HIV: an epidemic transformed Flashcards
define retrovirus by the transcription of information between DNA and RNA.
A virus that is composed not of DNA but of RNA. Retroviruses have an enzyme, called reverse transcriptase, that gives them the unique property of transcribing their RNA into DNA after entering a cell. The retroviral DNA can then integrate into the chromosomal DNA of the host cell, to be expressed there
what enzymes are involved in the replication of HIV?
protease, transcriptase, and integrase
recognize that helper T lymphocyte cells (CD4) cells are the main target of HIV. Explain what CD4 cells do to/for HIV, why they are important to the host and how these facts relate to the opportunistic infections that accompany AIDS.
HIV infects CD4 cells by bindings to the CD4 molecule on the surface of helper T-cells and replicating within them. This results in destruction of CD4+ T-cells and leads to a steady decline in this population of T-cells.
they are important to the host because they help in the immune system regularly. they relate to the opportunistic infections that accompany AIDS because when their count is low, the host is more vulnerable to infections.
describe the 3 phases of HIV infection and how CD4 and HIV levels appear in each
primary infection phase: decrease in CD4 count but increase in viral replication leading to very high viral loads, greater than 1,000,000 copies/mL
Infectious mononucleosis symptoms (fever, fatigue, myalgias, sore throat, night sweats, GI problems, macopapular rash, headache, lymphadenopathy)
chronic asymptomatic/latency phase: person has no signs/symptoms of illness. median time 10 years.
CD4 count falls from the normal range of 800 to 1000 cells/microliter to 200 cells/microliter or fewer.
overt aids: occurs when a person has a CD4 count of 200 CD4 cells/microliter or fewer. Without antiretroviral therapy, this can lead to death, and the risk of opportunistic infections is highly increased.
in simple terms, explain what the 2 classes of antiretroviral drugs (NRTIS and protease inhibitors do to impair viral replication or function)
NRTIS inhibit HIV replication by suppressing synthesis of viral DNA.
protease inhibitors prevent HIV maturation by blocking the HIV enzyme protease.
explain why HIV infection does not cause death for people directly, but the other events that develop with AIDS are what are more associated with a shortened life expectancy.
HIV is the precursor to AIDS, and so people die from the depleted CD4 cells when AIDS attacked. HIV is a cause, but AIDS is a bigger cause because the patients are so vulnerable to infection and don’t have the strength to fight it off.
