Murine typhus and
scrub typhus are important
human rickettsial diseases in
Thailand. Small
mammals, including many species of
rodents and
shrews, serve as the
reservoir host of
rickettsial diseases.
Rickettsia typhi can be transmitted to
humans by
fleas causing
murine typhus, while
infection with
Orientia tsutsugamushi causing
scrub typhus in
humans is transmitted by
chiggers. The
prevalence of rickettsial
infection depends on the geographic area. The
seroprevalence of antibody to R. typhi and O. tsutsugamushi was studied in commensal
rodents and
shrews trapped in markets in the Bangkok Metropolitan Area (BMA). R. typhi and O. tsutsugamushi
antigen prepared in the
yolk sac of embryonated
eggs were used to determine the specific antibody in trapped
animals' sera by using
fluorescein isothiocyanate (
FITC)-anti
rat immunoglobulins as a second antibody. Antibody to R. typhi was found in 25 (5%) of 500 sera tested and no antibody to O. tsutsugamushi was detected. R. typhi antibody titer ranged from 40-1280 and was found in
Rattus norvegicus (4.2%),
Rattus rattus (0.4%),
Rattus exulans (0.2%), and
Mus musculus (0.2%) trapped in 8 of 47 markets in the BMA. R. typhi antibody was commonly found in R. norvegicus. The authors concluded that
murine typhus is an important
rickettsial disease and R. norvegicus is an important
reservoir species of
rodents found in markets of the BMA.