We have reported a novel bovine rotavirus, the AzuK-1 (G21P [29]) strain, isolated from an asymptomatic calf. We isolated another bovine rotavirus, the Dai-10 strain, bearing new G24P [33] genotypes, assigned by the Rotavirus Classification Working Group (RCWG), from an asymptomatic cow in Hyogo Prefecture, Japan in 2007. To gain an insight into the origins and evolution of these strains, we determined the complete ORF sequences of all 11 genes of the two strains. The NSP3 genes of both strains were confirmed to belong to a new NSP3 genotype, T9, by the RCWG. Genotype determination of AzuK-1 and Dai-10 strains revealed that eight gene segments of both strains possessed genotypes typically observed in bovine rotaviruses, with the exception of VP4, VP7 and NSP3 gene segments. Unexpectedly, phylogenetic analyses showed that VP6 and NSP2 gene segments of the AzuK-1 and Dai-10 strains were clustered with those of simian or canine/feline rotaviruses, rather than with those of bovine rotaviruses. These findings indicate the possibility that both strains originated by interspecies transmission and multiple reassortment events involving bovine, simian and canine/feline rotaviruses, resulting in the introduction of some genes into the genetic background of bovine rotaviruses. INTRODUCTIONGroup A rotaviruses are the major pathogens causing acute gastroenteritis in infants and a wide range of animals, including birds. Rotavirus-induced diarrhoea is a serious public health problem worldwide, responsible for more than 600 000 child deaths each year (Parashar et al., 2006). Likewise, in domestic animals, rotavirus-induced diarrhoea is a major problem causing significant economic losses (Dhama et al., 2009;Martella et al., 2010).Rotaviruses are members of the family Reoviridae. Rotaviruses possess a genome of 11 segments of dsRNA, which encode six viral structural proteins (VP1-VP4, VP6 and VP7) and six non-structural proteins (NSP1-NSP6). Because of the segmented nature of the genome, a reassortment event can occur in cells co-infected with two or more different strains (Estes & Kapikian, 2007;Palombo, 2002;Ramig, 1997). The rotavirus virion is a triple-layered icosahedral particle. The outer capsid is composed of VP7 and VP4. They elicit neutralizing antibodies independently. In a dual classification system, rotaviruses are classified into 24 G genotypes and 32 P genotypes based on the nucleotide sequences of VP7 and VP4 genes, respectively (Collins et al., 2010; Esona et al., 2010;Matthijnssens et al., 2006Matthijnssens et al., , 2008a Schumann et al., 2009; Solberg et al., 2009;Ursu et al., 2009). Recently, a new classification system has been established using nucleotide sequences of all of the 11 genomic RNA segments by the Rotavirus Classification Working Group (RCWG) (Matthijnssens et al., 2008b). In this system, the The GenBank/EMBL/DDBJ accession numbers for the sequences reported in this paper are AB513836-AB513838 and AB573070-AB573086.Supplementary material is available with the online version of this paper. , 2...

