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
Hematological Function TestAIDS Acquired Immunodeficiency Syndrome