Reverse-transcriptase polymerase chain reactions (RT-PCRs) were used to examine RNA extracted from mouth/nasal swabs from pheasants exhibiting signs of respiratory disease. The oligonucleotides used were based on sequences of infectious bronchitis virus (IBV), the coronavirus of domestic fowl. A RT-PCR for the highly conserved region II of the 3' untranslated region of the IBV genome detected a coronavirus in swabs from 18/21 estates. Sequence identity with the corresponding region of IBVs and coronaviruses from turkeys was > 95%. A RT-PCR for part of the S1 region of the spike protein gene was positive with 13/21 of the samples. Sequence analysis of the RT-PCR products derived from nine of the pheasant viruses revealed that some of the viruses differed from each other by approximately 24%, similar to the degree of difference exhibited by different serotypes of IBV. Further analysis of the genome of one of the viruses revealed that it contained genes 3 and 5 that are typical of IBV but absent in both the transmissible gastroenteritis virus and murine hepatitis virus groups of mammalian coronaviruses. The nucleotide sequences of genes 3 and 5 of the pheasant virus had a similar degree of identity (approximately 90%) with those of coronaviruses from turkeys and chickens, as is observed when different serotypes of IBV are compared. This work: (a) confirms that coronaviruses are present in pheasants (indeed, commonly present in pheasants with respiratory disease); (b) demonstrates that their genomes are IBV-like in their organization; and (c) shows that there is sequence heterogeneity within the group of pheasant coronaviruses, especially within the spike protein gene. Furthermore, the gene sequences of the pheasant viruses differed from those of IBV to similar extents as the sequence of one serotype of IBV differs from another. On the genetic evidence to date, there is a remarkably high degree of genetic similarity between the coronaviruses of chickens, turkeys and pheasants.

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Eighteen isolates of infectious bronchitis virus (IBV) from

Intestinal contents of 13-day-old turkey poults in Great Britain were analysed as the birds showed stunting, unevenness and lameness, with 4% mortality. At post mortem examination, the main gross features were fluid caecal and intestinal contents. Histological examination of tissues was largely unremarkable, apart from some sections that showed crypt dilation and flattened epithelia. Negative contrast electron microscopy of caecal contents revealed virus particles, which in size and morphology had the appearance of a coronavirus. RNA was extracted (turkey/UK/412/00) and used in a number of reverse transcription-polymerase chain reactions (RT-PCRs) with the oligonucleotides based on sequences derived from avian infectious bronchitis virus (IBV), a coronavirus of domestic fowl. The RT-PCRs confirmed that turkey/UK/412/00 was a coronavirus and, moreover, showed that it had the same partial gene order (S-E-M-5-N-3' untranslated region) as IBV. This gene order is unlike that of any known mammalian coronavirus, which does not have a gene analogous to the gene 5 of IBV.The gene 5 of the turkey virus had two open reading frames, 5a and 5b, as in IBV and the coronaviruses isolated from turkeys in North America. The turkey/UK/412/00 also resembled IBV, but not mammalian coronaviruses, in having three open reading frames in the gene encoding E protein (gene 3). The percentage differences between the nucleotide sequences of genes 3 and 5 and the 3' untranslated region of turkey/UK/412/00 when compared with those of IBVs were similar to the differences observed when different strains of IBV were compared with each other. No sequences unique to the turkey isolates were identified. These results demonstrate, for the first time, that a coronavirus was associated with disease in turkeys outside of North America and that it is a Group 3 coronavirus, like IBV.