This Article Full Text Full Text (PDF) Other Versions of this Article: CVI.00475-06v1 14/8/998    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kuwabara, M. Articles by Tsunemitsu, H. Search for Related Content PubMed PubMed Citation Articles by Kuwabara, M. Articles by Tsunemitsu, H.

 Previous Article  |  Next Article 

Clinical and Vaccine Immunology, August 2007, p. 998-1004, Vol. 14, No. 8
1071-412X/07/$08.00+0     doi:10.1128/CVI.00475-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

First Isolation of Cytopathogenic Bovine Torovirus in Cell Culture from a Calf with Diarrhea

Nishimikawa Livestock Hygiene Service Center, Zizouno 1-306, Miai, Okazaki, Aichi 4440805,¹ Viral Diseases Research Team, National Institute of Animal Health, Kannondai 3-1-5, Tsukuba, Ibaraki 3050856, Japan²

Received 14 December 2006/ Returned for modification 21 February 2007/ Accepted 15 May 2007

A cytopathogenic virus (designated the Aichi/2004 strain) was isolated in a human rectal adenocarcinoma cell line (HRT-18) from the ileum contents of a calf with diarrhea. Oval and elongated particles, approximately 100 to 170 nm in diameter, with club-shaped projections were seen in the infected culture supernatant, and torovirus-like (tubular and torus nucleocapsid) structures were seen in the infected cells by electron microscopy. An antiserum against bovine torovirus (BToV) reacted with the infected cells by immunofluorescence and neutralized the isolate. However, antisera against bovine coronavirus (BCV) failed to react with the infected cells by immunofluorescence or did not neutralize the isolate. Further, the isolate was positive for BToV by reverse transcription-PCR (RT-PCR) targeting fragments of the nucleocapsid (N), membrane (M), and spike (S) genes. Comparison of the nucleotide sequences of the PCR products with those of the published N, M, and S genes (476 to 497, 672, and 687 to 690 nucleotides, respectively) of toroviruses showed high sequence identities (up to 99.4%, 98.7%, and 94.9% for the N, M, and S genes, respectively) between the isolate and BToVs. In contrast, the isolate was negative for BCV by RT-PCR. In a serological survey of serum samples from 355 calves at 33 farms, 92% of calves were positive for neutralizing antibodies to the isolate. These results indicate that the isolate in this study was BToV and that BToV infection might be common in cattle in Japan. To our knowledge, this is the first isolation of BToV in tissue culture.

Published ahead of print on 13 June 2007.