As the name, Acquired Immunodeficiency Syndrome indicates, AIDS is a health condition that results from the deficiency in the body's immunity following HIV infection. HIV attacks the human body by breaking down its immune system that is meant to fight diseases. Over a period of time, the immune system weakens and the body loses its natural ability to fight diseases. At this stage, various diseases affect the infected person

1. Unprotected sex: If a person engages in sexual intercourse with an infected person without using a condom, s/he can get infected. The sexual act can be both vaginal and anal.
   
2. Sharing of needles: If a person shares the needle or syringe used by/on an infected person, either for injecting drugs or drawing blood or for any other purpose involving piercing, s/he can get infected. Instruments used for piercing and tattooing also carry a small risk of infection.
   
3. Unsafe blood: A person can get the infection, if he/she is given transfusion of infected blood.
   
4. Improperly sterilized hospital tools: If surgical devices like syringes and scalpels, or even certain instruments, used on an infected person, are used on another person without proper sterilization, they can transmit the infection.
   
5. Parent to Child: An HIV positive mother can transmit the virus to child during pregnancy or birth.

Many people do not develop any symptoms when they first become infected with HIV. Some people, however, get a flu-like illness within three to six weeks after exposure to the virus. This illness, called Acute HIV Syndrome, may include fever, headache, tiredness, nausea, diarrhea and enlarged lymph nodes (organs of the immune system that can be felt in the neck, armpits and groin). These symptoms usually disappear within a week to a month and are often mistaken for another viral infection.

During this period, the quantity of the virus in the body will be high and it spreads to different parts, particularly the lymphoid tissue. At this stage, the infected person is more likely to pass on the infection to others. The viral quantity then drops as the body's immune system launches an orchestrated fight

Once HIV enters the human body, it attaches itself to a White Blood Cell (WBC) called CD4. Also, called T4 cells, they are the main disease fighters of the body. Whenever there is an infection, CD4 cells lead the infection-fighting army of the body to protect it from falling sick. Damage of these cells, hence can affect a person's disease-fighting capability and general health.

After making a foothold on the CD4 cell, the virus injects its RNA into the cell. The RNA then gets attached to the DNA of the host cell and thus becomes part of the cell's genetic material. It is a virtual takeover of the cell. Using the cell's division mechanism, the virus now replicates and churns out hundreds of thousands of its own copies. These cells then enter the blood stream, get attached to other CD4 cells and continue replicating. As a result, the number of the virus in the blood rises and that of the CD4 cells declines

Because of this process, immediately after infection, the viral load of an infected individual will be very high and the number of CD4, low. But, after a while, the body's immune system responds vigorously by producing more and more CD4 cells to fight the virus. Much of the virus gets removed from the blood. To fight the fast-replicating virus, as many as a billion CD4 cells are produced every day, but the virus too increases on a similar scale. The battle between the virus and the CD4 cells continues even as the infected person remains symptom-free

But after a few years, which can last up to a decade or even more, when the number of the virus in the body rises to very high levels, the body's immune mechanism finds it difficult to carry on with the battle. The balance shifts in favour of the virus and the person becomes more susceptible to various infections. These infections are called Opportunistic Infections because they swarm the body using the opportunity of its low immunity. At this stage, the number of CD4 cells per millilitre of blood (called CD4 Count), which ranges between 500 to 1,500 in a healthy individual, falls below 200. The Viral Load, the quantity of the virus in the blood, will be very high at this stage.

Opportunistic infections are caused by bacteria, virus, fungi and parasites. Some of the common opportunistic infections that affect HIV positive persons are: Mycobacterium avium complex (MAC), Tuberculosis (TB), Salmonellosis, Bacillary Angiomatosis (all caused by bacteria); Cytomegalovirus (CMV), Viral hepatitis, Herpes, Human papillomavirus (HPV), Progressive multifocal leukoencephalopathy (PML) (caused by virus); Candidiasis, Cryptococcal meningitis (caused by fungus) and Pneumocystis Carinii pneumonia (PCP). Toxoplasmosis. Cryptosporidiosis (caused by parasites). HIV positive persons are also prone to cancers like Kaposi's sarcoma and lymphoma.

