HIV is present to variable degrees in the blood and genital secretions of almost all individuals infected with HIV, regardless of whether they have symptoms or not.
The spread of HIV can occur when these secretions come in contact with tissues such as those lining the vagina, anal area, mouth, or eyes (the mucus membranes), or with a break in the skin, such as from a cut or puncture by a needle. The most common ways in which HIV is spreading throughout the world include sexual contact, sharing needles, and by transmission from infected mothers to their newborns during pregnancy, labor, or breastfeeding. How ever HIV-2 is transmitted less frequently from pregnant mother to her child and sexual route than HIV-1. The different modes of transmission of HIV are:
Sexual transmission of HIV is most common means of transmission of HIV and unprotected sexual relationship is the most common reason for HIV transmission. Transmission occurs when infected secretions of one person come into contact with the genital, oral, or rectal mucous membranes of other person.
Blood or blood product:
Transmission through this route is common in intravenous drug users, hemophiliacs and those who receive blood transfusions and blood products.
Health care workers like nurses, doctors, tattooing, piercing etc. are high risk behavior and can lead to infection by HIV. The spread of HIV by exposure to infected blood usually results from sharing needles, as in those used for illicit drugs. HIV can also spread by sharing needles for anabolic steroids to increase muscle, tattooing, and body piercing.
Pregnant mother to child:
The transmission of the HIV from the mother to the child can occur during pregnancy, during childbirth or through breast milk. The risk of transmission to the child is high in absence of treatment.
With treatment the rate and extent of transmission of the infection in newborn and fetus reduces dramatically. For prophylaxis antiretroviral drugs are prescribed to infants also.
HIV can also be transmitted by saliva, tears and urine of infected individuals but at present no data is available.
This is because saliva, in contrast to genital secretions, has been shown to contain very little HIV. Still, theoretical risks are associated with the sharing of toothbrushes and shaving razors because they can cause bleeding, and blood can contain large amounts of HIV.
Consequently, these items should not be shared with infected people. Similarly, without sexual exposure or direct contact with blood, there is little if any risk of HIV infection.
Facts about HIV Transmission
I. HIV cannot survive for very long outside of the body.
II. HIV cannot be transmitted through routine daily activities such as using a toilet seat, sharing food utensils or drinking glasses, shaking hands, or through kissing.
III. The virus can only be transmitted from person to person, not through animals or insect bites.
IV. People infected with HIV who are taking antiretroviral therapy can still infect others through unprotected sex and needle-sharing.
V. HIV is not transmitted by insects. No evidence of HIV transmission through insects -even in areas where there are many cases of AIDS and large populations of insects such as mosquitoes.