HIV/AIDS – a brief history : HIV/AIDS – a brief history Slide 2: In New York several young gay men developed Kaposi’s sarcoma – a rare cancer usually affecting old people
In California and New York a number of young gay men developed an unusual lung infection, PCP or pneumocystis carinii pneumonia
What was happening? 1981 A new disease : A new disease Doctors quickly realised they were facing a new disease: but what was causing it?
Because the first cases of HIV/AIDS were all found in gay men doctors assumed it might be something to do with the gay lifestyle. Was it … Immune system overload?
Cytomegalavirus – a virus found in more than half the population ?
Poppers – drugs heavily used in the gay community? 1982 : The new disease became know as AIDS Acquired – people acquire the disease, they don’t inherit it
Immune – it affects the immune system of the body
Deficiency – the immune system stops working properly
Syndrome – it involves a range of illnesses and symptoms, not a single disease 1982 The 1980s : The picture of AIDS as an American ‘gay’ disease began to change:
People with haemophilia showed symptoms of the new disease
People who injected drugs began to develop symptoms of AIDS
People in many European countries began to develop the symptoms of AIDS
Doctors in Uganda noticed a new wasting disease locally known as ‘slim’
Heterosexual women were found to have AIDS The 1980s People who had received blood, including a 20 month old baby, began to show symptoms and die of AIDS related infections The virus behind the disease : Once AIDS was recognised as an infectious disease, the hunt for the pathogen could begin.
In 1984, French and Americanscientists independently isolatedthe virus (a retrovirus) which has becomeknown as HIV –Human Immunodeficiency Virus The virus behind the disease So now people know that the main ways in which the HIV virus is spread are: : Unprotected sex between heterosexuals or homosexuals
Intravenous drug users sharing needles
Contaminated blood transfusions (where the blood isn’t screened before use)
From mother to baby during pregnancy, birth or breast-feeding
But all this information was not enough to stop the disease spreading around the world - because many governments failed to act quickly enough and many people didn’t take any notice when they did. So now people know that the main ways in which the HIV virus is spread are: 1987 : The WHO (World Health Organisation) listed 43,880 AIDS cases in 91 countries
Norman Fowler, (UK politician) and Princess Diana shook hands publicly with AIDS patients
Many people knew little or nothing about the fast-spreading AIDS epidemic. Major advertising campaigns were launched in countries including the UK, USA, France and Australia to try and inform people about HIV/AIDS – and how to avoid infection. 1987 1989 : Estimates suggest 5-10 million people infected with HIV world-wide
Zidovudine (better known as AZT) is released - the first drug to have an impact on AIDS. It delayed the move from infection with HIV to full-blown AIDS symptoms 1989 Second drug developed for treating AIDS – dideoxyinosine, or ddI Early 1990s : Third anti-viral drug, ddC, comes into use and combination therapy using two or more antiviral drugs is used to improve the survival time of people with HIV/AIDS
High profile figures such as Freddie Mercury and the US basketball star ‘Magic’ Johnson went public with the fact they had HIV/AIDS
Worldwide number for HIV/AIDS up to over nine million people, with over three million women infected Early 1990s 1994 : The number of people affected by HIV worldwide has risen to more than 14 million
The number of people with active AIDS is 2.5 million
Caesarian sections and AZT treatment through pregnancy are found to greatly reduce the spread of HIV/AIDS from mothers to babies 1994 1996 : UNAIDS – Joint United Nations Programme on AIDS is set up - six agencies working together against AIDS
New combination therapies raise (false) hopes that AIDS might become a chronic disease rather than a death sentence. 1996 Approximately 6.4 million people world-wide have already died of AIDS 1998 : Most developing countries still can’t afford the cost of anti-viral drugs like AZT
US government refuses to fund needle exchanges to help prevent spread of infection in intravenous drug users
Severe side effects develop in some patients on combination therapy 1998 First human trial of a AIDS vaccine 2000 : In Africa:
1 in every 4 adults in Botswana affected
25% of the population of Zimbabwe’s 12 million people HIV positive
South Africa has the highest number of HIV/AIDS infections in the world - but President Mbeki claims AIDS in Africa is not caused by HIV. 2000 The extent of the AIDS problem across the world becomes better known. Slide 15: In China, the infection is often spread by drug use and contaminated blood transfusions. At least 5 million people will be infected by 2005! 4 million people are infected in India and the numbers keep on growing 2005 : 2005 7 out of 10 people with HIV/AIDS live in sub-Saharan Africa
Women and men are equally affected by HIV/AIDS
HIV/AIDS still cannot be cured or prevented using medicines.
