|D. Antoine1, V. Schwoebel 1, J. Veen 2, M. Raviglione3, H.L. Rieder4 and the national coordinators for tuberculosis surveillance in 50 countries* of the WHO European Region
1. European Centre for the Epidemiological Monitoring of AIDS, Saint Maurice, France.
* Albania, Andorra, Armenia, Austria, Azerbaijan, Belarus, Belgium, Bosnia-Herzegovina, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Georgia, Germany, Greece, Hungary, Iceland, Ireland, Israel, Italy, Kazakstan, Kyrgyzstan, Latvia, Lithuania, Luxembourg, Macedonia, Malta, Moldova, Monaco, Netherlands, Norway, Poland, Portugal, Romania, Russian Federation, San Marino, Slovakia, Slovenia, Spain, Sweden, Switzerland, Tajikistan, Turkmenistan, Ukraine, United Kingdom, Uzbekistan, Yugoslavia
The EuroTB programme for the surveillance of tuberculosis in Europe was set up in 1996 to collect, analyse, and disseminate data on tuberculosis cases notified in the World Health Organization (WHO) European Region. Following a feasibility study performed in 1996-1997 on cases notified in 1995 (1), a routine system of data collection has been implemented. The programme is managed jointly by the European Centre for the Epidemiological Monitoring of AIDS (CESES) in Saint-Maurice, France and the Royal Netherlands Tuberculosis Association (KNCV) in the Hague, the Netherlands.
The principles and methods are those recommended by a working group set up by the WHO and the International Union against Tuberculosis and Lung Disease (IUATLD) and approved by European country representatives (2,3). The European definition of a notifiable case of tuberculosis is used (box).
The 51 countries of the WHO European Region are invited to participate on a voluntary basis. A national correspondent is identified in each country and is responsible for the quality of the data provided. Individual anonymous computerised data on age, sex, geographical origin, status of the case (new or recurrent), site of disease, culture, and sputum smear results are requested. Countries that cannot provide this information are asked to supply aggregate data.
Data collection on 1996 notification was complemented by a questionnaire about the implementation of European recommendations (2,3).
In 1996, 315 892 cases of tuberculosis were notified in the 50 countries that took part (all countries of the WHO European Region except Turkey) compared with 276 811 from 46 countries in 1995 (1). Differences were observed in the case definition. Forty-seven countries reported all new and recurrent cases, two countries (Greece and Kazakstan) reported only new cases, and one country (Spain) reported only new respiratory cases. In addition, differences in the coverage of notification were observed : 21 countries did not include at least one category of foreigners (legal immigrants, illegal immigrants, asylum seekers) and 12 countries did not include prisoners among cases notified. The definition of recurrent cases included in the notifications varied: 20 countries defined recurrent cases as relapses according to the WHO recommendations (4) and 23 used a broader definition.
The notification rate varied across countries from zero in Monaco and San Marino to 195 per 100 000 population in Georgia, with a median of 26 (map 1).The notification rate was:
– lower than 20/100 000 in 21 countries, all located in the western part of Europe except for the Czech Republic and Israel;
– ³ 20 cases /100 000 in 29 countries, all but Portugal and Spain located in the eastern part of Europe.
|Figures may slightly differ from those published by WHO because WHO figures are collected several months prior to those collected by EuroTB, and as such, are often provisional
Between 1995 and 1996, the notification rate decreased in 18 countries, remained stable in five, and increased in 24. The rate increased by more than 10% in 12 countries, including ten republics of the former USSR (Armenia, Azerbaijan, Belarus, Estonia, Kazakstan, Kyrgyzstan, Latvia, Lithuania, Russian Federation, Uzbekistan) (map 2).
In 1996, the age and sex specific notification rates varied according to the overall rates in the country. In countries with a notification rate under 20/100 000, notification rates were highest in patients aged 65 years or over. In countries with rates ³ 20/100 000, the highest rates seen were in men aged 35 to 54 years and women aged 25 to 34 years. Rates in males were higher than those in females and the sex difference was larger in countries with higher notification rates.
Data on the geographical origin of cases were available from 23 countries (21 for 1995 data), based on birthplace (as recommended) in 18 and citizenship in eight, with three countries (France, Luxembourg, and Switzerland) providing both. Patients of foreign origin accounted for 30% to 49% of the cases in five countries (Belgium, Iceland, Malta, Netherlands, Norway), and for 50% or over in six countries (Andorra, Denmark, Israel, Luxembourg, Sweden, and Switzerland). Data on the continent of origin of the patients were available from 15 countries for 1996 (12 for 1995 data): 27% of the foreign patients originated from Europe, 26% from Asia, and 39% from Africa. Similar proportions were observed in 1995 (1).
Twenty-four countries provided detailed information on major and minor sites of disease or classified cases as pulmonary or extra-pulmonary. Seventy-seven per cent of cases were pulmonary.
