title: Prevalence and Phylogenetic Analysis of Orientia tsutsugamushi in Small Mammals in Hanoi, Vietnam.
abstract: Rodents are important reservoirs of many human pathogens transmitted via arthropod vectors. Arthropod-borne bacteria belonging to the family Rickettsiaceae cause acute febrile diseases in humans worldwide, but the real burdens of rickettsial diseases appear to be underestimated in Hanoi, Vietnam, because differential diagnosis on the basis of clinical signs and symptoms is confounded by the presence of other tropical infectious diseases with similar signs and symptoms. To know the prevalence of bacteria of the family Rickettsiaceae among small mammals in Hanoi, 519 animals thriving in the public places were captured and examined for the presence of bacterial sequences using duplex PCR. Nucleotide sequences specific for Orientia tsutsugamushi were detected in seven samples (1.3%). Out of seven animals, two were captured in a market, whereas five were in hospitals. None of the captured small mammals tested positive for the genus Rickettsia. The nucleotide sequence analysis of the genes encoding the 47-kDa high-temperature requirement A (47-kDa HtrA) and 56-kDa type-specific antigen (TSA) showed that these seven isolates were indistinguishable from each other. O. tsutsugamushi isolated in this study was closely related phylogenetically to the Gilliam strain, which was originally isolated at the border of Assam and Burma, rather than to those isolated in the central to southern part of Vietnam. It should be emphasized that Vietnamese hospitals were heavily infested by small rodents and some of them harbored O. tsutsugamushi. Strict hygienic control should be implemented to mitigate the potential risk posed by O. tsutsugamushi in hospital settings.
authors.affiliation: 1 Graduate School of Agricultural and Life Sciences, University of Tokyo , Tokyo, Japan .
authors.forename: Kozue
authors.initials: K
authors.lastname: Hotta
authors.affiliation: 2 National Institute of Hygiene and Epidemiology , Hanoi, Vietnam .
authors.forename: Hang T T
authors.initials: HT
authors.lastname: Pham
authors.affiliation: 2 National Institute of Hygiene and Epidemiology , Hanoi, Vietnam .
authors.forename: Huong T
authors.initials: HT
authors.lastname: Hoang
authors.affiliation: 2 National Institute of Hygiene and Epidemiology , Hanoi, Vietnam .
authors.forename: Tu C
authors.initials: TC
authors.lastname: Trang
authors.affiliation: 2 National Institute of Hygiene and Epidemiology , Hanoi, Vietnam .
authors.forename: Thuy N
authors.initials: TN
authors.lastname: Vu
authors.affiliation: 3 Vietnam Research Station, Nagasaki University , c/o National Institute of Hygiene and Epidemiology, Hanoi, Vietnam .
authors.forename: Trang T H
authors.initials: TT
authors.lastname: Ung
authors.affiliation: 4 Graduate School of Medicine, Hokkiado University , Hokkaido, Japan .
authors.forename: Kenta
authors.initials: K
authors.lastname: Shimizu
authors.affiliation: 4 Graduate School of Medicine, Hokkiado University , Hokkaido, Japan .
authors.forename: Jiro
authors.initials: J
authors.lastname: Arikawa
authors.affiliation: 1 Graduate School of Agricultural and Life Sciences, University of Tokyo , Tokyo, Japan .
authors.forename: Akio
authors.initials: A
authors.lastname: Yamada
authors.affiliation: 2 National Institute of Hygiene and Epidemiology , Hanoi, Vietnam .
authors.forename: Hoa T
authors.initials: HT
authors.lastname: Nguyen
authors.affiliation: 2 National Institute of Hygiene and Epidemiology , Hanoi, Vietnam .
authors.forename: Hang L K
authors.initials: HL
authors.lastname: Nguyen
authors.affiliation: 2 National Institute of Hygiene and Epidemiology , Hanoi, Vietnam .
authors.forename: Mai T Q
authors.initials: MT
authors.lastname: Le
authors.affiliation: 5 Institute of Tropical Medicine, Nagasaki University , Nagasaki, Japan .
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hayasaka
mesh_terms: D000818:Animals; D004199:Disease Vectors; D006786:Hospitals, Urban; D012285:Orientia tsutsugamushi / Q000235:genetics / Q000302:isolation & purification*; D010802:Phylogeny; D015995:Prevalence; D012377:Rodentia / Q000382:microbiology*; D012612:Scrub Typhus / Q000453:epidemiology / Q000662:veterinary; D012788:Shrews / Q000382:microbiology*; D014744:Vietnam / Q000453:epidemiology
keywords: Orientia tsutsugamushi; Rodents; Vietnam; Zoonosis