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| Journal of the New Zealand Medical Association,
11-March-2005, Vol 118 No 1211
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Is syphilis resurgent in New Zealand in the
21st century? A case series of infectious
syphilis presenting to Auckland Sexual Health Service
Sunita Azariah
There has been an alarming rise in the incidence of
bacterial sexually transmitted infections (STI) in New Zealand in recent years.
The last annual STI surveillance report produced by Environmental Science and
Research Ltd (ESR) in 2003 indicated a 65.5% increase in the incidence of
chlamydia and a 57% rise in the incidence of gonorrhoea since
1999.1 Infectious syphilis, however, has (until
recently) remained a relative rarity, except for occasional cases in New
Zealanders who have had sex overseas or in immigrants from endemic areas. In
2003, a total of 30 cases of infectious syphilis were reported to ESR: all seen
at sexual health clinics.1 The majority of
cases were in males (63.3%). In the first ESR quarterly report for 2004 (January
to March), 10 cases have been reported, again the majority (70%) were men.
Unfortunately there is currently no way to verify whether
the incidence of infectious syphilis in New Zealand is increasing. Unlike
chlamydia and gonorrhoea, there is no laboratory surveillance of syphilis nor is
it a notifiable disease—although individuals that refuse treatment may be
referred to the medical officer of health under the Health Act of 1956.
Another complicating factor is that the symptoms and signs
of primary and secondary syphilis may be very subtle (or easily confused with
other conditions), and most medical practitioners in New Zealand (including
sexual health physicians) have very little practical experience of the disease.
Indeed, some incubating cases may never be identified due to inadvertent partial
treatment with antibiotics prescribed for other conditions.
In the previous 2 and a half years (between January 2002 and
September 2004), there appears to have been more cases of infectious syphilis
presenting to Auckland Sexual Health Service. This article comprises clinical
information about all the cases of infectious syphilis that have been identified
at Auckland Sexual Health Service (ASHS) between January 2002 and September
2004. The aims of this paper are firstly, to examine risk factors for syphilis
in patients presenting to ASHS and secondly, to alert medical practitioners
outside sexual health when to consider the diagnosis.
MethodsBackground—Auckland
Sexual Health Service is the largest public sexual health clinic in New Zealand.
There are four regional clinics that are located in Mangere, Henderson,
Glenfield, and Auckland City Hospital. There are also two out-reach clinics.
ASHS routinely collects clinical data on patients seen at all regional and
out-reach clinics. The clinician seeing a particular patient assigns them with a
diagnostic code on each presentation to the clinic with a new problem. Anonymous
data on newly diagnosed cases of STIs (including infectious syphilis) are sent
on a quarterly basis from all public sexual health clinics to ESR for
surveillance purposes.
Inclusion
criteria—The database at ASHS was searched to identify all cases of
infectious syphilis presenting to the Service during the period from January
2002 to September 2004. The identified notes were examined to check whether the
patients fulfilled the case definition for infectious syphilis, and then
demographic characteristics and risk factors were identified. All patients being
tested for syphilis at ASHS have an initial screening enzyme immunoassay (EIA)
test. If this is positive, a rapid plasma reagin (RPR) test and a
Treponema pallidum haemaglutination
assay (TPHA) are performed on the same blood sample.
Infectious syphilis is considered to encompass primary,
secondary, and early latent syphilis. These are the stages of infection when
syphilis is easily transmitted through sexual or intimate contact with an
infected individual. The incubation period for primary syphilis is 10 to 90 days
(average 3 weeks) and the classic presenting sign is a painless ulcer or chancre
in the anogenital area with regional lymphadenopathy. When lesions are present,
the most specific and easiest means of diagnosing syphilis is by direct
detection of the organism by either dark-field
microscopy, or direct fluorescent antibody (DFA)
testing.2 Serological tests for syphilis (STS)
are less sensitive in primary syphilis than later on, as seroconversion usually
takes several weeks after exposure to occur.
Secondary syphilis typically presents 2 weeks to 6
months after exposure (average 6 weeks) with systemic symptoms of malaise and a
generalised rash and lymphadenopathy. There may also be other skin
manifestations such as condyloma lata, alopecia, and mucous ulcers. Serological
tests are 100% sensitive,2 and non-treponemal
tests (such as RPR) typically have very high titres.
