The human immunodeficiency virus (HIV) is a blood borne retrovirus that was first recognised in 1981.
Disease
Between two weeks and several months following
infection, seroconversion may result in an acute self-limited illness,
similar to infectious mononucleosis, lasting for a week or two. Infected
people may then be free of symptoms or clinical signs for many months
to years before other clinical manifestations appear.
acquired immune deficiency syndrome (AIDS) represents
the late clinical stage of infection with HIV, which most often results
in progressive damage to the immune system, resulting in opportunistic
infections and malignancies, constitutional and neurological disorders
and other organ damage.
The concentration of HIV in the bloodstream is very high
in the early stages of infection, including the window period between
acquisition of HIV and the seroconversion illness. After the resolution
of this illness, HIV viral load decreases due to host immune responses
and stabilises at a lower level. As immunodeficiency progresses and AIDS
develops the HIV viral load rises again. Viral load is also influenced
by antiretroviral therapy. Most patients on combination antiretroviral
therapy have low HIV viral load.
Mode of transmission
Infectivity is believed to begin shortly after primary
infection and continue throughout life, irrespective of whether the
patient is symptomatic. Infective HIV particles are present in the
blood, semen and other body fluids of infected individuals.
HIV is a blood borne and sexually transmissible virus.
HIV may be transmitted by direct contact with blood or other body
fluids, through mucous membranes, nonintact skin or through percutaneous
injury. Needle stick injury with HIV positive blood has resulted in
sero-conversion ranging from 0-0.42% in various studies.
Standard precautions are sufficient to prevent HIV transmission.
Additional precautions for patients with HIV are
required only for those patients with opportunistic infections such as
pulmonary tuberculosis.
Significance in endoscopy
HIV is sensitive to many chemical disinfectants
including aldehydes. A variety of studies have shown that when the virus
is protected within a dried protein coagulum, some chemical
disinfectants including 1% glutaraldehyde will fail to inactivate the
virus within 5 minutes. However, in another series of studies in which
the surface and internal channels of endoscopes were contaminated with
high titre HIV serum, simple manual cleaning removed HIV activity from
all except a single endoscope. The remaining viral activity was removed
from this endoscope after 10 minutes or less in 2% glutaraldehyde.
Where endoscopes were sampled after removal from HIV
positive patients, all HIV present on endoscopes was removed by manual
cleaning alone. This emphasises the absolute necessity to ensure that
scrupulous manual cleaning removes all traces of blood and proteinaceous
material. such cleaning should be undertaken without delay.
To date there has been no unequivocal demonstration of
transmission of human immunodeficiency virus by gastrointestinal
endoscopy. The extremely long incubation time for clinical AIDS would
however make the detection of a very isolated instance of HIV
transmission difficult to detectsource: http://www.health.qld.gov.au/EndoscopeReprocessing/module_1/1_3e.asp
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This video shows the whole process of HIV attacking the whole body. Downloaded from www.nucleusinc.com