4 L. Awada et al.
animals and in wildlife separately and, since
2012, to provide both the scientific and common
names of the wildlife species affected. Bovine
tuberculosis has been listed by the OIE since
1964.
1.3 Trend in the Presence of Bovine
Tuberculosis over the Past 30 YearsThis section presents the results of an analysis of
changes in the presence of bovine tuberculosis
over the past 30 years, based on data collected by
the OIE. From 1986 to 1995, the annual occur-
rence of bovine tuberculosis in member coun-
tries was compiled in the annual OIE publication
World Animal Health. Thereafter, the data were
digitized and from 1996 to 2004 they were
recorded in the ‘Handistatus’ information sys-
tem. Since 2005, they have been collected
through WAHIS.
For each year between 1986 and 2015, the
annual percentage of affected countries among
those providing the OIE with information was
calculated, as well as the 95% confidence inter-
val (Fig. 1.2).
The number of OIE member countries var-
ied during the period of the analysis, increasing
from 103 in 1986 to 180 in 2015. The historical
trend in the presence of bovine tuberculosis is
therefore influenced by the variation in the
number of reporting member countries
throughout the years.
The percentage of reporting countries that
notified bovine tuberculosis present decreased
between 1986 and 2015, from 84% (CI95% =
80%–88%) to 50% (CI95% = 46%–54%)
( Spearman’s rank correlation = 8764, p < 0.001;
rho = - 0.95), indicating a general improvement
in the global situation over the past 30 years.
This trend followed a simple linear model
(R^2 = 0.9; p < 0.001). Even if the data present a
high degree of variability among the different
years, the overall tendency is clearly shown by
the regression model. Variability in the observed
trend can be explained by different levels of
accuracy and quality of the information pro-
vided to the OIE by member countries. The diag-
nostic capabilities and the degree of preparedness
of the veterinary services may vary from month
to month during the year and among the coun-
tries. These differences should be considered
when assessing historical trends in disease.Fig. 1.2. Percentage of the reporting countries for each year between 1986 and 2015 that notified
bovine tuberculosis present, with the 95% confidence interval, and simple linear regression trend line.
1008060PercentageYear1985 1990 1995 2000 2005 2010 201540200