WHY THE "AIDS TEST" DOESN'T WORK IN AFRICA
By Christine Johnson
Rethinking AIDS
Jan. 2001
Last summer's events at the 13th International AIDS conference in Durban,
and South African President Thabo Mbeki's refusal to adhere to the
"conventional wisdom" on AIDS, have made it more crucial to reevaluate all
aspects of AIDS in Africa.
It is widely believed that Africa is being devastated by a plague of
"AIDS." This is in spite of the fact that, according to the World Health
Organization's (WHO) Weekly Epidemiological Record, 19 years' worth of
AIDS cases for the entire continent of Africa has amounted to only
876,009. (In the US, more people than this die in one year of heart
disease.) Africa is generally blamed as the origin of AIDS, yet statistics
point towards a more likely source of this disease: the United States.
It was not until 1997 that the cumulative number of AIDS cases in Africa
surpassed those in the United States. The most current statistics
(November 2000) show that the cumulative tally stands at Africa 876,009
and the United States 733,374 -- not much of a difference considering
WHO's estimate that 25.3 million Sub-Saharan Africans have HIV/AIDS,
whereas in the United States it is well below one million. Why is there
this huge discrepancy? The main reason is many Africans test positive on
HIV antibody tests -- while very few Americans do -- and few HIV-positive
people in any country go on to develop AIDS.
Researchers originally targeted Africa as the source of AIDS for three
rather feeble reasons:[21]
(1) Robert Gallo's discredited theory that AIDS was caused by HTLV-1,
another retrovirus similar to HIV, and thought to be endemic in Africa;
(2) the prevalence of Kaposi's sarcoma in Africa (even though Kaposi's
sarcoma was a new disease in American gay men, it had existed in Africa
since ancient times, and hence could not indicate a brand-new disease
there); and
(3) a small number of AIDS patients of African origin who were living in
Europe.
When researchers began taking HIV antibody test kits to Africa around
1985, they immediately found verification of the above ideas. Small groups
of Africans were tested and found to be positive on these tests, and these
numbers were extrapolated to the entire continent. On this basis, and
although only a few thousand AIDS cases had been reported in Africa at
that time, the WHO immediately began estimating that millions of Africans
were infected with HIV and that Africa would have to contend with an
imminent plague.
In the mid-80s when HIV antibody tests first became available, it became
apparent that there were problems associated with using these tests in the
African population.[1-5] In 1985, Hunsmann found that positive HIV (then
called HTLV-III) ELISA tests had a low frequency of confirmation using a
different type of antibody test, the immunoprecipitation method. This led
him to question the specificity of ELISA in African blood samples.[1]
Biggar found correlations between positive HIV antibody tests and age and
poverty.[2] He also found correlations with malaria and parasitic diseases
in Africans (but not in Asians or South Americans). Labius Mutanda of the
Ugandan Public Health Service and guest lecturer at St. Louis University
(US) in 1991 reported that "existing ELISA and Western Blot assays may not
always be able to reliably ascertain HIV infection in many African
individuals."[3] Mutanda told me that his experience with both ELISA and
Western Blot in Uganda was that often an individual could be positive if
tested with the test kit from one manufacturer and negative if tested with
the kit of a different manufacturer.
Serious questions have arisen as to whether HIV antibody tests are
specific in any population,[6] although mainstream AIDS researchers still
believe they are accurate, and considerations of test failure in Africa
have never prevented the tests from being used there for many purposes
including estimating HIV infections. Mulder in 1994 demonstrated that
HIV-positive Africans died at a much greater rate than HIV-negative
Africans, and offered this as definitive proof that HIV causes AIDS.[7] In
reality, the only thing Mulder proved was the utility of HIV antibody
tests when employed as generalized indicators that something is wrong,
i.e., they can be used as surrogate markers of AIDS risk.
The ELISA test contains a mixture of broken-up HIV proteins called a
"whole viral lysate." In theory, if a person's blood contains any HIV
antibodies, the ELISA will react. The Western Blot is more sophisticated
(and much more expensive). The HIV proteins are separated into bands on a
strip. That way, if any antibodies cause a reaction, it can be determined
exactly which HIV protein they are reacting to. The most important HIV
proteins are p24, p32, gp41, gp120, and gp160.
