Eurosurveillance weekly releases

Syphilis transmission in homo/bisexual men : New outbreak in London, continuing outbreak in
Dublin
Salmonella newport infection in England associated with the consumption of ready to eat salad
Cases of legionnaires' disease in the UK and Sweden linked with a London site
Behavioural intervention does not reduce incidence of sexually transmitted diseases in
homosexual men

Syphilis transmission in homo/bisexual men : New outbreak in London, continuing outbreak in
Dublin

In the past eight weeks, 18 cases of infectious syphilis have been diagnosed in homo/bisexual
men attanding sexually transmitted infection clinics in North, East and South East London (1).
Fifteen of the cases are in men who are known to be infected with HIV, including some who are
known to have been HIV-infected for a considerable period of time. Local surveillance has been
intensified. Outbreak control measures have been instituted, including increased syphilis
testing in known HIV-infected patients and increased health promotion activities in venues
frequented by homo/bisexual men.
The enhanced syphilis surveillance in Ireland has ascertained over 10 cases of primary and
secondary syphilis each month since the beginning of 2001, including 17 cases in March and 13
cases in April (2). Of the 109 cases reported since January 2000, 106 are associated with the
outbreak in Dublin (3). Four-fifths of the cases are in homo/bisexual men.

These syphilis outbreaks in homo/bisexual men in London and Dublin follow the large outbreak
reported recently from Antwerp (4), and earlier outbreaks in Paris (5) and Oslo (6), and in
Manchester and Brighton in England (7).

References :
PHLS CDSC (London). News Bulletin 25/01, week beginning June 18th 2001.
Domegan L, Cronin M. Enhanced surveillance of syphilis. EPI-INSIGHT 2001; 2 (June):4.
NDSC. Update: Syphilis outbreak. EPI-INSIGHT 2001; 2 (April):1.
De Schrijver K. Syphilis outbreak in Antwerp, Belgium. Eurosurveillance weekly 2001; 5: 010510.
Doherty L, Fenton K, O'Flanagan D, Couturier E. Evidence for increased transmission of syphilis
among homosexual men and heterosexual men and women in Europe. Eurosurveillance Weekly 2000; 4:
001214.
Blystad H, Nilsen Ø, Aavitsland P. An outbreak of syphilis among homosexual men in Oslo,
Norway. Eurosurveillance Weekly 1999; 3: 991118.
Fenton K. Syphilis continues in gay men in Greater Manchester, England. Eurosurveillance Weekly
2001; 5: 010419.
Reported by Noel Gill, (ngill@phls.org.uk), Public Health Laboratory Service, Communicable
Disease Surveillance Centre, London.

Salmonella newport infection in England associated with the consumption of ready to eat salad

Nine human cases of infection with Salmonella newport with a possible link to a salad item have
been identified in England. The cases were identified following the isolation of S. newport
from a salad item as part of the PHLS/LACOTS survey of retail prepared pre-packed ready-to-eat
salad vegetables in the United Kingdom (1).
Cases range in age from 4 to 74 years (median 33 years) and are distributed throughout England.
Onset dates of illness range from June 2nd to 8th. Salad consumption has been confirmed in six
cases and food histories are awaited from the other two. The two cases from one area (who are
not related to each other) are known to have consumed the implicated salad item three and six
days prior to the onset of illness. One of the six cases from whom a food history has been
obtained, is known to be a vegetarian. None of the cases travelled abroad during the incubation
period.

Isolates from the salad item and the nine cases exhibit an unusual reaction with the PHLS
Laboratory of Enteric Pathogens phage typing scheme for S. newport. Additional molecular work
has shown that isolates from the salad and five of the human cases have a unique plasmid
profile. The salad isolate and three of the human isolates are also indistinguishable using
pulsed field gel electrophoresis. Examination of the remaining human isolates using molecular
methods is underway.

On June 22nd an urgent request for information was sent to all participants in the Enter-net
(http://www.Enter-net.org.uk) surveillance network (2). Of the seven countries that had replied
by June 28th, none reported an increase in human cases of S. newport in recent weeks. Several
countries reported on foodstuffs contaminated with this serotype, but these were predominantly
strains from poultry samples, and a few strains had been isolated from reptiles.

