[afro-nets] PCR screening for syphilis in persons at risk for HIV/AIDS

[John Scythes <jscythes@infinity.net>]

PCR screening for syphilis in persons at risk for HIV/AIDS
----------------------------------------------------------

Dear STD/AIDS colleagues,

Enclosed is our paper presented at the European Academy of
Dermatology and Venereology Second Spring Symposium, held 29
April ­ 1 May, 2004 in Budapest, Hungary. The abstract was
published in the Journal of the European Academy of Dermatology
and Venereology. The text can also be found online at
http://colman.net/eadv

This brief historical review raises the concern that syphilis
screening, including standard treponemal antibody testing,
continues to miss a substantial amount of syphilis in STD
populations worldwide. Syphilis may prove to be a contributing
co-factor in the morbidity and mortality associated with
HIV/AIDS.

Any comments on the points raised in this paper would be greatly
appreciated.

Kindest regards,

John Scythes
mailto:jscythes@infinity.net


--
A NEW GOLD STANDARD FOR SYPHILIS?

John B. Scythes (1), Colman M. Jones (1), and Robert H.
Notenboom (2)

Poster Presentation for European Academy of Dermatology and
Venereology - II. Spring Symposium
29 April ­ 1 May, 2004, Budapest, Hungary

Abstract published in
Journal of the European Academy of Dermatology and Venereology
Volume 18, Supplement 1, May 2004, PS 230

(1) Community Initiative for AIDS Research 32 Beaty Avenue,
Toronto, Ontario, Canada M6K 3B4 <jscythes@infinity.net>
<eadv@colman.net>

(2) Phoenix BioTech Corporation 6810 Kitimat Road, Mississauga,
Ontario, Canada L5N 5M2 <bnotenboom@phoenixbiotech.com>

ABSTRACT

Novel PCR screening on whole blood has found T. pallidum DNA in
erythrocytes of young gay men in Budapest who are repeatedly
negative in all other standard syphilis tests, including tre-
ponemal antibody screening (TPHA). This follows on historical
evidence suggesting syphilis has been under-diagnosed ever since
screening with non-specific anti-lipoidal antigens began in
1906.

The first half of the 20th century saw the development of
complement fixation and precipitation/flocculation assays, which
were often used together to increase sensitivity and
specificity, because many cases proved difficult. Syphilis
sequelae often occurred despite lifelong negative anti-lipoidal
serology.

The arrival of treponemal tests (TPI in 1949) further increased
the sensitivity, and also excluded many false positives,
although this class of test lacked sensitivity in primary
syphilis. Vienna's teaching hospitals have also confirmed over
many years that the TPHA finds nearly twice as many undetected
cases as the VDRL. The avidity/affinity index as a surrogate for
IgM antibody (Boltzmann Institute for Serodiagnosis, Vienna)
found many active cases with no VDRL reactions. Despite these
refinements, Ontario's Public Health Laboratory has documented
the selective loss of treponemal antibody among HIV antibody(+)
gay men, making it difficult - if not impossible - to assess the
prevalence of syphilis.

Since the early 1990s, recombinant antigens have provided even
greater sensitivity, confirmed again in Toronto by reactive
immunoblots - both IgG and IgM - among men at high risk for
syphilis. Yet these VDRL(-) and often TPHA(-) persons remain
undiagnosed. Using the PCR in South Africa, the CDC's Multiplex
assay has proven that the VDRL misses most primary syphilis when
the DNA of other ulcerative STDs is present.

The increased sensitivity of newer tools will allow a better
assessment of the true morbidity and mortality caused by
syphilis, and suggests the gold standard for screening select
populations will ultimately require gene amplification.

----------------------------------------------------------------

RETHINKING THE WASSERMANN TEST

Since the beginning of syphilis antibody screening in 1906,
there have always been concerns about the sensitivity of the
non-specific anti-lipoidal tests and their more recent
variations, the RPR and VDRL. Before 1950, these non-specific
tests, often named after their developers, were run together to
increase sensitivity in suspected syphilis cases. (1) In the
years just before WWII, these versions of the Wassermann
technique were quantifiable, and the VDRL researchers worked to
standardise these tests, leading to our current screening
paradigm.

