Transmission
HIV
is spread most commonly by sexual contact with an infected partner. The virus
can enter the body through the lining of the vagina, vulva, penis, rectum or
mouth during sex.
HIV
also is spread through contact with infected blood. Prior to the screening of
blood for evidence of HIV infection and before the introduction in 1985 of
heat-treating techniques to destroy HIV in blood products, HIV was transmitted
through transfusions of contaminated blood or blood components. Today, because
of blood screening and heat treatment, the risk of acquiring HIV from such
transfusions is extremely small.
HIV
frequently is spread among injection drug users by the sharing of needles or
syringes contaminated with minute quantities of blood of someone infected with
the virus. However, transmission from patient to health-care worker or
vice-versa via accidental sticks with contaminated needles or other medical
instruments is rare.
Women
can transmit HIV to their fetuses during pregnancy or birth. Approximately
one-quarter to one-third of all untreated pregnant women infected with HIV will
pass the infection to their babies. HIV also can be spread to babies through the
breast milk of mothers infected with the virus. If the drug AZT is taken during
pregnancy, the chance of transmitting HIV to the baby is reduced significantly.
If AZT treatment of mothers is combined with cesarean sectioning to deliver
infants, infection rates can be reduced to 1 percent.
Although
researchers have detected HIV in the saliva of infected individuals, no evidence
exists that the virus is spread by contact with saliva. Laboratory studies
reveal that saliva has natural compounds that inhibit the infectiousness of HIV.
Studies of people infected with HIV have found no evidence that the virus is
spread to others through saliva such as by kissing. No one knows, however, the
risk of infection from so-called "deep" kissing, involving the
exchange of large amounts of saliva, or by oral intercourse. Scientists also
have found no evidence that HIV is spread through sweat, tears, urine or feces.
Studies
of families of HIV-infected people have shown clearly that HIV is not spread
through casual contact such as the sharing of food utensils, towels and bedding,
swimming pools, telephones or toilet seats. Insects such as mosquitoes or
bedbugs do not spread HIV.
HIV
can infect anyone who practices risky behaviors such as:
·
Sharing drug needles
or syringes;
·
Having sexual contact
without using a latex male condom with an infected person or with someone whose
HIV status is unknown.
Having
another sexually transmitted disease such as syphilis, herpes, chlamydial
infection, gonorrhea or bacterial vaginosis appears to make someone more
susceptible to acquiring HIV infection during sex with an infected partner.
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Sex