Salmonellosis associated with the consumption of salad items is relatively uncommon, although
two notable outbreaks occurred last year. In a widespread outbreak of multiresistant S.
typhimurium DT104 infection in England, where 361 people were affected and one person was known
to have died, illness was epidemiologically linked to the consumption of lettuce away from home
in the three days prior to the onset of illness. Investigations in Iceland into a Europe-wide
outbreak of multiresistant S. typhimurium DT204b (which included 125 cases in England and
Wales) revealed an association between illness and the consumption of imported iceberg lettuce
(3).

References :
LACOTS/PHLS co-ordinated Food Liaison Group Studies: microbiological examination of retail
prepared pre-packed ready-to-eat salad vegetables; sampling protocol. Available to subscribers
online at (<http://www.LACOTS.com>.)
IST Fisher on behalf of the Enter-net participants. The Enter-net international surveillance
network - how it works. Eurosurveillance1999; 4: p 52-5.
(http://www.eurosurveillance.org/eurosurveillance/v4n5/en33-22.htm)
PHLS. Outbreaks of Salmonella typhimurium DT204b infection in England and Wales and elsewhere
in Europe. Commun Dis Rep CDR Wkly 2000; 10 (39): 349.
http://www.phls.co.uk/publications/CDR00/cdr3900.pdf)

Reported by Sarah O'Brien (sobrien@phls.org.uk), Public Health Laboratory Service Communicable
Disease Surveillance Centre, and Ian Fisher, Enter-net scientific co-ordinator,
(ifisher@phls.org.uk), London, England.

Cases of legionnaires' disease in the UK and Sweden linked with a London site

Three confirmed cases of legionnaires' disease have been associated with central London, in
particular the area of Portman Square. The cases are all men aged between 31 and 61 years in
whom illness onsets were 22 May, 25 May, and 3 June. Two cases had worked in the area. The
third case was reported to the PHLS Communicable Disease Surveillance Centre (CDSC) by the
Swedish collaborator in the European Surveillance Scheme for Travel Associated Legionaires'
Disease (1). This case had visited London and been in the Portman Square area before the onset
of his illness. All cases were diagnosed in their admitting hospital by urinary antigen
detection. Legionella pneumophila serogroup1 infection has been confirmed in the two British
cases by the Respiratory and Systemic Infection Laboratory at the PHLS Central Public Health
Laboratory.
An outbreak control team has been convened and possible environmental sources of infection
within a 500 metre radius of Portman Square are being investigated. L. pneumophila serogroup 1
has been identified in water systems and cooling towers in three buildings in the vicinity.
Control measures have been taken at all three sites and further investigations are in hand.

All Consultants for Communicable Disease Control in England and Wales have been alerted to the
outbreak. Information has been disseminated in Europe through the European Surveillance Scheme
for Travel Associated Legionnaires' Disease and in the United States via the Centers for
Disease Control and Prevention (CDC). CDSC would be grateful for information on any other
suspected cases of legionnaires' disease who became ill during May or June that might be
associated with this incident. Please contact Carol Joseph, European legionella surveillance
scheme project co-ordinator (tel: 0208 200 6868 ext 4497; email cjoseph@phls.org.uk).

Information on the European surveillance scheme for travel associated legionnaires' disease can
be obtained from its website www.ewgli.org

Reported by Carol Joseph, (cjoseph@phls.org.uk), Public Health Laboratory Service, Communicable
Disease Surveillance Centre, London.

Behavioural intervention does not reduce incidence of sexually transmitted diseases in
homosexual men

The need for effective HIV prevention strategies based on reducing sexual risk behaviour
remains important. A study reported in the BMJ found, however, that even a carefully designed,
brief, behavioural intervention did not reduce the risk of participants acquiring new sexually
transmitted infections (STIs) as a proxy for unprotected anal intercourse (1).
The researchers conducted a randomised controlled trial with 12 months' follow up. Participants
were 343 gay men attending a sexual health clinic in London from September 1995 to November
1997 who presented with an acute STI, reported having had unprotected anal intercourse in the
past year, or expressed concern about their sexual practices.

