Project BORDERNET 2005-2007

III. CROSS-BORDER COOPERATION — 3.2. Sentinel Surveillance


The Sentinel Surveillance in the BORDERNET project is co-ordinated by the team of the Robert Koch-Institut (RKI) in Berlin. It comprises mainly of the collection of epidemiological data of HIV/AIDS and Sexually Transmitted Infections (STI). The data should be used as a base for targeted prevention measures. Surveillance data will be gained by collecting anonymous data of newly diagnosed HIV/AIDS, Gonorrhoea, Chlamydia and Syphilis infections in special institutions, like public health offices or STI in- and outpatient clinics. These institutions will be recruited in cooperation with the regional coordinators depending on the specialties of the country. The data will be sent over the regional and overall coordinators to the Robert Koch-Institut (RKI) in Berlin.

The task of RKI will be the scientific counselling and support for the development of the sentinel survey in the model regions, as well as the construction and analysis of the database.
The sentinel will record the occurrence, as well as the trends in time and place of the observed STIs in the participating regions. This should lead to a better detection of risk behaviour and outbreaks. After analysing the results recommendations for prevention and intervention activities can be issued. The success of these efforts can also be monitored by the system.
After a successful start, an extension of Bordernet to other eastern European border regions is planned.

Background of the Sentinel-Surveillance

In the context of EU-Enlargement new challenges of diagnosis, therapy and preven-tion of HIV/AIDS and sexually transmitted infections (STI) arose. STIs can cause chronic diseases with severe impact on quality of live and high costs for the health care systems.
The morbidity and mortality due to bacterial infections like gonorrhoea and syphilis decreased considerably in Western Europe and other industrialised countries since the 1970s. Causes discussed concerning this topic were the improving of antibiotic treatment and the increased use of condoms (also in the context of the HIV-epidemic). However, the numbers of STIs in Western Europe are again on the rise. Reduced sexual protection behaviour, immigration from endemic regions, increased mobility and insufficient diagnosis and therapy offers for specific risk groups have been discussed as reasons for this situation.
In this context the EU enlargement poses new challenges. The border regions be-tween the new and old EU-members form particular areas due to cultural, economic and political differences. Crossing border and changing place of residence or work became easier. This is of high importance in the context of spreading infectious diseases in general, of STIs in particular. However, missing or insufficient epidemiological data on HIV/AIDS and STIs on national and regional level make effective prevention difficult.
An improvement and integration of the existing structures of the national health care systems seems necessary to establish appropriate health care offers in these special border regions. Therefore 13 partner organisations, coming from Germany (D), Poland (P), Slovakia (SK), Slovenia (SLO), Italy (I) und Austria (A), are working together in four defined model regions:

- Region 1: Mecklenburg -Vorpommern (D) – Zachodniopomorskiego (P)
- Region 2: Brandenburg (D) – Zielona Gora/Lubuskie (P)
- Region 3: Wien (A) – Bratislava (SK)
- Region 4: Veneto (I) – Maribor (SLO)


To analyse the situation in the involved regions and to find possibilities to improve STI prevention, reliable data is necessary. A sentinel surveillance system will be able to find answers to a lot of these questions. Therefore establishing such a system is one of the central aims of Bordernet and has been realised by the Robert Koch-Institut in Berlin and the regional coordinators.


The objectives of the STI-Sentinel in the Bordernet project are to detect and analyse the frequency and distribution of HIV/AIDS and STIs in the border regions between the old and new EU-member states. The focus of the sentinel is not to collect repre-sentative data but to detect early trends in risk groups or regions as well as specific risk behaviour. This should lead to an improvement of diagnosis, therapy and above all of prevention in the involved regions.


The STI-Sentinel-Surveillance has the following objectives:

- Assessment of the frequency and regional distribution of the STIs
- Early detection of epidemiologic trends
- Identification of special risk groups for the different STIs
- Detection of need for intervention
- Recommendations for intervention and further detailed surveys
- Documentation of success of the interventions through reduction of new infections


Reported should be newly diagnosed and laboratory confirmed infections with

- Chlamydia
- Gonorrhoea
- Syphilis


Due to HAART HIV infections and AIDS are becoming more and more a chronic dis-ease.
In Western Europe the number of HIV diagnosis increased slowly since 1998. In 2002 and 2003 the rise was distinct again (+ 26%, resp. + 9%). Infections through heterosexual contacts increased significantly in the last years (2003: 58% of the re-ported ways of transmission). In 2002, 30% of the reported infections were due to homo- or bisexual contact. A further decrease showed the numbers of infections through drug abuse (2003: 11% of reported way of transmission). In Western Europe 29% of the persons with HIV diagnosis are under 30 years and 37% are women [1].
In Central Europe no distinct trends were found in the transmitted data of the last years. In 2003, 44% of transmissions were associated with heterosexual contact, 27% with drug abuse and 19% with homo- or bisexual contact (of the cases, where the way of transmission was reported). 45% of the persons were under 30 years, 31% women [1].
Drug abuse is of much higher importance in eastern European countries as it is in Western Europe. Prevention offers are not conferrable easily form Western to East-ern European regions.


