We report the sequence and phylogenetic analysis of the entire M1, M2, and M3 genome segments of the novel duck reovirus (NDRV) NP03. Alignment between the newly determined nucleotide sequences as well as their deduced amino acid sequences and the published sequences of avian reovirus (ARV) was carried out with DNASTAR software. Sequence comparison showed that the M2 gene had the most variability among the M-class genes of DRV. Phylogenetic analysis of the M-class genes of ARV strains revealed different lineages and clusters within DRVs. The 5 NDRV strains used in this study fall into a well-supported lineage that includes chicken ARV strains, whereas Muscovy DRV (MDRV) strains are separate from NDRV strains and form a distinct genetic lineage in the M2 gene tree. However, the MDRV and NDRV strains are closely related and located in a common lineage in the M1 and M3 gene trees, respectively.

Circulating monocytes and tissue macrophages were suggested to be susceptible to avian reovirus (ARV) infection. To determine if ARV infects and replicates in mononuclear phagocytes (KUL01-positive cells), we infected 3-day-old specific-pathogen-free chickens with ARV strain 2408 by inoculation of the left footpad. The left footpads and spleens were collected for analysis at 1.5 and 2.5 d after inoculation. Replication of ARV in the footpad and spleen was demonstrated by detection of the viral protein σNS using immunohistochemical testing and viral S1 RNA expression by real-time quantitative polymerase chain reaction (qPCR). Furthermore, immunofluorescent double-staining assay of cytocentrifuged cells and cryosections of the footpad and spleen for the viral protein σNS and the surface marker recognized by monoclonal antibody (MAb) KUL01 indicated that KUL01-positive cells costained with MAb H1E1, which recognizes ARV protein σNS. In addition, more ARV S1 RNA was measured by qPCR in the KUL01-positive cell samples prepared from the footpad or spleen 1.5 d after inoculation compared with non-KUL01-positive cell samples. The amounts of ARV S1 RNA in the spleen were significantly lower (P < 0.05) than the amounts in the footpad 1.5 d after inoculation. The results suggest that ARV infects mononuclear phagocytes and then replicates within these cells before migrating to the spleen, where it infects and replicates in KUL01-positive cells.

T-cell-mediated and humoral immune responses were measured in chickens infected with standard and variant strains of infectious bursal disease virus. One-day-old and 3-week-old chickens were infected with these viruses and then given sheep RBC, killed Brucella abortus strain 19, and Newcastle disease virus. Appropriate serologic tests were used to monitor the primary and secondary responses to the antigens. Lymphoblast transformation assays were performed weekly. The response to the infectious bursal disease virus was determined by virus neutralization tests, microscopic examination of bursas, and bursal to body weight ratios. One-day-old chickens had T-cell-mediated and humoral immune suppression with both strains of virus, compared with controls. The lymphoblast transformation responses indicated that the variant strain was significantly (P < 0.05) more suppressive than the standard strain. Three-week-old chickens had humoral immune suppression with the standard strain, but not with the variant strain. The lymphoblast transformation response was transiently suppressed at this age by the variant strain only. During the first week of infection, 1-day-old and 3-week-old chickens had lower neutralizing antibody titers to the variant strain than to the standard strain.

The double-stranded RNA genome from 117 field isolates of bluetongue virus (BTV) serotypes 10, 11, 13, and 17 was blotted onto nitrocellulose paper and hybridized with a radioactively labeled cloned copy of DNA genome segment 2 of BTV-17. Viral RNA from BTV prototype strains 2, 10, 11, 13, and 17 were used as controls. The probe hybridized only with the viral RNA from prototype BTV-17 virus and field isolates of BTV-17. There was no cross hybridization with field isolates of BTV serotypes 10, 11, and 13. A complementary DNA probe developed from genes coding for BTV serotype specificity was effectively used in a slot-blot hybridization system for efficiently characterizing the viral serotype.