But all along assumptions were made - assumptions based on
clinical acute cases - that these tests could almost always
detect the disease, and sensitivity may have been sacrificed for
the sake of this reproducibility. There was never a gold
standard for latent syphilis, only these assumptions - a concern
voiced by one of America's greatest syphilis authors in 1944.
(2)

With the arrival in 1949 of the first reproducible treponemal
antibody test (T. pallidum Immobilisation or TPI), (3) cases of
latent syphilis could be verified without obvious symptoms or
positive anti-lipoidal test results. This is why every subse-
quent summary of syphilis screening acknowledges much greater
sensitivity for the treponemal tests (TPHA, FTA-Abs, TPI) in di-
agnosing the late latent stages.

Evidence from the syphilis animal models further demonstrates
that detection by anti-lipoidal serology misses many or most
cases of the disease:

-In the mouse model, many pre-1960 investigators, such as Paul
Rosahn from Yale, and Europe's Levaditi & Kolle, proved
undoubted silent syphilis infection without the standard anti-
lipoidal reaction. The 100% absence of a VDRL reaction in the
FTA-Abs(+) mouse model was confirmed again recently in Budapest.
(4)

-In the rabbit model, the adapted Nichols laboratory strain of
T. pallidum was manipulated specifically for its ability to
reliably cause symptoms and seroconversion, as well as provide a
source of antigen for research. However, depending on the timing
of re-exposure, rabbits could be demonstrably re-infected with
the Nichols strain with no classical blood reaction. (5-7) As
well, this model was unreliable for the serodiagnosis of
syphilis following mucosal inoculation: intra-meatal, sub-
preputial, oral, and intra-vaginal infection with the Nichols
strain led very often to seronegative but proven systemic
infection in this model. (8)

-In the primate model, J. Lawton Smith at the University of
Miami studied the serology and morbidity of owl monkeys with
ocular syphilis, and found that most were negative or equivocal
in the VDRL after mucosal T. pallidum challenge, and only
sometimes reactive in the FTA-Abs treponemal test. (9)

As a result of these inconsistencies in the animal test results
(implying defective antigen processing), seronegative syphilis
in humans could be a regular occurrence. Hence, investigators in
the first half of the 20th century tried to establish a gold
standard for the direct detection of T. pallidum in clinical
specimens. In addition to darkfield and staining in ultrathin
sections, the rabbit infectivity test (RIT) was helpful in often
proving syphilis when suspected but not serologically or
clinically confirmed. But RIT detects only virulent organisms,
and hence was often negative in the presence of treponemes
confirmed by darkfield microscopy, (8) and/or serologic testing.
(10)

IMPROVING SYPHILIS DIAGNOSIS

These sensitivity concerns were well understood by some
investigators as syphilis rates began to soar in the 1960s and
1970s. Screening with treponemal tests, including ELISA testing
with recombinant T. pallidum antigens, has been undertaken in
several centres. Two teaching hospitals in Vienna recently
summed up 20 years of experience, concluding that, in the
aggregate, treponemal screening with TPHA or MHA-Tp identified
about twice as much syphilis as the VDRL. (11)

T. pallidum cannot be cultured in an artificial medium, which
has proven to be a major problem in getting useful and afford-
able quantities of antigen for specific and sensitive tests, and
for vaccine research as well. But with the use of the recombi-
nant antigens, Toronto investigators have achieved greater sen-
sitivity without losing specificity, finding otherwise unde-
tected latent syphilis in at least five percent of specimens
from at-risk male patients. (12) Most of these cases were un-
known to public health authorities, were untreated, and were
RPR(-) and TPHA(-).

Detection of primary syphilis can be just as problematic
serologically, as nearly two-thirds of ulcerative STD containing
T. pallidum DNA have been found to be seronegative in the RPR
test when the DNA of other ulcerative STDs is also present in
the lesions. (13)

As a result, one could conclude that the diagnosis of syphilis
has become more and more a task for the laboratory - and less
for the clinician - and a recent preliminary PCR screening
effort on whole blood adds yet another level of sensitivity.
(14)

A total of 105 gay males attending a dermatology practice in
Budapest have all been screened with four tests: RPR, TPHA, HIV
Elisa, and the whole blood syphilis nested PCR. Seven cases of
syphilis (average age 26) were detected using syphilis PCR, but
only two with a treponemal assay, the accepted standard for
detecting latent syphilis. The results of all tests were as
follows:

