Detection and characterization of bovine torovirus from the respiratory tract in Japanese cattle

Abstract

Bovine torovirus (BToV), a member of the Coronaviridae family, is a causative agent of diarrhea in cattle, but it may also possess tropism for the respiratory tract. However, no surveys concerning with the relation between respiratory symptoms and the detection of BToV have been conducted in wide range. Among 311 nasal samples, BToV gene products were detected in seven samples (rBToV-1 to -7) derived only from calves with respiratory symptoms, suggesting that BToV may be a predisposing factor and/or causative agent for bovine respiratory disease. Regarding the degree of similarity between the spike and hemagglutinin-esterase coding regions, the rBToVs showed over 90.8% similarity with one another and 73.5-99.0% similarity with fecal tract-derived BToVs. rBToV-1, -2, and -3 were identical despite their being collected during different seasons; in comparison, rBToV-4 and -5 were distinct despite the fact that they were collected from the same herd, suggesting the existence of diversity among domestic rBToVs. One animal with a BToV-positive nasal sample also shed the virus in its feces, suggesting dual tropisms for BToV.

Whole genome analysis of Japanese bovine toroviruses reveals natural recombination between porcine and bovine toroviruses

“…3D-G). Ito et al classified Japanese BToVs using 5′ portion of S coding region into three genotypes, Clusters 1-3 (Ito et al, 2007(Ito et al, , 2009(Ito et al, , and 2010. In the phylogenetic tree, the 5′ portion of S coding region of BToVs in this study showed that BToV Ishi and BToV Tochi clustered with Cluster-1 and Cluster-2 strains, respectively, while BToV Kago and BToV Tokyo clustered with Cluster-3 strain, though enough bootstrap support could not be obtained.…”

“…ToVs are identified in various animals and humans and are thought to cause diarrheic and respiratory diseases (Duckmanton et al, 1997;Ito et al, 2009;Kroneman et al, 1998;Uziel et al, 1999;Vanopdenbosch et al, 1991;Woode et al, 1982). Berne virus (EToV Berne), the first isolated ToV, was isolated from a horse with diarrhea in 1972 in Switzerland (Weiss et al, 1983).…”

Genetic and Antigenic Characterization of Newly Isolated Bovine Toroviruses from Japanese Cattle

“…Toroviruses identified thus far have been further classified into human, bovine, porcine, and equine toroviruses on the basis of their hosts. Several studies have established associations between human and bovine toroviruses with gastrointestinal and respiratory symptoms (1,10,11,21). However, the research on toroviruses has been limited, compared to that on coronaviruses, primarily because toroviruses, with the exception of equine torovirus, are very difficult to propagate in cell culture (20).…”

“…This strain was isolated from the intestinal contents of a calf with diarrhea in 2004 using the stable cell line HRT-18, derived from a human rectal tumor (13). Although several studies on the genetic characterization of toroviruses have been published, almost all were dependent on analyses of PCR products from biomaterials (5,9,10,12,18). Thus, antigenic variation among toroviruses and relationships between their genetic and antigenic properties using cultivatable viruses in cell cultures remain to be investigated.…”

Detecção e caracterização genética de Torovírus Bovino (BToV) em amostras fecais de bovinos com diarreia proveniente de diferentes regiões brasileiras

“…(HOET et al ., 2002). No Japão, em um estudo com 311 swabs nasais, foi detectada a presença do BToV em 7 amostras, provenientes de animais com sintomas respiratórios (ITO et al, 2009 …”