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Explanation of HIV/AIDS
Status
Exposure to the HIV virus
1.
2.
3.
4.
Transmission
Blood to blood
Sexual contact
Pregnancy
Acute infection
•
•
•
Flu like symptoms
1-6 weeks after exposure
Usually not noted unless looked at
retrospectively
Seroconversion:
•
•
Development of detectable antibodies in
the blood
When antibodies are numerous then HIV
test is positive
Latency
•
•
•
•
HIV positive
Once status is know, the blood count (T
cells) determines health
Transmission to others is possible
No symptoms
Change from HIV to AIDS status
–
–
HIV+
First physical symptoms
» Thrush
» Herpes zoster (shingles)
» Pheumococcal pneumonia
» Not PCP pneumonia
» Considered to be an AIDS defining illness
»
»
»
»
»
Women
Vaginitis
increase severity
increase frequency
resistant to treatment
AIDS
•
What defines AIDS
– 1982 – opportunistic infection for an
unknown cause
– 1986 –specific list of opportunistic infection
or tumors
– 1992 – anyone with HIV+ status and T cell
cont less
Diagnosis that are AIDS defining
–
–
–
Pneumocysitis carinii pneumonia
» Parasitic and acquired early in life
Karposi Sarcoma
Mycobacterium Avium infection
» Gastric
» Lungs
» Liver
–
–
–
–
–
Toxoplasma encephalitis
Cryptococcosis
Cryptosporidiosis
» Usually related to cat care
» Can be in drinking water
Herpes simples
Cytomegalovirus
General constitutional symptoms
»
»
»
»
Weight loss
Diarrhea
Fever
Fatigue
TREATMENT
– When AIDS first surfaced in the United
States, there were no medicines to combat
the underlying immune deficiency and few
treatments existed for the opportunistic
diseases that resulted.
– The Food and Drug Administration (FDA)
has approved a number of drugs for treating
HIV infection.
•
The first group of drugs used to treat HIV
infection, called nucleoside reverse transcriptase
(RT) inhibitors, interrupts an early stage of the
virus making copies of itself.
– AZT (Azidothymidine)
– ddC (zalcitabine)
– ddI (dideoxyinosine)
– d4T (stavudine)
•
Health care providers can prescribe nonnucleoside reverse transcriptase inhibitors
(NNRTIs), such as
– Delavridine (Rescriptor)
– Nevirapine (Viramune)
•
Efravirenz (Sustiva) (in combination with
other antiret
FDA also has approved
•
a second class of drugs for treating HIV infection.
These drugs, called protease inhibitors, interrupt
the virus from making copies of itself at a later
step in its life cycle. They include
– Ritonavir (Norvir)
– Saquinivir (Invirase)
FDA also has introduced a third
new class of drugs
• known at fusion inhibitors, to treat HIV
infection. Fuzeon (enfuvirtide or T-20), the
first approved fusion inhibitor, works by
interfering with HIV-1's ability to enter into
cells by blocking the merging of the virus
with the cell membranes
•
This inhibition blocks HIV's ability to
enter and infect the human immune cells.
Fuzeon is designed for use in
combination with other anti-HIV
treatment. It reduces the level of HIV
infection in the blood and may be active
against HIV that has become resistant to
current antiviral treatment schedules.
•
,. Because HIV can become resistant to
any of these drugs, health care providers
must use a combination treatment to
effectively suppress the virus. When
multiple drugs (three or more) are used
in combination, it is referred to as highly
active antiretroviral therapy, or HAART,
and can be used by people who are
newly infected with HIV as well as people
with AIDS.
Side effects
•
Despite the beneficial effects of HAART,
there are side effects associated with the
use of antiviral drugs that can be severe.
•
Some of the nucleoside RT inhibitors
may cause a decrease of red or white
blood cells, especially when taken in the
later stages of the disease.
Some may also cause inflammation of the pancreas and painful nerve damag
•
Therefore, health care experts
recommend that you be routinely seen
and followed by your health care provider
if you are on antiretroviral therapy.
The most common side effects
•
associated with protease inhibitors
include nausea, diarrhea, and other
gastrointestinal symptoms. In addition,
protease inhibitors can interact with other
drugs resulting in serious side effects
HIV IS A RETROVIRUS
• Retroviruses are RNA (ribonucleic acid)
viruses, and in order to replicate
(duplicate). They must make a DNA
(deoxyribonucleic acid) copy of their RNA.
It is the DNA genes that allow the virus to
replicate.
•
Like all viruses, HIV can replicate only
inside cells, commandeering the cell’s
machinery to reproduce. Only HIV and
other retroviruses, however, once inside
a cell, use an enzyme called reverse
transcriptase to convert their RNA into
DNA, which can be incorporated into the
host cell’s genes.
Slow viruses
– HIV belongs to a subgroup of retroviruses known as
lentiviruses , or “slow” viruses.
•
The course of infection with these
viruses is characterized by a long interval
between initial infection and the onset of
serious symptoms
Other lentiviruses infect nonhuman
species
»
»
»
the feline immunodeficiency virus (FIV) infects cats
the simian immunodeficiency virus (SIV) infects
monkeys
These animal viruses primarily infect immune
system cells, often causing immune deficiency and
AIDS-like symptoms.
STRUCTURE OF HIV
Vaccine Research
– The intervention most anticipated by
everyone working to stop the HIV/AIDS
epidemic is a vaccine to prevent infection.
– Vaccine development must not endanger
progress already made in HIV prevention.
– Until a vaccine is available, and even
afterwards, we must continue to reinforce
the already proven methods of HIV
prevention.
History Of HIV/AIDS
• AIDS is caused by the Human
immunodeficiency virus (HIV), which
originated in non-human primates in SubSaharan Africa and was transferred to
humans during the late 19th or early 20th
century.
Scientists generally accept that the known strains (or groups) of HIV-1 are
most closely related to the simian immunodeficiency viruses (SIVs)
endemic in wild ape populations of West Central African forests.
Particularly, each of the known HIV-1 strains is either closely related to the
SIV that infects the chimpanzee subspecies Pan troglodytes troglodytes
(SIVcpz), or to the SIV that infects Western lowland gorillas (Gorilla gorilla
gorilla), called SIVgor.
Using HIV-1 sequences preserved in
human biological samples along with
estimates of viral mutation rates, scientists
calculate that the jump from chimpanzee to
human probably happened during the late
19th or early 20th century, a time of rapid
urbanisation and colonisation in equatorial
Africa.
According to the natural transfer theory
(also called 'Hunter Theory' or 'Bushmeat
Theory'), the "simplest and most plausible
explanation for the cross-species
transmission"[7] of SIV or HIV (post
mutation), the virus was transmitted from
an ape or monkey to a human when a
hunter or bushmeat vendor/handler was
bitten or cut while hunting or butchering the
animal.
a human population;
a nearby population of a host animal;
an infectious pathogen in the host animal
that can spread from animal to human;
interaction between the species to transmit
enough of the pathogen to humans to
establish a human foothold, which could
have taken millions of individual
exposures;
ability of the pathogen to spread from
human to human (perhaps acquired by
mutation);
some process allowing the pathogen to
disperse widely, preventing the infection
from "burning out" by either killing off its
human hosts or provoking immunity in a
local population of humans
EARLY CASES
• In 1958 an English sailor who never visited
Africa
• 1969 a young man died of Karposi’s
sarcoma in a St. Louis Hospital
• Gaetan Dugay a french flight attendant,
while not the first patient in the United
States , his sexual partners accounted for
40 of 248 know cases in 1983