HIV virus belongs to Lentivirinae sub family of retrovirus. Retrovirus have RNA genome and the unique property of transcribing a DNA copy of the RNA genome following the penetration of the host cell. Lentivirus generally evade host immune responses and cause persistent infections in several species.HIV has a core consisting of the RNA genome and core protein surrounded by an envelope with high lipid content rendering it sensitive to organic solvents. The unique feature of the virus is that it gains entry to host cells by binding to the CD 4 receptor using viral surface membrane glycoprotein 120. The CD4 receptors are present predominantly on T Helper lymphocytes, which are major target for the virus. Following the penetration of host cells, the virus RNA is transcribed by the viral enzyme reverse transcriptase into a DNA copy which becomes incorporated into the host cell genomic DNA. The viral DNA will lie dormant within the cell or undergo replication resulting in transcription of RNA copies and translation to viral proteins resulting in new virus formation and assembly. Viruses then bud from cell surface. The new virus is then available to infect other cells and repeat the process.
HIV occurs in two types- HIV1 AND HIV 2.
Clinical features: following a latent period of a few weeks, HIV infection is followed by seroconversion, which in a third of individuals, coincides with a brief clinical illness for about two weeks after which HIV antibodies appear in the blood. Symptoms of the illness include fever, malaise, headache, fleeting arthralgia, mucular papular rash, tender lymphadenopathy, and occasionally encephalitis, there after is followed by asymptomatic phase which lasts many years. In recent study in sanFrancisco of patients infected with HIV 11 years previously, 50% died of AIDS and of survivors 20% had AIDS. However it is thought that all individuals infected with HIV will eventually proceed to AIDS which is fatal.
Many of the opportunist infections and secondary neoplasms seen in AIDS are disseminated at presentation. Infections likes Cytomegalo virus, Bacterial Septicimia,M tuberculosis,M aviumintracellulare, Toxoplasmosis, Cryptococcosis, Histoplasmosis and Secondary neoplasms like Kaposi’s sarcoma and Non Hodgkins lymphoma.’
As the CD4 lymphocyte count in the blood decreases, opportunist infections and neoplasms present clinically.
Along with ART medication as an adjuvant our treatment can be continued to increase the quality of life.
