder: Your bladder is the hollow organ at the top of your pelvis that stores urine. It is similar to a balloon, only with stronger walls. It fills up with urine until you go to the toilet.
cervix: The cervix is a piece of tissue that sits between a woman's womb and her vagina. It has a small opening in it that gets much bigger when a woman is having a baby.
rectum: The rectum is the last 15 to 20 centimetres (six to eight inches) of the large intestine, ending with the anus (where you empty your bowels from).
pneumonia: Pneumonia is an infection in your lungs. Anything that causes infections (bacteria, viruses or fungi, for example) can give you pneumonia.
antibiotics: These medicines are used to help your immune system fight infection. There are a number of different types of antibiotics that work in different ways to get rid of bacteria, parasites and other infectious agents. Antibiotics do not work against viruses.

This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.