Epidemiologic classification of Salmonella
is based on the host preferences. The first group
includes host-restricted serotypes that infect only
humans such as S.Typhi. The second group includes
host-adapted serotypes which are associated with
one host species but can cause disease in other hosts
serotypes such as S. Pullorum in avian. The third
group includes the remaining serotypes. Typically,
SalmonellaEnteritidis, SalmonellaTyphimurium and
Salmonella Heidelberg are the three most frequent
serotypes recovered from humans each year