Infections with Chlamydia trachomatis are one of the most frequent STIs in Western Europe. Surveillance data show a further increase of reported disease with an peak at the age of 16 to 24 years [2, 3].
In a representative survey of the female population of Berlin in 1996, 3,6% of the 20 to 40 year old women showed a Chlamydia infection [4]. Studies for Italy showed lower infection rates (1,2%) und an higher average age (36 years) [5]. Data for the Czech Republic and Slovakia indicates higher infection rates in sex workers (22,9%) und university students (8,2%) [6]. But in most of the countries reliable data do not exist.


Gonorrhoea is worldwide the most common STI. In some European countries like Belgium, France, Italy, Netherlands, Sweden, Finland, U.K. as well as in Canada a massive increase of gonorrhoea cases was observed since 1995 [7-10].
Moreover, the increased numbers of resistant gonorrhoea give reason to be concerned [7, 11-13].


Since the end of the 1990s the number of newly diagnosed syphilis increased mark-edly in many European countries. For example in Switzerland the numbers doubled in 2002 compared to the years before. [8]. Also in the Netherlands and Belgium the infection rates showed in 2002 and 2003 a 1.5- and 3-fold increase, respectively [10, 14]. In England an raise even to factor 8 was seen from 1997 – 2002 [15]. In Germany the numbers of reported syphilis cases nearly doubled between 2001 and 2003. In three quarters of these cases sexual contact between men was reported as way of transmission [16].
In the new EU countries similar trends have been observed. In Slovenia an increas-ing syphilis rates could be shown. Increasing numbers of syphilis infections have been found in sex workers along the German-Czech border [17-19].

Study design

A sentinel surveillance was chosen to collect the needed data. With this design the frequency of STIs can be properly estimated with limited resources. Information about circulation and distribution of STIs within the population is available as well as the detection of special risks, outbreaks or trends for the observed STIs. In this sentinel the national differences in health care can be considered by recruiting the participating institutions. The sentinel design makes it possible to get data despite the very different systems of data collection throughout the participating countries.

Study population

The study population consists of all persons out of the four regions being infected with HIV, Syphilis, Chlamydia or Gonorrhoea at the time of the study and attending a sentinel site.


All HIV, Syphilis, Chlamydia or Gonorrhoea infections, which are newly diagnosed within the study period in the participating sentinel sites should be reported, including asymptomatic infections. Also different or repeating STIs in one person should be reported separately.


Selection and Recruiting of the reporting sites

To establish a reasonable sentinel-system, detailed information is needed about the number and kind of institutions which might be participating in each country. Literature analysis and questionnaires sent to the regional coordinators and the WHO STI-Coordinators in the regions brought up this information. The sites were also chosen with the aim to reach a maximum of infected persons in the regions as well as a maximum of risk groups. The participation in Bordernet is voluntary and can be quit at any time. The leaving sites should be replaced.

The chosen sites which should report to the sentinel depend on the differences of the local health systems. That will be local health authorities, STI-clinics and specialised outward clinics for STIs.


- Basic questionnaire for sentinel-sites: information about size, equipment, staff, area where the
patients come from, monthly number of patients and STI-tests, special patient groups.
- Monthly questionnaire: aggregated number of patients tested and diag-nosed for HIV, Syphilis,
Chlamydia or Gonorrhoea. Numbers of men/women.
- Diagnosis questionnaire: anonymous reporting for every STI-diagnosis with age, sex, possible
risk group and most likely mode of transmission.
- Patient questionnaire: voluntary anonymous reporting of social demo-graphic background, most
likely mode and place of transmission, sexual behaviour and drug abuse.

Data processing

The questionnaires are sent from the local sentinel sites to the regional coordinator, who checks for consistency. From there they are sent to the overall coordinator SPI who builds up the database. The database is sent regularly to the Robert Koch-Institute, where the data analysis will be done. The transmission can be done by mail, fax or email.