The fixed rabies virus (RV) strain Nishigahara kills adult mice after intracerebral inoculation, whereas the chicken embryo fibroblast cell-adapted strain Ni-CE causes nonlethal infection in adult mice. We previously reported that the chimeric CE(NiP) strain, which has the phosphoprotein (P protein) gene from the Nishigahara strain in the genetic background of the Ni-CE strain, causes lethal infection in adult mice, indicating that the P gene is responsible for the different pathogenicities of the Nishigahara and Ni-CE strains. Previous studies demonstrated that RV P protein binds to the interferon (IFN)-activated transcription factor STAT1 and blocks IFN signaling by preventing its translocation to the nucleus. In this study, we examine the molecular mechanism by which RV P protein determines viral pathogenicity by comparing the IFN antagonist activities of the Nishigahara and Ni-CE P proteins. The results, obtained from both RV-infected cells and cells transfected to express P protein only, show that Ni-CE P protein is significantly impaired for its capacity to block IFN-activated STAT1 nuclear translocation and, consequently, inhibits IFN signaling less efficiently than Nishigahara P protein. Further, it was demonstrated that a defect in the nuclear export of Ni-CE P protein correlates with a defect in its ability to cause the mislocalization of STAT1. These data provide the first evidence that the capacity of the RV P protein to inhibit STAT1 nuclear translocation and IFN signaling correlates with the viral pathogenicity.The host immune response to viral infection is a key factor in defining viral pathogenicity and the outcome of the infection. This depends not only on the capacity of the host to mount an innate and/or adaptive immune response against the virus but also on the ability of the virus to evade/subvert this response (22).The principal response of host cells to viral infection is the production of type I interferons (IFNs) (including alpha interferon [IFN-␣] and IFN-␤), which, on binding to IFN receptors on the cell surface, activate the JAK/STAT intracellular signaling pathway that culminates in the phosphorylation, heterodimerization, and nuclear translocation of the transcription factors signal transducer and activator of transcription 1 (STAT1) and STAT2. In the context of a complex called IFNstimulated gene factor 3 (ISGF3), the activated STATs bind to promoters in the DNA that contain an IFN-stimulated response element (ISRE) sequence, resulting in the transcription of a plethora of IFN-stimulated genes (ISGs) encoding antiviral proteins which act to establish the antiviral state in cells (reviewed in reference 22).To propagate efficiently in host cells, viruses have had to evolve multiple strategies to dampen the host IFN system, which appear to involve the expression of viral proteins with IFN antagonist functions. These IFN antagonists are reported to exert their effect by a variety of mechanisms, reflecting the diversity of host antiviral responses, but the STATs are known as common targ...

The rabies virus Ni-CE strain causes nonlethal infection in adult mice after intracerebral inoculation, whereas the parental Nishigahara (Ni) strain kills mice. We previously reported that the chimeric CE(NiN) strain with the N gene from the Ni strain in the genetic background of the Ni-CE strain kills adult mice, indicating that the N gene is related to the different pathogenicities of Ni and Ni-CE strains. In the present study, to obtain an insight into the mechanism by which the N gene determines viral pathogenicity, we compared the effects of Ni, Ni-CE, and CE(NiN) infections on host gene expressions using a human neuroblastoma cell line. Microarray analysis of these infected cells revealed that the expression levels of particular genes in Ni-and CE(NiN)-infected cells, including beta interferon (IFN-␤) and chemokine genes (i.e., CXCL10 and CCL5) were lower than those in Ni-CE-infected cells. We also demonstrated that Ni-CE infection activated the interferon regulatory factor 3 (IRF-3)-dependent IFN-␤ promoter and induced IRF-3 nuclear translocation more efficiently than did Ni or CE(NiN) infection. Furthermore, we showed that Ni-CE infection, but not Ni or CE(NiN) infection, strongly activates the IRF-3 pathway through activation of RIG-I, which is known as a cellular sensor of virus infection. These findings indicate that the N protein of rabies virus (Ni strain) has a function to evade the activation of RIG-I. To our knowledge, this is the first report that the Mononegavirales N protein functions to evade induction of host IFN and chemokines.Rabies virus, which belongs to Lyssavirus of the family Rhabdoviridae, which belongs to the order Mononegavirales, is known as a highly neurotropic virus and causes fatal encephalitis accompanied by severe neurological symptoms in almost all mammals, including humans. The genome is an unsegmented negative sense RNA and contains five genes (N, P, M, G, and L genes) encoding nucleoprotein (N protein), phosphoprotein (P protein), matrix (M) protein, glycoprotein (G protein), and large (L) protein, respectively (12). The N, P, and L proteins form helical ribonucleoprotein (RNP), together with the viral genomic RNA. The N protein participates in encapsidation of the genomic RNA. Only the encapsidated genomic RNA can be a template for replication of the viral genome and transcription of the viral mRNAs by the RNAdependent RNA polymerase, L protein. The P protein binds to both N and L proteins and functions as a cofactor of the viral RNA polymerase. During virus assembly, the RNP is wrapped into an envelope containing an inner layer of the M protein and the transmembrane spike protein, G protein.In response to viral infection (e.g., picornavirus, bunyavirus, and flavivirus infections), neurons in the brain produce type I interferon (IFN) comprised of the IFN-␣ family and IFN-␤, which induces an antiviral status of a cell and functions as a main player for the host innate immunity (8, 9). The brain neurons are also capable of responding to the produced type I

