Avian rotaviruses (AvRVs) represent a diverse group of intestinal viruses, which are suspected as the cause of several diseases in poultry with symptoms of diarrhoea, growth retardation or runting and stunting syndrome (RSS). To assess the distribution of AvRVs in chickens and turkeys, we have developed specific PCR protocols. These protocols were applied in two field studies investigating faecal samples or intestinal contents of diseased birds derived from several European countries and Bangladesh. In the first study, samples of 166 chickens and 33 turkeys collected between 2005 and 2008 were tested by PAGE and conventional RT-PCR and AvRVs were detected in 46.2%. In detail, 16.1% and 39.2% were positive for AvRVs of groups A or D, respectively. 11.1% of the samples contained both of them and only four samples (2.0%) contained rotaviruses showing a PAGE pattern typical for groups F and G. In the second study, samples from 375 chickens and 18 turkeys collected between 2009 and 2010 were analyzed using a more sensitive group A-specific and a new group D-specific real-time RT-PCR. In this survey, 85.0% were AvRV-positive, 58.8% for group A AvRVs, 65.9% for group D AvRVs and 38.9% for both of them. Although geographical differences exist, the results generally indicate a very high prevalence of group A and D rotaviruses in chicken and turkey flocks with cases of diarrhoea, growth retardation or RSS. The newly developed diagnostic tools will help to investigate the epidemiology and clinical significance of AvRV infections in poultry.

Rotaviruses are a leading cause of viral acute gastroenteritis in humans and animals. They are grouped according to gene composition and antigenicity of VP6. Whereas group A, B, and C rotaviruses are found in humans and animals, group D rotaviruses have been exclusively detected in birds. Despite their broad distribution among chickens, no nucleotide sequence data exist so far. Here, the first complete genome sequence of a group D rotavirus (strain 05V0049) is presented, which was amplified using sequence-independent amplification strategies and degenerate primers. Open reading frames encoding homologues of rotavirus proteins VP1 to VP4, VP6, VP7, and NSP1 to NSP5 were identified. Amino acid sequence identities between the group D rotavirus and the group A, B, and C rotaviruses varied between 12.3% and 51.7%, 11.0% and 23.1%, and 9.5% and 46.9%, respectively. Segment 10 of the group D rotavirus has an additional open reading frame. Generally, phylogenetic analysis indicated a common evolution of group A, C, and D rotaviruses, separate from that of group B. However, the NSP4 sequence of group C has only very low identities in comparison with cogent sequences of all other groups. The avian group A NSP1 sequences are more closely related to those of group D than those of mammalian group A rotaviruses. Most interestingly, the nucleotide sequences at the termini of the 11 genome segments are identical between group D and group A rotaviruses. Further investigations should clarify whether these conserved structures allow an exchange of genome segments between group A and group D rotaviruses.Rotaviruses are a major cause of acute gastroenteritis in young children (22,32,54,55). They are also etiological agents of diarrhea in several mammalian and avian species (7,9,10,39,52,65,75). Rotaviruses belong to the family Reoviridae and have a nonenveloped viral capsid containing a genome of 11 double-stranded RNA (dsRNA) segments (21, 62). The outer layer of the virus particle is formed by VP4 and VP7 proteins, which possess neutralization antigens. The intermediate layer consists of VP6, a conserved protein, which defines the rotavirus groups. The inner layer is formed by VP2 surrounding a complex of VP1 and VP3, which represent the RNA-dependent RNA polymerase and the guanylyl transferase, respectively (12, 60), and the viral genomic RNAs. In addition, at least five nonstructural proteins are encoded by the rotavirus genome and have diverse functions, e.g

Rotavirus groups A to E are mainly defined by antibody reactivity to the capsid protein VP6. Additionally, two putative rotavirus groups (F and G) have been identified in birds. Here, the first nucleotide sequences of the VP6-encoding genome segment of group F (strain 03V0568) and group G (strain 03V0567) rotaviruses, both derived from chickens, are presented. The group F rotavirus is most closely related to avian group A and D rotaviruses, with 49.9-52.3% nucleotide and 36.5-39.0% amino acid sequence identity. The group G rotavirus is most closely related to mammalian group B rotaviruses, with 55.3-57.5% nucleotide and 48.2-49-9% amino acid sequence identity. The terminal sequences of the genome segment were similar in groups A, D and F, and in groups B and G. The findings indicate a long-term evolution of rotavirus groups in two separated clades and support the development of a sequence-based classification system for rotavirus groups.

This paper summarizes results obtained by multiplex PCR screening of human clinical samples for respiratory viruses and corresponding data obtained after passaging of virus-positive samples in MDCK 33016PF cells. Using the ResPlexII v2.0 (Qiagen) multiplex PCR, 393 positive results were obtained in 468 clinical samples collected during an influenza season in Germany. The overall distribution of positive results was influenza A 42.0%, influenza B 38.7%, adenovirus 1.5%, bocavirus 0.5%, coronavirus 3.3%, enterovirus 5.6%, metapneumovirus 1.0%, parainfluenza virus 0.8%, rhinovirus 4.1%, and respiratory syncytial virus (RSV) 2.5%. Double infections of influenza virus together with another virus were found for adenovirus B and E, bocavirus, coronavirus, enterovirus and for rhinovirus. These other viruses were rapidly lost upon passages in MDCK 33016PF cells and under conditions as applied to influenza virus passaging. Clinical samples, in which no influenza virus but other viruses were found, were also subject to passages in MDCK 33016PF cells. Using lower inoculum dilutions than those normally applied for preparations containing influenza virus (total dilution of the original sample of ∼10(4)), the positive results for the different viruses turned negative already after 2 or 3 passages in MDCK 33016PF cells. These results demonstrate that, under practical conditions as applied to grow influenza viruses, contaminating viruses can be effectively removed by passages in MDCK cells. In combination with their superior isolation efficiency, MDCK cells appear highly suitable to be used as an alternative to embryonated eggs to isolate and propagate influenza vaccine candidate viruses.

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