HIV D S O’Briain March 2007

Pathology of HIV Epidemic disease Influenza pandemic Legionnaire’s disease 1976 HIV 1981 Heroin, Dublin 2000 SARS 2003

AIDS to end of the 1980s

Pathology of HIV Epidemiology Modern Plague, 40 million infected by 2000 Sub-Saharan Africa (high) East and South East Asia (moderate) Europe, USA (‘low’)

Pathology of HIV Lymphadenopathy 1980 Cluster of cases, New York, San Francisco 1981 Delineation of risk groups: homosexual, haemophiliacs: blood products/blood, IVDU Later: mother to child, heterosexual, unknown HCW

Pathology of HIV HIV 1 and 2: retrovirus attach to CD4 receptor Acute seroconversion: 50%; mono-like illness Latent period 2-10 years+ –Persistent generalised lymphadenopathy AIDS relatated complex ARC (diarrhoea, sweats, oral candida, lymphadenopathy, weight loss) CD /uL vs viral load Neural disease: meningitis, encephalomyelopathy at seroconversion: meningitis, encephalopathy, dementia later Opportunistic infections Malignancy

Pathology of HIV Infections (decreased CD4 cells, HAART) Candida: (mouth, oesophagus) Pneumocystis Carinii (pneumonia) Tuberculosis (early), atypical mycobacterial infections (late) CMV (eye, GI) or Herpes Simplex Cerebral toxoplasmosis Parasitic infections of GI Systemic fungal infection Bacterial infection

Pathology of HIV Kaposi Sarcoma Before AIDS: a rare lesion in elderly Jewish or mediterranean patients, transplant recipients, young Africans (Lake Victoria) AIDS: male homosexuals, venereally transmitted Skin lesion, also GI, lung, other sites Morphology: vascular granulation tissue-like Human Herpes virus 8

Pathology of HIV Neoplasia Kaposi Sarcoma (HHV 8) Lymphoma (EBV), B cell, aggressive –Brain, Extranodal sites, Nodal, body cavity –Other lymphoma, Hodgkin, T cell Cervix (HPV)