Mrs.SHEEJA MP PGT BIOLOGY.KV PORTTRUST HEALTH AND DISEASES Mrs.SHEEJA MP PGT BIOLOGY.KV PORTTRUST

AIDS ACQUIRED IMMUNO DEFICIENCY SYNDROME. Caused by HIV-human immuno deficiency virus. Drastic reduction in helper T4 lymphocytes due to infection of HIV

The first AIDS case –U.S.A in 1981 The virus was isolated by Montagnier et ai -1983in France It was names HIV in 1986 by international committee on taxonomy of viruses. Two kinds of HIV strains-HIV-1 and HIV-II In India HIV was first reported in 1986 from Chennai

Structure of HIV

Structure of HIV Rounded retrovirus with a core having 2 single strands of genomic RNA,enzyme reverse transcriptase, inner covering of (p-24) and an outer covering (of p-18) The number of genes in HIV is 8.It is 9 in HIV-II The envelope has spikes with receptors capable of recognising T-4 antigen receptor found on helper T-cells,Macrophages and nerve cells.

TRANSMISSION Through body fluid contact-blood,semen,vaginal secretions,and placenta. It can not be spread through mosquitoes, hugging,shaking hands cough, sneezing, sharing meals etc.

INCUBATION PERIOD 2-3 Years but can be up to 10 years. Initial 2-6 weeks are window period when infection can not be detected.

HIV Tests A human immunodeficiency virus (HIV) test detects antibodies to HIV in the blood. This determines whether an HIV infection is present (HIV-positive). HIV infects white blood cells called CD4+ cells, which are part of the body's immune system that help fight infections . After the original infection, it takes between 2 weeks and 6 months for antibodies to HIV to appear in the blood. The period between becoming infected with HIV and the point at which antibodies to HIV can be detected in the blood is called the seroconversion or "window" period

Enzyme Linked Immuno-sorbent Assay (ELISA test):This test is usually the first one used to detect infection with HIV. If antibodies to HIV are present (positive), the test is usually repeated to confirm the diagnosis. If ELISA is negative, other tests are not usually needed. This test has a low chance of having a false result after the first few weeks that a person is infected. Western blot. :This test is more difficult than the ELISA to perform, but it is done to confirm the results of two positive ELISA tests. Polymerase chain reaction (PCR). This test finds either the genetic material RNA of HIV.

Being HIV-positive, or having HIV disease, is not the same as having AIDS.

Virus multiplication

HIV sticks by means of its spike to antigen receptor sites of helper t cells macrophages and certain nerve cells. With RNA template and reverse transcriptase viral genome is transcribed over DNAThe copy of DNA virus is called provirus It attaches to a chromosome of the cellprovirus multiplies forms genomic RNAreverse transcriptase and viral proteins.They form new viral particles.in the processthe host cell is destroyed.

SYMPTOMS As HIV disease continues, it slowly wears down the immune system. Viruses, parasites, fungi and bacteria that usually don't cause any problems can make you very sick if your immune system is damaged. These are called "opportunistic infections Unexplained weight loss-slim disease.rashes leading to ulcers.diarrhoea, low grade fever,cough,nauseanight sweatingTb, pneumoniabrain damage etc.

THERE is no vaccine to cure AIDS , but can be used to slow down infection of HIV. 1. Nonnucleoside Reverse Transcriptase Inhibitors (NNRTIs) 2. Nucleoside Reverse Transcriptase Inhibitors (NRTIs) 3. Protease Inhibitors (PIs) 4. Fusion Inhibitors

PREVENTION OF AIDS ABC of AIDS prevention A bstinence for youth, including the delay of sexual debut and abstinence until marriage B eing tested for HIV and being faithful in marriage and monogamous relationships C orrect and consistent use of condoms for those who practice high-risk behaviours.

ARC AIDS related complex- It is a mild form of AIDS. The patient suffers from swollen lymph glands weight loss and night sweating .Recovery can occur..

World AIDS day-ist December NARI-national AIDS research institute.Pune NACO-National AIDS control organisation,Delhi World AIDS capital-South Africa