Eighteen countries in 1996 (17 in 1995) provided individual data on culture results. Culture was reported to have been performed in a median of 80% of cases. A median of 54% of cases (range 20% to 88%) had a positive culture. Among the 14 countries that provided data on culture for 1995 and 1996, the median proportion of culture positive cases was stable (59% in 1995 and 60% in 1996). Fifteen countries provided data on individual sputum smear results among pulmonary cases for 1996 (13 for 1995 data). Sputum smears were reported to have been performed in a median of 89% of pulmonary cases. A median of 37% (range 14% to 57%) of pulmonary cases were smear positive.
The results of this two year surveillance project show how widely the epidemiology of tuberculosis varies in Europe. As in 1995, countries with lower notification rates in 1996 were mostly situated in the western part of Europe and most of the countries that reported 20 cases/100 000 or more were situated in the eastern part of Europe with the notable exceptions of Spain and Portugal. Between 1995 and 1996, notification rates declined or stabilised in most countries with low notification rates, but increased in many countries with high notification rates. The largest increases were reported from republics of the former USSR.
These results must be interpreted with caution because of the differences in reporting systems between countries. For example, some population groups, such as foreigners or prisoners, are systematically excluded from notification in several countries. Definitions of recurrent cases included in national reports also differ. Trends are particularly difficult to interpret since data are available for two years only, but the short term changes reported seem to confirm some trends already observed in the late 1980s and early 1990s.
Large increases in notification rates observed in some countries, especially in the eastern part of Europe, may be related to impoverishment of population subgroups and disruption of health services, which may be due to socioeconomic and political difficulties. Deterioration of tuberculosis control programmes has contributed to some of the recent increases, and resulted in high prevalences of multidrug resistance recently reported from several countries in eastern Europe (5). Migration from countries where the incidence of tuberculosis is high has also influenced the epidemiological situation, particularly in western Europe. In addition, the impact of HIV infection has been limited to a few countries (6) but could be substantial in the future in countries with rapidly developing HIV epidemics.
The results highlight improvements in the availability of data and adherence to the European recommendations. Data quality still varies substantially between countries, however, particularly bacteriological data. These variations may be related to differences in diagnostic practices and in patterns of reporting. Indeed, laboratory facilities for culture are not fully available in some countries and the recommended involvement of laboratories in the notification process exists only in a few countries. This is likely to change in the future as some national reporting systems are modified according to the European recommendations.
The worsening situation in several countries and the heterogeneous epidemiological pattern observed in Europe stress the importance of the surveillance of tuberculosis in the European region. EuroTB will continue the surveillance of tuberculosis notifications and plans to introduce surveillance of resistance to antituberculosis drugs.
Note: EuroTB is supported financially by the Commission of the European Communities (DGV). The CESES has been nominated as WHO collaborating centre for the surveillance of tuberculosis in Europe.
Detailed results can be found in: Surveillance of tuberculosis in Europe – Report on tuberculosis cases notified in 1996 – September 1998. This report is available on request from CESES, Hôpital National de Saint Maurice, 14 rue du Val d’Osne, 94410 Saint Maurice, France and on the Internet ( http://www.ceses.org/eurotb ).
1. Perrocheau A, Schwoebel V, Veen J, National Coordinators for Tuberculosis Surveillance in 46 Countries of the WHO European Region. Surveillance of tuberculosis in the WHO European Region in 1995: results of the feasibility study. Eurosurveillance, 1998; 3: 2-5.
2. Rieder HL, Watson JM, Raviglione MC, Forssbohm M, Migliori GB, Schwoebel V, et al. Surveillance of tuberculosis in Europe. Recommendations of a working group of the World Health Organization (WHO) and the European Region of the International Union Against Tuberculosis and Lung Disease (IUATLD) for uniform reporting on tuberculosis cases. Eur Resp J 1996; 9: 1097-104.
3. Schwoebel V, Rieder HL, Watson JM, Raviglione MC for the Working Group for Uniform Reporting on Tuberculosis Cases in Europe. Surveillance of tuberculosis in Europe. Eurosurveillance, 1996; 1: 5-8.
4. WHO. Treatment of tuberculosis. Guidelines for National Programmes. World Health Organization, Geneva: World Health Organization 1997. (WHO/TB/97.220)
5. Pablos-Méndez A, Raviglione MC, Laszlo A, Binkin N, Rieder HL, Bustreo F, et al. Global surveillance for antituberculosis-drug resistance, 1994-1997. N Engl J Med 1998; 338: 1641-49.
6. Schwoebel V, Delmas MC, Hamers F, Alix J, Brunet JB, National Coordinators of AIDS Surveillance. Tuberculosis as an AIDS-defining disease in Europe. Clinical Microbiology and Infection 1996; 1: 286-8.