Early latent syphilis is often defined as consisting of
a duration of infection of less than 12
months.3 About 25% of untreated individuals may
experience relapse of clinical manifestations during the first year of infection
but recrudescence is extremely rare after 2
years.4 After the early latent period, syphilis
becomes defined as late latent and is regarded as non-infectious to sexual
partners although untreated women may transmit the infection to their foetuses
for much longer.5 Unfortunately many
individuals with positive STS have no recall of any signs and symptoms of
syphilis and unless they have a clearly documented previous negative test, it
may be difficult to accurately determine the duration of infection.
ResultsFirst some general data pertaining
to all the cases will be presented, and then some case histories will be given
in more to detail to highlight common pitfalls in diagnosis.
General dataA total of 40 cases of infectious
syphilis were identified and verified as fitting the case definitions during the
defined time period. That was more than twice as many cases as had been
diagnosed in the preceding 4 years (19 cases). The cases ranged in age from 19
to 63, with a mean age of 34.2 years. The majority (82.5%) of cases were in
males: reflecting similar trends to national data. The ethnic breakdown was as
follows: 17 Europeans (42.5%), 4 New Zealand Maori (10%), 5 Indians (12.5%), 6
Pacific Islanders (15%), 5 Asian (12.5%), 2 ethnic Fijians (5%), and 1 Latin
American (2.5%).
Fourteen cases presented with some sort of genital
ulceration or genital lesion as well as having positive STS (one case
couldn’t have a complete genital examination on initial presentation due
to a phimosis). Nine (22.5% of total) of these cases were confirmed primary
syphilis as the lesions tested positive for
Treponema pallidum pallidum by DFA
testing. Three of these cases also had positive dark-field microscopy. Enzyme
immunoassay was 100% sensitive for all these 9 confirmed cases of primary
syphilis but RPR (sensitivity 77.7%) and TPHA (sensitivity 66.6%) yielded some
false negative results (Table 1).
Table 1 Confirmed direct fluorescent antibody
(DFA)-positive cases of primary syphilis
EIA=enzyme immunoassay test;
TPHA=Treponema
pallidum haemaglutination assay test;
RPR=rapid plasma reagin test; ND=not done.
Sensitivities of different STS for primary syphilisTPHA=66.6%
(6/9)
RPR=77.7%
(7/9)
Fourteen (35%) of the total cases presented with a
generalised rash and were considered to be secondary syphilis. In all 14
identified cases of secondary syphilis, all of the STS were positive (EIA, TPHA
and RPR) and all had high RPR titres ranging from 1:16 to 1:128.
Twelve cases had no symptoms or signs consistent with
primary or secondary syphilis and were managed as early latent syphilis with
respect to partner notification—because they had high RPR titres, they
were recent contacts of infectious syphilis, or they had had recent documented
treatment overseas with inadequate sero-reversal.
In all cases of early latent syphilis, all three STS were
uniformly positive, with RPR titres ranging from 1:4 to 1:2560 (mean 304).
Determining the duration of infection was difficult in some cases, as there was
no previous documented syphilis serology. All cases of syphilis of unknown
duration received treatment and follow-up as recommended for late latent
syphilis.
The two main risk factors identified for acquisition of
infectious syphilis appeared to be either: a history of sex overseas within the
last 3 months or men who had sex with men (MSM). There were 19 cases (47.5%) who
had a history of sex overseas and 18 cases (45%) who were MSM. There was very
little overlap between these two main risk categories. The 19 people who gave a
history of sex overseas within 3 months of presentation were nearly all
heterosexual (68.4%). The most commonly cited country for overseas sex was Fiji,
which is known to have a high prevalence of syphilis. (Table 2)
Table 2. Cases of infectious syphilis acquired
overseas
*Her partner had sex in Fiji;
MSM=men who have sex with men.
Out of the seven cases of infectious syphilis (33.3%) that
were identified in heterosexuals without a recent history of sex overseas, three
had other possible significant risk factors. One female patient, who was
diagnosed on routine antenatal screening, had a male partner from Iraq. One
patient was a Japanese male resident in New Zealand who had recently had
unprotected sex with a casual female Japanese partner. One heterosexual male was
also HIV-positive, so may have had other undisclosed risk factors. By contrast,
only six cases in MSM (33.3%) gave a history of recent sex overseas.
