Brucellosis is one of the main zoonoses in the world. In Saudi Arabia,
it was recognized as a major health problem in 1983G and since then m
any measures have been implemented to control the disease. We conducte
d a study to determine the yearly incidence and seasonal variation of
blood culture positive brucellosis (Brucella cases) diagnosed at King
Khalid University Hospital (KKUH) in Riyadh between 1985G and 1991G. T
he results showed that there was a fivefold decline in the incidence o
f Brucella cases over the seven years of the study from 8.6 cases/1000
admissions in 1985G to 1.4 cases/1000 admissions in 1991G. The diseas
e showed a prevalence that extended throughout the year with the major
ity of cases occurring during spring, summer and early fall. The possi
ble reasons for the seasonal variation and decreasing incidence of bru
cellosis noted in this study are discussed.