Data analysis

The following analysis is planned:

- Absolute and relative frequency of diagnosed cases of HIV, Syphilis, Chlamydia and Gonorrhoea with
- distribution analysed by region
- distribution analysed by demographic detail (age, sex, place of residence, origin)
- distribution analysed by most likely mode of transmission (homo/bisexual, iv.-drug abuse,
sexworker, heterosexual, other)

- Analysis of risk parameters and identification of risk behaviour for the dif-ferent STIs

- Identification of
- trends in time
- trends in regional distribution
- changes of risk behaviour


A sentinel survey will not bring up representative data of the population. Therefore direct comparison between different nations is difficult. But trends are fast and easily detectable.
The national differences of the previous recording and also the social attitude of the included STIs can influence the common collection of the data in the beginning. Also the distinctions in the national health systems will have an impact on diagnosis and reporting within the sentinel. Some risk groups will be difficult to reach (e.g. sexworkers, drug users, migrants). Also the several languages could be a problem while conducting the study although the questionnaires were translated into other languages.
Regular meetings with the participating institutions as well as a good local coopera-tion will help to detect problems early and to find solutions.

Ethical aspects / Data protection

STIs are diseases often associated with stigma and shame for the concerned per-sons. Hence the confidentiality is a very important topic for the study. It should be guaranteed through organisational measures.
There are several ways to ensure a high level of transparency and anonymity:

- The participation of the institutions is voluntary and can be ended at any time.

- The reporting will be pseudonymous in a first step between the sentinel sites, the regional
coordinators and the overall coordinator. In a second step total anonymity is guaranteed for
the database.

- In connection with the patient questionnaires an information letter is given to the patients from
their diagnosing sites. It explains the study, the data protection and also the voluntary participation.
This should improve the confidence between the patients and the local institutions and increase
the response rate.

- The questioning of the patients will also be pseudonymous respectively anonymous and completely
voluntary. The questionnaires are sent in closed envelopes to the regional coordinators.

- For the correct matching of the diagnosis and the patient questionnaire to one patient the reporting
sites will assign a reference numbers on both questionnaires (pseudonymous reporting). After the
matching the numbers will be separated and destroyed.

- The collected data will be kept in rooms which can be locked not accessi-ble for others than the
members of the project team.

Expected results

It is expected, that the STI-Sentinel in Bordernet will show the following results:


Continuous collection of data concerning the frequency of STIs

It is planned that the STI sentinel will be carried out over a longer period of time. That makes it possible to analyse the frequency and geographical distribution continuously and to compare the results with the known literature. So the situation of STIs in the model regions as well as possible prevention measures can be evaluated. In combination with the national reporting systems a more precise analysis of the STI situation can be carried out.

Detection of epidemiological trends

With the comparison of former results the sentinel provides information about possible trends of the reported STIs. An unexpected rise of cases as well as geographical clusters can be detected early with this system and outbreaks can be examined.

Identification of risk groups und risk factors

Due to the patient questionnaire the STI sentinel provides information about risk fac-tors and vulnerable groups. Also a detailed analysis of these risk factors will be pos-sible (e.g. sexual practice, drug use, frequent partners)
Background for further studies
These results will be the starting point for three planned surveys within Bordernet in certain risk groups and concerning certain STIs.

Border crossing network for HIV/AIDS and STI report

Due to the cooperation between the participating regions a border crossing network for early detection of trends in the distribution of HIV/AIDS and STIs will be build. That supports an improvement of diagnosis, therapy and prevention of the concerned infections.


The collected data will help to strengthen the existing prevention and intervention measures and also can help to detect further needed measures, as the situation for STIs in the regions improves.

The existing and the new prevention and intervention measures will be analysed continuously through the sentinel, so their success or further needed development can be described.

The results of the STI-Sentinel should be published in several ways. The participating institutions receive regular feedback with the abstract of the collected data. Selected topics may be published in the national or European epidemiological bulletin. In regional and national meetings the findings should be discussed by the institutions and the coordinators. In this meetings needed improvements or adjustments will be also a topic.
The experiences with the STI-Sentinel will be published in scientific journals to pre-sent them to the interested public, so others can also profit from the results of the Bordernet project.

Organisational and regional

Different partners are involved in building and organising Bordernet, as well as in the recruiting of the participating institutions.


