daze-ga,
This was quite and interesting question! While there certainly is a
lot more data available about HIV-1, I found quite a bit about HIV-2
for you.( I will get to the seronegative issue towards the end of the
answer.)
Harvard researchers did indeed first report the presence of HIV-2 in
Africa, in 1985. The first case of HIV-2 in the United States appeared
1987, but there are no accurate statistics as testing fro HIV-2 is not
routine in the US. The presence of HIV-2 is more prevalent in Western
Africa, particularly Senegal, The Ivory Coast, Gambia, Guinea-Bissau,
Mali, Mauritania, Nigeria, and Sierra Leone. One out of every 100
people in these countries is infected with HIV-2.
HIV-1 and HIV-2 share many genetic similarities.
This Harvard site offers a very nice graphic of the HIV-1 and the
HIV-2 genome, displaying the similarities and the differences.
http://www.hsph.harvard.edu/hai/images/laboratories/figure_HIV1and2.jpg
The rate of AIDS development from HIV-1 infection is over ten times
greater than the rate of developing AIDS from HIV-2. Some in vitro
studies suggest that HIV-2 may actually provide immunity against
HIV-1 (A sore of vaccine effect). The development of antibodies is
similar in HIV-1 and HIV-2. Antibodies usually become detectable
within 3 months of infection.
http://www.hsph.harvard.edu/facres/knk.html
According to this Harvard site, researchers have found that infection
with HIV-2 reduced the chances of acquiring HIV1 infection by
approximately 70%, in a study in Senegal, West Africa.
http://www.apin.harvard.edu/senegal.html
According to the CDC, both HIV-1 and HIV-2 have the same modes of
transmission. Full-blown AIDS seems to develop slower and be less
severe than people infected with HIV-1.
http://www.cdc.gov/hiv/pubs/facts/hiv2.htm
This report, from Aaron Diamond AIDS Research Center, Rockefeller
University, New York discusses how HIV-2 arrived from cross-species
transmission from a simian form of the retrovirus found in sooty
magabeys.
http://www.ncbi.nlm.nih.gov/htbin-
post/Entrez/query?uid=97248444&form=6&db=m&Dopt=b
(Sooty magabeys—(such an odd sounding name!) are a simian species,
closely resembling a baboon). To learn about this species visit:
http://brainmuseum.org/Specimens/primates/sooteymangabey/
Or
http://www.szgdocent.org/pp/p-mangbey.htm
This Harvard site shows that infection with HIV-2,which is a far less
virulent form of the virus, protects against infection with HIV-1, a
finding with implications for vaccine development.
http://www.hsph.harvard.edu/press/releases/press032499.html
=================================
For more reading about HIV-2, visit these links:
http://www.cdc.gov/hiv/pubs/facts/hiv2.htm An excellent
comprehensive explanation of HIV-2, testing, and people at risk.
This site, from the University of North Carolina, describes their
testing for HIV-1 and HIV-2
http://www.pathology.med.unc.edu/path/labs/test/h/hiv_ab.htm
http://www.ccsf.edu/Departments/Biology/resist.htm
http://www.aegis.com/pubs/beta/1995/BE952634.html
http://glossary.hivatis.org/index.asp
A glossary of HIV-2 terms.
http://www.med.umich.edu/intmed/infectious/faculty/markovitz/markovitzresint.htm
http://hiv-web.lanl.gov/content/hiv-db/HelpDocs/subtypes-more.html#HIV-2
http://grants2.nih.gov/grants/guide/notice-files/not95-017.html
http://www.adarc.org/hiv/stages/index.htm
Graphic of how HIV enters and infects a T-cell.
http://www.avert.org/hivtypes.htm
http://www.avert.org/aidsinafrica.htm
A page of interesting links to many sources of information about
Aids/HIV in Africa.
http://www.avert.org/testing.htm
Excellent explanation of testing.
http://www.avert.org/origins.htm
====================================
Finally,
In your question, you ask “How does the seronegative form of HIV-2
differ from the regular HIV-2?”. If a person is seronegative, it
indicates one of two possibilities. The person is free of the HIV-2
virus, OR, the person has been so recently infected that they have not
yet developed a sufficient HIV-2 antibody titer to test positive. (
It can take up to three months for antibodies to be detected, using
serological testing)
Dr. Phyllia Kanki, Professor of Immunology and Infectious Diseases
Department of Immunology and Infectious Diseases , Harvard writes
“HIV-2 proviral load is similar to that of HIV-1 but plasma viral
titers are at least 30 fold lower suggesting quiescent infection.