There were two cases diagnosed in pregnant women (one
mentioned above) on routine antenatal screening, both of whom were asymptomatic
and both who had partners with infectious syphilis.
Only four patients in this series had HIV infection: all
were male and three of the four were MSM. Three men were already known to have
HIV and one was newly diagnosed but had probably acquired his infection some
time before the syphilis infection.
Following are three case histories chosen to highlight how
easily a diagnosis of syphilis may be missed by a health professional.
Case 1A 22-year-old Maori male presented
to ASHS complaining of a lump on his penis for the previous week from which he
could express pus. He had had a male sexual partner who was from South America.
Examination revealed a large infected cyst on his penile shaft, which was
treated with flucloxacillin. His STS were positive with a reactive EIA, reactive
TPHA, and an RPR of 1:64, so he was recalled for treatment and partner
notification. He had been treated 9 months previously by the Urology Service at
Auckland Hospital so his old notes were requested. These confirmed that he had
been treated for a paraphimosis. Examination findings at that time also included
bilateral firm inguinal lymphadenopathy, which in hindsight was most likely due
to early syphilis.
Case 2A 38-year-old European male sex
worker (with both male and female clients) presented to ASHS with a 1-month
history of fever, sweating and a rash. He had seen his GP recently within the
last few days and had been prescribed antihistamines for the rash. On
examination, he was noted to have a blotchy maculopapular rash on his trunk and
arms with no involvement of his legs, palms or soles. There was no
lymphadenopathy and genital examination was normal. He was thought initially to
be possibly having an HIV seroconversion illness. HIV serology was negative but
STS revealed a reactive EIA, reactive TPHA, and a reactive RPR 1:128. This case
illustrates how easily the rash of secondary syphilis may be confused with other
diagnoses.
Case 3A 41-year-old European male
attended ASHS requesting an HIV test. He had been diagnosed as having pytariasis
rosea 5 days earlier by his GP. His only genital symptoms were two red
‘blotches’ on his penis that were visible during erection. He had
had a recent sore under his tongue that had been treated as oral candidiasis by
his GP and had resolved. He had a regular male partner and disclosed having had
unprotected anal and oral sex with a casual male partner 4 months prior to his
presentation. Genital examination was unremarkable and there was no
lymphadenopathy noted. His oral cavity was normal to inspection. He had a
‘typical pytariasis rosea rash’ noted. A routine sexual health
screen was performed and serology for syphilis and HIV was also requested. STS
were positive with a reactive EIA, reactive TPHA, and an RPR of 1:64. (Another
example of how the rash of secondary syphilis may be easily misdiagnosed.) The
lesion under his tongue could possibly have been a chancre. Syphilis may easily
be transmitted by orogenital contact.
DiscussionSyphilis was once a common disease
both in developed and undeveloped countries. By the nineteenth century, syphilis
was one of the most common diseases in the United States and Europe, especially
in urban areas, where 8%–14% of the population had serological evidence of
being infected.6 The advent of effective
antibiotic therapy (in the form of penicillin) nearly came close to eradicating
the disease in developed nations after the Second World War. As well as
dramatically affecting the prevalence of syphilis, antibiotics have altered its
clinical presentation and course. The causative organism
Treponema pallidum pallidum, remains
highly susceptible to many antibiotics, therefore late manifestations are seldom
seen today.5
In New Zealand, the numbers of cases of syphilis have
remained low for the last two and a half decades. A national rate was put at
3:100, 000 in 1977 and no change in incidence was reported from sexual health
clinics between 1986 and 1993.7 However
sentinel surveillance of STD clinic attendees between 1991–1992 found that
a history of male-male sex was associated with higher rates of syphilis and
gonorrhoea, and lower rates of
chlamydia.8
Certainly the trend for low incidence rates of infectious
syphilis appears to have reversed recently in other Western countries. For
example, in the United States and Western Europe, there has been a resurgence in
cases of infectious syphilis, particularly among MSM in the previous few years.
