HIV and AIDS A Global Pandemic. The basics. NM1726

Transcription

1 HIV and AIDS A Global Pandemic. The basics. NM1726

2 Learning Outcomes To understand the epidemiology and transmission of HIV To have an understanding of treatment issues To be able to assess the problems patients face To be ready to apply knowledge to practice

3 HIV and AIDS Human Immune-deficiency Virus (HIV) is a virus spread by contact with sexual fluids and blood. It destroys the body s ability to fight off infection. As the immune system fails, a person is vulnerable to a range of exotic opportunistic infections. AIDS (Acquired Immune Deficiency Syndrome) is the end stage of HIV infection. The immune system has collapsed and opportunistic infections are present A person can catch HIV, you don t catch AIDS you develop it

4 Where did it come from? A zoonotic pathogen, an infection that jumped from one species to another. Probable source of origin Africa. HIV closely resembles simian immune deficiency virus (SIV), an infection which affects apes. Species jump probably occurred when an infected ape was being butchered (bush meat), or when an ape, kept as a pet, bit or scratched its owner.

5 Two main types, many mutants HIV-1, the predominant type found all around the world. HIV-2, much rarer, mainly found in some countries in West Africa. In general, less virulent than HIV-1. HIV multiplies in its millions within the human body. As it does so, some mistakes in replication are made. Thus even within a single individual, multiple variants of HIV, known as quasi-species, are produced.

6 Routs of transmission Blood and certain body fluids Prime mode of infection is sexual transmission Sharing drug injecting materials Vertical transmission Occupational exposure Transfusion of unscreened blood products (solid organ transplantation)

7 Sexual risk Pyramid Anal sex receptive Anal sex insertive Vaginal sex receptive Vaginal sex insertive Oral sex receptive Increasing Risk Oral sex insertive Mutual masturbation

8 Retrovirus Epidemiology Transmission Lifecycle Immune system Know your enemy

9 HIV infects a CD4 cell

10 HIV Prevalence 2007 Number of people living with HIV in million

11 Grim Demographics

12 Why no vaccine? As HIV mutates so readily, it is a moving target. Currently has not proved possible to develop a vaccine. Research is looking at two types of vaccines A preventative vaccine, to stop people catching HIV. A therapeutic vaccine which would make a person with HIV less likely to pass on the infection and in addition help slow down damage to an individual s immune system.

13 We have increasingly effective treatment but no cure We give patients highly active anti-retroviral therapy (HAART). HAART is a combination of different medication which block HIV at different stages of its cycle of replication. Unfortunately HAART can only slow down the damage that HIV causes to the immune system, not stop it. Nonetheless, for the majority of people living with HIV, we can give several, perhaps many, years of reasonable quality of life. Sadly, only a minority of the world s population has access to HAART. Much of the developing world, which faces the greatest burden of HIV can neither access or afford medication

14 HIV represents a catastrophic economic and social burden

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16 Scale of the Problem in the UK An estimated 77,400 people were living with HIV in the UK at the end of 2007, of whom over a quarter (28%) were unaware of their infection. During 2007 there were 7734 new diagnoses of HIV, a similarly high figure to the diagnoses made in each of the previous four years. New HIV diagnoses among men who have sex with men continue to increase and over four-fifths of these infections were probably acquired in the UK. The estimated number of people infected through heterosexual contact within the UK has increased from 540 new diagnoses in 2003 to 960 in 2007, and has doubled, from 11% to 23%, as a proportion of all heterosexual diagnoses during this period

17 Adjusted number of new HIV diagnoses by prevention group, UK Proportional adjustment for missing information applied HIV and AIDS New Diagnoses and Deaths

18 Diagnosis and monitoring There is no such thing as an AIDS test. Remember, AIDS is a syndrome which develops after time. HIV is the pathogen which causes the damage. There is an HIV test. The test looks for the presence of antibodies that the body eventually develops against HIV. It takes 12 weeks after contracting HIV before an accurate test can be performed. There is a second test which looks for the presence of viral antigen (particles of the virus itself). This test is much more sensitive and can be performed within days of a risky sexual contact. However, it can lead to false positive results and for this reason is not routinely performed.

19 The patient s journey Initial diagnosis Asymptomatic HIV infection Symptomatic HIV infection AIDS diagnosis An uncertain future but now, diagnosis does not equal death thanks to new treatments

20 HIV continuum Diagnosis of AIDS based on four criteria: CD4 count falling below 200 Opportunist Infections Opportunist tumours, Neurological Conditions

21 Therapy HAART (Highly Active Anti- Retroviral Therapy) Combo/combination therapy (drugs are always given in combination, at least three drugs) Remember, a treatment, not a cure

22 Aims of therapy Suppression of the virus Elevation of CD4 count Improved quality and length of life Slowing disease progression Preventing opportunistic infections (OIs)

23 RESOURCES National AIDS manual website on line current magazine United Nations AIDS Organisation World Health Organisation Health Protection Agency HIV AIDS Information Adler,M.W.(2001) ABC of AIDS (5 th Ed) London. BMJ Publishing Pratt,R.J.(2003) HIV&AIDS (5 th ed) A Foundation for Nursing and Healthcare Practice. London. Arnold Smith,U (2002) PDNT: HIV/AIDS Part 1: Microbiology and Virology Nursing Times 98(5):41-44 Smith,U (2002) PDNT: HIV/AIDS Part 2: Modes of transmission, testing for HIV antibodies and Occupational Exposure to HIV Nursing Times 98(6): Smith U (2002) PDNT: HIV/AIDS Part 3: Treatment and Care Issues Nursing Times 98(7):41-44