4 cases were PCR (+) TPHA (-) RPR (-) HIV (-)
1 case was PCR (+) TPHA (+) RPR (+) HIV (-)
1 case was PCR (+) TPHA (+) RPR (-) HIV (-)
1 case was PCR (+) TPHA (-) RPR (-) HIV (+)

Interestingly, the only HIV (+) case out of these 105 men was
also syphilis PCR (+), as were the only two TPHA (+) treated
cases. One of these TPHA (+) cases was the only reactor in the
RPR test in the entire cohort, none of whom had signs or
symptoms of early syphilis. The probability that these PCR
results are a chance observation is very remote. Others have
proven persistent syphilis using this technique. (15) The
clinical implications of all these findings remain unknown.

DISCUSSION

It is disturbing to find so much unexpected syphilis every time
a new experimental technique is introduced. But the fact may
well be that syphilis prevalence has always been underestimated.
Indeed, the greatest morbidity and mortality caused by syphilis
may be going unaddressed by our current assumptions about
diagnosis and treatment.

Many pre-penicillin authors speculated that excess mortality -
reactivation tuberculosis, pneumonias, and cancers - could
result from inadequately treated or untreated syphilis. (16-20)
In the classical natural history studies, these complications
were at least twice as prevalent as the classical late fatal
sequelae. (21, 22)

It could also be argued that syphilis shortens the life of the
mouse (23, 24) and owl monkey, (9, 25) but investigators did not
understand what may have been going on when their experimental
subjects wasted away and died prematurely. J. Earle Moore, edi-
tor of the American Journal of Syphilis, may have been quite
right in asking in 1939 whether it was "justifiable to assume,
as did Osler, that syphilis actually ranks first, instead of its
apparent tenth, among killing infections?" (26)

It has been generally assumed that latent syphilis is inactive
syphilis, as opposed to a chronic active process. However, Evan
Thomas' 1949 summary of two thousand syphilitic cases in New
York City (27) provides good clinical evidence that latent
syphilis may indeed be very active from an immunological point
of view, likely as a result of the development of
tolerance/peripheral inhibition (i.e. immune deviation).

While there is resistance to syphilis in the early stages of the
disease, it appears that, unless promptly treated, the host
eventually loses the battle. After several months, immune
deviation silently develops over time in most untreated latent
cases, making the disease much harder to detect and cure,
especially in cases of re-infection. Evan Thomas concluded that
after two years of untreated disease, there is a near-universal
loss of the host's ability to respond to T. pallidum again, a
state irreversible by therapy. If left untreated long enough,
patients very rarely developed typical early signs or symptoms
or reactive tests again upon re-exposure.

This non-responsiveness was once known as "syphilisation", (28)
a concept developed following observations that after a few
exposures, the classical symptoms were never seen again. Natural
immunity (immunitas in Latin means "exemption from") does not
exist in syphilis, and prior infection does not lead to
protection against re-challenge. (29)

This absence of natural immunity was also apparent in the failed
attempts to make a skin test for syphilis, despite success with
many other immunogens as precedents: leishmanin, coccidiodin,
histoplasmin, pneumocystin, blastomycosin, and tuberculin. All
of these antigens could be made to work reliably, and provide
evidence on the prevalence of exposure and natural immunity.
Almost all healthy and exposed persons in endemic areas skin-
tested with these antigens had the G & C type IV response, the
indurated erythema. But luetin preparations from T. pallidum
suspensions could not be manipulated to reliably produce this
recall phenomenon.

These kinds of concerns have led many investigators to study the
immunophenotypes of antigen processing cells in syphilis. (30-
39) The available evidence suggests that syphilis, if not
diagnosed and cured in its early stages, leads to global
suppression of the Th1 immune response and the regulation of
immunity towards the Th2 phenotype. (40-42)

Clinically, the work of authors 50 years ago suggested this
phenomenon of immune regulation in human subjects. (43, 44)
Tuberculin recall screening in late syphilitics at the
University of Vienna showed most subjects had lifelong loss of
TB recall, in distinct contrast to the regular hospital
admissions. (45)

Looking at these concerns in our modern era of HIV/AIDS, mil-
lions of cases of syphilis seem to have disappeared among the
very populations recently saturated with this old STD, (46-48)
but who are now said to be dying of a "new" disease of
immunodeficiency. Indeed, Houston syphilis author Daniel Musher
has remarked that syphilis seems to have "melted away" in these
at-risk populations. (49) Or has a reservoir of latent disease
become invisible because of the syphilisation effect and the
accompanying insensitive diagnostic paradigm?

