TRANSMISSION

The most common way that HIV is spread is by having unprotected sex with someone who is infected.  The virus is able to enter the body through the lining of the vagina, vulva, penis, rectum, or mouth during sex.

HIV can infect anyone who practices risky behaviors such as

• • Sharing drug needles or syringes
• • Having sexual contact with an infected person without using a condom.
• • Sexual contact with a person whose HIV status is unknown

Infected blood

HIV can also be spread through contact with infected blood.  All donated blood is screened for HIV infection and heat-treated to destroy HIV in blood.  Before these safeguards were put in place, people were infected through transfusions of contaminated blood or blood components.  Today, studies have shown that there is now less then a 1 in 1 million chance of getting HIV infected blood from transfusions.

Contaminated needles

HIV is commonly spread among drug users by the sharing of syringes or needles.  The blood of someone who is HIV positive can infect these needles.  It is rare for a health care worker to become infected with HIV by accidental sticks with contaminated needles or other medical instruments.

Mother to child

It is possible for a woman to transmit HIV to their babies during pregnancy or birth.  It is estimated that one quarter to one third of untreated pregnant women who are infected with HIV will pass the virus to their babies.  HIV can also be spread to babies through the breast milk of mothers who are infected with the virus.  There are treatments now that can significantly reduce the chances that a baby will get infected from their mother.  If health care providers treat HIV infected pregnant women with certain drugs and the baby is delivered by cesarean section, the chances of the baby being infected can be reduced to less then 1 percent.  HIV infection of newborns has been almost eradicated in the United States due to appropriate treatment.  Unfortunately, infections of newborns in developing countries, is still very prevalent.

There have been recent studies that have found a highly effective and safe drug for preventing the transmission of HIV from an infected mother to her newborn.  The study shows that a single oral dose of the drug nevirapine (NVP) given to an HIV infected women in labor and another to her baby within 3 days of being born reducing the transmission rate by half when compared to a similar course of AZT (Azidothymidine).

Saliva

Researchers have found HIV in the saliva of infected people.  However there is no evidence that the virus can be spread by contact with saliva.  Studies have shown that saliva has natural properties that limit HIV’s power to infect and the amount of HIV in saliva is very low.  There is no evidence that HIV can be transmitted through saliva by kissing.  It is possible to be infected with HIV through oral intercourse.  Scientists have found no evidence that HIV is spread through sweat, tears, urine, or feces.

Casual contact

Studies of families who have HIV infected people have shown that HIV is not spread through casual contact such as sharing food utensils, towels, bedding, swimming pools, telephones, or toilet seats.  It is also not spread by insects such as mosquitoes or bedbugs.

Sexually transmitted infections

People with sexually transmitted infections (STI’s) such as syphilis, genital herpes, chlamydial infection, gonorrhea, or bacterial vaginosis are more susceptible to be infected during sex with an infected partner.

EARLY SYMPTOMS OF HIV INFECTION

Many people do not have any symptoms when they are first infected with HIV.  They may, however have a flu-like illness a month or two after exposure to the virus.  Some symptoms of the illness are

• • Fever
• • Headache
• • Tiredness
• • Enlarged lymph nodes (glands of the immune system easily felt in the neck and groin.
  

These symptoms will usually disappear within a week to a month and are often mistaken for symptoms of another viral infection.  During this period, people are very infectious as HIV is present in large quantities in genital fluids.

It may be 10 years or more after a person is first infected with HIV before more severe or persistent symptoms appear.  For children born with HIV symptoms may not appear for 2 years.   This period of “asymptomatic” infection will vary greatly person to person.  One person may have symptoms within a few months and others may have no symptoms for more then 10 years.

While a person may not experience any symptoms of HIV, the virus is still actively multiplying, infecting, and killing cells of the immune system.  The virus is able to hide in infected cells and lay dormant.  The most noticeable effect of HIV infection is the decline in the number of CD4 positive T cells.  These cells are the immune system’s key infection fighters.  HIV slowly disables or destroys these cells without causing symptoms.

A variety of complications start to happen as the immune system worsens.  The first signs of infection for many people are large lymph nodes that can be enlarged for more then 3 months.  

Other symptoms often experienced months to years before the onset of AIDS include

• • Lack of energy
• • Weight loss
• • Frequent fevers and sweats
• • Persistent or frequent yeast infections (oral or vaginal)
• • Persistent skin rashes or flaky skin
• • Pelvic inflammatory disease in women that does not respond to treatment
• • Short-term memory loss

DIAGNOSIS

Early HIV infections often cause no symptoms, so the best way to diagnose it is by testing a person’s blood for the presence of antibodies to HIV.  These antibodies do not usually reach noticeable levels for 1 to 3 months.  However it may take up to 6 months for the body to produce enough antibodies to show up on standard blood tests.  

The best way to determine whether a person has been infected is to be screened for the presence of HIV genetic material.  Someone who believes they have been exposed to the virus should get an HIV test within 6 weeks to 12 months after exposure.  Early detection is key to prevent further transmission and to start treatment for HIV and opportunistic infections.

HIV infection is diagnosed by using two different types of antibody tests: ELISA and Western Blot.  If a person is highly likely to be infected with HIV but has tested negative then more tests may be required.  A person may also be told to repeat antibody testing at a later date, when antibodies to HIV are more likely to have developed.

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