In the US, ELISA is considered to be very inaccurate, and no diagnosis of
HIV infection is made without a Western Blot (considered to be more
accurate) as confirmation. Interestingly, in the UK, just the opposite is
true and Western Blots are considered to be inaccurate!
For the most part, Africans aren't tested. It's simply too expensive. But
when they are tested, the ELISA is used. HIV ELISAs are not accurate
enough to diagnose an American with HIV infection, but they are accurate
enough for Africans!
To compound the problem in Africa, AIDS in Africa is diagnosed not with
antibody tests but rather on the basis of clinical symptoms. This is
called a "clinical case definition," and was originally developed by WHO
in 1985. It consists mainly of persistent fever, diarrhea, and weight
loss. These symptoms are identical to many common African diseases. Only
in Africa can you be diagnosed with AIDS on the basis of these symptoms
alone.
To make matters worse, individual countries have felt free to develop
their own clinical case definitions. Thus, there is no consistency between
countries as to exactly what constitutes an AIDS case, and some of these
clinical case definitions are extremely broad, making it easy to classify
almost anything as AIDS.[34] Often new cases are registered which don't
fulfill even these extremely lax criteria.[34]
Antigen/antibody reactions are nonspecific
My search of the scientific literature on HIV antibody testing produced
references to approximately 70 diseases or conditions that can possibly
cause false-positive reactions on HIV ELISAs and/or Western Blots[28] Many
of the conditions are quite prevalent in Africa. These include
tuberculosis, malaria, leprosy, Q-fever, tapeworms or other parasites, and
leishmaniasis.
In order for these tests to work properly, it must be true that a protein
(also called an antigen) will react only with the antibody that matches
it. In reality, antigen/antibody reactions are nonspecific. Antibodies
cross-react with antigens other than the ones that originally elicited
them. Scientists routinely ignore this well-known phenomenon when it comes
to HIV antibody tests.
This wide range of naturally occurring cross-reactivity does not in itself
invalidate HIV antibody tests, or any antibody test. However, it does
demand, as an absolute requirement, verification by an independent gold
standard. The accuracy of any antibody test must be ascertained by
determining that all people with positive antibody tests have the microbe
in question isolated from their blood, and conversely that all people who
are negative have no microbe isolated from their blood. The fatal flaw in
HIV antibody testing is that virus isolation has never been used as a gold
standard, and it is the only proper gold standard.[6] Without virus
isolation, no one knows what antibodies are causing the reaction when the
test comes back positive.
The problems of antibody/antigen cross-reactivity are compounded in
relationship to the infectious disease burden of the person being tested.
The more varying antibodies a person carries, the more likely that person
is to possess some type of antibody that will cross-react on HIV antibody
tests. Many Africans, exposed to a variety of diseases, tend to carry a
multitude of antibodies. In this regard they can be compared to certain
members of the recognized AIDS risk groups in the West (but not the
general population of Westerners). The general rule is: The more diseases/
microbes/foreign proteins, the more antibodies, and thus the more likely
an HIV antibody test will be positive.
Test kit manufacturers "verify" the specificity of their tests
(specificity is a measure of how often false-positives will occur) by
testing several thousand random blood donors (by definition at low risk
for AIDS or HIV infection), with 20 or 30 subjects thrown in who represent
several of the more commonly recognized cross-reacting conditions such as
rheumatoid arthritis or systemic lupus erythematosus. The other known
cross-reacting factors[8] more prevalent in Africa are not added to the
equation.
This practice of omitting Africans from the test sample (either healthy
Africans or those with similar non-AIDS conditions that might elicit
cross-reactions) results in a picture of test accuracy that fits only the
type of population in the test sample. This creates severe bias and
overestimates test specificity.[9] Constantine stated, "Test parameters
thus obtained with this sort of a biased sample cannot be validly
extrapolated to assess a test's performance in different diagnostic
situations."[10] In other words, an HIV antibody test kit developed in the
West will yield different results in Westerners and Africans.
