Detection and characterization of group C rotaviruses in asymptomatic piglets in Ireland.
Group C rotaviruses are important human enteric pathogens that have also been detected in a variety of mammalian species, including pigs. Group C rotaviruses have been identified in piglets with diarrhea, but their ecology remains to be elucidated. By screening of 292 fecal samples collected from 4- to 5-week-old asymptomatic pigs from four herds in Ireland between 2005 and 2007, 13 (4.4%) samples tested positive by reverse transcription-PCR for group C rotavirus. Group A rotaviruses were also detected in 19 samples but not in conjunction with group C viruses. The gene encoding the major group C neutralization antigen, the outer capsid protein VP7, was sequenced. The majority of the strains were very closely related to each other (>99% amino acid [aa] identity) and were characterized as genogroup G1 since they were genetically related to the prototype porcine strain Cowden (92.6% aa identity). Conversely, two strains (1GA/05/Cork/Ire and 281/07/Dublin/Ire) were characterized as genogroup G6 since they displayed the highest identity (89.2 to 94.0% aa) to porcine G6 strains (43/06-22-like). Unexpectedly, one such G6 strain, 1GA/05/Cork/Ire, lacked the 4-aa insertion in the VP7 variable region VR8 found in all the other G6 group C rotaviruses. This study provides evidence that porcine group C rotavirus may be detected not infrequently in asymptomatic piglets. In addition, it provides evidence that, unlike the human viruses, porcine group C rotaviruses display broad genetic heterogeneity, which may pose a challenge for the development of prophylactic tools.
Collins
P J
PJ
Department of Biological Sciences, Cork Institute of Technology, Rossa Avenue, Bishopstown, Cork, Ireland.
Martella
V
V
O'Shea
H
H
D000818:Animals; D005243:Feces / Q000821:virology; D007494:Ireland; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012401:Rotavirus / Q000235:genetics; D012400:Rotavirus Infections / Q000662:veterinary* / Q000821:virology; D013552:Swine / Q000821:virology; D013553:Swine Diseases / Q000821:virology