Human Immunodeficiency Virus

HIV is a member of the lentivirus subfamily of retroviruses. Retroviruses carry their genetic information on RNA (rather than DNA) but require the formation of viral DNA as a step in reproduction. This is accomplished by harnessing the machinery of the cell that the virus infects, wherein the viral enzyme reverse transcriptase facilitates forming DNA from the two strands of viral RNA within the infected host cell. The viral DNA so formed is integrated into the cell's genetic material and directs the host cell to manufacture new viral constituents. Essentially, these consist of a viral core surrounded by a glycoprotein envelope. Steps involved in viral replication are illustrated schematically in Fig. 1.

From a genetic standpoint, there are two types of HIV: HIV-1 and HIV-2. The predominant cause of AIDS worldwide is HIV-1, whereas HIV-2 remains limited to portions of western Africa. HIV-1, in turn, is classified on the basis of genetic analysis into a major group (group M) and an outlier group (group O). Again, the vast majority of infections worldwide are with group M viruses, with subtype B of group M

predominating in the industrial world. The greatest diversity of subtypes is found in Africa.

Understanding And Treating Autism

Understanding And Treating Autism

Whenever a doctor informs the parents that their child is suffering with Autism, the first & foremost question that is thrown over him is - How did it happen? How did my child get this disease? Well, there is no definite answer to what are the exact causes of Autism.

Get My Free Ebook


Post a comment