HIV/AIDS is one of the most rapidly prevailing lethal infections. There were 36.7 million people that are infected with HIV in 2017 (Gong et al., 2017). Out of these 36.7 million people, one million people died. Sub Saharan Africa was the most suffered area of this deadly infection. From 1980 to 2017 the AIDS has caused thirty-five million deaths all over the world and this is a huge population (Rangel et al., 2006). HIV is believed to be originated from Africa in a late 19th century. AIDS was first recognized by the United States Centers for Disease Control and Prevention (CDC) in 1981 and it was soon discovered that it is caused by HIV infection. Following graph shows a global number of AIDS-related deaths, new HIH infection (Acute HIV Infection) and people living with HIV from 1990 to 2015. (Fig. 5) shows the HIV infection the deaths caused by it over the globe.
Transmission of HIV
There are three most common ways to transfer HIV from an infected person to the healthy ones. The first one is unprotected sex. If a person is having sex with multiple partners, it is highly likely that the healthy person may get HIV from the infected person during sex. Usage of a condom is the prevention of this transmission method. The second way to transmit the HIV is from pregnant mother to its baby (Naidoo et al., 2017). As the baby gets food and other nutrients from mother, so if the mother is HIV infected, the baby may also be infected by HIV. The third method is the usage of the same syringe of the infected person to healthy one (Adachi et al., 2018). In short, HIV is transferred from the infected patient to health ones often by unprotected oral or anal sex, contaminated blood transfusions, subcutaneous needles and from a pregnant woman to her child during her delivery or breastfeeding. Some other body fluids that are falsely considered to spread HIV are saliva and tears.
The main reason for not curing the HIV is its genetic variability that is produced during the reverse transcription of the viral RNA after entering the host cell by reverse transcriptase. As this process is very fast and error-prone, it produces many variants of HIV. Some of these variants are drug resistance. HIV produces 1010 Virus particle per day in the infected patient that creates high mutation rate approximately 3 x 10−5 per nucleotide base per cycle of replication along with recombinogenic properties of the RT. This complex phenomenon leads to the production of myriads of variants of HIV in a single day in merely one patient. Now, when these variants infect the same T cell in the same patients, RT produces cDNA that is the combination of both parental RNS of the variant HIV. The other reason for not producing a vaccine against HIV is the very fact that it attacks the T helper cells and normal antibody production do not occur in contrast to other viruses. For this reason, HIV infection progress to AIDS very often and leads to the death of millions of people every year (Kaur & Mehra, 2009).
Most of the infected people develop a special kind of antibodies called seroconvert. That is detected by ELISA. But before seroconversion, HIV is tested by measuring the amount of HIV-RNA or an antigen p24. Positive screening tests lead to the confirmation test by different antibodies or PCR. In children younger than eighteen months, it is not possible to test HIV by antigen as the child contains most of the antibodies from his mother. That is why HIV can be detected only by PCR Testing of HIV-RNA/DNA or p24 antigen test (Martin Vogel et al., 2010).