Module 1

1. Module 1 Unit 2: Epidemiology of HIV

2. Objectives At the end of this session, the participant should be able to: • Describe the history of HIV • Explain the global, regional and national/local distribution of HIV • Discuss the distribution of HIV by age and sex • Discuss changes in morbidity and mortality due to HIV/AIDS • define different modes of HIV transmission • Discus factors that facilitate HIV transmission-biological and social

3. Historical background • 1981 - doctors in US recognized a previously unseen syndrome (PCP) in homosexual males • Later recognized that they were all immune suppressed • 1983/4 - scientist described the cause of the syndrome as a retrovirus • Lymphadenopathy Associated Virus (LAV) • AIDs Associated Retrovirus (ARV) • Human T-lymphotrophic Virus Ш (HTLV-Ш) • In Kenya the 1st case described in 1984 • 1986 - HIV accepted as international designation for the retrovirus in a WHO consultative meeting

4. Fourth biggest killer in the world Estimated 40 million living with HIV by end of 2003 About one-third of PLHA are between 15-24 years Most people are unaware they are infected Young women are more vulnerable Epidemic Update: Global Picture

5. Adults and children estimated to be living with HIV/AIDS as of end 2003 Eastern Europe & Central Asia 1.2 – 1.8 million Western Europe 520 000 – 680 000 North America 790 000 – 1.2 million East Asia & Pacific 700 000 – 1.3 million North Africa & Middle East 470 000 – 730 000 Caribbean 350 000 – 590 000 South & South-East Asia 4.6 – 8.2 million Sub-Saharan Africa 25.0 – 28.2 million Latin America 1.3 – 1.9 million Australia & New Zealand 12 000 – 18 000 Total: 34 – 46 million

6. Global summary of the HIV/AIDS epidemic, December 2003 Number of people living with HIV/AIDS Total 40 million (34 – 46 million) Adults 37 million (31 – 43 million) Children under 15 years 2.5 million (2.1 – 2.9 million) People newly infected with HIV in 2003 Total 5 million (4.2 – 5.8 million) Adults 4.2 million (3.6 – 4.8 million) Children under 15 years 700 000 (590 000 – 810 000) AIDS deaths in 2003 Total 3 million (2.5 – 3.5 million) Adults 2.5 million (2.1 – 2.9 million) Children under 15 years 500 000 (420 000 – 580 000) The ranges around the estimates in this table define the boundaries within which the actual numbers lie, based on the best available information. These ranges are more precise than those of previous years, and work is under way to increase even further the precision of the estimates that will be published mid-2004.

7. Epidemic Update:Sub-Saharan Africa • HIV is now the leading cause of death • 25.0 – 28.2 millionliving with HIV infection by end of 2003 • 10-15% of need ARV • Estimated 3-3.4 million new HIV infections in 2003 • 70% found in sub Saharan Africa • 10% (600 million) of world’s population live in sub Saharan African • By 2010, an estimated 106 million children under age 15 will have lost one or both parents, with 25 million of this group orphaned due to HIV/AIDS

8. Updates HIV/AIDS in Kenya

9. Impact on Morbidity and mortality of other infections • People with HIV/AIDS are susceptible to other infections • Due to lowered immunity • High HIV prevalence increases the pool of people with suppressed immunity • Any other infectious condition within such population (e.g.TB) therefore finds a highly susceptible group of people.

11. HIV Transmission • Modes of Transmission • Biological Factors Affecting Transmission • Socio-economic Factors Facilitating Transmission

12. Modes of Transmission • Sexual contact • Male-to-female, female-to-male, male-to-male, and female-to-female • Parenteral • Blood transfusion of infected blood or blood products • Exposure to infected blood or body fluids- IDU through needle-sharing or needle stick accidents • Donated organs • Perinatal • Transplacental, during labour/delivery and breastfeeding • Worldwide, sexual transmission is the predominant mode • HIV cannot be transmitted by casual contact, surface contact, or from insect bites

13. Percent infection by transmission route….

14. Biological factors influencing HIV transmission • Stage of HIV infection: • High riskduring primary infection (weeks) • Lower when asymptomatic (several years) • Rises as immune function deteriorates and viral load increases (months to years) • Presence of untreated ulcerative STIs • A major reason for high prevalence in SSA • Gender differences in susceptibility

15. Socio-economicFactors Facilitating Transmission • Social Mobility • Global Economy • HIV/AIDS follows routes of commerce • Stigma and Denial • Denial and silence is the norm • Stigma prevents acknowledgment of problem and care-seeking • People in Conflict • Context of war and struggle of power spreads AIDS • Cultural Factors • Traditions, beliefs, and practices affect understanding of health and disease and acceptance of conventional medical treatment

16. Socio-economicFactors (cont’d) • Gender • In many cultures men are expected to have many sexual relationships • Women suffer gender inequalities • Many women unable to negotiate condom use • Poverty • Lack of information needed to understand and prevent HIV • Drug Use and Alcohol Consumption • Impaired judgment • Sharing of needles and equipment

17. Factors not associated with risk of transmission • Factors not associated with risk of transmission • insect bites • Saliva • sneezing or coughing • skin contact (e.g. hugging) • shared use of facilities (e.g. toilets)

18. Summary • HIV has spread worldwide after its discovery • It is a major cause of morbidity and mortality in many countries • Many factors contribute to HIV transmission in a society • Knowledge of these factors can be used to design control strategies.