ELISAs with estimated specificities in the high 90s have been used in
Africa, with very poor results, for exactly this reason. Constantine
reports "unsatisfactory test performance has been described in studies
with east African serum from Tanzania and Egypt."[10] Indeed, the
specificity of one test dropped to an abysmal low of 51% when used in
Africa.[11] (The way the math works out, even a specificity of 99% would
produce extremely high numbers of false posi-tives,[29] so you can imagine
how inaccurate a specificity of 51% would be!).
Confounding this is the widely-acknowledged propensity of antibodies to
one retrovirus to cross-react with the antigens of another retroviruses.
[12,13] Gallo and his colleagues have repeatedly stated that the p24 of
HIV and of two other human retroviruses, HTLV-I and HTLV-II, which Gallo
claims to have isolated from humans, immunologically cross-react.[14]
Since HTLV-1 is endemic in sub-Saharan Africa,[1] many people infected
with HTLV-1 may be mis-diagnosed as being HIV infected.
Are the new "third generation" test kits any better?
The World Health Organization (WHO) addressed this problem by providing
local clinics test kits that use genetically engineered HIV antigens
called recombinent antigens (as opposed to the usual whole viral lysate
antigens which contained many cross-reacting contaminants). Local lab
technicians were trained to use these tests properly. Gordon Stewart, a
British epidemiologist (and member of RA's editorial board) who had
visited Kenya, described such a clinic to me. However, several years ago
Panafrica News Agency correspondent Eliezer Wangulu described another part
of Kenya where "most health facilities have dysfunctional laboratories
that have also run out of reagents."
There are many centers where testing is performed by trained staff using
recombinant antigen for ELISA tests. Western Blot is used by some, but
certainly not even the majority, of centers as a confirmatory test.
Stewart told me, however, he suspected that "much of the testing in Africa
is done with miscellaneous test kits, unsupervised and unvalidated."
Proper performance and interpretation of Western Blots requires a high
degree of expertise. Lab proficiency is highly variable and sometimes
completely unacceptable.[30] Even reference labs, the highest quality labs
in the United States, have quality control issues,[31] and it can be
expected that the specificity of any test kit will deteriorate by an order
of magnitude or more in less experienced labs, where most of the testing
is done.[11,32] So one must wonder how excellent quality control could
exist in Africa, where health care budgets are often minuscule, and lab
experience is much less in comparison. In addition, the chaos of civil
unrest and warfare in many countries has a profound effect on health care
budgets and the ability to organize proper health care resources.
Whether or not a significant portion of African populations has access to
properly run and equipped labs and testing programs, the use of
recombinant antigen test kits will not solve the problem. It is claimed
that these "third generation" test kit antigens are "purified" to the
extent that unwanted cross-reactions, and thus false-positives, will not
occur. However, recombinant antigens are derived from E. coli and may
contain additional bacterial epitopes, and in test sera from some
individuals with antibacterial antibodies, false positives occur as a
result of the interaction of these antibodies with the antigens of the
enteric bacilli.[15,16]
Other false positives can occur for reasons unique to recombinant
technology, e.g., immunoreactive epitopes may rely on either primary amino
acid sequence or conformational shape for antigenicity and therefore,
nonspecific reactivity may result if similar epitopes exist on different
viruses, such as the common flu virus.[15] The fact that other microbes
share epitopes with HIV is amply document-ed.[17] Test systems based on
recombinant HIV antigens have yielded positive results much more often
than those based on whole viral lysate due to cross-reaction with antigens
of enteric bacilli.[16] A study of two groups of random blood donors,
which should have yielded similar results, showed positives to occur more
than twice as frequently in the group tested with
recombinant-antigen-based tests (617/119,004) as in the group tested with
lysate-antigen-based tests (246/119,178).[18]
Another study was done in the former USSR to determine the positive
predictive value (how often a positive test result indicates a true
infection) of various confirmatory tests. This study yielded the following
results in AIDS high-risk groups:[19]
Whole viral lysate antigens: 99.4% specificity
Recombinant peptide antigens: 95.1% specificity
Synthetic peptide antigens: 86.1% specificity
As mentioned above, a specificity of 95% indicates an extremely inaccurate
test in terms of potential false-positives.