As we understand more about how the virus works grow, new medicines are being developed.
Cheap anti-retroviral drugs are being made available to countries in the developing world. Persuading people to change their behaviour to prevent the spread of HIV/AIDS is one of the biggest challenges faced across the world Toll of HIV& AIDS Epidemic : First AIDS case was reported from USA in 1981
Nearly 60 million people have been infected
More than 25 million have already died of AIDS
About 33.2 million people are now living with HIV/AIDS and Toll of HIV& AIDS Epidemic Slide 18: Global summary of the HIV and AIDS epidemic 2007 People living with HIV 33.2 million
New HIV infections in 2007 2.5 million
Deaths due to AIDS in 2007 2.1 million Slide 19: Share of the Disease Burden Slide 20: UNAIDS/WHO HIV Epidemic definitions Concentrated:Percentage of HIV sero-positivity, below 1% in the general population, over 5% in High-risk groups. Low level: Percentage of HIV sero-positivity, below 1% in the general population, under 5% in High-risk Generalized: Percentage of HIV sero-positivity, over 1% in the general population. Slide 21: Some important notes for HIV reproduction The half life of free HIV in plasma is 6 hours
The half life for CD4 is 1.6 days
Each generation of virus takes 2.6 days
140 generations per year within one individual
10 billion virions are produced per day
2 billion CD4 cells are infected and destroyed each day Laboratory Diagnosis of HIV infection : Antibody (Ab) detection tests: Late infection
- Rapid HIV tests
- ELISA: Ab to P24, RT, and gp120
- Western blot
Antigen (Ag) detection tests: Acute infection
- HIV P24 antigen (viral protein)
- HIV proviral DNA through PCR Laboratory Diagnosis of HIV infection Rapid HIV tests: a new strategy for changing epidemic : Rapid HIV tests: a new strategy for changing epidemic Rapid HIV tests are to:
Facilitate access to early diagnosis in high prevalence areas, for high-risk individuals
HIV testing opportunities can be expanded to both medical and non-medical settings and
Facilitates patients receiving their test results the same day, usually at the encounter where the test specimen was collected. Slide 24: The test kit’s colorimetric reagent binds to these antibody and an indicator is visible Reactive Non-Reactive Slide 25: Time taken to develop AIDS from beginning of HIV infection
Time taken to develop AIDS from beginning of HIV infection
5 years - 20%
8 years - 50%
15 years - 60% 60% of HIV infected individuals will develop AIDS after a variable period averaging about 8
60% of HIV infected individuals will develop AIDS after a variable period averaging about 8 years Slide 26: India Situation India is experiencing serious, localized epidemics.
In 2006, some 2.5 million people were living with the virus and
HIV prevalence among adults was around 0.36%. Slide 27: Oral Candidiasis more common Opportunistic Infection Slide 28: SLIM Disease –Weight loss Slide 29: Other Opportunistic Infections Cytomegalovirus Retinitis Slide 30: Other Opportunistic Infections Oral Leukoplakia (EBV) Pneumonia-PCP Slide 31: Other Opportunistic Infections Kaposi’s Sarcoma Oral Herpes simplex infection Advances in Treatment : The development of antiretroviral therapy has been one of the most dramatic progressions in the history of medicine for reducing HIV related morbidity and mortality
HAART prescribed to many HIV-positive people, even before they develop symptoms of AIDS.
There is definite progress in the field of opportunistic infections (OI) management Advances in Treatment HAART includes : one nucleoside analog
one protease inhibitor and
either a second nucleoside analog or a non-nucleoside reverse transcription inhibitor (NNRTI). HAART includes PREVENTION OF HIV TRANSMISSION : Abstinence
Sex with one partner, Reduce multiple sexual partners
Remain faithful to partner
Consistent and correct use of condom
Safe blood and blood product transfusion
Use disposable or sterilized syringe-needle
Use sterilized instrument for all medical surgery
Do not share your personal instrument with other (razor, blade, nail cutter etc.)