Blood samples were obtained from sentinel beef cattle at monthly intervals, and the sera were tested for antibodies, using a bluetongue virus (BTV) immuodiffusion test (IDT) and virus-neutralization test (VNT), for 5 BTV serotypes (2, 10, 11, 13, and 17) and 2 epizootic hemorrhagic disease virus (EHDV) serotypes (1 and 2). The cattle tested were transported from Tennessee to Texas in 1984 and 1985. All cattle were seronegative by the BTV IDT at the initial bleeding in Texas in 1984 and 1985. In 1984, 16 of 40 (40%) cattle seroconvertedas assessed by results of the BTV IDT. In 16 seropositive cattle in 1984, neutralizing antibodies were detected to BTV serotypes 10 (n = 7), 11 (n = 3), and 17 (n = 11), and EHDV serotypes 1 (n = 1) and 2 (n = 7). In 1984, no cattle seroconverted to BTV-2 or BTV-13. In 1985, 10 of 36 (27.8%) cattle seroconverted as assessed by results of the IDT. Of the 10 seropositive cattle in 1985, neutralizing antibodies were detected to BTV serotypes 10 (n = 10), 11 (n = 10), 13 (n = 7), and 17 (n = 5), and EHDV serotypes 1 (n = 1) and 2 (n = 7). In 1985, no catttle seroconverted to BTV-2. Clinical diseases attributable to BTV or EHDV was not detected in these cattle in 1984 or 1985.

Three independent 1-year studies were conducted during 3 consecutive years to better define the prevalence of bluetongue virus (BTV) infection in Mexico. Serologic data were obtained by use of agar-gel immunodiffusion for identification of BTV group-reactive antibodies, and virologic data were obtained by virus isolation. Samples were obtained from sheep in 6 states over a 1-year period, with 9% seropositive; samples were obtained from cattle in 11 states during the same 1-year period, with 35% seropositive. Two years later, samples were obtained from cattle in 4 additional states, with 69% seropositive. Virus isolation was conducted on pooled blood samples obtained from cattle in 7 states. Six virus isolates were recovered and included 2 isolates each of BTV serotypes 11 and 13 and 1 isolated each of serotypes 10 and 17. All virus isolates were partially characterized by electrophoretic analysis of genomic RNA migration profiles (electropherotypes) in polyacrylamide gels. All Mexican isolates of BTV differed considerably in electropherotype profile, as compared with their respective US prototype strain of the same serotype. Such differences appeared to be much more extensive than those described to exist between numerous California isolates of the same serotype.

Epizootic hemorrhagic disease virus was isolated from cattle and sheep in northeastern Colorado during July and August 1984. The isolates were identified as serotype 2 by plaque-inhibition serotyping, genome electropherotyping, and protein analysis.

This paper describes articular lesions induced by inoculation of one-day-old broiler chicks with an avian reovirus strain (S-1133) by oral and foodpad routes. The hock joint of five birds from inoculated and control groups were collected in the periods of 24, 48, 72 hours and at weekly intervals from 1 to 8 weeks post inoculation for histopathological examination. The first inflammatory changes were seen in tendon sheaths one week post inoculation. On the second week postinoculation there were fibroplasia, formation of lymphoid follicles and sinovial membrane cells hyperplasia, progressive lesions seen until the end of experiment. The articular lesions were similar occurring simultaneously in both inoculated groups, nevertheless the lesions were more severe in the group inoculated via footpad. | Este trabalho descreve as lesões articulares induzidas pela inoculação oral e podal de uma amostra de reovírus aviário (S-1133) em pintos de corte de um dia de idade. Realizou-se o exame histopatológico de fragmentos da articulação tibiotársica utilizando-se cinco aves dos grupos inoculados e grupo controle nos períodos de 24, 48, 72 horas e semanalmente até a oitava semana após a inoculação. A primeira alteração observada foi um infiltrado inflamatório misto nas bainhas tendinosas uma semana após a inoculação. Na segunda semana após a inoculação, houve fibroplasia, formação de folículos linfóides e hiperplasia das células da membrana sinovial, alterações progressivas observadas até o final do período experimental. As lesões articulares foram similares, ocorrendo simultaneamente nos dois grupos inoculados, contudo as alterações foram mais severas no grupo inoculado no coxim plantar.