Yet another study demonstrated cross-reactions between the sera of people
with autoimmune disorders (for example, systemic lupus erythematosus and
Sjogren's syndrome) and HIV synthetic peptides or recombinant gp120, gp41,
and p24 proteins.[17] The purity of the antigens is really not the issue.
Regardless of the source of antigens, all serological tests are subject to
nonspecific and unpredictable reactivity.[15] It does not matter whether
the HIV antigens are "natural or engineered, or even derived from HIV
itself (e.g., a serological test for infectious mononucleosis employs
sheep red blood cells)." [20] What does matter is whether the reactions of
patients' sera with these antigens are shown to be specific for the
presence of HIV in vivo. A fundamental principle of antibody testing is
that "for a test to be valid, regardless of time of development,
generation, or appellation, its specificity must be authenticated by the
use of an independent gold standard."[20]
Mycobacteria can cause false-positive HIV antibody tests
In 1994, Essex found significant levels of false-positive reactions on
both ELISA and Western Blot in people with leprosy, a disease associated
with Mycobacterium leprae infection.[5] Antibodies to the carbohydrate
structures found in the mycobacterial cell wall, lipoara-binomannan (LAM)
and phenolic glycolipid (PGL), were noted to "[yield] significant
cross-reactivities with the HIV-1 pol [p31] and gag [p24] proteins." Essex
stated that the "data suggest that mycobacterial cell wall antigens may
share common epitopes with HIV" and warned that "ELISA and Western Blot
may not be sufficient for HIV diagnosis in AIDS-endemic areas of Central
Africa where the prevalence of mycobacterial diseases is quite high."
These carbohydrate-containing antigens are also present in other
mycobacteria, in particular Mycobacterium tuberculosis. It is particularly
significant to note:
1. Of the 661 million people in sub-Saharan Africa, 2-3 million have
active TB with an annual mortality of 790,000;[21]
2. TB has now become an AIDS-defining illness, and 30-50% of African
"AIDS" deaths are from TB; [21]
3. "HIV infection" as defined by a positive HIV antibody test does not
precede TB infection but rather follows it; [21]
4. In a tuberculosis sanatorium in Kinshasa, Zaire, half of the suspected
pulmonary cases, one-third of the confirmed cases and two-thirds of the
confirmed extra-pulmonary cases had a positive HIV Western blot
test.[21,22]
The presumption is that HIV infection leads to tuberculosis as an AIDS
indicator disease. But from the above data it is more reasonable to
conclude the opposite -- that tuberculosis causes false-positive HIV
seropositivity, without HIV infection being present.
Anti-carbohydrate antibodies cross-react with HIV proteins
It has been recognized since 1980 that naturally-occurring
anti-carbohydrate antibodies cross-react with retroviral proteins.[23]
Healy speculated that false-positive HIV Western blot gp41 bands were
actually due to anti-carbohydrate antibodies, since gp41 and non-viral
proteins share similar antigenic structures.[24] Tomiyama stated that
"normal human serum contains antibodies capable of recognizing the
carbohydrate moiety of the HIV envelope glycoproteins (gp41, gp120 and
gp160)."[25] This is of particular significance when one realizes that
African criteria for reading HIV Western blots allow a positive diagnosis
based on two envelope bands alone.
Eleopulos states "Not only mycobacteria (M. leprae, M. tuberculosis, M.
