Acquired immunodeficiency syndrome (AIDS)

Contents

•       AIDS

•       HIV

•       Etiology

•       Pathogenesis

Objectives

At the end of this Lecture, student will be able to

•       Define  AIDS

•       Describe the structure of HIV

•       Discuss  the etiology Of AIDS

•       Explain the pathogenesis of AIDS

AIDS

HIV

•       HIV stands for the Human Immunodeficiency Virus

•       A group of viruses known as retroviruses

•       After getting into the body, the virus kills or damages cells of the body’s immune system

•       Body tries to keep up by making new cells or trying to contain the virus

•       Destroys the body’s ability to fight infections and certain cancers

TYPES OF HIV

•       HIV 1 & HIV 2

•       Although all HIV viruses are similar

•       Small variations or mutations in the genetic material of the virus create drug-resistant viruses

•       Larger variations in the viral genes are found in different viral subtypes

•       HIV-1 is the predominant subtype that causes HIV/AIDS

HIV Structure

AIDS Acquired Immunodeficiency Syndrome

•        HIV is the virus that causes AIDS

•        Disease limits the body’s ability to fight infection

•       A person with AIDS has a very weak immune system

•       No Cure

Etiology of HIV

•       Virus can enter the body through the lining of the vagina, vulva, penis, rectum, or mouth – during sexual contact

•       HIV frequently spreads among injection

•       Drug users who share needles or syringes contaminated with blood from an infected person

•       Women can transmit HIV to their babies during pregnancy or birth

•       When infected maternal cells enter the baby’s circulation, or through breastfeeding

•       HIV can be spread in health-care settings through accidental needle sticks or contact with contaminated fluid

•       Very rarely – transfusion of contaminated blood or blood components

•       People who already have a sexually transmitted infections, such as

•       Syphilis, genital herpes

•       Chlamydial infection

•       Human papillomavirus (HPV)

•       Gonorrhea or bacterial vaginosis

Pathogenesis of HIV

Two main systems which are targets of HIV

•       Immune system

•       CNS

Immunopathogenesis

•       Profound immunosuppression

•       Depletion of CD4+ T- cells

•       Infections & impairment of function

•       Macrophages and dendritic cells are main targets

Sequence of events

•       Selective tropism and internalisation

•       Uncoding and proviral DNA integration

•       Budding and cynctia formation

•       Cytopathic effect

•       Effect on monocyte and macrophages

•       B- cell dysfunction

•       CNS involvement

Signs & symptoms of HIV

•       Many people with HIV do not know they are infected

•       No symptoms after infection with HIV

•       Others – flu-like illness within several days to weeks after exposure

•       Early HIV symptoms – fever, headache, tiredness, and enlarged lymph nodes in the neck

Major symptoms

–      Weight loss

–      Chronic diarrhoea  for more than one month

–      Fever lasting for more than one month

Minor

–      Recurrent candidiasis in oropharyngeal membrane

–      Lymph adenopathy

–      Persistent cough for more than 1 month

–      Pruritic dermatitis

–      The infections that happen with AIDS are called opportunistic infections

–      Pneumonia caused by Pneumocystis

–      brain infection with toxoplasmosis which can cause trouble thinking or symptoms that mimic a stroke

–      widespread infection with a bacteria called MAC (mycobacterium avium complex) which can cause fever and weight loss

–      Certain fungi like histoplasmosis, which can cause fever, cough, anemia, and other problems

–      lymphoma in (a form of cancer of the lymphoid tissue) in the brain,Vwhich can cause fever and trouble thinking

–      A cancer of the soft tissues – Kaposi’s sarcoma, which causes brown, reddish, or purple spots that develop on the skin or in the mouth

Summary

•       HIV  is a retro virus that causes AIDS and weekens the immune system of the body

•       Main causes are IV drug users, multiple sex partners, sex with infected partner, in hospital needle sticks, contamination of blood products, pregnant mothers to babies

•       Currently 40 million people live with that and 25 million died

•       Free virus after  binding and fusion in to the cell wall causes infection by reverse transcription followed by integration and transcription which forms mature virus

Also, Visit: Pathophysiology Notes

Pathophysiology PDF Notes

Hematological Function TestAIDS Acquired Immunodeficiency Syndrome