Retroviruses
&
Human Immunodeficiency Virus
(HIV)
1
, Important properties:
•HIV primarily infects CD4 T cells and cells of the macrophage
lineage
•Monocytes
•Macrophages CD4 proteins on their surface
•Dendritic cells (skin)
•Microglial cells (CNS)
Genome consists of single-strand, RNA
2
,3
,
,Routes Specific Transmission
Known Routes of Transmission
Inoculation in Transfusion of blood and blood products
blood Hemophilia (clotting factor)
Needle sharing among intravenous drug abusers
Needlestick, open wound, and mucous membrane exposure in
health care workers
Tattoo needles
Sexual Anal and vaginal intercourse
transmission
Perinatal Intrauterine transmission
transmission
Postpartum transmission
Breast milk
Routes Not Involved in Transmission
Close personal Household members
contact
Health care workers not exposed to blood
5
,HIV enter the body via the bloodstream either during
sexual intercourse
needle drug abuse
transfusion with contaminated blood products
or via the placenta
During sexual intercourse, HIV 1 infects Langerhans dendritic
cells in the epithelium and these can then travel to lymph nodes.
The virus reaches the lymph node within 2 days of infection
and there the CD4 T cells are infected.
Reduction in the numbers of CD4 T cells
.
6
,Clinical findings
Signs and symptoms of the mild mononucleosis-type illness
associated with HIV infection
- fever,
malaise, lymphadenopathy, maculopapular rash
Infected cells are still present, and at a later stage the infected individual
may develop weight loss, fever, persistent lymphadenopathy, oral
candidiasis and diarrhea
complicated by the persistent infections that are activated and
give rise to their own CNS pathology.
HSV, VZV, Toxoplasma gondii,
Cryptococcus neoformans
, Laboratory diagnosis
• Usually diagnosed by detecting HIV- antibody.
Tests are as follows:
• Latex agglutination, if positive ELISA is done
• ELISA, if positive repeat ELISA is done ,
• Western blot- confirmatory
CD4 cell count : if < 400/cm, stage of AIDS has been
reached
• Diagnosis can also be done by:
– PCR- detects HIV RNA
– Antigen detection
– Virus culture
8
, Prevention
1. To avoid exposure to the virus
• using condoms
• Not sharing needles
• Discards donated blood containing HIV
2. Postexposure prophylaxis-
-given after a needle-stick injury
(PEP is the use of antiretroviral drugs after a single high-risk
event to stop HIV seroconversion. PEP must be started as
soon as possible to be effective—and always within 72 hours
of a possible exposure).
3. HIV infected mothers should not breast feed.
4. Caesarean section 9
, Prevention
• "safe sex" (i.e., the relatively safer sex
accomplished by the use of condoms),
• No sex with infected partner
• Do not share the needles of Dru users.
(including needles, syringes, filters, spoons,
swabs, tourniquets).
• Covering any open sores, cuts or abrasions
with waterproof dressings
• Public awareness
This will minimize and generally eliminate the
risk of transmission of HIV
10
&
Human Immunodeficiency Virus
(HIV)
1
, Important properties:
•HIV primarily infects CD4 T cells and cells of the macrophage
lineage
•Monocytes
•Macrophages CD4 proteins on their surface
•Dendritic cells (skin)
•Microglial cells (CNS)
Genome consists of single-strand, RNA
2
,3
,
,Routes Specific Transmission
Known Routes of Transmission
Inoculation in Transfusion of blood and blood products
blood Hemophilia (clotting factor)
Needle sharing among intravenous drug abusers
Needlestick, open wound, and mucous membrane exposure in
health care workers
Tattoo needles
Sexual Anal and vaginal intercourse
transmission
Perinatal Intrauterine transmission
transmission
Postpartum transmission
Breast milk
Routes Not Involved in Transmission
Close personal Household members
contact
Health care workers not exposed to blood
5
,HIV enter the body via the bloodstream either during
sexual intercourse
needle drug abuse
transfusion with contaminated blood products
or via the placenta
During sexual intercourse, HIV 1 infects Langerhans dendritic
cells in the epithelium and these can then travel to lymph nodes.
The virus reaches the lymph node within 2 days of infection
and there the CD4 T cells are infected.
Reduction in the numbers of CD4 T cells
.
6
,Clinical findings
Signs and symptoms of the mild mononucleosis-type illness
associated with HIV infection
- fever,
malaise, lymphadenopathy, maculopapular rash
Infected cells are still present, and at a later stage the infected individual
may develop weight loss, fever, persistent lymphadenopathy, oral
candidiasis and diarrhea
complicated by the persistent infections that are activated and
give rise to their own CNS pathology.
HSV, VZV, Toxoplasma gondii,
Cryptococcus neoformans
, Laboratory diagnosis
• Usually diagnosed by detecting HIV- antibody.
Tests are as follows:
• Latex agglutination, if positive ELISA is done
• ELISA, if positive repeat ELISA is done ,
• Western blot- confirmatory
CD4 cell count : if < 400/cm, stage of AIDS has been
reached
• Diagnosis can also be done by:
– PCR- detects HIV RNA
– Antigen detection
– Virus culture
8
, Prevention
1. To avoid exposure to the virus
• using condoms
• Not sharing needles
• Discards donated blood containing HIV
2. Postexposure prophylaxis-
-given after a needle-stick injury
(PEP is the use of antiretroviral drugs after a single high-risk
event to stop HIV seroconversion. PEP must be started as
soon as possible to be effective—and always within 72 hours
of a possible exposure).
3. HIV infected mothers should not breast feed.
4. Caesarean section 9
, Prevention
• "safe sex" (i.e., the relatively safer sex
accomplished by the use of condoms),
• No sex with infected partner
• Do not share the needles of Dru users.
(including needles, syringes, filters, spoons,
swabs, tourniquets).
• Covering any open sores, cuts or abrasions
with waterproof dressings
• Public awareness
This will minimize and generally eliminate the
risk of transmission of HIV
10