CONCLUSION

Given all these unknowns in the diagnosis and treatment of
syphilis, more basic research into the prevalence of the disease
and its immunopathology is urgently required, especially within
the context of our recent recognition of immunosuppression and
HIV/AIDS:

-The widely-held assumption that most patients retain their
treponemal antibody status following seropositive early syphilis
needs to be revisited, in light of the Toronto experience of
testing and treating HIV cases who had selectively lost their
treponemal antibody response during the polyclonal B-cell
activation of advancing HIV disease. (50-52)

-The specificity of our 47kDa-based PCR test (53) needs to be
further confirmed, perhaps using genes for one of the T.
pallidum enzymes. DNA isolation results then need to be
quantified and evaluated to see whether there is a relationship
with depressed cellular immunity. This relationship may well be
largely independent of HIV status, as low T-cell levels have
been found in populations with high syphilis rates, (54) and it
is unclear what effect - if any - HIV has on the course of
syphilis and the response to treatment. (55-56) More aggressive
treatment may be needed to clear the treponemal DNA, given the
problems achieving adequate serologic response by conventional
criteria. (57)

-The primate syphilis model needs to be revisited, including
within the HIV model, to confirm earlier findings suggesting
global immune suppression due to unresolved syphilis. There may
also be a more affordable model in the mouse, guinea pig or
rabbit.

-There needs to be investigation of node biopsies from HIV and
AIDS cases in whom a whole blood syphilis PCR is positive. The
histology of lymph node changes in syphilis is remarkably
similar to that seen in advancing HIV disease. (58)

-Clinicians worldwide need to re-screen all their patients -
including those without HIV - for treponemal antibody, using
recombinant tests, until revised guidelines are issued. These
test results must be prospectively analysed for years alongside
some type of nucleic acid amplification system, in order to
establish whether antibody screening can identify all those
infected with T. pallidum. Blood donor lots also need to be
screened this way, as is done routinely in the case of HIV.

If syphilis detection is better managed through the use of a new
gold standard, we may reduce not only the incidence and preva-
lence of syphilis, but also rates of HIV transmission and pro-
gression to AIDS. There may well be an immunological synergy be-
tween these two ancient infections that goes far beyond the al-
ready well-documented role of ulcerative STDs in HIV acquisi-
tion.

SOBERING QUOTES

"In spite of 400 years of study, we still do not know the actual
importance of syphilis as a cause of death. To what extent does
death directly from syphilis masquerade under other diagnoses:
or to what extent is syphilis an indirect cause of death from
other conditions? Is it justifiable to assume, as did Osler,
that syphilis actually ranks first, instead of its apparent
tenth, among killing infections?" -J. Earle Moore, 1939 (26)

"Within 2 years after infection, untreated syphilis produces
immune changes in the host which, with rare exceptions, are
permanent and make it impossible for tissues to react to
subsequent infection with development of early syphilitic
lesions." -Evan W. Thomas, 1949 (27)

"Far from eradicating syphilis, antibiotics are driving the
disease underground and increasing the difficulty of detection.
Although the incidence of disease has more than tripled since
1955, the chancre and secondary rash no longer are commonly
seen. Undoubtedly, some of these lesions are being suppressed
and the disease masked by the indiscriminate use of antibiotics.
The ominous prospect of a widespread resurgence of the disease
in its tertiary forms looms ahead." -Armand J. Pereyra, 1970
(59)

"A substantial proportion of HIV-infected men may have
unrecognized, latent, inadequately treated syphilis. These
findings support more aggressive treatment of T. pallidum
infection in this patient population." -Daniel M. Musher, 1990
(60)

"The clinical manifestations of syphilis, which have taken
various forms over the centuries, have now been transformed to
mimic the appearance of the opportunistic infections and cancers
that may accompany HIV infection, as well as the clinical
symptoms of AIDS itself." -Sandra A. Larsen, 1991 (61)

