HIV-AIDS.ppt for the community health nursing

HIV aids topic presentation

1. HIV / AIDS
Dr Farhan Rasheed
Assistant Prof Pathology

2. 2
Transfer of HIV to Humans
“Natural transfer” theory (Science 2000)
HIV was transferred to humans through hunting and
handling of chimpanzees
The epidemic required urbanization and increased
population mobility

3. People Living with HIV/AIDS by End of 2013
North America
950,000
Latin America
1.5 million
Western Europe
560,000
East Europe & Central Asia
1’000,000
Sub-Saharan Africa
28.5 million
North Africa &
Middle East
500,000
Australia &
New Zealand
15,000
South/South East Asia
5.6 million
East Asia & Pacific
1’000,000
Total: 40 million people
Caribbean
420,000

4. HIV-1 is the most prevalent HIV type throughout
the world;
HIV-2 has been found in Africa

5. Mode of transmission
Person to person transmission through
unprotected (heterosexual or homosexual)
intercourse;
Contact of abraded skin or mucosa with body
secretions such as blood, CSF or semen;
The use of HIV-contaminated needles and
syringes, including sharing by intravenous
drug users; transfusion of infected blood or
its components

6. Mode of transmission (cont.)
Transplantation of HIV-infected tissues or
organs.
The presence of a concurrent sexually
transmitted disease, especially an ulcerative
one, can facilitate HIV transmission.
Unprotected intercourse (no condom—
unprotected sex) with many concurrent or
overlapping sexual partners.

7. Mode of transmission (cont.)
HIV can be transmitted from mother to child (MTCT or
vertical transmission).
From 15% to 35% of infants born to HIV-positive mothers are
infected through placental processes at birth.
HIV-infected women can transmit infection to their infants
through breastfeeding and this can account for up to half of
mother-to-child HIV transmission.
Giving pregnant women antiretrovirals such as zidovudine
results in a marked reduction of MTCT.

8. Mode of transmission (cont.)
While the virus has occasionally been found in
saliva, tears, urine and bronchial secretions,
transmission after contact with these secretions
has not been reported.

9. HIV Transmission in United States and
Rest of the World

10. Incubation period
Although the time from infection to the
development of detectable antibodies is
generally 1–3 months, the time from HIV
infection to diagnosis of AIDS has an
observed range of less than 1 year to 15
years or longer.

11. Period of Communicability
Not known precisely; begins early after onset of
HIV infection and presumably extends
throughout life.
Infectivity during the first months is considered to
be high; it increases with viral load, with
worsening clinical status and with the presence
of other STIs.

12. 12
Classification of HIV
HIV class: Lentivirus
Retrovirus: single stranded RNA transcribed to double
stranded DNA by reverse transcriptase
Integrates into host genome
High potential for genetic diversity
Can lie dormant within a cell for many years,
especially in resting (memory) CD4+ T4 lymphocytes
HIV type (distinguished genetically)
HIV-1 -> worldwide pandemic
HIV-2 -> isolated in West Africa; causes AIDS much
more slowly than HIV-1 but otherwise clinically similar

13. 13

14. 14

15. Overview of HIV life cycle
HIV life cycle:
1.Binding and Fusion
2.Entry
3.Reverse transcription
4.Integration
5.Viral RNA and protein expression
6.Assembly and budding
7.Maturation
HIV target cells:
CD4T cells,
Macrohpages,
Dendritic cells

16. 16
HIV at Surface
of CD4
Lymphocyte
Courtesy of CDC

17. 17
HIV ReceptorsHIV Receptors
HIV and Cellular Receptors
Copyright © 1996 Massachusetts Medical Society. All rights reserved.

