MODES OF TRANSMISSION

HIV is transmitted primarily by sex (anal, vaginal or oral sex with an infected partner), by injections (sharing contaminated needles for drug use or accidental piercing with a contaminated needle), or from infected mother to child through pregnancy or breast-feeding.Infected semen and vaginal fluids, infected blood and blood products lead to the transmission of HIV. Drug abuse with unsterilized needles is another high-risk activity. Unprotected sex with multiple partners is the primary cause of infection. During unprotected sex, the infected fluid could enter the bloodstream through a tiny cut or a sore. Anal penetration has a higher risk of transmission, which is why a high percentage of homosexuals develop the disease. Bleeding during sex also raises the chances of infection. Therefore unprotected sex during menstrual periods and anal intercourse are best avoided. An infected mother can also transmit the virus to her baby before or during birth or through breast milk. Although traces of HIV have been detected in body fluids (saliva, urine, faeces and tears) there is no evidence that HIV spreads through these fluids. Nor is it water-borne, air-borne or transmitted through mosquitoes and other insects. Some HIV-infected patients progress to AIDS quickly while others can remain healthy for 10 years or more. Between initial infection and full-blown disease, a middle phase called symptomatic HIV infection, or AIDS-related complex (ARC), occurs, prompting symptoms such as weight loss, diarrhea, and swollen lymph glands.Scientists have recently discovered clues to why some patients develop AIDS quickly. In a study published last March in the journal Science, National Cancer Institute researchers found that inherited genes may set the clock for AIDS progression. Certain gene patterns tend to stave off AIDS, while others promote it. The researchers say the study may help lead to an AIDS-preventive vaccine or improved therapies against the virus.

Gender Differences in the Risk of HIV Infection

HIV risk factors among injection drug users (IDUs) differ markedly by gender, according to a 10-year study funded by the National Institute on Drug Abuse (NIDA). A recent study by researchers at the Johns Hopkins University reported that while drug-related risk behaviors and homosexual activity are the most important predictors of HIV seroconversion among males, factors consistent with high-risk heterosexual activities are the main predictors among females. The findings, reported in the May 28 (2001) issue of the Archives of Internal Medicine, provide insight into the relationship between gender and high-risk sexual behaviors in the development of HIV infection."Early studies of injection drug users suggested that most HIV infections were due primarily to sharing needles," said NIDA Director Alan I. Leshner, Ph.D. "This study adds to the body of evidence that supports the need for gender-specific interventions in the treatment of that group of drug users."Between 1988 and 1998, a team of researchers, led by Dr. Steffanie Strathdee at the Johns Hopkins University Bloomberg School of Public Health, examined both drug related and sexual risk factors for HIV transmission in a study of more than 1,800 injecting drug users in Baltimore, Maryland. Study participants were aged 18 or older, did not have an AIDS defining illness at enrollment, and reported a history of illicit injection drug use within the previous 10 years. Through semiannual interviews, researchers collected data on drug use history, sociodemographics, and drug use and sexual behavior within the last 6 months. Blood samples were also obtained at each study visit. Researchers used commercial HIV and antibody ELISA to identify those participants who had become HIV positive since their last visit.Dr. Strathdee and her colleagues found that the greatest predictor for HIV seroconversion among both male and female IDUs was high-risk sexual behavior. Study findings revealed that male injection drug users who reported recent homosexual activity were four times more likely to become infected with HIV.Among females, indicators of high-risk heterosexual activity outweighed needle-sharing behaviors as independent predictors of HIV seroconversion. HIV incidence was more than two times higher among women who reported recently having sex with another injection drug user.Another common predictor of HIV seroconversion observed by researchers among both male and female IDUs was younger age. Investigators found that IDUs who were aged 30 or younger at enrollment were more than twice as likely to seroconvert than those aged 40 or older."This is consistent with several reports which indicate that younger IDUs are more likely to engage in needle sharing and other behaviors that place them at higher risk of acquiring HIV and hepatitis B or C viruses," stated Dr. Strathdee.

PREVENTION

While AIDS is a high-risk disease it can be prevented if proper precautions are taken and greater awareness meted out to those who are ignorant of the virus and its repercussions on the human body. Here we have listed a few measures which can be adopted by everyone inorder to stave off the insidious entry of HIV.• Prevention is still the best bet. Promiscuous sexual behavior can leave a person highly susceptible to contracting the virus. Where abstinence is not possible, always use latex condoms. The female condom can also help protect both partners. Use only water-based lubricants. Oil lubricants (such as Vaseline) might even tear latex condoms. Use spermicidal (birth control) foams and jellies in addition to condoms. By themselves, spermicides may not be effective in preventing HIV.
• Avoid alcohol or drugs during sex, you might lose control of your senses and engage in unsafe sex. Stick to safer sex practices at all times and avoid having multiple partners. Practice monogamy. If this is a tall order, serial relationships are a lesser evil than multiple ones.• High-risk sexual behavior should be avoided at all costs. These include: oral genital sex involving contact with semen or vaginal fluids, oral anal sex, vaginal sex without a condom, anal sex sans a condom (active or passive), fisting or manual anal intercourse, the sharing of sex toys, using saliva for lubrication and blood contact of any kind during performance. If unable to resist oral sex, use a dental dam. If a woman is infected, avoid sex during the menses as menstrual blood is infectious• For transfusions, use disposable syringes and needles. Ensure you get blood that is screened and certified as HIV-free. Better still, get blood from close family members rather than professional donors whose medical antecedents are nebulous. • The presence of sexually transmitted diseases (STDs) increases the risk of contracting HIV from an infected partner. STDs could cause breaks in the skin of the vagina, penis or anus permitting the virus to enter your bloodstream. If you ever contract an STD of any kind, ensure you get prompt treatment.• The CDC recommends that an HIV-positive woman should not breast-feed her baby. The infant should be given AZT for the first several weeks to substantially reduce the risk of infection.