----------------------------------------------------------------

REFERENCES

1. Pierce, L. Multiple Test Method for Syphilis Serodiagnosis.
Am J Syph Gonor and Ven Dis 1938; 22(1):59-71

2. Stokes JH. Modern Clinical Syphilology. 3rd ed. Philadelphia:
W.B. Saunders (1944), Chapter 1

3. Nelson RA, Mayer MM. Immobilization of Treponema pallidum in
vitro by antibody produced in syphilitic infection. J Exp Med
1949, 89:369-393

4. Horvath I. Experimental Mouse Syphilis for the Syphilis
Eradication Program. WHO Biology and Pathogenicity of Treponemes
conference, University of Birmingham, 11-13 April 1989

5. Arnold RC, Mahoney JF, Cutler JC. Reinfection in experimental
syphilis in rabbits following penicillin therapy. Am J Syph
Gonor Ven Dis 1947; 31(3):264-7

6. Arnold RC, Mahoney JF, Cutler JC. Reinfection in experimental
syphilis in rabbits following penicillin therapy. Am J Syph
Gonor Ven Dis 1947; 31(5):489-92

7. Magnuson HJ, Rosenau BJ, Clark JW. The Duration of Acquired
Immunity in Experimental Syphilis. Am J Syph Gonor & Ven Dis
1949; 33:297-302

8. Hinton, William A. Syphilis and Its Treatment. New York: The
MacMillian Company, 1936. p. 23, 31, 62, 81

9. Smith JL. Spirochetes in Late Seronegative Syphilis.
Springfield, Ill.: Charles C. Thomas, 1969. p. 181-221

10. Turner TB, Hardy PH, Neuman B. Infectivity Testing in
Syphilis. Br J Vener Dis 1969; 45:183-196

11. Geusau A, Kittler H, Hein U, et al. Syphilis screening based
on an analysis of 300,000 sera tests; Schmidt B, Gschnait F.
Parallel testing with VDRL Laboratory Test and MHA-Tp in
Syphilis Serology. Int J STD AIDS. 2002 Aug;13(Suppl 1):O30, O31

12. denHollander N, Berry R, Fearon M. Treponemal Based
Screening for Syphilis - Detecting Latent Cases. General Meeting
of the American Society for Microbiology. 2000; C-367, online at
http://www.cbc.ca/ideas/features/Aids/asm2000.html

13. Ballard RC, Ye Htun, Fehler G et al. Interpretation of
serologic tests for primary syphilis in the era of HIV infection
and multiplex PCR for genital ulcer disease. Int J STD AIDS.
2001 Jun;12(Suppl 2):43

14. Nagy K, Scythes JB, Horvath I, et al. Experience of
Molecular Screening of Syphilis by PCR. ISSTDR 2003, Abstract
312; Talha E, Kemeny B, Horvath I, et al. Syphilis PCR:
molecular detection of T. pallidum in seronegative cases. Review
of Dermato-Venerology (Hungary) 2003; 79 (2):65-68

15. Wicher K, Abbruscato F, Wicher V, et al. Identification of
persistent infection in experimental syphilis by PCR. Infect
Immun. 1998 Jun; 66(6):2509-13

16. Blakely DN. Syphilis from the Life Insurance Standpoint. Med
Ins & Health Conserv 1927; 42:446

17. Neisser & Landsteiner, cited in Chesney, A. Immunity in
Syphilis. Baltimore: Williams and Wilkins Co., 1927, p. 26

18. Strickler A. Diseases of the Skin and Syphilis.
Philadelphia: F.A. Davis Co., 1927. p. 369

19. Hall AF. Under-Treatment Versus Over-Treatment of Syphilis.
J Indiana Med Ass 1935; 28:587

20. Morgan HJ. The Prognosis of Syphilis. JAMA 1939; 112:311-7

21. Gjestland T. The Olso study of untreated syphilis: an epide-
miologic investigation of the natural course of the syphilitic
infection based upon a re-study of the Boeck-Bruusgaard
material. Acta Derm Venereol 1955; 35 Suppl 34:343-366

22. Aboul-Saad, Shereen. The Tuskegee Syphilis Experiment, Trust
and AIDS. The Citizen (John F. Kennedy School of Government
student newspaper), February 26, 2001

