51 - Human Immunodeficiency Virus (w/ Brianne Barker!)
51. Human Immunodeficiency Virus
Human Immunodeficiency virus is a virus that functions within the cell differently than any virus we’ve discussed before. HIV has led to Nobel prizes, societal discussion and discrimination, and significant morbidity and mortality, but it was only first named in 1986. Today we’ll discuss HIV and the development of acquired immunodeficiency syndrome. Let’s learn to be scientifically conversational.
General Learning Concepts
1) Relevant Background
a. Virus (definition): Viruses are obligate intracellular parasites that are capable of infecting nearby cells. They contain instructions for making more viruses (with either RNA or DNA). It is common (but not entirely correct) to associate viruses with diseases (or symptoms) that they cause: the common cold, flu, warts, fever, paralysis, immunodeficiencies.
b. Common symptoms: After two to four weeks of infection, common symptoms include fever, chills, rash, night sweats, muscle aches, sore throat, fatigue, swollen lymph nodes, mouth ulcers.
i. Acquired immunodeficiency syndrome (AIDS): HIV infects specific cells within your body that are responsible for fighting off infection / responding to foreign identities. This can lead to a severely weakened immune system that puts the individual at risk from minor infection. Progession to AIDS from initial infection has a variable timeline that is often considered to be around 10 years.
c. The viral lifecycle: The virus has to get into the human cell to make more virus (CD4 cell, CCR5 receptor). The virus then fuses its membrane coating to release the RNA genomes and HIV enzymes (integrase, reverse transcriptase) into the cell. Unlike DNA based organisms which use DNA as instructions to make an RNA message, retroviruses use RNA as a message and also can make DNA. Because humans do not have the capability to turn RNA into DNA, viruses must have a message to make a protein (molecular machine) capable of doing this. This enzyme is known as the RNA-dependent-DNA polymerase (reverse transcriptase). Once viral DNA is produced and integrated into the host cell DNA (forming a provirus), the normal cellular machinery are coopted to replicate viral proteins. Then, the genome is replicated many, many times so each virus has instructions to make another virus during their subsequent infection. Those genomes can be used to translate (make protein from the message) more proteins required for packing the viral capsids with the genomes before being released from the human cell. The human cell usually ends up dead or very sick after viral infection for a multitude of reasons, one of which being that the virus steals a bit of the host cells membrane while leaving.
2) Free discussion of HIV between Brianne and Calvin
3) Fun Tidbits
a. HIV is not spread by mosquitoes, sweat, tears, pools, or casual contact: Even if mosquitoes could carry the HIV virus, they do not inject blood into your skin. No transmission of this type has ever been reported around the world. Also, you cannot get HIV from shaking hands, using the toilet, or coming into contact with someone's sweat or tears from their eyes. The only bodily fluids that are known to transmit HIV are semen, vaginal fluids, anal fluids, breastmilk, and blood (including menstrual blood).
b. Post-exposure prophylaxis: PEP (post-exposure prophylaxis) means taking antiretroviral medicines (ART) after being potentially exposed to HIV to prevent becoming infected. PEP interferes with the pathways that HIV uses to cause a permanent infection in the body. For HIV to cause infection the virus must enter the body, infect certain immune cells, make copies of itself (replicate) within these immune cells, then spread throughout the body. When PEP is taken, the HIV drugs get into the bloodstream and the genital and rectal tissues. If there is HIV in the body, the drugs can prevent HIV from replicating within the body’s immune cells, and help to prevent a permanent infection from developing. [2]
4) Solicited Questions
a. What is Simian Immunodeficiency Virus (SIV)? SIV attacks the immune systems of monkeys and apes and is genetically related to HIV.
BERLIN PATIENT: [1]