Biology Questions and Answers
symptoms) ranges in average from 10
to 15 years.
Acute AIDS is the clinical situation
characterizthat may aed by signs and symptomsppear in 5 to 30 days after (^)
the infection by the HIV, due to the high
replication rate period. Acute AIDS does not alwaysof the virus on this (^)
happen and many times it is mistaken
for commocold. The patient can pn diseases like the commoresent fever, n
malaise, myalgia (muscle pain) and
arthrallymphadenomegaly (gia (joint pain),enlargement of (^)
lymphnodes), sweating aThe manifestation often lastsnd diarrhea. from 3 to (^)
15 days.
- What are the three phases
into which the HIV infection is
often divided?
The HIV infection is oftthree phases: the acute pen divided intohase, from the (^)
infection to infection, a 1 until 9 weeks after phase in which the virusthe
replicates and the number of CD4
lymphocytes isasymptomatic phase, lasting fr reduced; the (^) om 9
weeks to often more than 10 years, in
which the the CD4 couviral load remains stable nt is not abnormally low;and
the AIDS stage, high, CD4 count is awhen the viral loabnormally low d isand (^)
opportunistic diseases manifest.
- How do antibody-based
tests detect how HIV infection
works?
After the infection by the HIV the
immune systemof antibodies (primary imm begins the productionune
response) against the virus. The testsELISA (enzymassay) and Westee-linkern-blot search fd immunosorbor theent (^)
presence of specific antibodies against
HIV antigens in blood samples. Sinconly one positive ELISA is not e
conclusive, as false positive tests may
happen, the Westerused after the positive ELn-blot tISA.est is often
- What is the window phase
of an infection? How is this
concept important for the test
of HIV infection in blood
banks?
The primary immune response of the
body facing immediate. Tany infection he window phase is this not (^) e
period from thformation of detectable e infection uspecificntil the
antibodies against the infective agent.
In this period, immunocthat indirectly search infections, like hemical teststhe (^)
ELISA and the Western-blot for HIV,
give a negative ris actually infected besult even if the persony the agent. In the
case of HIV, the window phase can last
about 2 weeks to 3 months.
The window phase is a big problem for
blood banks that perform onlyimmunochemical tests on the donated (^)
blood. This is the reason why in some
countries thsubmitted to e blood donors ara series of questionse (^)
regarding their prior behavior, mainly
sexual and drug use related, in themonths preceding the donation and also (^)
to voluntary coin which they declare nfidential self exclusion,whether their
blood may be used or should be
excluded. Instead of facing thisdangerous problem, modern blood (^)
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