23. Rosahn PD. The adverse influence of syphilitic infection on
the longevity of mice and men. Am Med Ass Arch Derm Syph 1952;
66(5):547-568

24. Horvath I. personal communication, 1991

25. Chandler FW, McClure HM, Campbell WG, et al. Pulmonary
pneumocystosis in nonhuman primates. Arch Pathol Lab Med 1976;
100(3):163-7

26. Moore JE. Unresolved Clinical Problems of Syphilology. Am J
Syph Gonor and Ven Dis 1939; 23(1):701-11

27. Thomas EW. Syphilis: Its Course and Management. New York:
Macmillan, 1949. p. 10

28. Sherwood J. Syphilization: human experimentation in the
search for a syphilis vaccine in the nineteenth century. J Hist
Med Allied Sci 1999; 54(3):364-86

29. New York State Department of Health, Syphilis Fact Sheet
(Revised: March 2003), online at
http://www.health.state.ny.us/nysdoh/consumer/syph.htm

30. Hrncir Z, Kraus Z, Tichy M. Non-specific humoural immunity
response in latent and tertiary syphilis. Br J Vener Dis 1972;
48(2):108- 12

31. Wright DJ, Grimble AS. Why is the infectious stage of
syphilis prolonged? Br J Vener Dis 1974; 50(1):45-9

32. Shannon R, Booth SD. The pattern of immunological responses
at various stages of syphilis. Br J Vener Dis 1977; 53(5):281-6

33. Jensen JR, Jorgensen AS, Thestrup-Pedersen K. Depression of
natural killer cell activity by syphilitic serum and immune
complexes. Br J Vener Dis 1982; 58(5):298-301

34. Jensen JR, From E. Alterations in T lymphocytes and T-
lymphocyte subpopulations in patients with syphilis. Br J Vener
Dis 1982; 58(1):18-22

35. Gschnait F, Schoenwald E, Schmidt BL, et al. Laboratory
evidence for impaired cellular immunity in different stages of
syphilis. J Invest Dermatol 1982; 79(1):40-1

36. Wicher K, Wicher V. Immunopathology of syphilis. In: Schell
RF, Musher DM, editors. Pathogenesis and Immunology of Trepone-
mal Infection. New York: Marcel Dekker, 1983. p. 139

37. Baughn, RE. Immunoregulatory Effects in Experimental Syphi-
lis. In: Schell RF, Musher DM, editors. Pathogenesis and Immu-
nology of Treponemal Infection. New York: Marcel Dekker, 1983.
p. 271

38. Pope V, Larsen SA, Rice RJ et al. Flow cytometric analysis
of peripheral blood lymphocyte immunophenotypes in persons
infected with Treponema pallidum. Clin Diagn Lab Immunol 1994,
1:121­124

39. Fan YM, Zeng WJ, Wu ZH, et al. Immunophenotypes, Apoptosis,
and Expression of Fas and Bcl-2 From Peripheral Blood
Lymphocytes in Patients With Secondary Early Syphilis. Sex
Transm Dis, April 2004, 31(4):221­224

40. Fitzgerald TJ. The Th1/Th2-like switch in syphilitic
infection: is it detrimental? Infect Immun 1992; 60(9):3475-9

41. Podwinska J, Zaba R, Chomik M, et al. The ability of
peripheral blood mononuclear cells of rabbits infected with
Treponema pallidum to produce IL-2. FEMS Immunol Med Microbiol
1993; 7(3):257-64

42. Podwinska J, Lusiak M, Zaba R, et al. The pattern and level
of cytokines secreted by Th1 and Th2 lymphocytes of syphilitic
patients correlate to the progression of the disease. FEMS
Immunol Med Microbiol 2000; 28(1):1-14

43. Beerman H. The Problem of Reinoculation of Human Beings with
Spirochaeta Pallida. Am J Syph Gonor Ven Dis 1946; 30(2):173-92

