S. Typhimurium, S. Stanley, and S. Enteritidis of serogroup
D1 being the three most prevalent serovars overall.
Although the prevalence of serogroups C1 and C2-C3
were similar (around 11%), 4 prevalent serovars and 2
main serovars were found in serogroup C1 and serogroup
C2-C3, respectively. In the present study, a shift in prevalence
was observed in these four prevalent serogroup C1
serovars: a rapidly decrease in the prevalence of S. Choleresuis,
mainly due to enhancement of sanitation and
control of swine in Taiwan, and an increase in prevalence
of S. Bareilly and other serovars (Table 1). Compared to
the 1.6% increase in the prevalence of S. Braenderup from
1978 to 1987 in southern Taiwan [21], the change in the
prevalence of isolates in this study ranged from 1.6% to
3.8%, with a trend of decrease from 2004 to 2007, except
an increase of S. Braenderup infection in 2006 (Table 1),
suggesting possibly occurrence of outbreaks in this year