AIDS Transmission

HIV infection is a contagious disease and can be transmitted from person to person. It is most commonly transmitted by having sex without a condom or by sharing needles infected with the virus.

HIV is found in all the body fluids including saliva, nervous system tissue and spinal fluid, blood, semen, pre-seminal fluid (which is the liquid that comes out before ejaculation), vaginal secretions, secretions from the anus or anal lining walls, tears and breast milk.

Only blood, semen, and breast milk have been shown to transmit infection to others. The virus does not spread via air like flu.

How AIDS Is Transmitted

Methods of HIV transmission

In most countries worldwide the common methods by which this disease is transmitted includes:

  • Having unprotected or condom-less vaginal, oral and anal sex especially with high risk groups like those who are injection drug abusers or are likely to have HIV infection.
  • Sharing needles for injections with other drug users and patients who are likely to be HIV positive.
  • Sharing sexual toys and objects with an infected person
  • Among healthcare workers who can accidentally prick themselves with an infected needle. The risk is extremely low.
  • From an infected mother to her baby before or during birth. Transmission may also occur via breast milk during lactation. If the mother is treated with anti-HIV medications, the risk of transmission is low.
  • Via transfusion of blood contaminated with HIV. This is very rare these days since blood is screened for HIV before being transfused.
  • Getting a surgical operation with unsterile instruments that may have been used on HIV positive individuals
  • Being exposed to blood, organs or products of an infected person. This is common among healthcare workers.
  • Those who get tattoos or body piercing with shared needles or improperly sterilized devices.

The virus can enter the blood stream of an individual via cuts and sores in the skin, via the thin lining on or inside the anus, penis or vagina and via the thin lining of mucus the mouth and eyes.

What does not cause spread of HIV?

HIV infection is not spread by:

  • casual touching
  • hugging
  • light kissing
  • contact with unbroken, healthy skin
  • being sneezed upon by an infected person
  • sharing items of daily use like towels or cutlery and baths, toilets and swimming pools
  • via mosquito or animal bites
  • by mouth-to-mouth resuscitation

Spread via saliva of an infected person is rare. HIV is a very fragile virus and so does not live long outside the body

Who’s at risk?

  • Homosexual men who have unprotected anal intercourse
  • Heterosexual men and women who have unprotected sex
  • Those who have lived in or travelled extensively in black Africa and have indulged in high risk behaviors like unprotected sex and injection drug use.
  • Those who have had unprotected sex with a person who has lived in or travelled in black Africa
  • Injection drug abusers who share needles between themselves.
  • Sexual partners of illegal injection drug abusers
  • Those with sexually promiscuous behaviors who already have another sexually transmitted infection
  • People who have received a blood transfusion while in Africa, eastern Europe, the countries of the former Soviet Union, Asia or central and southern America where blood may not have been screened for HIV.

Further Reading

Last Updated: May 29, 2019

Dr. Ananya Mandal

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.


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  1. Uday Kumar Uday Kumar India says:

    If any body fluid contains HIV then why will the virus be transmitted only through blood, semen and breast milk ?

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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