BackgroundInfections with Babesia bovis, Babesia bigemina, Theileria species and Anaplasma marginale are endemic in Kenya yet there is a lack of adequate information on their genotypes. This study established the genetic diversities of the above tick-borne hemoparasites infecting cattle in Kenya.MethodsNested PCR and sequencing were used to determine the prevalence and genetic diversity of the above parasites in 192 cattle blood samples collected from Ngong and Machakos farms. B. bovis spherical body protein 4, B. bigemina rhoptry-associated protein 1a, A. marginale major surface protein 5, Theileria spp. 18S rRNA, T. parva p104 and T. orientalis major piroplasm surface protein were used as the marker genes.ResultsB. bovis, B. bigemina, T. parva, T. velifera, T. taurotragi, T. mutans and A. marginale were prevalent in both farms, whereas T. ovis, Theileria sp. (buffalo) and T. orientalis were found only in Ngong farm. Co-infections were observed in more than 50 % of positive samples in both farms. Babesia parasites and A. marginale sequences were highly conserved while T. parva and T. orientalis were polymorphic. Cattle-derived T. parva was detected in Machakos farm. However, cattle and buffalo–derived Theileria were detected in Ngong farm suggesting interactions between cattle and wild buffaloes. Generally, the pathogens detected in Kenya were genetically related to the other African isolates but different from the isolates in other continents.ConclusionsThe current findings reaffirm the endemicity and co-infection of cattle with tick-borne hemoparasites, and the role of wildlife in pathogens transmission and population genetics in Kenya.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-1106-9) contains supplementary material, which is available to authorized users.

e Rabies virus (RABV), which is transmitted via a bite wound caused by a rabid animal, infects peripheral nerves and then spreads to the central nervous system (CNS) before causing severe neurological symptoms and death in the infected individual. Despite the importance of this ability of the virus to spread from a peripheral site to the CNS (neuroinvasiveness) in the pathogenesis of rabies, little is known about the mechanism underlying the neuroinvasiveness of RABV. In this study, to obtain insights into the mechanism, we conducted comparative analysis of two fixed RABV strains, Nishigahara and the derivative strain Ni-CE, which cause lethal and asymptomatic infections, respectively, in mice after intramuscular inoculation. Examination of a series of chimeric viruses harboring the respective genes from Nishigahara in the genetic background of Ni-CE revealed that the Nishigahara phosphoprotein (P) gene plays a major role in the neuroinvasiveness by mediating infection of peripheral nerves. The results obtained from both in vivo and in vitro experiments strongly suggested that the Nishigahara P gene, but not the Ni-CE P gene, is important for stable viral replication in muscle cells. Further investigation based on the previous finding that RABV phosphoprotein counteracts the host interferon (IFN) system demonstrated that the Nishigahara P gene, but not the Ni-CE P gene, functions to suppress expression of the beta interferon (IFN-␤) gene (Ifn-␤) and IFN-stimulated genes in muscle cells. In conclusion, we provide the first data strongly suggesting that RABV phosphoprotein assists viral replication in muscle cells by counteracting the host IFN system and, consequently, enhances infection of peripheral nerves. R abies virus (RABV), a member of the genus Lyssavirus of the family Rhabdoviridae, infects almost all kinds of mammals, including humans, and causes a severe neurological disease with a high mortality rate of about 100% after a long and inconstant incubation period (usually 20 to 90 days in humans) (reviewed in reference 1). It is estimated that more than 55,000 people die of rabies every year, mainly in Asia and Africa (2), due to the absence of an effective cure and also the complexity and expensiveness of current postexposure prophylaxis, which requires medical treatment (i.e., rabies vaccination) five times over a period of 28 days. In order to develop both therapeutic and novel prophylaxis approaches for rabies, it is necessary to fully understand the pathogenesis of rabies.The pathogenesis of rabies essentially relies on viral spread to and in the nervous system of the infected individual (reviewed in reference 1). RABV secreted into saliva of a rabid animal is generally transmitted via a bite wound caused by the infected animal. After transmission, RABV infects peripheral nerves and then spreads to the central nervous system (CNS) via retrograde axonal transport, followed by active viral replication and spread in the CNS, culminating in severe neurological symptoms and lethal outcome. To date, studies...