HIV (Human immunodeficiency Virus)
HIV is causative Agent of AIDS and belongs to family Retroviridae.
HIV occurs in two main types;
1. HIV-1
2. HIV-2
It is spherical enveloped RNA virus.
Source and Mode of Transmission
1. Sexual contact;
Unprotected sex; seman or vaginal fluids
2. Transfusions
3. Infected blood and bodily fluids
4. Infected blood and blood products
5. Contaminated needle
6. Sharing drug injection needle
7. Perinatal transmission
Through Transplacenta
During delivery infected birth canal.
Ingestion of breatmilk carrying virus.
Pathogenesis
HIV causes AIDS disease in human beings. When HIV enters a human cell. It releases its RNA and an enzyme called reserve transcriptase (RT) make DNA copy of HIV RNA.
Resulting HIV DNA is integrated into infected cells DNA.
Bind CD4 cells of host - (2 copies) ssRNA rt - ds RNA - Viral DNA - Integrate infected host cell DNA.
HIV can be isolated from blood, lymphocytes, cell free plasma, semen, cervical secretion, saliva, tears, urine and breast milk.
Major damage occurs in cellular immunity and also affect humoral immunity of T cell activity causing opportunistic infection.
And progresses into AIDS ( acquired immunodeficiency syndrome).
HIV virus enters and cause damage helper Tcells, which are primary target.
Inside, virus makes may copies of itself damaged helper Tcell and leave to infect other cells.
T cell losses it's ability to protect the body.
HIV spread and kill more helper T cells, B cells weakening immune system.
As a result other type of infection causes to body inability to defend itself, called opportunistic infection.
Different Stages of HIV
Acute HIV infection
Asymptomatic infection (continuing to weaken immune system)
Symptomatic infection
Damage and weakened by HIV and symptoms develop.
For example; enlargement of lymph nodes
Progression of HIV to AIDS
HIV infection with opportunistic Infection, called AIDS.
Opportunistic infection such as;
Pneumoniae/ tuberculosis
Inflammation of tissues covering brain and spinal cord (meningitis).
Gastrointestinal infection; chronic diarrhoea
Encephalitis; inflammation of brain
Kaposi sarcoma
Structure of HIV
It is spherical enveloped RNA virus.
About 90-120nm in diameter.
It contain two identical copies of single stranded RNA (ss RNA) associated with viral RNA is reverse transcriptase enzyme (RT enzyme).
RT enzyme; initiate transcription of RNA into DNA, usually this transcription occurs from DNA to RNA.
Laboratory Diagnosis
Specimen collection
Blood and serum sample
Immunological test
Include;
Total leucocytes count
Lymphocyte count
T cell count
Platelets count
Level of IgG and IgA
Specific tests
Antigen detection; antigen P24 appear in blood.
ELISA used for detection of this antigen.
2. Virus isolation
3. PCR (Polymerase chain reaction); Used for diagnosis and monitoring level of viraemia in all stages of HIV infection.
4. Antibody detection
IgG and IgA antibodies to appear in blood, which is highly Infectious agent.
Level of IgG and IgA raised in serum.
Anti HIV antibodies test
1. ELISA test; if ELISA test is positive.
2. Western blot test (Confirmatory test)
Immunochromatography test
Rapid screening test of HIV infection.
Prevention
1. Safe sex method
2. Use clean needle
3. Aware about proper disposal of biomedical wastes.
4. Avoid direct contact or indirect contact with blood, semen, other body fluids of patient and carrier's.
5. Avoid sharing if needle and injury
6. Avoid injectable drug abuse
7. Screening blood and blood products
8. Screening for pregnant women for HIV
9. Screening of donation of cornea
Treatment
Specific treatment with anti- retroviral therapy (ART).
Universal Precaution taken while Handling HIV/AIDS
1. Stop you from contracting of acquiring infection
2. Prevent you from transmitting infection
Universal Precaution, Protective barriers reduce risk of;
Exposure to blood
Body fluid; vaginal secretion, pleural fluid, semen
Other fluids; CSF fluid, peritoneal fluid, synovial fluid
Universal Precaution include;
1. Universal Precautions
2. Using Protective Barriers
3. Prevent needlestick injury
4. Frequent Handwashing
5. Handling Infectious item carefully
6. Biomedical segregation
7. Prevent of transmission of infection from mother to baby by pregnancy, safe labour.
8. Safety measure while blood transfusion or through breast feeding or nursing.
9. Management of Exposure;
Identify route of exposure
Prophylaxis in case of exposure.
Prevent HIV patient to hepatitis B and C disease transmission.
Healthcare coworker should wear PPE to prevent exposure
8. Antiseptics or Disinfectant agent
Clean the contaminated floor With 1:100 dilution of bleach.
9. Wound or skin site should wash immediately with soap and running water.
11. Pregnant women should be tested.
12. Prevent penetrating injury due to contaminated needle or other sharps instruments.
13. Counseling importance of starting prophylaxis and psychological changes.
14. Sterilization of equipment
15. Hospital Waste first disinfectant and then disposed.
Separate disposal container for HIV patient.
16. Isolate the HIV/AIDS patients
17. Used to aseptic procedures to obtain these fluids for diagnostic.
18. Record with date and time, follow up, monitoring.
19. Document the asymptomatic symptoms daily basis.
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