What pathogens are involved in hiv?

Answer 1

HIV is different in structure from other retroviruses. It is about 120 nm in diameter (120 billionths of a meter; around 60 times smaller than a red blood cell) and roughly spherical.[36]

It is composed of two copies of positive single-stranded RNA that codes for the virus's nine genes enclosed by a conical capsid composed of 2,000 copies of the viral protein, p24.[37] The single-stranded RNA is tightly bound to nucleocapsid proteins, p7 and enzymes needed for the development of the virion such as reverse transcriptase, proteases and integrase. A matrix composed of the viral protein p17 surrounds the capsid ensuring the integrity of the virion particle.[37] This is, in turn, surrounded by the viral envelope which is composed of two layers of fatty molecules called phospholipids taken from the membrane of a human cell when a newly formed virus particle buds from the cell. Embedded in the viral envelope are proteins from the host cell and about 70 copies of a complex HIV protein that protrudes through the surface of the virus particle.[37] This protein, known as Env, consists of a cap made of three molecules called glycoprotein (gp) 120, and a stem consisting of three gp41 molecules that anchor the structure into the viral envelope.[38] This glycoprotein complex enables the virus to attach to and fuse with target cells to initiate the infectious cycle.[38] Both these surface proteins, especially gp120, have been considered as targets of future treatments or vaccines against HIV.[39]

Of the nine genes that are encoded within the RNA genome, three of these genes, gag, pol, and env, contain information needed to make the structural proteins for new virus particles.[37] env, for example, codes for a protein called gp160 that is broken down by a viral enzyme to form gp120 and gp41. The six remaining genes, tat, rev, nef, vif, vpr, and vpu (or vpx in the case of HIV-2), are regulatory genes for proteins that control the ability of HIV to infect cells, produce new copies of virus (replicate), or cause disease.[37] The protein encoded by nef, for instance, appears necessary for the virus to replicate efficiently, and the vpu-encoded protein influences the release of new virus particles from infected cells.[37] The ends of each strand of HIV RNA contain an RNA sequence called the long terminal repeat (LTR). Regions in the LTR act as switches to control production of new viruses and can be triggered by proteins from either HIV or the host cell.[37]

Answer 2

HIV itself is caused by a retro virus. It was initially identified in the early 1980s simultaneously by the Pasteur Institute in Paris and by Joe Gallo at the National Cancer Institute in the US. The virus appears to occur in monkeys in Central Africa in whom it does not cause an illness. It seems to have been transferred to humans through monkey-human bites. The incidence of HIV in the US seems to be under control if that is at all appropriate to say but in Africa and India it remains a serious problem. As HIV blunts the immune response it is associated with a variety of opportunistic infections - space does not permit a complete list.