18. 18
Viral-host Dynamics
About 10 billion virions are produced daily
Average life-span of an HIV virion in plasma is
~6 hours
Average life-span of an HIV-infected CD4
lymphocytes is ~1.6 days
HIV can lie dormant within a cell for many years,
especially in resting (memory) CD4 cells, unlike
other retroviruses

19. Pathogenesis of HIV

20. 20
Cells Infected by HIV
Numerous organ systems are infected by HIV:
Brain: macrophages and glial cells
Lymph nodes and thymus: lymphocytes and dendritic
cells
Blood, semen, vaginal fluids: macrophages
Bone marrow: lymphocytes
Skin: langerhans cells
Colon, duodenum, rectum: chromaffin cells
Lung: alveolar macriphages

21. 21
General Mechanisms of HIV
Pathogenesis
Direct injury
Nervous (encephalopathy and peripheral neuropathy)
Kidney (HIVAN = HIV-associated nephropathy)
Cardiac (HIV cardiomyopathy)
Endocrine (hypogonadism in both sexes)
GI tract (dysmotility and malabsorption)
Indirect injury
Opportunistic infections and tumors as a
consequence of immunosuppression

22. 22
General Principles of
Immune Dysfunction in HIV
All elements of immune system are affected
Advanced stages of HIV are associated with
substantial disruption of lymphoid tissue
Impaired ability to mount immune response to new
antigen
Impaired ability to maintain memory responses
Loss of containment of HIV replication
Susceptibility to opportunistic infections

23. 23
Mechanisms of CD4
Depletion and Dysfunction
Direct
Elimination of HIV-infected cells by virus-specific
immune responses
Loss of plasma membrane integrity because of viral
budding
Interference with cellular RNA processing
Indirect
Syncytium formation
Apoptosis
Autoimmunity

24. 24
Syncytium Formation
Observed in HIV infection, most commonly in the
brain
Uninfected cells may then bind to infected cells
due to viral gp 120
This results in fusion of the cell membranes and
subsequent syncytium formation.
These syncytium are highly unstable, and die
quickly.

25. Mechanism of CD4 T cell depletion in HIV
infection

26. Natural History of
HIV Infection

27. 27
Primary HIV Infection
The period immediately after infection characterized by
high level of viremia for a duration of a few weeks
Associated with a transient fall in CD4
Nearly half of patients experience some mononucleosis-
like symptoms (fever, rash, swollen lymph glands)
Primary infection resolves as body mounts HIV-specific
adaptive immune response
Cell-mediated response (CTL) followed by humoral
Patient enters “clinical latency”

28. 28
Window Period: Untreated Clinical
Course
--------------------------------------------PCR
P24
ELISA
0 234
Weeks since infection
a bTime from a to b is the window period
viremia
antibody
Asymptomatic
Acute HIV syndrome
Primary
HIV
infection
Source: S Conway and J.G Bartlett, 2003
years

29. 29

30. 30
Consequence of Cell-mediated
Immune Dysfunction
Inability to respond to intracellular infections and
malignancy
Mycobacteria, Salmonella, Legionella
Leishmania, Toxoplama, Cryptosporidium,
Microsporidium
PCP, Histoplamosis
HSV, VZV, pox viruses
EBV-related lymphomas

