Essay on Human Immunodeficiency Virus ( Hiv )
Human immunodeficiency virus (HIV) is a Lentivirus from the family Retroviridiae ,which infects CD4+ T cells, dendritic cells and macrophages. This results in a loss in immune function and eventually acquired immune deficiency syndrome (AIDS) when CD4+ cell count is very low. There were approximately 1.5 million deaths in 2013 as a result of HIV-related causes , many of these deaths occur due to the immune system being too weak to defend itself against opportunistic infections .
HIV has 2 different forms, HIV-1 and HIV-2. HIV-2 is less virulent and also less infective, limiting it to West Africa because of its lower transmission rate . HIV-1 is further divided into M,N, O and P groups, with M being the pandemic form of HIV, while N,O and P are restricted to west Africa and account for fewer than 1% of global HIV-1 infections. HIV-1 has been thought to originate from chimpanzees in Cameroon, with humans being infected by HIV-1 precursors through exposure with infected chimpanzee fluids. On the other hand HIV-2 originates from sooty mangabeys in West Africa and the transmission of its associated HIV-2 precursor to humans is likely due exposure to blood due to hunting them as pests.
HIV Replication in host cell
Figure 1 (taken from Nature Reviews Microbiology ) Showing cell entry, integration, transcription, translation, assembly and release of the HIV virus. As well as sites for antiretrovirals to act (shown in green boxes)