Lecture 29 Transmission of HIV Transmission of HIV Most common methods of transmission of HIV are Unprotected sex with an infected partner Sharing needles with infected person Transmission from infected mother to fetus Infection from blood products Crossing of the Skin Layer From semen vaginal fluid blood or breast milk The HIV virus can penetrate the outer surface of fragile skin rectal or vaginal lining Then the virus enters the blood stream The HIV virus can enter the body through a cut scratch sore or needle puncture Then the virus enters the blood stream HIV Transmission Trends United States 64 of transmissions happened from men having sex with men Varying Stats on Modes of Transmission Across World Across the world it varies to region or mode of transmission Drug injection transmission rates are very high in Eastern Europe compared to Africa Routes of Exposure and Risk of Transmission Sexual Transmission Female to male transmission 1 out of 700 to 1 out of 3 000 Male to female 1 out of 200 to 1 out of 2 000 Male to male transmission 1 out of 10 to 1 out of 600 Parental Transmission Transfusions of infected blood 95 out of 100 Needle sharing 1 out of 150 Needle stick 1 out of 200 Needle stick AZT PEP 1 out of 10 000 Transmission from Mother to Infant Without AZT treatment 1 out of 4 With AZT treatment Less than 1 out of 10 Viral Load Affects Transmission HIV stages Risks of transmission reflects viral burden High viral load 1 30 1 200 Low viral load 1 1 000 1 10 0000 Starting HIV progression 1 100 1 1 000 AIDS 1 50 1 1 000 Condoms Use Reduces HIV Transmission Best case Pregnancy 97 and HIV 96 Typical case Pregnancy 86 and HIV 87 Drug Use Alcohol and HIV Infection clean needles for drug users The needle paraphernalia that is supplied in a needle exchange pack provide Pipe used to smoke cocaine makes you more susceptible to HIV Drug use leads to risky behavior Alcohol use is associated with high risk sexual behavior and IV drug use two major modes of HIV transmission Risk of HIV Transmission STI STD Along with risky sexual behavior it can lead to STDs and crossed with HIV it can STDs are often associated with open sores or other opportunities for the infection increase the viral load to spread STD and HIV together increase the chance of transmission Criminal deliberate and Reckless HIV Transmission 1 Use needles or other implements to intentionally infect others with HIV 2 HIV people who have had sex with the primary purpose of transmitting the virus to their partner 3 Considered grievous bodily harm or reckless endangerment HIV Laws and Policy in the USA In July 2010 the White House announced a major change in its HIV AIDS policy The official National HIV ADIS strategy for the United States concluded that the continued existence and enforcement of these types of laws criminalizing HIV infection run counter to scientific evidence about routes of HIV transmission and may undermine the public health goals of promoting HIV screening and treatment HIV Transmission Risk and Sexual Behavior Transmission depends on HIV viral load and type of sexual behavior The relative risk for HIV transmission varies depending on sexual act HIV transmission is reduced by approximately 80 with condom use 100 for receptive anal sex 20 for receptive vaginal sex 13 for insertive anal sex 10 for insertive vaginal sex 2 for receptive oral sex versus 1 for insertive oral sex Rise in HIV Among Women HIV transmission correlated highly with HIV viral load of the infected partner Is most likely with receptive rather than insertive activities Is 5X greater with receptive anal sex versus receptive vaginal sex Women more Susceptible to Infection Lower in heterosexual Hispanic latino or white men Mother to Child Transmission Very high in developing countries Mothers need to be on a regimen of drugs that are very expensive HIV Does NOT Spread By Insects including mosquitoes or ticks Air or water Saliva tears or sweats including spiting Casual contact like shaking hands or sharing dishes Closed mouth or social kissing Toilet seats Water Sharing musical instruments HIV does not survive for long outside of the body You cannot get HIV by donating blood HIV Transmission Viral Load is very important for transmission Timing during infection cycle HAART to keep viral load down Co occurring Sexually Transmitted Infections can increase viral load and physical exposure Types of exposure important for transmission Rectal lining is very delicate and tears Vaginal lining can tear and large surface area of mucous membrane Sores and open wounds increase exposure warts and mouth sores Trauma of pregnancy When to Have An HIV Test CDC recommends people should have an HIV test if they fall unto one or more of the following categories Having three or more partners in the last 12 years Have received a blood transfusion prior to 1985 or have a sexual partner who received a transfusion and later tested positive for HIV Not sure about one s sexual partner s risk behaviors Being a male who has had sex with another male Using street drugs by injection especially when sharing needles and or equipment Having a sexually transmitted disease STD Being a healthcare worker with direct exposure to blood on the job HIV Mandatory Testing in the U S Current U S laws enforce mandatory testing for the following populations Blood and organ donors Military applicants and active duty personnel Federal and state prison inmates under certain circumstances Newborns in some states HIV Counseling Testing Support Before you take the test Consider telling someone you trust you are having the HIV test Find out how private your test results will be Set a time to get your results There is a window of opportunity that can result in a false negative Seroconversion The time at which protein antibodies have increased to detectable 1 Screening Tests Highly sensitive results may be positive in a small percentage levels in blood Types of HIV Tests There are 3 broad categories of HIV tests of uninfected individuals A ELISA Urine and serum blood samples B Rapid tests blood oral fluid C Home Testing Kits 2 Confirmatory Test Western blot 3 A HIV viral load B CD4 cell count C Tropism test Tests of HIV Progression and Tropism
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