HIV and AIDS Flashcards
HIV is a:
non transforming retrovirus of the lentivirus subfamily
what are the two main subtypes of HIV
HIV-1 and HIV-2
which type of HIV is more common and where are they both found
- HIV-1: sub-saharan Africa - more common
- HIV-2: West Africa
which type of HIV has a slower disease course
HIV-2
what percentage of eastern and southern africa are infected with HIV
54%
more than ______ people have been infected with HIV and ______ have died from AIDS
70,000,000; 35,000,000
an estimated ______ people across the globe are newly infected with HIV each year
2.7 million
the vast majority of people infected with HIV are in ______ countries
low and middle income
aprroximately ______ people in the US are living with HIV today
1.2 million
the CDC indicates there are ______ new HIV infections each year
38,000
the rate for males was ______ than the rate for females
5 times higher
new HIV diagnosis was highest among people aged:
25-44
what is the largest single risk factor for HIV
male to male sexual contact
what body fluids can HIV be transmitted through
blood, semen, breast milk and vaginal secretions are the main fluids that have shown to be associated with the transmission of the virus.
- can also be found in tears, saliva, CSF, amniotic fluid and urine
transmission of HIV is by:
exchange of infected bodily fluids predominantly through intimate sexual contact and by parenteral means
HIV infection can occur through:
oropharyngeal, cervical, vaginal and GI mucosal surfaces, even in the absence of mucosal disruption
infection with HIV is aided by the presence of other:
sexually transmitted diseases that can produce mucosal ulceration and inflammation
the most common method of sexual transmission in the US is:
anal intercourse in men who have sex with men in whom the risk of HIV infection is 40 times higher in other men and in women
_______ is the second most common form of transmission in the US
heterosexual transmission
transmission from _____ is the third largest group affected in the US
sharing needles
why is transmission by oral fluids rarely seen
saliva contains a number of HIV inhibitory factors which appear to reduce the ability of the virus to infect its target cells
what are the key antigenic components in HIV
- gag
- pol
- env
- p17
-p24
-p7
-p66/51
-p32
-p11
what are the regulatory proteins for viral replication in HIV and accessory proteins in HIV
- regulatory proteins: Tat and Rev
- accessory: Nef, Vif, Vpu,Vpr
what is the cell cycle in the pathophysiology of HIV
entry -> replication -> release
describe the entry phase in the pathophysiology of the HIV virus
- HIV mainly infects cells with CD4 cell-surface receptor molecules (CD4+ T helper lymphocytes mainly) at the site of HIV entry
- infected is aided by langerhans cells in mucosal epithelial surfaces which can become infected delivering HIV to underlying T cells resulting in dissemination to lymphoid organs
- the virus uses CD4+ cells to gain entry by fusion with a susceptible cell membrane or by endocytosis
- the probability of infection depends on the number of infective HIV virions in the body fluid which contacts the host and the number of cells with appropriate CD4 receptors available at the site of contact
describe the replication phase of the pathophysiology of HIV
- once in the cell the viral particle uncoats from its spherical envelope to release its RNA
- the enzyme product of the pol gene, a reverse transcriptase that is bound to HIV RNA, synthesizes linear double stranded cDNA that is the template for HIV integrase
- it is this HIV proviral DNA which is then inserted into the host cell genomic DNA by the integrase enzyme of the HIV
describe the release stage of the pathophysiology of HIV
- just before the budding process, HIV protease cleaves Gag proteins into their functional form which gets assembled at the inner part of the host cell membrane and virions then begin to bud off
- nucleocapsid (NC) protein interacts with the RNA within the capsid
- Capsid (Ca) protein surrounds the RNA of HIV
- Matrix (MA) protein surrounds the capsid and lies just beneath the viral envelope
- the cells HIV selects for replication are soon “swell and burst” by caspase-3-mediated apoptosis (5%), the remaining greater than 95% of quiescent lymphoid CD4 T cells die by caspase-1 mediated pyroptosis triggered by abortive viral infection
- the spectrum of HIV disease changes as CD4+ cell count declines
what is seroconversion
the transition from the point of viral infection to when antibodies of the virus become present in the blood (circulating antibodies)
what are the CDC stages of HIV infection in adults and adolescnts
- stage 1: immediately after HIV exposure and may last for years
- stage 2: progressive immunosuppresion and early symptomatic disease
- stage 3: AIDS, variety of immunosuppression related diseases