44. Magnuson HJ, Thomas EW, Olansky S, et al. Inoculation
Syphilis in Human Volunteers. Medicine 1956; 35:33-82

45. Dattner B. The Management of Neurosyphilis. New York: Grune
& Stratton, 1944. p. 333

46. Holmes KK, in Wintrobe MM, ed. Harrison's Principles of
Internal Medicine. 7th ed. New York: McGraw Hill, 1974

47. Fichtner RR, Aral SO, Blount JH, et al. Syphilis in the
United States: 1967-1979. Sex Transm Dis 1983; 10(2):77-80

48. Centers for Disease Control. Sexually Transmitted Diseases
Fact Sheet. 35th ed. U.S. Dept. of Health and Human Services,
Center for Prevention Services, Atlanta, GA. 1981; 81-8195

49. Musher, DM. Oral session, ISSTDR 1995, New Orleans

50. MacFadden DK, Notenboom RH, Scythes JB. Syphilis - A Role In
Sexually Acquired AIDS? WHO Biology and Pathogenicity of
Treponemes conference, University of Birmingham, 11-13 April
1989, online at
http://www.cbc.ca/ideas/features/Aids/birming.html

51. Notenboom RH, MacFadden DK. Reliability of Syphilis Tests in
Patients with HIV. Int Conf AIDS 1992; 8(2):B94 (abstract no.
PoB 3044), online at
http://www.cbc.ca/ideas/features/Aids/notenboom.html

52. Fralick RA, Scythes JB, Notenboom RH, et al. Syphilis and
HIV: Seroprevalence and Clinical Observations in HIV Clinic, To-
ronto. Sex Trans Dis 1994; 21: Suppl 183, abstract 271, online
at http://www.cbc.ca/ideas/features/Aids/helsinki.html

  53. Zoechling N, Schluepen EM, Soyer HP et al. Molecular
detection of Treponema pallidum in secondary and tertiary
syphilis. Br J Dermatol. 1997 May;136(5):683-6

54. Bartholomew C, Saxinger WC, Clark JW, et al. Transmission of
HTLV-I and HIV among homosexual men in Trinidad. JAMA 1987;
257(19):2604-8

55. Rolfs RT, Joesoef MR, Hendershot EF, et al. A randomized
trial of enhanced therapy for early syphilis in patients with
and without human immunodeficiency virus infection. The Syphilis
and HIV Study Group. N Engl J Med. 1997 Jul 31;337(5):307-14

56. Marra CM, Maxwell CL, Tantalo L, et al. Normalization of
Cerebrospinal Fluid Abnormalities after Neurosyphilis Therapy:
Does HIV Status Matter? Clin Infect Dis. 2004 Apr 1;38(7):1001-6

57. Smith NH, Musher DM, Huang DB et al. Response of HIV-
infected patients with asymptomatic syphilis to intensive
intramuscular therapy with ceftriaxone or procaine penicillin.
Int J STD AIDS. 2004 May;15(5):328-32

58. Farhi DC, Wells SJ, Siegel RJ. Syphilitic lymphadenopathy:
Histology and human immunodeficiency virus status. Am J Clin
Pathol 1999 Sep;112(3):330-4

59. Pereyra AJ, Voller RL. A graphic guide for clinical
management of latent syphilis. Calif Med 1970; 112(5):13-8

60. Musher DM, Hamill RJ, Baughn RE. Effect of human
immunodeficiency virus (HIV) infection on the course of syphilis
and on the response to treatment. Ann Intern Med 1990;
113(11):872-81

61. Larsen SA. Syphilis Diagnosis Dynamics. 9th International
Meeting of the ISSTDR 1991 Banff, Alberta, abstract no. C-12 273

This paper is available online at: http://colman.net/eadv

----------------------------------------------------------------

See also:
Other abstracts and papers by John Scythes and colleagues
http://www.cbc.ca/ideas/features/Aids/scythes.html

Déja Vu: AIDS in Historical Perspective 2-hour 1996 radio docu-
mentary prepared by Colman Jones, aired on CBC Radio's IDEAS,
and winner of the Canadian Science Writers' Association 1996
Science in Society Journalism Award. Listen to excerpts in Real
Audio >> http://colman.net/dejavu.ram . Visit website
http://cbc.ca/ideas/features/Aids/index.html

Lest We Forget: Syphilis in the AIDS Era Edited 1-hour summary
of award-winning TV series "The Cause of AIDS: Fact and Specula-
tion" produced by Colman Jones. Watch with Real Player
http://colman.net/aids/video.html