The HIV virus is found in semen, blood, rectal fluids, vaginal fluids and breast milk.
The most common ways of getting HIV is through unprotected vaginal or anal sex, by sharing sex toys without using condoms, or by sharing syringes or needles to inject drugs.
HIV can also be passed from an infected mother to baby during pregnancy or through breastfeeding.  It is very rare in the UK for HIV to be passed on to babies because of testing and effective treatment. 
Other risk factors  can include; 

• Medical treatment abroad 
• Blood transfusion  with unscreened blood (UK blood screened)

You can't get HIV:

• From sharing food, cooking or eating utensils
• From kissing 
• From shaking hands or hugging
• From the toilet or swimming pools
• From spitting or biting
• From sneezing

It is extremely unlikely that you will get HIV from oral sex although it is possible.

HIV needs to be diagnosed through a blood test.
HIV infection can be hard to spot in its early stages. Left untreated, a person with HIV will become very unwell over time. HIV mimics many other conditions so can be missed.
Many people with the infection will not have any symptoms for many years.
If you or your partner think you may have been infected with HIV, it is important for both of you to get tested.
HIV can be present for months or years before health problems begin. However, the person with HIV can still pass on the virus to other people during this time and their immune system will slowly become damaged.
If detected early, medicines should help the person with HIV stay well and lead a healthy and normal life. This is why it's important for anyone who has been at risk of catching HIV to get tested.

Testing for HIV is straightforward, highly accurate and is the only way to know if you are infected. If you have never tested for HIV you should consider a test. 
Also consider a repeat test if:

• you've had unprotected sex with a new partner
• you’ve shared injecting equipment
• you’ve been in hospital abroad where equipment may not have been sterile or was used on more than one person or had a blood transfusion abroad
• Had a tattoo or piercing where it might not have been done as a sterile procedure

All pregnant women in the UK are offered HIV testing as part of their routine antenatal care. This is because steps can be taken to prevent the virus from being passed on to the baby.
Because HIV can be passed on through sexual intercourse, if you are thinking about having sex without a condom you should consider  both you and your partner testing before doing so.
You can be tested for HIV at your local sexual health service or by your GP, or you can buy a test to do at home. Some charities also offer free testing.
Tests at a clinic or GP
Tests at a sexual health clinic or GP are completely free and confidential. An HIV test involves a trained health professional taking a small amount of blood from you, usually from your arm.
If you get infected with HIV, your body reacts to the infection and produces ‘antibodies’. The test looks to see if you have these HIV antibodies in your blood. If you do have HIV antibodies this means you have HIV. Nowadays blood tests also test for HIV itself by looking at the same time for the virus or ‘antigen’.
In some areas, saliva tests are available. In this test, a sample of saliva is taken using a mouth swab. In some areas dried blood spot tests are available, in which the finger or heel is pricked and a spot of blood is blotted onto filter paper.
You may get the result straight away or you may have to wait for them to send the sample to a laboratory for testing. Either way they will let you know your result and what this means. If you have any questions just ask the person taking the test or giving the result.
Self-test kits
You can now buy tests online (and some pharmacies may also stock them soon) to test your own blood for HIV. You must make sure that any test you buy is licenced for use in the UK, licenced tests will have a “CE” mark. You should never use a test that doesn’t have this mark as the results could be inaccurate. The test involves taking a drop of blood from your finger. 
The test will then check for antibodies in your blood. You must follow the instructions very carefully to ensure you get an accurate result.

If you have had a reactive result from a self-test kit, you should get a confirmation test from your GP or sexual health clinic to make sure it is accurate. If you were tested in a clinic or GP they will still do a second test just to confirm that the first result is correct.If your test shows that you do have HIV, you will be referred to a specialist for further advice, support and treatment. All of this is free. 
Having HIV may be a big shock but remember it is a treatable medical condition and you can stay healthy and live a normal life span.
Being HIV positive does not mean that you can’t have a sexual partner, but it is important to disclose to sexual partners your HIV status. When you are initially diagnosed you will be supported to contact previous sexual partners to advise them to have a test. Your specialist will talk to you about who else you might want to tell.
Legislation in the UK protects people with HIV from discrimination at work. It's up to you if you tell people at work that you have HIV. You don't have to tell anyone you don't want to although you might want to tell your boss so that you can have time off for medical appointments. Read more about telling people you have HIV here.

It can take up to three months after you have been infected with HIV for the virus to show up on a test. If your most recent risk of getting HIV was within the last three months you can test straight away as HIV can show up earlier, but you will be advised to have another test three months after your last risk to be entirely sure. This is an opportunity to look at how you can keep yourself safe in the future and reduce risk of picking up HIV.

Although there is no cure for HIV, there are effective treatments available that allow people with the infection to stay well and to lead normal healthy lives.
Treatment can also prevent mothers passing the virus to their children.
The sooner treatment starts, the more effective it will be.
HIV is treated with a range of drugs that slow the process of the disease. They can therefore prevent the infection causing health problems for many years but you need to keep taking them for them to continue working.
Regular blood testing to look at the amount of virus in the blood is used to show whether the treatment is working or whether a change in medicines is needed.
Nowadays many people just take one to two pills every day and see an HIV specialist every 6-12 months for a check-up.

The best way to prevent all sexually transmitted infections including HIV, is to practise safer sex. This means using a condom for vaginal or anal sex, a dam or condom for oral sex or practicing safer sex alternatives.
You can still have sex if you are HIV positive, but you are advised to practise safer sex. 
Alternatively, you can choose only to engage in types of sex that carry a lower risk of passing on sexually transmitted infections (STIs). HIV treatment reduces the chance of being able to pass the virus on. For more information, check out our risk-o-meter.
You should practise safer sex even if you and your partner both already have HIV. This is to avoid either of you becoming infected with more than one type of HIV or any other STI.
If you think you have recently been at risk of HIV (in the last 72 hours) you can take 
medication for a short time to reduce the risk of you getting the virus. This is called post-exposure prophylaxis (PEP) and is available at all sexual health clinics and A&E departments out of hours. Remember, if you have been at risk of HIV then the sooner you take this medication, the more effective it is at preventing infection (and certainly needs to be taken within 72 hours). Speak to your sexual health clinic (or A&E out of hours) as soon as you can for more information about this.

HIV can be passed from an infected mother to her child before or during birth. However, medicines are available that help to prevent this from happening. HIV can be passed from an infected mother to her child before or during birth. However, medicines are available that help to prevent this from happening. This is why all pregnant mothers in the UK are tested.
You might need to change the type of treatment you take and how you take it if you are already taking medicines for HIV and become pregnant.
Your midwife, GP and HIV service you are in contact with will advise you on what's best for you and your child and make sure you both get the right treatments.
HIV positive mums are currently in the UK advised not to breastfeed (as HIV can be passed on to the baby through breast milk) but children of HIV positive mums and dads are not at risk from other normal parental contact with their child. If you are newly diagnosed I pregnancy your existing children may advised to have a test.