All participants received standard management consisting of a 20 minute one to one counselling
session about sexual risk behaviour. Contact tracing was offered to those with a newly
diagnosed infection; and participants could also be referred to clinic-based or community-based
education on HIV prevention and counselling services. Additionally, participants assigned to
the intervention were invited to a one-day workshop.

Behavioural outcomes were followed up by using postal questionnaires. Clinic and laboratory
databases were reviewed to identify new STIs diagnosed at the clinic. Attendance at other
clinics in greater London was determined by matching individuals to a regional database.
Re-attendance at the clinic was not required by the protocol.

Self reported changes in sexual behaviour were modest, but generally there was more improvement
in the intervention group, where the proportion of men engaging in unprotected anal intercourse
in the past month decreased from 37% (63/172) at baseline to 24% (32/136) at 6 months and 27%
(31/114) at 12 months. In the control group the proportion changed little: from 30% (50/166) at
baseline to 32% (44/139) at 6 months and 32% (39/124) at 12 months. After adjusting for
infections and unprotected anal intercourse at baseline, differences in these proportions
between the arms of the trial were not significant (P=0.07 at 6 months and P=0.31 at 12
months). Findings were similar for the proportions having unprotected anal intercourse in the
past 12 months (61% (106/174) in the intervention group and 63% (104/166) in the control group
at baseline, compared with 50% (58/116) and 59% (76/128) respectively at 12 months).

However, 31% (38/123) of the intervention group and 21% (35/168) of controls had had at least
one new STI diagnosed at the clinic. Considering only men who requested a check up for STIs,
the proportion diagnosed with a new infection was 58% (53/91) for men in the intervention group
and 43% (35/81) for men in the control group (adjusted odds ratio 1.84, 95% confidence interval
0.99 to 3.40). The higher risk of acquiring a STI among participants in the intervention arm
was unexpected, at odds with the data on sexual behaviour, and clearly a cause for concern.

Despite its promise and acceptability, the brief cognitive intervention aimed at gay men at
high risk of STI did not reduce their risk of acquiring new infections. Even carefully
formulated behavioural interventions should not be assumed to bring benefit. It is important to
evaluate their effects in randomised trials by using clinical end points wherever possible.

References :
Imrie J, Stephenson JM, Cowan FM, Wanigaratne S, Billing ton AJP, Copas AJ, et al. A cognitive
behavioural intervention to reduce sexually transmitted infections among gay men: randomised
trial BMJ 2001;322:1451-6. (http://www.bmj.com/cgi/content/full/322/7300/1451)
Reported by Birte Twisselmann (btwisselmann@phls.org.uk), Eurosurveillance editorial office.

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Citation style for articles

- Article 1 : Gill O.  Syphilis transmission in homo/bisexual men: New outbreak in London,
continuing outbreak in Dublin . Eurosurveillance Weekly [1812-075X]. 2001 Jun 28;6(26) 010628.
Available from: http://www.eurosurveillance.org/ew/2001/010628.asp#1

- Article 2 : Fisher I,  O'Brien S.  Salmonella newport infection in England associated with
the consumption of ready to eat salad . Eurosurveillance Weekly [1812-075X]. 2001 Jun 28;6(26)
010628. Available from: http://www.eurosurveillance.org/ew/2001/010628.asp#2

- Article 3 : Joseph C.  Cases of legionnaires' disease in the UK and Sweden linked with a
London site . Eurosurveillance Weekly [1812-075X]. 2001 Jun 28;6(26) 010628. Available from:
http://www.eurosurveillance.org/ew/2001/010628.asp#3

- Article 4 : Twisselmann B.  Behavioural intervention does not reduce incidence of sexually
transmitted diseases in homosexual men . Eurosurveillance Weekly [1812-075X]. 2001 Jun 28;6(26)
010628. Available from: http://www.eurosurveillance.org/ew/2001/010628.asp#4

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