Reducing Risk of STIs and HIV, Care and Support
Senior 2 · Biology
Reducing Risk of STIs and HIV, Care and Support
Lesson 1 of 5
22 min
Sexually transmitted infections (STIs) are infections passed from one person to another mainly through sexual contact. They are common among young adults worldwide, and many cause no symptoms at all, so people pass them on without knowing. Untreated, some STIs cause infertility, harm babies at birth, or damage the heart and brain. The good news is that the three bacterial STIs in this lesson can all be cured with antibiotics if they are found early.
| Chlamydia | Gonorrhoea | Syphilis | |
|---|---|---|---|
| Cause | The bacterium Chlamydia trachomatis | The bacterium Neisseria gonorrhoeae | The spiral-shaped bacterium Treponema pallidum |
| Signs in males | Often none; sometimes a discharge from the penis, pain when urinating, painful testes | Burning pain when urinating; a white, yellow or green discharge from the penis; sometimes swollen, painful testes | See the stages below |
| Signs in females | Usually none; sometimes an unusual vaginal discharge, pain when urinating, pain in the lower abdomen | Often none; sometimes vaginal discharge, pain when urinating, bleeding between periods | See the stages below |
| If untreated | The infection can spread up to the uterus and oviducts, causing pelvic inflammatory disease (PID). Scarring can block the oviducts, causing infertility and ectopic pregnancy (a pregnancy that grows outside the uterus, usually in an oviduct, which is life-threatening). In men, the tubes beside the testes can become inflamed. A baby can be infected in the eyes at birth, and gonorrhoea can spread through the blood to the joints and heart. | Progresses through stages over many years and can damage the heart, brain and nerves; it can kill. | |
| Treatment | Antibiotics | Antibiotics. Some strains have become resistant to several antibiotics, so testing and completing treatment are important. | Antibiotics, usually a penicillin injection |
Congenital syphilis is passed from an untreated mother to her unborn baby and can cause miscarriage, stillbirth or serious deformities. This is why every pregnant woman is tested for syphilis at her first antenatal visit.
Sores from syphilis and other STIs break the skin's barrier, which makes it much easier for HIV to enter. Treating STIs therefore also helps prevent HIV.
A young married man comes to the health centre with burning pain when urinating and a yellow discharge from the penis. His wife feels well. What is the likely cause, and what should happen?
Tip
"No symptoms" does not mean "no infection". This is the most tested idea in this topic. Chlamydia and gonorrhoea are often silent, especially in women, and syphilis has a silent latent stage.
Syphilis stages in order: sore → rash → silence → serious damage (primary → secondary → latent → tertiary).
Name the organism that causes each STI: (a) syphilis (b) gonorrhoea (c) chlamydia. What type of organism are they all?
Answer: (a) Treponema pallidum; (b) Neisseria gonorrhoeae; (c) Chlamydia trachomatis. All three are bacteria, which is why antibiotics can cure them.
Explain how untreated chlamydia can make a woman unable to become pregnant.
Answer: The infection can spread to the uterus and oviducts, causing pelvic inflammatory disease. Healing leaves scars that can block the oviducts, so sperm cannot reach the egg and the egg cannot reach the uterus.
Why do many people with primary syphilis fail to seek treatment?
Answer: The chancre is painless, may be hidden inside the body, and heals by itself within a few weeks, so the person thinks the problem has gone. The bacteria, however, remain and spread.
Why are pregnant women tested for syphilis?
Answer: Untreated syphilis can pass to the unborn baby, causing miscarriage, stillbirth or deformities. Found early, it is easily cured with penicillin, protecting both mother and baby.
Remember
Sources and credits
