Chapter 26

What is the pandemic situation of AIDS?

An estimated 25 million people have died from AIDS, and nearly 40 million are currently infected with about 5 million becoming infected each year.

What is the relation between AIDS and opportunistic infections? List one such pathogen from each major category?

Most patients died of associated opportunistic infections, the life of an AIDS patient can be prolonged by treatment of opportunistic infections.

What is the classification of HIV? What is dominant strain of HIV in the US?

There are two stains of HIV: HIV-1 and HIV-2. HIV-1 is more virulent, relatively easily transmitted, and is the cause of the majority of HIV infections globally. HIV-2 is less transmittable and is largely confined to West Africa. HIV genome separates into genetically distinct groups called clades. Dominant species is HIV-1, clade B.

What is HIV?

(Human Immunodeficiency Virus) the virus that causes AIDs. Transmitted by sexual contact, however, direct contact of mucous membrane or the bloodstream with a bodily fluid containing the HIV, is enough to transmit the virus.

What are the three major mechanisms for HIV to evade the immune system?

1. Latency within T-helper cells or vacuoles of macrophages shelter it from the immune system. 2. Cell-cell fusion (syncytium formation) allows it to spread while protected from the immune system. 3. Rapid antigenic change due to proofreading-lacking reverse transcription, which may amount to 1 million variants of the virus in an asymptomatic person. (antigenic variation)

What is the difference between AIDS and HIV?

AIDS is the final stage of HIV.

What is AIDS?

Acquired immune deficiency syndrome o acquired immune-deficiency syndrome, is caused by the human immune-deficiency virus HIV. AIDS is the final stage of HIV infection.

What is the most common pathogen of urinary tract infections? How is struvite formed due to urinary tract infections?

Bacteria from the intestinal normal microbiota. Escherichia coli causes about 70% of all infections. Struvite stones can caused by bacterial infection that hydrolyzes urea to ammonium and raises urine pH to neutral or alkaline values.

What is the causative agent of gonorrhoea? What is the function of its main virulence factors ?List examples of antigenic variation in bacteria and viruses?

Caused by the bacterium Neisseia gonorrhoeae. 1. Fimbriae are important for the gonococcus to attach to host cells. 2.Antiphagocytic capsule. 3. Surface Opa proteins (outer membrane proteins, cell wall components) can bind to T helper cells and inhibit adaptive immune response, which explains why infection carries an increased risk of acquiring other STD.

What is adhesin of HIV? What is the receptors and coreceptors for HIV? Why does HIV target helper T cells and macrophages?

It is when the spikes meet with the virus to bond together. HIV has a phospholipid envelope with gp120 spikes. HIV gp120 spikes attach to CD4 and a co-receptor (CCR5 or CXCR4) on host cells. THE CD4 receptor is found in helper T cells and macrophages. T cells have CCR5 or CXCR4 where macrophages only have CCR5.

What is STD? How are they transmitted besides sexually? Why do those pathogens prefer reproductive system for infection? List two STD pathogens that can be transmitted by skin contact?

Sexually transmitted diseases. Iv drug needles after used by infected person. Child birth and breast feeding. Because most of them are easily encountered through sexual intercourse, which is where reproduction occurs. Herpes simplex virus and human papilloma virus.

What are the basic components of HIV? What is their major function? How does the multiplication cycle of HIV work?

Spikes, capsid, envelope, RNA, and reverse transcriptase. HIV is a retrovirus with a single stranded RNA. Viral RNA is reverse transcribed to DNA by reverse transcriptase. The viral DNA becomes integrated into the host chromosome to direct synthesis of new viruses or to remain latent as a provirus,

Which stage is AIDS and what are the two major characteristics of this stage? How long for AIDS to development since initial infection?

Stage 3.CD4+ T cell count are below 350 cells/ul Ten years to develop. If they reach below 200 cells/ul defines AIDS. HIV levels in blood rise as the immune system breaks down due to the low count in CD4+ T cells.

What is opportunistic infection?

an infection caused by bacterial, viral, fungal, or protozoan pathogens that take advantage of a host with a weakened immune system or an altered microbiota. Many of these pathogens do not cause disease in a healthy host that has a normal immune system. A compromised immune system, however, presents an "opportunity" for the pathogen to infect.