avium-intracellulare) but also the walls of all fungi (Candida albicans,
Cryptococcus neoformans, Coccidioides immitis, Histoplasma capsulatum
including Pneumocystis carinii), contain carbohydrate (mannans). One
hundred per cent of AIDS patients (even those with ‘No candida
clinically') have Candida albicans anti-bodies...Since antibodies to
mannans react with the ‘HIV proteins' then, as Essex and his colleagues
have pointed out for mycobacterial infection in Africa, one would expect
the sera of all people infected with fungi and mycobacteria to cross-react
with the "HIV-1 glyco-proteins as well as to cause ‘significant
cross-reactivities with HIV-1 pol and gag proteins.'"[17]
The vast majority of opportunistic infections experienced by AIDS patients
in the West are due to PCP, candidiasis, cryptococco-sis,
coccidioidomycosis, histoplasmosis, tuberculosis or Mycobacterium
avium-intracellulare disease (88% of AIDS cases diagnosed between 1988 and
1992 had one or more fungal or mycobacterial infections).[17] At the very
least tuberculosis and histoplasmosis[26] are endemic in many parts of
Africa, and if AIDS in Africa and AIDS in the West are the same disease,
it can be presumed that many African AIDS patients will be infected with
the above organ-isms.[26]
Estimates of HIV infections in Africa have no scientific basis
In spite of the facts, the myth persists that Africa is suffering a
catastrophic AIDS epidemic. Last year Newsweek joined the incessant
proclamations that Africa is being ravaged by AIDS, citing "2.2 million
[AIDS deaths] in 1998 alone."[27] One should be astounded at this figure,
given that only 876,009 actual cases have been reported in 19 years.
However, Newsweek was merely doing its duty by repeating the estimates
promulgated by WHO.[33]
According to Stewart, WHO bases its estimates on the numbers of both
positive tests and of AIDS cases reported by member states, "accepted at
face value and, with rare exceptions, unvalidated." Estimates are
extrapolated from these data using flawed mathematical models.
Christian Fiala, an Austrian doctor who has extensively researched the
global epidemiological data on HIV and AIDS, states that WHO produces its
estimates by multiplying reported cases by a certain factor (on the
reasonable assumption that actual cases are more than reported cases).
However, this multiplication factor arbitrarily increases every year. In
1996 it was 12; only a year and a half later it had increased to 38![33]
Fiala states: "The well-known horror scenarios about an epidemic of a new
infectious disease exist exclusively in the heads of the statisticians
through untenable and escalating multiplications." [33]
Conclusion
The huge, alleged AIDS epidemic in Africa is based on several factors
which have no scientific basis: 1) WHO's faulty estimates, 2) the
nonspecific clinical case definition of AIDS, and 3) grossly inaccurate
HIV antibody tests which are not applicable in Africa.
While AIDS authorities proclaim that 25.3 million Africans are doomed to
die, in reality, no one knows if a single one of them is infected with
HIV.
Johnson is an independent free-lance journalist who lives in the Los
Angeles area and can be reached at cjohnson@rethinkingaids.com
References
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26:952-53.
2. Biggar, R. 1985. ELISA HTLV retrovirus antibody reactivity associated
with malaria and immune complexes in healthy Africans. Lancet.
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3. AIDS vaccine efficacy trial sites selected by WHO. 1991. The Blue
Sheet. 34(43):1-3.
4. Weiss, R. 1986. Lack of HTLV-I antibodies in Africans. Nature.
319:794-795.
5. Kashala, O 1994. Infection with human immunodeficiency virus type 1
(HIV-1) and human T-cell lymphotropic viruses among leprosy patients and
contacts: correlation between HIV-1 cross-reactivity and antibodies to
lipoarabinomannan. J. Infec. Dis. 169:296-304.
6. Papadopulos-Eleopulos, E., 1993. Is a positive Western blot proof of
HIV infection? Bio/Technology. 11:696-707.
7. Mulder, D.W. 1994 Two-year HIV-1-associated mortality in a Ugandan
rural population. Lancet 343:1021-1023.
8. Johnson, Christine. "Whose antibodies are they anyway?" Continuum.
Sept/Oct 1996.
9. Schwartz, J. 1988. Human immunodeficiency virus test evaluation,
performance, and use. JAMA. 259:2574-2579.
10. Constantine, N. 1989. Diagnostic usefulness of five screening assays
for HIV in an east African city where prevalence of infection is low.
AIDS. 3:313-317.
11. Mermin, J., Granich, R. 1993. More on routine HIV screening. NEJM.
328:1715.
