How do you get it? 
Hepatitis A is found in faeces. It can be acquired through contaminated food or water (which is why you should always wash your hands after using the toilet), or through sex acts such as rimming. Even just tonguing the outside of your partner's arsehole can be risky, more so if he has not showered beforehand. Fucking or fingering a guy's arse can also transmit hepatitis A, as it's easy to transfer it from your fingers to your mouth.

How do you prevent it? 
The best way to prevent hepatitis A is by getting vaccinated. The vaccine is available at most GUM clinics, travel clinics or you can ask your GP. The vaccine is a course of two injections taken six months apart.

How do you know you've got it? 
The symptoms appear two to six weeks after infection. These can include headache, fever, loss of appetite, nausea, vomiting, lethargy, and muscle and joint pains. Later your eyeballs and skin may become jaundiced (go yellow). Your urine can turn dark brown and your faeces can turn pale. Your liver (just below your ribs on the right side of your body) may become tender. Not everyone with hepatitis A will have such severe symptoms. A sexual health clinic can test you for hepatitis A. They will usually ask questions about the sex you've had to see if this test is necessary. It is tested for by taking a blood sample. Or your GP can do the test.

How do you treat it? 
The only treatment for hepatitis A is plenty of rest, a low-protein and high-carbohydrate diet, and avoiding fatty foods and alcohol. The illness clears up by itself within one to three months, causing no lasting damage. Once you have had hepatitis A you will be immune to catching it in the future. In more severe cases you may require a hospital stay, which is why it's important to get diagnosed and and receive professional medical advice. 

Which sexual partners should I inform if I've been diagnosed with hepatitis A?
If you have jaundice (yellowing of the skin), anyone you've had sex with two weeks before the jaundice appeared, plus anyone you had sex with within a week of the jaundice appearing.