• Lack of energy.
• Weight loss.
• Frequent fevers and sweats.
• A thick, whitish coating of the tongue or mouth (thrush) that is caused by a yeast infection and sometimes accompanied by a sore throat.
• Severe or recurring vaginal yeast infections.
• Chronic pelvic inflammatory disease or severe and frequent infections like herpes zoster.
• Periods of extreme and unexplained fatigue that may be combined with headaches, lightheadedness, and/or dizziness.
• Rapid loss of more than 10 pounds of weight that is not due to increased physical exercise or dieting.
• Bruising more easily than normal.
• Long-lasting bouts of diarrhoea.
• Swelling or hardening of glands located in the throat, armpit, or groin.
• Periods of continued, deep, dry coughing.
• Increasing shortness of breath.
• The appearance of discoloured or purplish growths on the skin or inside the mouth.
• Unexplained bleeding from growths on the skin, from mucous membranes, or from any opening in the body.
• Recurring or unusual skin rashes.
• Severe numbness or pain in the hands or feet, the loss of muscle control and reflex, paralysis or loss of muscular strength.
• An altered state of consciousness, personality change, or mental deterioration.

Till today, there is no conclusive treatment to eliminate HIV from the body; however, timely treatment of opportunistic infections can keep one healthy for many years. The commonly available treatment for AIDS is the treatment against opportunistic infections. Normally standard treatment regimens, used against such infections in non-HIV patients, also work well with the HIV-positive persons. If properly treated, almost all the opportunistic infections can be contained.

Babies born to mothers infected with HIV may or may not be infected with the virus, but all carry their mothers' antibodies to HIV for several months after birth. If these babies lack symptoms, a definitive diagnosis of HIV infection using standard antibody tests cannot be made until after 15 months of age. By then, the babies are unlikely to still carry their mothers' antibodies and will have produced their own, if they are infected. New technologies to detect HIV itself are being used to more accurately determine HIV infection in infants between ages 3 months and 15 months. A number of blood tests are being evaluated to determine if they can diagnose HIV infection in babies younger than 3 months

• Consult a clinician experienced in treating HIV/AIDS.
• Protect your sex partner(s) from HIV by following safe-sex guidelines.
• Inform sex partner(s) who may also be infected.
• Do not share needles.
• Get psychological support from a counselor and/or join a support group for people with HIV.
• Get information and social and legal support from AIDS service organizations.
• Don't share your HIV status with people who do not need to know. Only tell people you can count on for support. Think about whom do you want to share your HIV status with.
• Maintain a strong immune system with a healthy lifestyle and regular medical examinations.
• Consider using antiretroviral therapies that may slow the progress of the infection in consultation with a qualified physician.
• Because there is no effective vaccine and no cure for HIV, the only way to protect oneself is prevention.
• People should either abstain from having sex or use latex condoms, during oral, anal, or vaginal sex. Only condoms made of latex should be used, and whenever necessary only water-based lubricants should be used. People who are allergic to latex can use polyurethane condoms.
• Although some laboratory evidence shows that spermicides can kill HIV, there is no conclusive evidence if it can prevent transmission.
• The risk of HIV transmission from a pregnant woman to her baby is significantly reduced if she takes AZT during pregnancy, labour and delivery, and her baby takes it for the first six weeks of life. Nevirapine is also found to be useful. But, one should seek expert medical assistance in such situations.
• Having a sexually transmitted disease (STD) can increase manifold a person's chances of getting HIV through sexual contact. So, it is necessary to treat STD as soon as you suspect infection.

• Masturbation - mutual masturbation.
• Touching - massage.
• Erotic massage - body rubbing.
• Kissing.
• Oral sex on a man with a condom.
• Oral sex on a woman with a dental dam, glyde dam, plastic wrap, or cut-open condom.
• Not sharing drug injecting, body piercing instruments, needles, syringes.
• Using properly sterilized hospital tools.

• Deep kissing.
• Oral sex.
• Vaginal intercourse with a condom or female condom.
• Anal intercourse with a condom (Try not to get semen or blood into the mouth or on broken skin.)

• Vaginal intercourse without a condom.
• Anal intercourse without a condom.
• Sharing needles, syringes and other body piercing instruments.

The major and minor signs classified by World Health Organisation are:

Major Signs:-

• Weight loss greater than 10% of body weight.
• Fever for longer than one month, intermittent or continuous.
• Chronic diarrhea for longer than one month, intermittent or constant.

Minor Signs:-

• Persistent cough for longer than one month.
• General itchy dermatitis (skin irritation).
• Recurrent herpes zoster (shingles).
• Oropharyngeal candidasis (fungus infection in the mouth/throat).
• Chronic progressive and disseminated herpes simplex infection.
• Generalised lymphadenopathy (swelling of lymp glands).

If a person has two major and two minor signs he is diagnosed as having AIDS. It is important to note that these symptoms are fairly common in various non-AIDS conditions also.