Occurrence of Orientia Tsutsugamushi in Small Mammals From Thailand

Abstract

Abstract. Extensive sampling of small mammals was conducted in eight provinces of Thailand between September 9, 1992 and April 29, 2001. A total of 3,498 specimens representing 22 species were collected. Eighty-eight percent (3,089 of 3,498) of the animals were collected from a region in Chiangrai Province, which is commonly recognized as endemic for human scrub typhus. Blood and tissue samples from each animal were tested for the presence of Orientia tsutsugamushi, the etiologic agent of scrub typhus. The predominant species collected were Rattus rattus (53%, n ‫ס‬ 1,863), R. losea (18%, n ‫ס‬ 638), Bandicota indica (16%, n ‫ס‬ 564), and R. exulans (4%, n ‫ס‬ 146). Orientia tsutsugamushi was detected in 10 of the 22 species of mammals that included R. bukit (25% infected, 1 of 4), R. rattus (23%, 419 of 1,855), R. argentiventer (22%, 5 of 23), R. berdmorei (22%, 2 of 9), R. losea (13%, 82 of 638), B. indica (

Identification of potential hosts and vectors of scrub typhus and tick-borne spotted fever group rickettsiae in eastern Taiwan

“…The chigger assemblages were composed primarily of L. imphalum. This species was also identified as the predominant chigger in northern Thailand (41%), where it infested 15 of 16 small mammal species (Coleman et al, 2003). By contrast, L. deliense was found to be the most common and widespread chigger species in Southeast Asia, the southwest Pacific islands and parts of China (Kawamura et al, 1995).…”

Rodent-borne diseases and their risks for public health

“…Several Leptospira strains are directly linked to rodents, such as L. arborea, L. copenhagi, L. icterohaemorrhagiae, L. bim, and L. ballum (Bharti et al 2003;CollaresPereira et al 1997;Collares-Pereira et al 2000). The complex taxonomy of different Leptospira species is explained in an excellent review by Barthi and collegues (Bharti et al 2003).…”

Orientia tsutsugamushi, agent of scrub typhus, displays a single metapopulation with maintenance of ancestral haplotypes throughout continental South East Asia

“…Rodents and other small mammals are suspected to be natural hosts (Coleman et al, 2003) where recombination occurs through multiple infections (Duong et al, 2013a). Trombiculid mite larvae usually acquire the pathogen vertically from the mother and after hatching, they feed on only one host without moving from host-tohost.…”