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The results of this
two-year surveillance provide an improved picture of the epidemiological
situation of tuberculosis in Europe compared to previous reports.
Since 1995, consensus recommendations on uniform reporting
of tuberculosis [3,4], including
a common case definition and a common set of variables to be
collected, have been approved. In 1996, the European definition
of a notifiable case of tuberculosis was almost universally
used, but differential inclusion of some population groups
(e.g. illegal immigrants, prisoners) and some categories of
patients (e.g. recurrent cases), together with variable rates
of underreporting, may have introduced some biases in the comparisons
between countries. The availability and completeness of information
differed between countries. In particular, the quality of the
bacteriological information appeared to vary greatly [10]. Information on culture is essential in order
to validate case reporting since culture is currently the gold
standard for the diagnosis of tuberculosis in Europe. Information
on smear results is also essential since sputum smear positivity
is the best indicator of the infectiousness of a case. Inclusion
of high quality bacteriological information would be best achieved
by incorporating laboratories in the national notification
schemes, as recommended [3,4].
So far, only a few countries
have been able to implement all the European recommendations.
Several countries have partially applied these recommendations
and others are planning to do so in the near future. Substantial
improvements in the number of variables collected and in the
completeness of information can already be observed in 1996
compared with the previous year. Future changes in tuberculosis
surveillance systems will further improve the quality and the
comparability of data.Contrasting pictures emerge from data
on tuberculosis cases notified in 1995 and 1996 in Europe,
with large between-country variations. As in 1995, countries
with a lower notification rate in 1996 are mostly situated
in the western part of Europe (exceptions being Israel and
the Czech Republic). Most countries reporting more than 20
cases per 100 000 in 1996 are situated in the eastern part
of Europe with the notable exception of Spain and Portugal.
Between 1995 and 1996, notification rates appear to have declined
or to have stabilised in most countries with a lower notification
rate, while increases were observed in many countries with
a higher rate. This has resulted in a widening gap between
the two groups. Moreover, the higher the notification rate
in 1995, the larger the increase in 1996, as observed in many
republics of the former USSR.It is difficult to interpret trends
over only two years. However, these trends tend to confirm
some of the changes already observed in the late 1980s and
early 1990s after decades of continuing decreases in tuberculosis
morbidity and mortality. In western Europe[11],
the notification rate decreased regularly between 1974 and
1986, but stabilised or increased between 1986 and1990 in several
countries (Austria, Denmark, Iceland, Ireland, Italy, Netherlands,
Norway, Switzerland, United Kingdom). However, between 1990
and 1995, while increases were observed in some other countries,
there was no confirmation of a clear increase in incidence
in all western Europe: notifications increased only temporarily
(over 2 to 5 years) or appeared to remain fairly stable in
most countries. In eastern Europe [12],
tuberculosis mortality and morbidity also declined regularly
until 1985-1990. Substantial increases in notification rates
were observed between 1990 and 1995 in Bulgaria, Hungary, Romania
and in most republics of the former USSR, including the Baltic
States. This reversal of trends was not confirmed in other
countries (e.g. the Czech Republic, Poland, Slovakia), where
notification rates continued to decline.HIV infection has not
been a major factor in contributing to increases in tuberculosis
notification rates, except for a few countries such as France,
Portugal and Spain [13]. Since
1996, declining trends in AIDS incidence have resulted in a
decreasing number of AIDS-associated tuberculosis cases in
most western European countries, except in Portugal [14].
However, the rapidly emerging epidemic of HIV infections in
countries such as Ukraine or the Russian Federation represents
a serious threat since its impact on the incidence of tuberculosis
could be substantial in the near future. Patients of foreign
origin account for a highly variable proportion of tuberculosis
patients in Europe. In 1996, they accounted for more than 50%
of the cases in some western European countries. Although no
significant variation in this proportion was observed between
1995 and 1996, the recent influx of immigrants from countries
with a higher incidence of tuberculosis clearly had an important
influence on the epidemiology of the disease. This is reflected
by the substantial proportion of patients originating from
Somalia, Yugoslavia or Bosnia-Herzegovina, who probably immigrated
fairly recently.Impoverishment of subgroups of the population,
particularly in big cities, may be an important factor in contributing
to recent increases in tuberculosis incidence, particularly
if access to health care is decreased for these subgroups.
Disruption of health services due to war or economical and
political difficulties is also likely to have a major influence
on the epidemiology of tuberculosis. Indeed, delays in diagnosis
and treatment and inadequacies or interruptions of therapy
result in increased transmission of tuberculosis infection
and high rates of relapse. Deterioration of tuberculosis control
programmes is probably also responsible for the high prevalences
of multi-drug resistance which were recently reported in several
European countries (e.g. Estonia, Latvia, Russian Federation)
[15]. In the perspective of working
towards the elimination of tuberculosis in Europe [16], the surveillance of tuberculosis notifications
should be complemented by the surveillance of drug resistance
and the monitoring of treatment outcome [17].EuroTB
plans to extend the European surveillance system in the coming
year to include the surveillance of anti-tuberculosis drug
resistance. |
