2. HIV/AIDS
ā¢ AIDS: acquired
immunodeficiency syndrome
ā¢ Syndrome: a collection of
symptoms
ā¢ Opportunistic infections
ā¢ caused by HIV (HIV-1):
human immunodeficiency
virus
ā¢ HIV causes AIDS by directly
causing the death of CD4+ Tcells (immune cells that fight
infections) or interfering with
the cells' normal functions, and
by triggering other events that
deteriorate a person's immune
system (Ois)
3. AIDS considered an āemerging diseaseā
ā¢ HIV mutated in 1930s from a form exclusive to apes to
one that could live in humans.
ā¢ Such diseases that move from one species to another are
known as zoonoses.
Ebola and tuberculosis are both examples of other zoonoses.
Where did HIV come from?
ā¢ http://youtu.be/UF3JGrt9Zvo
4. HIV/AIDS
ā¢ HIV is a virus
ā¢ All viruses unable to multiply outside a host cell, and therefore, are classified
as intracellular, obligate parasites
ā¢ Most often causes some type of cell damage or death
ā¢ Many viruses exist within host at a low enough level that the host is not aware of this
ā¢ Since virusesā survival depends entirely on host, most viruses tend to cause
mild infections
ā¢ Death in host = death of virus
ā¢ this is not the usual mode of action for most viruses because their existence would
cease to be
ā¢ Exceptions human immunodeficiency virus, ebola virus, pandemic influenza
ā¢ HIV is lentivirus, a class of retroviruses
ā¢ Unlike other retroviruses, which typically bud from infected cell for a long period
of time, HIV can lyze cell or lie dormant for many years, especially in resting T4
(CD4) lymphocytes;
ā¢ while HIV may disappear from cells of circulation, viral replication and budding
continues to occur in other tissues.
ā¢ recrudescence of viral production occurs that ultimately destroys the cell.
5. Short hx
ā¢ AIDS 1st described in 1981 by physicians in U.S.- saw
healthy patients become sickly and develop opportunistic
infections and cancers
ā¢ described AIDS in the medical literature.
ā¢ Public health officials (PHOs) started with this information
and amassed additional data about the patients, hoping to
identify a cause for the new disease.
ā¢ By mid-1982, epidemiologists had data demonstrating that
AIDS was transmissible. A virus was suspect.
ā¢ 1983, a candidate retrovirus isolated and in 1984, it was
demonstrated to be causative pathogen.
ā¢ This retrovirus destroyed helper T-cells, the master cells of the bodyās
immune response.
6. 1984-95
ā¢ Intensive research period to learn how
HIV worked
ā¢ HIV found to mutate 1,000 times faster than
influenza virus, thus dashing hopes for
making a traditional vaccine
ā¢ Antiviral drugs tested; AZT rapidly approved
as 1st anti-AIDS drug1987
ā¢ Public fear of AIDS and hostility towards
people with AIDS reached their zenith
ā¢ PHOs had to deal with epidemic of fear as
well as biological epidemic.
ā¢ 1988-95
ā¢ Congress increased funding for AIDS
research across U.S.
ā¢ Surgeon General C. Everett Koop mailed a
brochure, āUnderstanding AIDS,ā to every
household in the U.S. so that citizens would
know facts about AIDS instead of believing
rumors.
ā¢ World Health Organizationās AIDS
Programme began functioning
7. 1995-2006
ā¢ With introduction of first protease inhibitor drug in
1995, Highly Active Anti-Retroviral Therapy
(HAART) transformed AIDS into a chronic
disease.
ā¢ epidemiological focus of epidemic shifted to
developing countries and marginalized
populations in U.S.
ā¢ 2006, universal screening guidelines for HIV
infection aimed to make AIDS a routinely reported
disease in U.S.
ā¢ 2013 UN agency reports ādramaticā progress on
reducing new HIV infections
8. 8
HIV/AIDS Key driver of change in public
health
ā¢ Enormous impact because
ā¢ no biological control mechanism
ā¢ enormous cost
ā¢ many are vulnerable
ā¢ Effect on other infectious disease programs
ā¢ TB surveillance and control programs were successful public health
interventions, until HIV/AIDS epidemic reversed this achievement
ā¢ rise in active cases
ā¢ Effect on maternal child health programs and reproductive
health programs
ā¢ Changes to program planning and infrastructure due to:
ā¢ use of antiretroviral drugs for treatment
ā¢ prophylactic treatment for exposed babies
ā¢ breast feeding
9. HIV/AIDS epidemiology
ā¢ 2.3 million adults and children newly
infected with HIV in 2012,
ā¢ represents 33 % reduction in annual new
cases compared to 2001.
ā¢ new HIV infections among children fell 52 %
to 260,000 in 2012.
ā¢ greater access to antiretroviral TX led to a
30 per cent drop in AIDS-related deaths from
the peak in 2005.
ā¢ In the U.S., deaths typically through
Pneumocystis carinii
ā¢ In other parts of the world, it is TB
ā¢ > 90% of new HIV infections are in
developing countries.
ā¢ In Africa (mostly sub Saharan), > 24 million
people with HIV infection and about 1 million
new cases of AIDS per year
ā¢ .
10. HIV/AIDS epidemiology
ā¢ Of adult infections, 40% are in
women and 15% in individuals of
15-25 years of age.