describe stage 1 of HIV
- lab confirmation of HIV infection
- no AIDS defining conditions and CD4+ T lymphocytes count greater than 500 cells/microL
- or CD4+ T lymphocyte percentage of total lymphocytes of greater than 29
describe stage 2 HIV infection
- laboratory confirmation of HIV infection
- no AIDS defining condition
- laboratory confirmation of HIV infection and CD4+ lymphocyte count of 200-499 cells/microL
- or CD4+ T lymphocyte percentage of total lymphocytes of 14-28
describe stage 3 HIV infection
- lab confirmation of HIV infection and CD4+ T lymphocyte count is less than 200 cells/microL
- or CD4+ T lymphocytes percentage of total lymphocytes is less than 14
- or documentation of an AIDS defining condition
- documentation of an AIDS defining condition supercedes a CD4+ T lymphocyte count of greater than 200 cells/microL and CD4+ T lymphocytes percentage of total lymphocytes of greater than 14
the average normal CD4 percentage for someone who is HIV negative is about: and the normal range is:
40%; 25-65%
during the first 2-6 weeks after initial infection with HIV:
70% of patients dvelop acute flulike sympotms marked by viremia
what are the symptoms of stage 1 HIV like
- mononucleosis like
- lymphadenopathy
- fever
- pharyngitis
- weakness
-diarrhea - nausea
-vomitting - myalgia
- headache
-weight loss - skin rash
a _____ in CD4+ cells occurs with high levels of plasma HIV
drop
how long does it take for the body to make antibodies against HIV
between 6 and 12 weeks
how long can the latent asymptomatic period last
8-10 years
what is happening in the latent period
virus disseminates throughout lymphoid tissue, incubates, replicates and alters many physiologic processes, resulting in hyperimmune activation, persistent inflammation and impaired gut function and flora
- progressive decline in immune function evident as progressive depletion of CD4+ cell count and increase in viral load
- silent clinically except for persistent lymphadenopathy
what is happening in the early symptomatic period/stage 2 and how long does it last
1-3 years
- viral load continues to increase
- CD4+ count drops below 500
- viral load increases more
-platelet decreases in 10% of pts
what are the symptoms in the early symptomatic period for HIV
- persistent generalized lymphadenopathy
- fungal infections
- vaginal yeast and trichomonal infections
- oral hairy leukoplakia
- HSV
- herpes zoster
- HIV related retinopathy
- constitutional symptoms: fever, night swets, fatigue, diarrhea, weight loss, weakness
what happens in stage 3 AIDS
- CD4+ count drops to below 200 cells or documentation of AIDS defining condition
- platelet counts low
- opportunistic infections
- neutrophil count may be low
- CD4+ cell count less than 50 and high risk for lymphoma and death
what are the malignancies associated with stage 3 HIV
- kaposi sarcoma
- burkitt lymphoma
- non hodgkin lymphoma
- primary CNS lymphoma
- invasive cervical cancer
-carcinoma of rectum - slim disease
what is a normal ratio of CD4 and CD8 cells
between 1 and 4
what are the 3 types of HIV tests available
- nucleic acid tests
- antigen/antibody tests
- antibody tests
CD4+ and CD8+ cell counts should be performed when
at the time of HIV diagnosis and every 3-4months after
HIV tests are performed on:
blood or oral fluid and sometimes urine
what do nucleic acid tests test
- viral load
- detect HIV sooner than other tests
when is the greatest viral load found in HIV
during the first 3 months after initial infection and during the late stages of the disease
what do antigen/antibody tests detect
both HIV antibodies and antigens in the blood
in HIV infected individuals _____ is produced even before antibodies begin to develop
p24
antibody tests detect:
antibodies to HIV in blood or oral fluid
more rapid tests and the only approved HIV self tests are:
antibody tests
what are the lab tests ordered in medical setting for HIV diagnosis
first ELISA
- second ELISA
- all positive results are then confirmed with western blot analysis
the combination of ELISA tests and western blot are accurate more than _____ of the time and the aptients are considered_______
99%; potentially infectious
what is the drug therapy recommended for HIV
antiretroviral medications
what is the ARV medication
three drug regiment
what is virologic failure defined as
a confirmed viral load greater than 200 copies/mL in the presence of ART
what is pre exposure prophylaxis
- a way for people who do not have HIV but who are at high risk of getting it to prevent it
- the pill (Truvada) contains two medicines
- when someone is exposed to HIV through sex or injection drug use, these medicines can work to keep the virus from establishing permanent infection
what is the management of infants born to women with HIV
all infants should receive postpartum ARVs to reduce the risk of perinatal transmission of HIV