Natural history of HIV/AIDS
Published on: Mar 3, 2016
Transcripts - Natural history of HIV/AIDS
Natural HISTORY OF HIV/AIDS Kumaravel Ilangovan MPH(first semester) Batch- Fall2012
WHAT?WHY?The natural history of disease refers to adescription of the uninterrupted progression ofa disease in an individual from the moment ofexposure to causal agents until recovery ordeath.Source:http://en.wikipedia.org/wiki/Natural_history_of_disease
Objectives– discovery and Evolution of HIV– Difference between HIV-1/HIV-2– describe HIV transmission routes– describe the pathogenesis and life cycle of HIV– describe the progression of HIV to AIDS– Stage at which the preventive and curative interventions available
Evolution of SIV into HIV• Retroviridae• Lentiviridae• Same modes of transmission.• Introduction of simian immunodeficiency virus into the human population.• primate simian immunodeficiency viruses: HIV-2 from SIVsm (sooty mangabey) and HIV-1 from SIVcpz (chimpanzee).
Discovery of HIV• In 5th june1981first article related to AIDS by MMWR.• Author name was MICHAEL GOTTLIEB.• Pneumocystitis carinii (PCP)• Sandra ford – a drug technician said to news letter “a gay man repeatedly called for refill the rare drug used to treat for PCP”• 3rd July another article reported outbreaks of KAPOSI SARCOMA among Homosexual males in Newyork.
continued• In 1982 the term ACQURED IMMUNO DEFICENCY SYNDROME (AIDS) first time coined by CDC.• KSOI (Kaposi sarcoma and Opportunistic infections) CDC task force identified 40 patients.• 1983 Heterosexual transmission.• AIDS is a suitable name. No cause, No tests.• 23rd April 1984 HIV discovered• 1985 test discovered to identify HIV infected persons.
Six decade story
HIV-1 versus HIV-2Table 1. Key differences between HIV-1 and HIV-2 HIV-1 HIV-2Geographic Distribution Worldwide West AfricaHeterosexual Transmission 3- to 6-fold lowerPerinatal Transmission 15%–45% 0%–5%Time to AIDS 7–10 years 10–25 yearsTreatment NNRTIs* ineffective .
BIOLOGY OF HIV
Modes of HIV Transmission Needle Stick Sexual contact Sharing Needles Injury & SyringesThrough Infected Blood During Pregnancy Breast Feeding or Birth NACO-2006
Routes of TransmissionINDIA 2010-2011 Gender variation Source: NACO 2006
Risk of HIV Transmission with Single Unprotected Exposure (Risk per 10,000 exposures) Source: NACO 2006
How HIV Infects the BodyHIV makes contact with cells located within the genital mucosa Virus is carried to regional lymph nodes (1-2 Days) Exponential viral replication Widespread systemic dissemination to the brain, spleen, distant lymph nodes, etc. (5-11 Days)
Life cycle of HIV
Clinical course of Infection correlated with Biological Assays
Stages of HIV Infection Viral transmission (2-3 wks) Acute retroviral syndrome (2-3 wks) Seroconversion (2-4 wks) Asymptomatic chronic HIV infection (Avg. 8yrs) Symptomatic HIV infection/AIDS (Avg. 1.3 yrs)
Primary Infection: Lab Diagnosis• ¨ ELISA: NEGATIVE (or only IgM• POSITIVE)• ¨ Western Blot: NON-REACTIVE /• INDETERMINATE• ¨ p24 antigenemia: licensed by US FDA for• diagnosis• ¨ Plasma HIV RNA: detectable and high level
Clinical latency¨Asymptomatic¨Ongoing viral replication¨‘Set-point’ for viral load¨Gradual decline in CD4cells¨Antibody tests remainpositive
Patterns of HIV Progression• Typical progressors (35-50 CD4 cells/year)• Rapid progressors ( >50 cells/month)• Slow progressors (very slow than typical )• Long-term non-progressors (stabilised)
ReferencesSources:1. HIV/AIDS epidemiology, pathogenesis, prevention, and treatment 2006 NIH publication (Lancet).2. Rothenberg RB et al. AIDS 1998;12:2095-2105.3. Am J Epidemiology 1999;150:306-11.4. NEJM 336(15):1072-8. (rates in Europe & U.S.)5. Am J Epidemiology 1999;150:306-116. CDC, MMWR 47;RR-17, 1998.7. Bell DM. Am J Med 1997;102(suppl 5B):9—15.8. Am J Epidemiology 1999;150:306-11 and CDC, MMWR 54; RR-2, 2005 (http://www.cdc.gov/mmwr/PDF/rr/rr5402.pdf).9. CDC, MMWR 47;RR-17, 199810. NACO report 2006, 201111. “AND THE BANDS PLAYED ON” 1993 Documentary film by HBO pictures12. Internet resources: Wikipedia and Encyclopedia
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