ā¢ Perinatal infection resulting in a
large # of children being born with
HIV.
ā¢ 30-50% of mother to child
transmissions of HIV results from
breast feeding and about a Ā¼ of
babies born to HIV-infected mothers
are themselves infected.
ā¢ Reduced through HAART
Figure 1. Prenatal Antiretroviral
Therapy and Impact on
Perinatal HIV Transmission
13. HIV/AIDS Risk Groups
ā¢ Paid/commercial sex workers (CSWs)
ā¢ Men who have sex with men (MSM)
ā¢ Injecting drug users (IDUs)
ā¢ Prisoners
ā¢ Any sexually active person who does not assume she/he is at
risk and take preventive measures
ā¢ Women
ā¢ HIV/AIDS Mother-to-child transmission
ā¢ Risk of
ā¢
ā¢
ā¢
ā¢
acquiring HIV during delivery without intervention: 15% to 30%
HIV transmission during delivery if the mother is taking ARVs: <2%
acquiring HIV from breastfeeding without intervention: 25% to 45%
HIV transmission during breastfeeding if the mother is taking ARVs: much
lower
14. Testing for HIV
ā¢ Antibody tests: Once infected, takes 3-6 months
for enough antibodies to be formed for screening
tests to be positive
ā¢ If test negative, person should be retested in 6 months
ā¢ ELISA (also called EIA)
ā¢ Western blot or indirect immunofluorescence assay
(IFA).
ā¢ Rapid assessment tests
ā¢ PCR tests.
ā¢ Once positive additional tests may be done for
ā¢ CD4 count. Important because healthy person's CD4
count can vary from 500 to more than 1,000. Even if a
person has no symptoms, HIV infection progresses to
AIDS when CD4 count becomes < 200.
ā¢ Viral load. measures amount of virus in blood; people
with higher viral loads generally fare more poorly than
do those with a lower viral load.
ā¢ Drug resistance. determines whether strain of HIV will
be resistant to certain anti-HIV medications and which
ones work better
15. The Course of the disease
From HIV Infection to AIDS
Acute infection (acute retroviral
syndrome)
ā¢ Initially, HIV infection produces a
mild disease
ā¢ . This is not seen in all patients.
ā¢ In period immediately after
infection, virus titer rises (about 4 to
11 days after infection) and
continues at a high level over a
period of a few weeks.
ā¢ Mononucleosis-like symptoms
(fever, rash, swollen lymph glands
but none of these are lifethreatening.
ā¢
may mimic the flu
ā¢ result is an initial fall in the number
of CD4+ cells but the numbers
quickly return to near normal.
16. The Course of the disease
From HIV Infection to AIDS
ā¢ No other symptoms may occur until enough CD4 cells
have been destroyed by HIV
ā¢ With loss of CD4 cells, the immune system cannot protect
ā¢ When CD4 count reaches 200 ā person considered to have AIDS
ā¢ Without therapy, time from infection to AIDS = approximately 8-10
years
ā¢ Despite possible co-factors associated with lifestyle, HIV infected
persons progress to AIDS at a remarkably similar rate
ā¢ Antiretroviral therapy can prolong this time span
ā¢ Some people naturally have not progressed from HIV
infection to AIDS
ā¢ Referred to as long-term nonprogressors
17. Preventive interventions for HIV/AIDS
ā¢ Safe sex, including condom use
ā¢ Unused needles for drug users
ā¢ Male circumcision
ā¢ Treatment of other sexually transmitted infections (STIs)
ā¢ Safe, screened blood supplies
ā¢ Antiretrovirals (ARVs) in pregnancy to prevent mother-to-
child transmission (MTCT) and after occupational
exposure
18. Treatment Interventions for HIV/AIDS
ā¢ Antitretroviral drugs (ARVs)
ā¢ Highly active antiretroviral therapy (HAART): combination of
antiretroviral drugs that are used as medications to control
retroviruses
ā¢ Extend years between infection and onset of clinical AIDS
ā¢ Extend years between onset of AIDS and death
ā¢ works against HIV by using drugs in combination to suppress HIV replication
as many times as possible.
ā¢ problems for HIV replication, keeps HIV offspring low, and reduces the possibility of
HIV mutating.
ā¢ must be used in combination to suppress HIV for long periods of time
ā¢ Treatment of opportunistic infections (OIs)
ā¢ Palliative care (pain management)
19. High Costs of HIV Medication Cause
'Terrible Dilemma' in Mozambique
ā¢ http://www.youtube.com/watch?v=sETtnySexxy
ā¢ 10:30
ā¢ In Mozambique, where 1 in 8 adults is living with HIV, the
number of patients on antiretroviral drugs has expanded
thanks to international AIDS funding, but a debate is
emerging over whether foreign donors can continue to
fund an ever-expanding pool of patients.
20. Role of Advocacy and Activism
ā¢ International response to epidemic
ā¢ U.S. PEPFAR program
ā¢ Global Fund to treat AIDS, TB, and Malaria
ā¢ Bill and Melinda Gates Foundation
ā¢ World Bank
20
21. HIV/AIDS Critical Challenges
ā¢ Developing a vaccine to prevent the 2.6 million new
infections per year
ā¢ Cost-effective approaches to prevention in different
settings
ā¢ Universal treatment for all those who are eligible
ā¢ Management of TB and HIV coinfection