HIV - Biomed PDF

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Discuss how transmission of hiv occurs  Infection with HIV may occur following- o sexual contact with an HIV positive individual o contaminated needles and/ or syringe amonst drug users o or very rarely through transfusion of contaminated blood or blood products  maternal- foetal transmission may ...

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Discuss how transmission of hiv occurs  Infection with HIV may occur followingo sexual contact with an HIV positive individual o contaminated needles and/ or syringe amonst drug users o or very rarely through transfusion of contaminated blood or blood products  maternal- foetal transmission may affect up to 25% of pregnancies to HIV positive women though this has been reduced to 1 % by successful antiretroviral therapy or delivery of caesarean section  a further 5-20% of babies born to HIV pos. women may be infected through breast feeding and consequently this is discourages  extra reading- maternal- foetal transmission is still a serious problem In developing countries due to poor education about disease transmission and prevention, poor or non-existent access to antiretroviral drugs and taboos surrounding breast- feeding  while healthcare workers have been infected with HIV after needlestick injury and through blood entering open wound or mucous membrane this is extremely rare though  The HIV virus can infect CD4+ T lymphocytes, macrophages and dendritic cells  Virus proliferation occurs mainly in peripheral lymphoid organs, spleen, lymph nodes and gut-associated lymphoid tissue (GALT) Discuss the clinical features of HIV infection Stage 1 – Primary HIV infection  In the first few months following infection the virus rapidly replicates (CD4+ count reduces)  Here it is an Asymptomatic infection- for period of between 2 and 15 years o Patient does not experience symptoms and may be unaware of infection  10% of individuals develop an acute illness called Acute retroviral seroconversion syndrome= usually 2-6 weeks after injection o Acute clinical illness (fatigue, fever, rash, myalgia, pharyngitis, encephalopathy, meningitits)  Persistent generalized lymphadenopathy o Persistent lymph node enlargement Stage 2 – clinical latency  In this phase the patient recovers from initial infection

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CD4+ T-lymphocyte count initially recovers Patient continues to be asymptomatic A Slow and progressive loss of CD4+ cells is seen HIV viraemia increases This Can last for years

Stage 3 – symptomatic disease  Here Patients health declines due to decreasing CD4+ T-cell count  opportunistic infections and secondary cancers occur  Early symptomatic disease seeno Candidiasis o Herpes zoster (shingles) o Listeriosis o Bacillary angiomatosis (Bartonella) Stage 3 – late symptomatic disease (AIDS)  Lymphocytopenia (CD4+ T-Lymphocyte count...