Detection of a coronavirus from turkey poults in Europe genetically related to infectious bronchitis virus of chickens

Abstract

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.

Isolation of avian infectious bronchitis coronavirus from domestic peafowl (Pavo cristatus) and teal (Anas)

“…The gene order of IBV is 59-replicase-S-3-M-5-N-39 UTR. We have established in this study that both pf/CH/LKQ3/03 and tl/CH/LDT3/03 have the same S-3-M-5-N gene order (the replicase and 39 UTR sequences were not determined in this study), as is the case for coronaviruses from turkeys (Breslin et al, 1999a, b;Cavanagh et al, 2001) and pheasant (Cavanagh et al, 2002). Consequently, the coronaviruses from domestic peafowl and teal are related closely to avian coronaviruses that are in group 3, and are distinct from mammalian coronaviruses that are in groups 1 and 2 (Lai & Cavanagh, 1997 tl/CH/LDT3/03, in contrast to pf/CH/LKQ3/03, was more similar to field IBV isolates from China than to the vaccine strains.…”

“…Sequence analysis of these clones revealed that both newly isolated avian coronaviruses had the S-3-M-5-N gene order that is typical of group 3 coronaviruses from chicken (IBV) (Boursnell et al, 1987), turkey (Breslin et al, 1999a;Cavanagh et al, 2001;Lin et al, 2002) and pheasant (Cavanagh et al, 2002).…”

“…The M genes of pf/CH/LKQ3/03 and tl/CH/LDT3/03 encoded a predicted protein of 226 aa, equivalent in size to the homologous protein of most IBV strains (Boursnell et al, 1987;Cavanagh et al, 2001). Although only limited IBV M gene sequences were available for comparison, Gene 5 of pf/CH/LKQ3/03 contained two ORFs, 5a and 5b, which were 198 and 249 nt long, respectively.…”

Enteric viruses in turkey flocks: a historic review

“…Then, differences between the nucleotide sequence of the S3 (Kapczynski et al, 2002) and S2 genes (Sellers et al, 2004) from turkeys, when compared with chicken and duck isolates were demonstrating, suggesting their classification in a different subgroup, the Orthoreovirus genus. Breslin et al (1999) and Cavanagh et al (2001) showed close genetic relationship between TCoV and infectious bronchitis virus, and Guy (2000) suggested a classification in the group 3 coronavirus, as confirmed by Gomaa et al (2008) by the analysis of the complete genome of TCoV . Imada et al (2000) sequenced the avian nephritis virus, which was classified as a member of the family Astroviridae, and this the first avian astrovirus which genome was completely sequenced, showing close similarity to the turkey astrovirus.…”

Sequence of the 3′-terminal end (8·1 kb) of the genome of porcine haemagglutinating encephalomyelitis virus: comparison with other haemagglutinating coronaviruses

“…Recent data from the USA and the UK indicate that coronaviruses associated with acute enteritis in turkey poults are genetically related to infectious bronchitis virus (IBV) of chicken and not to BCoV (Breslin et al, 1999;Cavanagh et al, 2001;Ismail et al, 2002;Loa et al, 2000), contrary to Canadian and US isolates characterized in the early 1990s (Dea et al, 1990 ;Verbeek & Tijssen, 1991) and even until very recently (Lin et al, 2002). In addition to the four structural proteins of all coronaviruses -N (nucleophosphoprotein, 50-60 kDa), M (matrix glycoprotein, 20-26 kDa), E (small membrane protein, 9n5 kDa) and S (peplomeric glycoprotein, 180-200 kDa) -coronaviruses of the second subgroup (haemagglutinating coronaviruses) also possess a 140 kDa envelope-associated glycoprotein, the haemagglutinin-esterase (HE), which is made of two 65 kDa subunits linked together by disulfide bonds (Dea & Tijssen, 1989 ;Hogue & Brian, 1986 ;King et al, 1985).…”