Further studies seek to identify the viral or host factors critical
for virus containment.” Dr. Kanki’s laboratory developed a viral load
test for the presence of HIV-1 and HIV-2.
http://www.hsph.harvard.edu/facres/knk.html
“Viral load testing measures the number of copies of viral RNA per one
milliliter of blood. Viral loads for HIV-infected people can range
from undetectable to more than a million copies per ml. The tests are
not sensitive enough yet to detect viral loads lower than about 25
copies per ml. So even though an undetectable viral load is a very
good sign, it does not necessarily mean that the person is
HIV-negative. It just means that there is not enough virus to be
detected. “
http://www.hivchannel.com/routinetesting/index.shtml#vir
More about viral load testing:
http://www.thebody.com/Forums/AIDS/Labs/Current/Q141448.html
========================================
Symptoms of HIV-2 are similar to HIV-1:
The following may be warning signs of infection with HIV:
· rapid weight loss
· dry cough
· recurring fever or profuse night sweats
· profound and unexplained fatigue
· swollen lymph glands in the armpits, groin, or neck
· diarrhea that lasts for more than a week
· white spots or unusual blemishes on the tongue, in the mouth, or in
the throat
· pneumonia
· red, brown, pink, or purplish blotches on or under the skin or
inside the mouth, nose, or eyelids
· memory loss, depression, and other neurological disorders
http://www.cdc.gov/hiv/pubs/faq/faq5.htm
=========================================
Hopefully this answer will provide you with the information you seek.
If this answer does not provide what you were searching for, please
ask for a clarification.
-Regards,
crabcakes
search strategy:
HIV-2
Viral load testing
Harvard + HIV-2
symptoms + HIV-2 |
Request for Answer Clarification by
daze-ga
on
14 Sep 2002 12:28 PDT
Hi, my question asks only about the seronegative FORM of HIV-2,, not
seronegative status, and not for the information you provided, The
seronegative form is a type of HIV-2, as I undersatnd it that has
recently been identified in India. It has been found in a few
people,, known as carriers.... They have been tested well beyond the
time frame usually used,, 3 or 6 months. see Intl J STD AIDS 2000
Jan;11(1):31-7. What is the clincial appearance of this variant? what
is known about this variant? How is it like HIV-2? How is it
different? For how long have the carriers been followed? Where is
the best information on this variant? Harvard? elsewhere? Pease try
again.
|
Clarification of Answer by
crabcakes-ga
on
14 Sep 2002 19:30 PDT
daze,
I am sorry you were unhappy with my answer. I included extra
information partly because your subject line read “ Symptoms HIV-2”.
I incorrectly assumed you were interested in knowing HIV-2 symptoms as
well. The other extra material I presented, was simply that, extra
information, in case you cared to read furthur.
When you say “ seronegative form of HIV-2”, I must assume you mean
people who have been infected with the HIV-2 virus, but still test
negative (seronegative). I have found no form or subtype of HIV,
that uses “seronegative form of HIV-2” as a naming convention.
I believe this site will answer many of your questions, regarding
similarities of the HIV types, origin, and epidemiology.
