Sexually transmitted infectionsSpec 5.8
Sexually transmitted infections (STIs) are spread by sexual contact. You need two examples: chlamydia and HIV.
| Chlamydia | HIV | |
|---|---|---|
| Pathogen | Bacterium | Virus |
| How it spreads | Unprotected sexual contact | Unprotected sexual contact; sharing needles; contact with infected blood; from an infected mother to her baby |
| Effects | Often no symptoms; can cause infertility | Destroys white blood cells and can lead to AIDS |
| How spread can be reduced | Use condoms; screening and testing; treating infected people with antibiotics; informing partners | Use condoms; do not share needles; screen donated blood; drug treatment to lower the amount of virus |
Condoms act as a barrier that stops body fluids passing from one person to another. Using a condom, having fewer partners and being tested regularly all reduce the spread.
Quick check
Name the four types of pathogen.
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Viruses, bacteria, fungi and protists.
How is cholera spread, and how can its spread be reduced?
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Through contaminated water; provide clean water and treat sewage.
What is the vector for malaria?
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The mosquito.
Triple only: what happens to the host cell in the lytic pathway?
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It bursts open (lyses), releasing new viruses.
Name a bacterial STI and a viral STI.
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Chlamydia (bacterial) and HIV (viral).