After declining every year during 1990 to 2000, infectious syphilis rates
increased in 2001 in the United States.9 There
was a further 12.4% increase the following year and, as in 2001, the increase
was primarily in men. In the United Kingdom, there have also been recent
outbreaks of infectious syphilis. Between 1999 and 2000, the number of diagnoses
of infectious syphilis in London rose by 41% from 154 cases to 217
cases.10 The largest rises were seen in MSM.
More locally, in the Pacific region, syphilis appears to be
mainly a problem in heterosexuals. Fiji, in particular, is known to have high
rates of syphilis infection and is also a common holiday destination for New
Zealanders. A study looking at antenatal screening at a maternity unit in Suva
in 1987, found that 14.2% of Fijian women and 1.1% of Indian women were
seropositive for syphilis.11
What does this mean for New Zealand? Certainly there does
appear to have been a recent increase in the numbers of people being diagnosed
with infectious syphilis at ASHS, with a total of 40 cases between January 2002
and September 2004. These were twice as many cases as were diagnosed in the
preceding 4 years (January 1998 to December 2001). (We have also had anecdotal
reports from other hospital services that they appear to be seeing more cases of
infectious syphilis than is usual. Unfortunately as other hospital services do
not participate in STI surveillance this data will not be reported anywhere.)
The fact that MSM comprised 45% of the sample and that the
majority acquired their infection in New Zealand suggests that we may be
starting to experience a similar trend to Australia and other Western countries.
But the disease still appears to be relatively rare in heterosexuals who have
not had sex overseas.
What could be contributing to this apparent increase in
infectious syphilis in Auckland? The increased rates in MSM could also possibly
be related to a reduction in safer sex practices in recent years. Forty five
percent of participants in the Gay Auckland Periodic Sex
Survey12 reported never or infrequently using
condoms for anal intercourse with regular partners.
Participants were much more likely to report using a condom
for anal sex with casual partners than with regular partners, however 5% of men
whom had a regular sexual partner also admitted to infrequent condom use with
casual sexual partners. There is also some objective evidence of possible
increases in unsafe sexual behaviour in MSM with the recent rise in HIV
incidence in New Zealand. The number of new cases of HIV diagnosed in 2003 was
higher than at any time since surveillance
began13 with 71 new infections identified - a
rise of 37% over 2002.
Men who have sex with men still make up the majority of
cases (74%) where infection was acquired in New Zealand. This recent rise in HIV
incidence is concerning AIDS epidemiologists. If we are also experiencing a rise
in the incidence of infectious syphilis in New Zealand it could influence the
HIV epidemic, as syphilis (to a greater degree than other bacterial STI) is
known to markedly enhance HIV transmission.
The apparent increase in heterosexual cases may be a
reflection of the fact that many New Zealanders now travel overseas to countries
with high endemic rates of syphilis. Travellers often have casual sexual
relationships when on holiday14 and may take
risks under the influence of drugs and alcohol. Indeed, overseas travel seems to
be responsible for a small but important proportion of acute STIs in other
Western countries such as the United Kingdom. For example, in one genitourinary
medicine clinic, 21% of infectious syphilis infections in heterosexual men were
acquired from sexual contacts
abroad.14
The increase in syphilis incidence is a potential serious
public health issue and more information is required on its epidemiology in New
Zealand. The most expedient manner to gather more information would be to make
infectious syphilis a notifiable condition so that anonymous data can be
collected in a similar manner to HIV infection.
In particular, medical practitioners need to be aware that
syphilis infection is occurring in New Zealand. As well as pregnant women, those
who should be screened for syphilis include New Zealanders who have had sex
overseas, recent immigrants, and men who have sex with men. Asymptomatic people
with these risk factors need to be screened serologically 2–3 months after
suspected exposure. Any person suspected of having infectious syphilis should be
urgently referred to a sexual health physician for evaluation, treatment, and
contact tracing.
Author information:
Sunita Azariah, Sexual Health Physician (and Fellow of the Australasian Chapter
of Sexual Health Medicine, RACP), Auckland Sexual Health Service, Auckland City
Hospital, Auckland
Correspondence:
Dr Sunita Azariah, Auckland Sexual Health Service, Building 16, Auckland City
Hospital, Private Bag 92024, Auckland. Fax: (09) 307 2884; email: SunitaA@adhb.govt.nz
References:
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