• AIDS: acquired
• Syndrome: a collection of
• Opportunistic infections
• caused by HIV (HIV-1):
• 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
AIDS considered an “emerging disease”
• HIV mutated in 1930s from a form exclusive to apes to
one that could live in humans.
• 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?
• HIV is a virus
• All viruses unable to multiply outside a host cell, and therefore, are classified
as intracellular, obligate parasites
• Most often causes some type of cell damage or death
• Many viruses exist within host at a low enough level that the host is not aware of this
• Since viruses‟ survival depends entirely on host, most viruses tend to cause
• Death in host = death of virus
• this is not the usual mode of action for most viruses because their existence would
cease to be
• Exceptions human immunodeficiency virus, ebola virus, pandemic influenza
• HIV is lentivirus, a class of retroviruses
• 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
• while HIV may disappear from cells of circulation, viral replication and budding
continues to occur in other tissues.
• recrudescence of viral production occurs that ultimately destroys the cell.
• AIDS 1st described in 1981 by physicians in U.S.- saw
healthy patients become sickly and develop opportunistic
infections and cancers
• described AIDS in the medical literature.
• Public health officials (PHOs) started with this information
and amassed additional data about the patients, hoping to
identify a cause for the new disease.
• By mid-1982, epidemiologists had data demonstrating that
AIDS was transmissible. A virus was suspect.
• 1983, a candidate retrovirus isolated and in 1984, it was
demonstrated to be causative pathogen.
• This retrovirus destroyed helper T-cells, the master cells of the body‟s
• Intensive research period to learn how
• HIV found to mutate 1,000 times faster than
influenza virus, thus dashing hopes for
making a traditional vaccine
• Antiviral drugs tested; AZT rapidly approved
as 1st anti-AIDS drug1987
• Public fear of AIDS and hostility towards
people with AIDS reached their zenith
• PHOs had to deal with epidemic of fear as
well as biological epidemic.
• Congress increased funding for AIDS
research across U.S.
• Surgeon General C. Everett Koop mailed a
brochure, “Understanding AIDS,” to every
household in the U.S. so that citizens would
know facts about AIDS instead of believing
• World Health Organization‟s AIDS
Programme began functioning
• With introduction of first protease inhibitor drug in
1995, Highly Active Anti-Retroviral Therapy
(HAART) transformed AIDS into a chronic
• epidemiological focus of epidemic shifted to
developing countries and marginalized
populations in U.S.
• 2006, universal screening guidelines for HIV
infection aimed to make AIDS a routinely reported
disease in U.S.
• 2013 UN agency reports „dramatic‟ progress on
reducing new HIV infections
HIV/AIDS Key driver of change in public
• Enormous impact because
• no biological control mechanism
• enormous cost
• many are vulnerable
• Effect on other infectious disease programs
• TB surveillance and control programs were successful public health
interventions, until HIV/AIDS epidemic reversed this achievement
• rise in active cases
• Effect on maternal child health programs and reproductive
• Changes to program planning and infrastructure due to:
• use of antiretroviral drugs for treatment
• prophylactic treatment for exposed babies
• breast feeding
• 2.3 million adults and children newly
infected with HIV in 2012,
• represents 33 % reduction in annual new
cases compared to 2001.
• new HIV infections among children fell 52 %
to 260,000 in 2012.
• greater access to antiretroviral TX led to a
30 per cent drop in AIDS-related deaths from
the peak in 2005.
• In the U.S., deaths typically through
• In other parts of the world, it is TB
• > 90% of new HIV infections are in
• In Africa (mostly sub Saharan), > 24 million
people with HIV infection and about 1 million
new cases of AIDS per year
• Of adult infections, 40% are in
women and 15% in individuals of
15-25 years of age.
• Perinatal infection resulting in a
large # of children being born with
• 30-50% of mother to child
transmissions of HIV results from
breast feeding and about a ¼ of
babies born to HIV-infected mothers
are themselves infected.
• Reduced through HAART
Figure 1. Prenatal Antiretroviral
Therapy and Impact on
Perinatal HIV Transmission
• Sexual Transmission
• Blood Transmission
• Mother to Child
HIV/AIDS Risk Groups
• Paid/commercial sex workers (CSWs)
• Men who have sex with men (MSM)
• Injecting drug users (IDUs)
• Any sexually active person who does not assume she/he is at
risk and take preventive measures
• HIV/AIDS Mother-to-child transmission
• Risk of
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
Testing for HIV
• Antibody tests: Once infected, takes 3-6 months
for enough antibodies to be formed for screening
tests to be positive
• If test negative, person should be retested in 6 months
• ELISA (also called EIA)
• Western blot or indirect immunofluorescence assay
• Rapid assessment tests
• PCR tests.
• Once positive additional tests may be done for
• 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.
• 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.
• Drug resistance. determines whether strain of HIV will
be resistant to certain anti-HIV medications and which
ones work better
The Course of the disease
From HIV Infection to AIDS
Acute infection (acute retroviral
• Initially, HIV infection produces a
• . This is not seen in all patients.
• 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.
• Mononucleosis-like symptoms
(fever, rash, swollen lymph glands
but none of these are lifethreatening.
may mimic the flu
• result is an initial fall in the number
of CD4+ cells but the numbers
quickly return to near normal.
The Course of the disease
From HIV Infection to AIDS
• No other symptoms may occur until enough CD4 cells
have been destroyed by HIV
• With loss of CD4 cells, the immune system cannot protect
• When CD4 count reaches 200 – person considered to have AIDS
• Without therapy, time from infection to AIDS = approximately 8-10
• Despite possible co-factors associated with lifestyle, HIV infected
persons progress to AIDS at a remarkably similar rate
• Antiretroviral therapy can prolong this time span
• Some people naturally have not progressed from HIV
infection to AIDS
• Referred to as long-term nonprogressors
Preventive interventions for HIV/AIDS
• Safe sex, including condom use
• Unused needles for drug users
• Male circumcision
• Treatment of other sexually transmitted infections (STIs)
• Safe, screened blood supplies
• Antiretrovirals (ARVs) in pregnancy to prevent mother-to-
child transmission (MTCT) and after occupational
Treatment Interventions for HIV/AIDS
• Antitretroviral drugs (ARVs)
• Highly active antiretroviral therapy (HAART): combination of
antiretroviral drugs that are used as medications to control
• Extend years between infection and onset of clinical AIDS
• Extend years between onset of AIDS and death
• works against HIV by using drugs in combination to suppress HIV replication
as many times as possible.
• problems for HIV replication, keeps HIV offspring low, and reduces the possibility of
• must be used in combination to suppress HIV for long periods of time
• Treatment of opportunistic infections (OIs)
• Palliative care (pain management)
High Costs of HIV Medication Cause
'Terrible Dilemma' in Mozambique
• 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.
Role of Advocacy and Activism
• International response to epidemic
• U.S. PEPFAR program
• Global Fund to treat AIDS, TB, and Malaria
• Bill and Melinda Gates Foundation
• World Bank
HIV/AIDS Critical Challenges
• Developing a vaccine to prevent the 2.6 million new
infections per year
• Cost-effective approaches to prevention in different
• Universal treatment for all those who are eligible
• Management of TB and HIV coinfection