- Public health offices (STI-/ HIV- advice offices)
- Specialized outpatient departments
- Practitioners specialized in HIV / STI
- Consultants (Dermato-Venerology, Gynaecology, Urology)
- Laboratories


Dr. Andreas Gilsdorf
Tel.: +49 - 30 - 4547 3487
responsible for the regions:
2) Brandenburg (D) / Zielona Gora - Lubuskie (P)
4) Veneto (I) – Maribor (SLO)


Dipl.-Psych. Klaus Jansen
Tel.: +49 - 30 - 4547 3403
responsonsible fort he regions:
1) Mecklenburg –Vorpommern (D) / Zachodniopomorskiego (P)
3) Wien (A) – Bratislava (SK)


Dr. Viviane Bremer
Tel.: +49 - 30 - 4547 3427


1. EuroHIV, HIV/AIDS Surveillance in Europe. End-Year report 2003. 2004, Institut de veille sanitaire:
2. CDSC, Sexually transmitted infections quarterly report: udpate on genital chlamydial infections in
the United Kingdom. Commun Dis Rep CDR Weekly, 2003. 13(5).
3. Health Protection Agency, S., ISD, National Public Health Service for Wales, CDSC Northern Ireland
and the UASSG., Renewing the Focus. HIV and other sexually transmitted infections in the United
Kingdom in 2002. 2003, Health Protection Agency: London.
4. Koch J, K.W., Schäfer A, Bestimmung der Prävalenz genitaler HPV- und Chla-mydia-trachomatis-
Infektionen in einem repräsentativen Querschnitt der weiblichen Normalbevölkerung in Berlin, in
Infektionsepidemiologische Forschung II/1997. 1997.
5. Grio, R., et al., Chlamydia trachomatis prevalence in North-West Italy. Minerva Ginecol, 2004.
56(5): p. 401-6.
6. Kacena, K.A., et al., Chlamydia, gonorrhea, and HIV-1 prevalence among five populations of
women in the Czech and Slovak Republics. Sex Transm Dis, 2001. 28(6): p. 356-62.
7. Herida, M., P. Sednaoui, and V. Goulet, Gonorrhoea surveillance system in France: 1986-2000.
Sex Transm Dis, 2004. 31(4): p. 209-14.
8. Lautenschlager, S., Sexually transmitted infections in Switzerland: return of the classics.
Dermatology, 2005. 210(2): p. 134-42.
9. Nicoll, A. and F.F. Hamers, Are trends in HIV, gonorrhoea, and syphilis wors-ening in western
Europe? Bmj, 2002. 324(7349): p. 1324-7.
10. van der Bij, A.K., et al., Increase of sexually transmitted infections, but not HIV, among young
homosexual men in Amsterdam: are STIs still reliable markers for HIV transmission? Sex Transm
Infect, 2005. 81(1): p. 34-7.
11. Dan, M., The use of fluoroquinolones in gonorrhoea: the increasing problem of resistance.
Expert Opin Pharmacother, 2004. 5(4): p. 829-54.
12. Ison, C.A. and I.M. Martin, Gonorrhoea in London: usefulness of first line thera-pies. Sex Transm
Infect, 2002. 78(2): p. 106-9.
13. Palmer, H.M., J.P. Leeming, and A. Turner, Investigation of an outbreak of ciprofloxacin-resistant
Neisseria gonorrhoeae using a simplified opa-typing method. Epidemiol Infect, 2001. 126(2): p. 219-24.
14. Sasse, A., A. Defraye, and G. Ducoffre, Recent syphilis trends in Belgium and enhancement of
STI surveillance systems. Euro Surveill, 2004. 9(12).
15. Brown, A.E., et al., Recent trends in HIV and other STIs in the United Kingdom: data to the end
of 2002. Sex Transm Infect, 2004. 80(3): p. 159-66.
16. Robert-Koch-Institut, Infektionsepedemiologisches Jahrbuch für 2003. 2004: Berlin.
17. Grgic-Vitek, M., et al., Syphilis epidemic in Slovenia influenced by syphilis epi-demic in the
Russian Federation and other newly independent states. Int J STD AIDS, 2002. 13 Suppl 2: p. 2-4.
18. Poto nik, M., et al., Syphilis in Slovenia--on the threshold of the European Un-ion. Int J STD
AIDS, 2000. 11(12): p. 795-7.
19. Resl, V., et al., Prevalence of STDs among prostitutes in Czech border areas with Germany in
1997-2001 assessed in project "Jana". Sex Transm Infect, 2003. 79(6): p. E3.
20. WHO/UNAIDS, WHO/UNAIDS epidemiological fact sheets on HIV/AIDS and Sexually Transmitted
Infections, 2004 Update. 2004.