| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210
3 Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210
2 Miyazaki Prefectural Public Health Laboratory, Miyazaki, Japan
* Corresponding author. Mailing address: Department of Veterinary Biosciences, College of Veterinary Medicine, 1925 Coffey Rd., Columbus, OH 43210-1093. Phone: (614) 292-9677. Fax: (614) 292-6473.
ABSTRACT
The organism designated the SF agent was originally isolated in Japan in 1962 from Stellantchasmus falcatus metacercaria parasitic on gray mullet fish. The SF agent resembles members of the genus Ehrlichia morphologically and exhibits weak antigenic cross-reactivity with Ehrlichia sennetsu. This organism causes mild clinical signs in dogs, but severe splenomegaly and lymphadenopathy in mice. This suggests that the SF agent may be similar to either Neorickettsia helminthoeca, an intracellular parasite of a fluke and the cause of salmon poisoning disease in dogs, or E. sennetsu, the causative agent of human sennetsu ehrlichiosis in Japan and Malaysia. In order to determine the phylogenetic relationship between the SF agent and other ehrlichial species, the 16S rRNA gene was amplified by the PCR and sequenced. The SF agent sequence was most closely related to the sequences of Ehrlichia risticii (level of sequence similarity, 99.1%), the causative agent of Potomac horse fever, and E. sennetsu (level of sequence similarity, 98.7%). The next most similar sequence was that of N. helminthoeca, but the level of sequence similarity was only 93.7%. E. sennetsu, E. risticii, the SF agent, and N. helminthoeca formed a distinct cluster that was separated from all other ehrlichial species. As determined by immunofluorescence labeling, antiserum against the SF agent cross-reacted strongly with E. sennetsu, E. risticii, and N. helminthoeca. When three genetically distinct ehrlichial isolates obtained from horses with Potomac horse fever were compared with the SF agent, we found that the SF agent was most closely related to Ohio isolate 081, followed by IllinoisT (T = type strain) and a Kentucky isolate. We observed strong antigenic cross-reactivities and similarities in Western blot (immunoblot) reaction profiles when we compared the SF agent, E. risticii, and E. sennetsu; however, weaker antigenic cross-reactivity was observed when the SF agent and N. helminthoeca were compared. Our results indicate that the SF agent is antigenically more closely related to E. risticii and E. sennetsu than to N. helminthoeca. The biological and antigenic characteristics and the 16S rRNA sequence data suggest that the SF agent is a new species that belongs to the genus Ehrlichia.
This article has been cited by other articles:
|
|
 |
|
  P. N. Newton, J.-M. Rolain, B. Rasachak, M. Mayxay, K. Vathanatham, P. Seng, R. Phetsouvanh, T. Thammavong, J. Zahidi, Y. Suputtamongkol, et al. Sennetsu Neorickettsiosis: A Probable Fish-Borne Cause of Fever Rediscovered in Laos Am J Trop Med Hyg, August 1, 2009; 81(2): 190 - 194. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Rikihisa, C. Zhang, M. Kanter, Z. Cheng, N. Ohashi, and T. Fukuda Analysis of p51, groESL, and the Major Antigen P51 in Various Species of Neorickettsia, an Obligatory Intracellular Bacterium That Infects Trematodes and Mammals J. Clin. Microbiol., August 1, 2004; 42(8): 3823 - 3826. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Wen, R. Jian, Y. Zhang, and R. Chen Simultaneous Detection of Anaplasma marginale and a New Ehrlichia Species Closely Related to Ehrlichia chaffeensis by Sequence Analyses of 16S Ribosomal DNA in Boophilus microplus Ticks from Tibet J. Clin. Microbiol., September 1, 2002; 40(9): 3286 - 3290. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Kanter, J. Mott, N. Ohashi, B. Fried, S. Reed, Y. C. Lin, and Y. Rikihisa Analysis of 16S rRNA and 51-Kilodalton Antigen Gene and Transmission in Mice of Ehrlichia risticii in Virgulate Trematodes from Elimia livescens Snails in Ohio J. Clin. Microbiol., September 1, 2000; 38(9): 3349 - 3358. [Abstract] [Full Text]
|
|
|
|
|
|
S.-i. Shibata, M. Kawahara, Y. Rikihisa, H. Fujita, Y. Watanabe, C. Suto, and T. Ito New Ehrlichia Species Closely Related to Ehrlichia chaffeensis Isolated from Ixodes ovatus Ticks in Japan J. Clin. Microbiol., April 1, 2000; 38(4): 1331 - 1338. [Abstract] [Full Text]
|
|
|
|
|
|
M. Kawahara, T. Ito, C. Suto, S. Shibata, Y. Rikihisa, K. Hata, and K. Hirai Comparison of Ehrlichia muris Strains Isolated from Wild Mice and Ticks and Serologic Survey of Humans and Animals with E. muris as Antigen J. Clin. Microbiol., April 1, 1999; 37(4): 1123 - 1129. [Abstract] [Full Text]
|
|
|
|
 |
|
 J. E. Barlough, G. H. Reubel, J. E. Madigan, L. K. Vredevoe, P. E. Miller, and Y. Rikihisa Detection of Ehrlichia risticii, the Agent of Potomac Horse Fever, in Freshwater Stream Snails (Pleuroceridae: Juga spp.) from Northern California Appl. Envir. Microbiol., August 1, 1998; 64(8): 2888 - 2893. [Abstract] [Full Text]
|
|
|
|
|
|
G. H. Reubel, J. E. Barlough, and J. E. Madigan Production and Characterization of Ehrlichia risticii, the Agent of Potomac Horse Fever, from Snails (Pleuroceridae: Juga spp.) in Aquarium Culture and Genetic Comparison to Equine Strains J. Clin. Microbiol., June 1, 1998; 36(6): 1501 - 1511. [Abstract] [Full Text]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