Prevent Parent to Child Transmission (PPTCT) PREVENTION OF HIV TRANSMISSION HIV - the AIDS virus : HIV - the AIDS virus Slide 36: H - human (because it infects people)
I - immunodeficiency (because it affects the immune system and eventually stops it working properly)
V- virus (because it is a retrovirus) What is a retrovirus? : Has RNA as genetic material
Takes over the nucleus of host cell but does not destroy the cell
HIV binds to CD4 receptors on the host cells using glycoproteins on the outside of the viral coat What is a retrovirus? HIV attacks the T-cells of the human immune system : Viral RNA translated into DNA by reverse transcriptase in host cell
Viral DNA then passes into nucleus and inserted into host DNA
Host transcriptase enzymes make viral mRNA and new viral genome RNA
Viral mRNA passes out into cytoplasm and new viral material (eg coat proteins) are synthesised
New virus particles put together and leave cell by exocytosis so cell isn’t destroyed
Viral DNA remains in host nucleus making more virus materials HIV attacks the T-cells of the human immune system The life cycle of HIV in a human immune cell : The life cycle of HIV in a human immune cell The virulence of HIV : 109 new viruses produced every day
On average there is one mutation during every replication cycle in the cellular genome - that’s a lot of new virus genomes
The high mutation rate means HIV can evade your immune system and develop resistance to drugs
There are already several different strains of HIV, some of which turn into full blown AIDS more quickly than others The virulence of HIV The Progression of HIV/AIDS : The Progression of HIV/AIDS Most infectious diseases follow a similar pattern.
You are exposed to a pathogen.
The pathogen replicates in your body and you feel ill.
Your immune system produces antibodies to the pathogen.
The pathogens are destroyed –and you feel better again HIV/AIDS is not like this : There are four stages in the progression of the disease from the initial infection to full blown AIDS.
The cells which are attacked by the virus are the cells of the immune system itself, so your body cannot overcome the pathogen and its effects. HIV/AIDS is not like this The stages of HIV/AIDS1. Acute HIV syndrome : The stages of HIV/AIDS1. Acute HIV syndrome Appears 3-12 weeks after you have become infected.
Some people feel unwell – symptoms include fevers, headaches, tiredness, and swollen glands, but not everyone infected with HIV feels ill.
HIV antibodies appear in your blood - you become HIV positive The stages of HIV/AIDS 2. Asymptomatic disease : The stages of HIV/AIDS 2. Asymptomatic disease No symptoms – so individual may be unaware that they are HIV positive. The HIV positive individual can infect other people in this stage
This stage may last from 10 years (HIV-1) up to 20 years (HIV-2)
The virus replicates rapidly, infecting the CD4 T-cells of the immune system. The stages of HIV/AIDS 3. Symptomatic disease : The stages of HIV/AIDS 3. Symptomatic disease Patients begin to suffer HIV-related clinical symptoms – weight loss, fatigue, diarrhoea, night sweats and infections such as thrush The stages of HIV/AIDS 4. Advanced AIDS : Severe weight loss.
Dementia as brain cells become infected.
Cancers, eg Karposi’s sarcoma.
Infections such as TB and cryptococcal meningitis.
The final stage of advanced AIDS is always death. The stages of HIV/AIDS 4. Advanced AIDS CD4 T-cells numbers fall; virus load climbs.Symptoms can include: How is HIV/AIDS spread? : How is HIV/AIDS spread? Slide 48: Many bacteria and viruses are spread by droplet infection through the air
Diseases such as colds, ‘flu, and TB are caught most easily in crowded conditions like airports, shops, factories - and schools! Slide 49: HIV/AIDS is
spread like this! HIV is a delicate virus : Some viruses can survive for a very long time in difficult conditions - but HIV is not one of them
Once HIV is outside of the body it dies within minutes unless it is still contained in body fluid eg blood in a needle HIV is a delicate virus HIV/AIDS is spread through body fluids : The main body fluids involved in the spread of HIV/AIDS are semen, vaginal fluids, blood and breast milk
Any behaviour which increases the risk of body fluids from an infected person mixing with the body fluids of a healthy person increases the risk of the healthy person being infected with HIV/AIDS HIV/AIDS is spread through body fluids How is HIV/AIDS most commonly spread? : Unprotected sex is the most common way in which HIV/AIDS is spread from one person to another.
If the skin is broken or damaged the risk is made higher
Having many sexual partners increases the risk of meeting someone with the virus How is HIV/AIDS most commonly spread? Slide 53: Infected blood is another common way of passing on HIV/AIDS
Since 1980 in the developed world blood transfusions are now screened and safe. In the developing world blood transfusions can still be a source of infection with HIV/AIDS Slide 54: Ways through HIV spreads-
Injecting Drug Use Slide 55: A woman infected with HIV/AIDS can infect her baby during pregnancy and birth
Even if the baby is born healthy, HIV/AIDS can be passed on in the milk if the mother breastfeeds her child