12. Cordes, R. 1995. Pitfalls in HIV testing. Postgraduate Medicine.
98:177.
13. Dock, N.1988. "Evaluation of atypical human immunodeficiency virus
immunoblot reactivity in blood donors. Transfusion. 28:142.
14. Wong-Staal,1985. Human T-lymphotropic retroviruses. Nature
317:395-403.
15. Ng, V. 1991 Serological diagnosis with recombinant peptides/proteins.
Clin. Chem. 37:1667-1668.
16. Karal'nik, B., Riazanova, G., Shuratov, I. 1991. The reasons for false
positive results with recombinant preparations in HIV infection.
(Language: Russian) Zhurnal Mikrobiologii, Epidemiologii i Immunobiologii.
Sep(9):32-5.
17. Papadopulos-Eleopulos, E., 1997. "HIV antibodies: Further questions
and a plea for clarification." Curr. Med. Res. Opin. 13:627-634.
18. Craske, J., 1990. Comparison of false-positive reactions in
direct-binding anti-HIV ELISA using cell lysate or recombinant antigens.
Vox Sang. 59:160-166.
19. Pokrovsky, VV.1990. "Epidemiological surveillance for HIV infection in
the USSR in 1987-1989." Int. Conf. AIDS. 6:243.
20. Papadopulos-Eleopulos, E., 1994. Letter in response to Mulder Study,
Rethinking AIDS.
21. Papadopulos-Eleopulos, E. 1995. "AIDS in Africa: Distinguishing fact
and fiction." World J. Micro. & Biotech. 11: 135-143.
22. Mann, J.M., 1986. "Surveillance for AIDS in a central African city."
JAMA. 255:3255-3259.
23. Snyder, H., 1980. Specificity of human antibodies to oncovirus
glycoproteins: Recognition of antigen by natural antibodies directed
against carbohydrate structures. Proc. Natl. Acad. Sci. 77:1622-1626.
24. Healey, D., 1993. Apparent HIV-1 glycoprotein reactivity on Western
blot in uninfected blood donors. AIDS. 7:655-658.
25. Tomiyama, T., . 1991. "Recognition of human immunodeficiency virus
glycoproteins by natural anti-carbohydrate antibodies in human serum."
Biochem. and Biophys. Res. Comm. 177:279-285.
26. Dietrich, P. 1986. "Disseminated histoplasmosis and AIDS in
Switzerland." Lancet. September 27, p752.
27. Kaheru, S., Santoro, L., Haller, V., Begley, S. "10 million orphans."
Newsweek. January 17, 2000. P42-45.
28. Johnson, Christine. "Whose antibodies are they anyway?" Continuum.
4(3):4. Sept/Oct 1996.
29. Johnson, Christine. "Mass HIV testing: A disaster in the making."
Zenger's. August 1996. p10.
30. Barnes, Deborah. 1987. New questions about AIDS test accuracy.
Science. 238:884-885.
31. Tu, X., Litvak, E., Pagano, M. 1992. Issues in human immunodeficiency
virus (HIV) screening programs. Am. J. Epi. 136:244-255.
32. Bennett, D. AIDS tests: From mail order to antigen detectors. AIDS
Patient Care. February 1988. p18-20.
33. . Fiala, Christian. "Dirty tricks over AIDS figures." New African.
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35. Weekly Epidemiological Record, November 27, 1998.
GMCarter - 19 Feb 2005 13:55 GMT
>WHY THE "AIDS TEST" DOESN'T WORK IN AFRICA
>
>By Christine Johnson
same crap, different day. this has been replied to
PaulKing - 20 Feb 2005 02:33 GMT
No it has not Carter.
The only crap on this board is you.
GMCarter - 20 Feb 2005 10:54 GMT
>No it has not Carter.
>
>The only crap on this board is you.
Oh heavens! And there I thought you were such a noble fellow, above
the fray--and yet, to my dismay--I see you name-calling! Oh, wail and
woe! My image of you has shattered.....
PaulKing - 21 Feb 2005 02:54 GMT
And that from someone who didn't start the name calling.......well, not
exactly.
Hypocrite.