31. Classification of HIV Disease: WHO Stages

32. Herpes Zoster (Shingles):
varicella zoster virus
Seborrheic Dermatitis:
Malassezia fungus

33. Classification of HIV Disease: WHO Stages
(cont.)

34. Classification of HIV Disease: WHO Stages
(cont.)

35. HIV wasting syndrome
(WHO stage IV)
Oral Candidiasis /
Thrush (WHO stage III)

36. Classification of HIV Disease: CDC Stages:
AIDS Defining Conditions
Bacterial infections, multiple or recurrent*
Candidiasis of bronchi, trachea, or lungs
Candidiasis of esophagus
†
Cervical cancer, invasive
§
Coccidioidomycosis, disseminated or
extrapulmonary
Cryptococcosis, extrapulmonary
Cryptosporidiosis, chronic intestinal (>1 month's
duration)
Cytomegalovirus disease (other than liver, spleen, or
nodes), onset at age >1 month
Cytomegalovirus retinitis (with loss of vision)
†
Encephalopathy, HIV related
Herpes simplex: chronic ulcers (>1 month's duration)
or bronchitis, pneumonitis, or esophagitis (onset at
age >1 month)
Histoplasmosis, disseminated or extrapulmonary
Isosporiasis, chronic intestinal (>1 month's duration)
Kaposi sarcoma
†
Lymphoid interstitial pneumonia or pulmonary
lymphoid hyperplasia complex*
†
Lymphoma, Burkitt(or equivalent term)
Lymphoma, immunoblastic(or equivalent term)
Lymphoma, primary, of brain
Mycobacterium aviumcomplex or Mycobacterium
kansasii,disseminated or extrapulmonary
†
Mycobacterium tuberculosis of any site,
pulmonary,
†§
disseminated,
†
or extrapulmonary
†
Mycobacterium, other species or unidentified
species, disseminated
†
or extrapulmonary
†
Pneumocystisjiroveciipneumonia
†
Pneumonia, recurrent
†§
Progressive multifocal leukoencephalopathy
Salmonellasepticemia, recurrent
Toxoplasmosis of brain, onset at age >1 month
†
Wasting syndrome attributed to HIV

37. Image modified from rom niaid.nih.gov
Detect
antibodie
s
Detect
virus
compone
nts

38. \

39. Available HIV Tests
Detection of virus components (early infection)
p24 Antigen test
HIV viral RNA test
Detection of host antibody response (2-3 weeks
after infection)
ELISA
Immunofluorescence assay
Western Blot
Rapid HIV test

40. Methods of control
A. Preventive measures:
HIV/AIDS prevention programs can be effective
only with full community and political
commitment to change and/or reduce high HIV-
risk behaviours.

41. Methods of control
WHO recommends immunization of
asymptomatic HIVinfected children with the EPI
vaccines; those who are symptomatic should not
receive BCG vaccine.
Live Measles-Mumps-Rubella and polio
vaccines are recommended for all HIV-infected
children.

42. Methods of control (cont.)
Public and school health education must stress
that having multiple and especially concurrent
and/or overlapping sexual partners or sharing
drug paraphernalia both increase the risk of HIV
infection.

43. Methods of control (cont.)
The only absolutely sure way to avoid infection
through sex is to abstain from sexual intercourse
or to engage in mutually monogamous sexual
intercourse only with someone known.
In other situations, latex condoms must be used
correctly every time a person has sexual
intercourse.

44. Methods of control (cont.)
Expansion of facilities for treating drug users
reduces HIV transmission.
HIV testing and counselling is an important
intervention for raising awareness of HIV status,
promoting behavioural change and diagnosing HIV
infection. HIV testing and counselling can be
undertaken for:
a) persons who are ill or involved in high-risk behaviours,
b) attenders at antenatal clinics, to diagnose maternal
infection and prevent vertical transmission;
c) couple counselling (marital or premarital);
d) anonymous and/or confidential HIV counselling and
testing for the “worried well”.

45. Methods of control (cont.)
All pregnant women must be counselled about
HIV early in pregnancy and encouraged to
undertake an HIV test as a routine part of
standard antenatal care.
Those found to be HIV-positive take a course of
ARV treatment, to reduce the risk of their infant
being infected.

46. Methods of control (cont.)
All donated units of blood must be tested for
HIV antibody; only donations testing negative
can be used.
People who have engaged in behaviours that
place them at increased risk of HIV infection
should not donate plasma, blood, organs for
transplantation, tissue or cells (including
semen for artificial insemination).

47. Methods of control (cont.)
Care must be taken in handling, using and
disposing of needles or other sharp instruments.
Health care workers should wear latex gloves,
eye protection and other personal protective
equipment in order to avoid contact with blood or
with fluids.

48. Test on 14 Nov 2017
Hypersensitivity reactions
HIV/AIDS
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