6 accidental or illegal transfers ( transfusion , drugs addiction ) or any direct contact between a contaminated fluid and the host ’ s blood , finally , with a low but an important risk of transmission , vertical mode ( Motherchild ) during pregnancy through placenta or through breastfeeding later on , which indicated the enormous infection potential of these elements , HIV-2 is a less aggressive virus with a lower risk of transmission and AIDS development .
Host cell vs . Virus ( Virus cell interaction )
Figure-2- : Acquired immune response scheme
( From Nature Reviews Microbiology [ 2007 ])
Once in the blood stream , the virus begins right away the process of invasion , facilitated by the complementarity between its surface antigens , and the target cell ’ s mentioned before , particularly , the viral gp120 and the cell CCR5 / CD4 , this link activates the rest of steps , fusion of the membranes , lysis of the matrix and the capsid which liberates the countenance of the core to the cytoplasm where the rTranscriptase transform the chains of RNA into DNA chains that can be translocated to the nucleus where they get included in the cell ’ s genome with the participation of the integrase ( enzyme of DNA modification ) announcing the end of invasion , the first step in HIV-infected cell natural history ( Figure-3- ).
On the other hand , the scenario described before supposes a defenseless cell , which is far from the reality of things , in a matter of fact , the cell is provided with some proteins with the ability to block fusion , transcription or integration of viral genome inside its own , a set of mechanisms known as intrinsic immunity , so the infection of a cell is the outcome of a conflict between the two parties and the replication begins in an explosive model , causing cell death , by many mechanisms : apoptosis , immune destruction of infected cells by LTCD8 and eventually , exhaustion of resources ; With periods of latency in between defining the nosologic entity known as HIV / AIDS .
HIV / AIDS
In the light of contamination , and after treating the microscopic Virus vs . Host conflict , it is only adequate to explain what happens in the macroscopic realm , the spectrum of the signs and symptoms that occur within the period of infection are classically divided into three different stages : Acute infection , clinical latency and AIDS stricto sensu without any obligate chronological sequence ( some forms do not express any signs until AIDS ).
Acute Infection
Corresponds to the period of massive invasion of immune system cells , two to four weeks following the contamination , the patient may expose a set of nonspecific signs , most experience influenza signs such as fever , headaches and fatigue , others feel some minor signs like a rash , lymph nodes , malaise , night sweats and anorexia , some rare forms in the other hand , may be accompanied with some serious health problems such as diarrhea , and neurological peripheral disorders marking a very poor prognosis and a fast development to AIDS , still , most of cases are exceptionally evocative at this stage .
Clinical latency
With a large duration variability ( from two to thirty years ), this stage corresponds to the period of chronic infection , clinically latent , no signs are usually noticed , giving a false impression of good health resulting from a
HIV / AIDS