Disease Prevention and Control 1 (HIV) PDF

Human Immunodeficiency Virus (HIV) Infection Learning objectives: 1- Identify the links of HIV chain of infection 2- Identify the prevention and control measures for HIV 3- Apply prevention and control measures on specific occasions Chain of infection Agent: Human immunodeficiency vi...

Human Immunodeficiency Virus (HIV) Infection Learning objectives: 1- Identify the links of HIV chain of infection 2- Identify the prevention and control measures for HIV 3- Apply prevention and control measures on specific occasions Chain of infection Agent: Human immunodeficiency virus (HIV). There are two types: Type1 (HIV1) is the most common and Type2 (HIV2) causes similar symptoms but less severe. Reservoir: Man: HIV infected persons from the time of infection until their death, unless they start treatment. Source of infection: Body fluids from infected individuals namely - blood, and its products - breast milk, - semen, - vaginal secretions. Donated organs from infected donor Exit: - Vagina: mucous discharges - Urethra: seminal fluid - Skin: syringes, skin piercing instruments - Placenta: transplacental transmission - Breast nipples: breast milk - Site of donated organ Modes of transmission: 1- Direct modes - Sexual transmission with infected partners. - Vertical: from infected mother to child: during pregnancy, labour or breast feeding. - Organ transplantation. 2- Indirect modes - Parenteral: infected blood or blood products transfusion, contaminated needles, syringes, any contaminated skin piercing instruments. Inlet: - Skin: injections, skin piercing instruments and blood transfusion  - mucous membranes: o vagina (sexual transmission) o urethra (sexual transmission) o mouth (breast milk transmission). - umbilical cord (transplacental to the fetus) - site of transplanted organ Period of communicability: Begins early after infection and extends throughout life if no treatment is given. Susceptible host: Man: Susceptibility is general. Most cases have occurred among sexually active person aged 20- 49 years. Presence of other STDs especially those with ulcerations increase susceptibility to infection. Behaviours and conditions that put individuals at greater risk of contracting HIV include: - having unprotected sex ; - having another sexually transmitted infection (especially when ulcerations are present) such as syphilis, herpes, chlamydia, gonorrhoea, and bacterial vaginosis ; - sharing contaminated needles, syringes and other injecting equipment and drug solutions when injecting drugs; - Presence of other STDs especially those with ulcerations increase susceptibility to infection. - receiving unsafe injections, blood transfusions, medical procedures that involve unsterile cutting or piercing; and - experiencing accidental needle stick injuries, as among health workers in health care settings. Prevention 1- Health education: about nature of disease, modes of transmission, protection, health services. 2- Recreation facilities for young people 3- Male and female condom use Correct and consistent use of male and female condoms can protect against the spread of sexually transmitted infections, including HIV. Male latex condoms have an 85% or greater protective effect against the sexual transmission of HIV and other sexually transmitted infections. 4- Voluntary medical male circumcision Medical male circumcision, when safely provided by well-trained health professionals, reduces the risk of heterosexually acquired HIV infection in men by approximately 60%. This is a key intervention in generalized epidemic settings in Africa with high HIV prevalence and low male circumcision rates. 5- Harm reduction for injecting drug users This refers to a comprehensive package of interventions for HIV prevention and treatment among injecting drug users and includes: - needle and syringe programmes;  - opioid substitution therapy for people dependent on opioids by a longer acting but less euphoric oral opioid (methadone or buprenorphine) under medical supervision - HIV testing and counselling; - access to condoms - HIV treatment and care, - management of STIs, tuberculosis and viral hepatitis. 6- Elimination of mother-to-child transmission of HIV (eMTCT) The transmission of HIV from an HIV-positive mother to her child during pregnancy, labour, delivery or breastfeeding is called vertical or mother-to-child transmission (MTCT). In the absence of any interventions HIV transmission rates are between 15- 45%. MTCT can be nearly fully prevented if both the mother and the child are provided with antiretroviral drugs throughout the stages when infection could occur. Antiretroviral therapy (ART) is given to the newborn to reduce the risk of perinatal transmission of HIV. ART is initiated as soon as possible after delivery preferably within 6 to 12 hours of delivery administered at doses determined based on maternal and infant factors: - For non-breast-fed infants, ARV prophylaxis given for 6 weeks after delivery. This is recommended in settings where safe water supply is available (high income countries) to prepare formula food. - For breast-fed infants: ARV prophylaxis should continue, preferably throughout the breastfeeding period and for one to four weeks after cessation of breast feeding. This is recommended in settings where safe water supply is not available (in low income countries). - If infant is diagnosed as HIV positive ART is started and continues for life. 7- No vaccine is available against HIV infection, though trials are ongoing. Control 1- Notification: Notification of HIV and AIDS cases 2- Diagnosis of HIV infection: Usually screening tests are based on detection of HIV antibodies. (tests of generations 1, 2, & 3) However, antigen/antibody tests detect both HIV antibodies and antigens. (tests of generations 4 & 5). 3- Isolation of AIDS and HIV infected person is not required as transmission occurs through limited modes of transmission. 4- Treatment: HIV can be suppressed by combination ART (antiretroviral therapy), consisting of three or more ARV (antiretroviral) drugs. ART does not cure HIV infection but controls viral replication within a person's body and allows an individual's immune system to strengthen and regain the capacity to fight off infections. Treatment includes also drugs for prophylaxis and treatment of opportunistic infections. 5- Concurrent and terminal disinfection: Contaminated surfaces and articles soiled with blood of infected person should be cleaned and then disinfected using sodium hypochlorite. 6- Contacts A- Condom use: as discussed under prevention B- Pre-exposure prophylaxis (PrEP) for HIV-negative partner. Oral pre- exposure prophylaxis (PrEP) of HIV is the daily use of ARV drugs by HIV- uninfected people to block the acquisition of HIV. Studies have demonstrated the effectiveness of PrEP in reducing HIV transmission among sero-discordant couples (where one partner is infected and the other is not), and injecting drug users. (Truvada=tenofovir+emtricitabine) C- Post-exposure prophylaxis for HIV (PEP): is the use of ARV drugs (2 or 3 drugs regimes) within 48 hours of exposure to HIV in order to prevent infection. PEP is often recommended for health-care workers following needle stick injuries in the workplace. In high prevalence countries PEP may be given following rape assault. PEP includes counselling, first aid care, HIV testing, and depending on risk level, and administering a 28-day course of ARV drugs with follow-up care.