MICROBIO 160 1st Edition Lecture 23 Outline of Last Lecture I. When should you have an HIV testII. Where can testing be found?III. Types of HIV testsIV. Types of Screening TestsV. How the HIV ELISA test worksVI. Rapid HIV testVII. HIV ProteinsVIII. Western BlotIX. Progression of HIV infectionOutline of Current Lecture I. Main SymptomsII. Viral and Host Factors Influence the Progression to AIDSIII. New AIDS DefinitionIV. The CDC’s Definition of AIDSV. Stages of HIV InfectionVI. Rapid Progression to AIDSVII. Set PointVIII. Viral Load and Progression to AIDSIX. AIDS OnsetX. Opportunistic InfectionsXI. The Virus cycle between Malnutrition and AIDSThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Current LectureHIV Progression to AIDS: people can control the body and never have symptoms- Fever/ weight loss- Malaise, headache, neuropathy- Lymphadenopathy - Sores and thrush in the mouth- Rash on the skin (most common)- Sores in esophagus- Myalgia in muscles - Nausea and vomiting in the gastric - Enlargement in liver and spleen Viral and Host Factors Influence the Progression to AIDS: - Viral load: the amount of virus in the blood of an HIV infected person - Enhancing Factors:o Anti-HIV antibodies can enhance virus infection permitting HIV spread to cell types including lymphocytes, macrophages and fibroblasts (350 fold!)o Most individuals with a rapid progression to disease have viruses that replicate rapidly and are more cytopathic with a wide cellular host range- Inhibiting Factors: o Cellular immune responses can destroy virus-infected cells or suppress virus release via the production of antiviral cytokines or mechanisms involving cell: cellinteractionNew AIDS Definition: cases peaked with the 1993 expansion of the case definition and then declined- CD4 T-Cells, Cervical Cancer, Pulmonary TB and recurring pneumonia were added (to theoriginal list of 23 symptoms) as AIDS defining illnesses- The most dramatic drops in both cases and deaths began in 1996, with the widespread use of combination antiretroviral therapyThe CDC’s Definition of AIDS: - All HIV-infected people with fewer than 200 CD4+ T-cells per cubic millimeter of blood (compared with CD4+ T-Cell counts of about 1,400 for healthy people)- If their CD4+ T-cells counts lower than 14% of all lymphocytes Being diagnosed with at least one or more of the two dozen AIDS-associated conditions that result from HIV’s attack on the immune systemThe Stages of HIV Infection:- STAGE 1: Primary HIV Infection - short flu-like illness; large amount of HIV in the peripheral blood; seroconversion (HIV antibodies) and cytotoxic lymphocytes (~3 weeks post infection)- STAGE 2: Clinically Asymptomatic Stage - lasts for an average of ten years; free from major symptoms; there may be swollen glands; HIV level in peripheral blood drops to very low levels; patient remains infectious; T helper cell infection - STAGE 3: Symptomatic HIV Infection - Over time the immune system loses the struggle to contain HIV; lymph nodes and tissues become damaged; HIV mutates and becomes more pathogenic; T helper cell destruction; emergence of opportunistic infections such as Oral Candidiasis (thrush—can coat the oral cavity) or hairy cell leukoplakia (immune system is losing—you look sink you feel sick)- STAGE 4: Progression from HIV to AIDS - As the immune system becomes more and moredamaged the illnesses presented become more and more severe leading eventually to an AIDS diagnosis; CD4 cell count below 200/mm3; opportunistic infections Immune Response and Stage of Infection: looking at actually counts of CD4 T-cells, p24 antigen, and gp120 Anti-HIV antibody Rapid Progression to AIDS: Progression to AIDS is more rapid under the following circumstances:- When Syncytia-forming HIV is presento Clumped together o When a CD4 cell gets infected by HIV, - When acute infection is symptomatic- When HIV infection occurs with a drug resistant straino If you’re infected with a resistant strain they can pass it on to someone else—numbers of HIV strain rapidly increasing - When a higher “set point” of HIV RNA follows initial viremia after infection (antibodies present, body begins to fight the infection)- When patient smokes (impacts and inhibits immune system)o Even if you don’t smoke often, it will impact your immune system for days - When opportunistic infections or neoplasms are present- When in congenital cases (born with this), there are signs of infection less than 3 monthsof ageSet point: the point at which antibodies have been produced and the body begins to fight infection- Body is knocking down the virus - If the viral load is really high at the time (progression to AIDS is much faster)- If the viral load is really low at the time (progression to AIDS is much slower)Viral Load and Progression to AIDS: relation between baseline viral load and median survival time - If your CD4+ T-cell count is HIGH and your viral load is LOW, your medicines ARE doing a good job of controlling the virus- If your CD4+ T-cell count is LOW and you viral load is HIGH, your medicines are NOT doing a good job of controlling the virus- If you have a really high number of molecules of HIV at set point, the median life expectancy is only about 3.5 years CD4 cell count predicts likelihood of developing AIDSSymptoms that signify AIDS onset:- How do you know you’re transitioning to AIDS? Everything that is white—yeast, herpes, shingles, shortness of breath - Fever, diarrhea, constipation, headache, nausea, shortness of breath, inflammation of lymph nodes, sore mouth, white coating on tongue, red skin, skin rash or pain, tiredness,pain or itchiness on genitals, impaired vision.Opportunistic Infections: caused by bacteria, viruses, and other microbes that a healthy immunesystem would normally be capable of fighting - What you contract can be predicted by your CD4 count- If you have an outbreak of thrush, they can conclude that your T-cell counts are below 200 The Virus cycle between Malnutrition and AIDS:- HIVo Poor nutrition: resulting in weight loss, muscle wasting, weakness, nutrient deficiencieso Impaired immune system: poor ability to fight HIV and other infections, increased oxidative stresso Increased vulnerability to infections: enteric infections, flu, TB hence, increased HIV replication, Hastened disease progression increased morbidity o Increased
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