26. hiv virus

MICROORGANISM

1. HUMAN IMMUNO DEFICIENCY VIRUS RATHEESH R.L

2. HIV AIDS or Acquired Immuno Deficiency Syndrome is the disease that is caused by HIV. It was first described in USA in 1981 among homosexuals and drug users. The agent was first isolated by Luc Montagnier in 1983 and was named as lymphadenopathy associated virus.

3. Later the name was changed to HTLV-3 and later in 1985 it was named as HIV. The HIV virus occurs in two main strain forms. HIV-I HIV-II

4. It is a type of RNA virus It is 90-120 nm in diameter and icosahedral in symmetry in shape. It contains 2 RNA in its genome. The genome also contains the reverse transcriptase for the replication.

5. TRANSMISSION Sexual contact Transmission via blood products Peri natal transmission

6. PATHOGENESIS After entry into the blood stream through infected semen, contaminated blood and blood products the virus attaches to CD4 lymphocytes. Inside the cell the virus releases RNA which leads to reverse transcription and the DNA is known as provirus.

7. Then the provirus causes latent infection. The virus grows slowly in the T4 cells and monocytes. Then it cause the destruction of the T4 cells and leads to decreased number of T4 cells in the body.

8. Finally it will affect to the lymphatic system and there will be altered immunological status and making the patient most susceptible to get other infections.

9. CLINICAL FEATURES The clinical picture of the HIV is divided into 4 groups, Acute infection or seroconversion illness: It occurs 2-6 weeks after infection Symptoms will be fever, night sweats, malaise, head ache, myalgia, arthralgia, diarrhea, depression, sore throat, enlarged lymph nodes and skin rashus .

10. Asymptomatic infection (incubation period): This is the period when the patient is completely asymptomatic and may vary from few months to more than 10 years. Usually children have shorter incubation period During this period reiters syndrome, guillain-barrie syndrome, chronic demyelinating neuropathy and polymyositis will occur.

11. AIDS related complex or persistent generalized lymphadenopathy: At the end of incubation period a number of signs and symptoms will appear which may include slight immunological, dermatological, haematological and neurological signs. Symptoms are fever, night sweats, diarrhea and lymphadenopathy.

12. Symptomatic HIV infection: When the CD4 cells count below 400 cells/ cumm the patient develops symptoms like fever, night sweats, weight loss and diarrhea. Then the patient will be susceptible to get other infections like bacterial infections, fungal infections, viral infections, tumors, neurological symptoms, GI symptoms.

13. DIAGNOSIS SPECIFIC TESTS Isolation of the virus Detection of HIV antigen Detection of specific antibodies NON SPECIFIC TESTS Blood count T-Cell subset hypergammaglobulinaemia

14. Isolation of the virus It is used in 70-90% of cases. The presence of virus can be confirmed by the reverse transcription ability of the virus.

15. Detection of HIV antigen It can’t be done in the latent stages of HIV disease. It is used to find out the antigen before the appearance of antibodies.

16. Detection of specific antibodies Elisa is the most common method Other screening tests are dot blot assay, particle agglutination test, HIV spot test and comb test.

17. Blood count Leukopenia Decreased lymphocytes Thrombocytopenia T-cells The T-cell counts will be decreased Hyper gammaglobulinaemia IgA and IgG levels will be raised

18. TREATMENT Thymus and bone marrow transplantation is recommended to maintain T cells. Antibiotics to prevent infection Combination of zidovudin , didanosine and nevirapine to reduce the viral load.

19. PROPHYLAXIS Safe sex Blood screening Avoid sharing needles Isolation of aids patients Identification of risk group