http://www.socgenmicrobiol.org.uk/JGVDirect/18253/18253ft.htm
“Some people are rapid progressors who develop AIDS in only a few
years following infection. Slow progressors remain asymptomatic for
over a decade following infection. A very small number of people are
nonprogressors, resistant to either HIV infection or progression to
AIDS. The best studied resistance mechanism is lack of the CCR5
chemokine receptor required for HIV to infect macrophages. This
mutation was discovered in people who were repeatedly exposed to HIV
but showed no sign of infection or seroconversion. People homozygous
for the CCR5 mutation (found in 1% of Caucasians but not in Japanese
or West African subjects) were nearly completely protected from
infection. (Interestingly, their immune responses were normal in spite
of the absence of CCR5, illustrating the redundant nature of chemokine
action). The few homozygotes who were infected are believed to have
been infected by the CXCR4-tropic form of the virus. Heterozygotes for
the CCR5 co-receptor showed a slower progression to AIDS. Other
populations of long term nonprogressors who are HIV-positive (have
antibodies to HIV) and of highly exposed but seronegative people who
have HIV-specific CTL and Th1 cells are being studied.” Located below
the middle of the page, this quote is from an immunology study module
of the University of Arizona, located here:
http://microvet.arizona.edu/Courses/MIC419/SystemModules/microbeevasion.html
An article in the Deccan Herald briefly discusses HIV which includes
subtype-C, which is found in India.
http://www.deccanherald.com/deccanherald/july16/snt2.htm
Several sub-types of HIV in India and Pakistan are discussed here
://www.google.com/search?q=cache:qn2Ycof_OqkC:www.pbrc.hawaii.edu/rcmi/symposium/docs/sample-abstract.doc+HIV+subtype-c+%2B+India&hl=en&ie=UTF-8
Discussing the gene sequencing of HIV variants in India, from Reuters:
http://www.aegis.com/news/re/1999/RE990103.html
From Harvard, about the early discovery of HIV-2 in India.
http://www.hsph.harvard.edu/hai/conferences_events/2001/vaccine_development/1998b/vacdev-10.html
From an article on the BBC website:
“Very few cases of HIV-2 infection occur outside Western Africa,
because the transmission of the virus is less efficient. The genome of
HIV-1 and HIV-2 are only partially homologous10. For that reason,
HIV-2 is not necessarily detected by conventional laboratory tests
which detect the HIV-1 antibody. The HIV-2 infection takes longer to
develop to AIDS. The course of the syndrome is less aggressive because
HIV-2 has a lower impact on the immune system (compared to HIV-1)
until late in the course of AIDS. The mortality rate from HIV-2
infection is only two-thirds that for HIV-1.” “HIV-1 is the
predominant type worldwide, and it is more aggressive than HIV-2
(HIV-2 is endemic in Western Africa). HIV-1 is further subdivided into
three groups of subtypes, mutants, namely M (major), O (outlier) and N
(because it is between M and O). HIV-1-M subtypes (A through H) vary
slightly. The geographical distribution of these subtypes is
inhomogenous.”
http://www.bbc.co.uk/dna/h2g2/A744770
From the CDC:
“The first pattern consists of a restricted number of HIV-1 viral
subtypes or their combination with HIV-2. Examples include HIV-1
subtypes E and B in Thailand (5) and HIV-1 subtype C and HIV-2 in
India “
http://www.cdc.gov/ncidod/eid/vol4no4/pieniaze.htm
A study at McGill University did a study of 28 individuals who were
exposed to the HIV virus. “Eighteen individuals were persistently
seronegative (group 1) while ten seroconverted within three months of
study entry.”
http://www.iavi.org/reports/280/aidsvax2001.htm
The Aaron Diamond AIDS Research Center studied HIV-exposed
seronegative men and the protective effects of chemokines.
http://www.cdc.gov/ncidod/eid/vol3no3/smith.htm
In this site, which I included above, in the first part of my
answer, mention is made that there were 2 patients in India with
HIV-2 (No sero-reactivity type given)
http://www.cdc.gov/hiv/pubs/facts/hiv2.htm
Prevalence of HIV-2 in India
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12170934&dopt=Abstract
An article that touches on testing differences of HIV-1 and HIV-2
http://www.fda.gov/ohrms/dockets/ac/00/backgrd/3620b1u.pdf
Tracking the HIV virus:
http://www.aidsinfonyc.org/hivplus/issue7/report/evolution.html
I was unable to find further information beyond the information you
already had, the previous information I supplied you with, and the
newest information. If you are not satisfied with this answer, feel
free to request a refund.
Regards,
crabcakes
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