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2 results on '"Alexander, Hazel"'

1. The emergence of a new strain of porcine circovirus-2 in Ontario and Quebec swine and its association with severe porcine circovirus associated disease — 2004–2006

Author

Carman, Susy, Cai, Hugh Y., DeLay, Josepha, A.Youssef, Sameh, McEwen, Beverly J., Gagnon, Carl A., Tremblay, Donald, Hazlett, Murray, Lusis, Peter, Fairles, Jim, Alexander, Hazel S., and van Dreumel, Tony

Subjects
Circovirus, Male, Ontario, Swine Diseases, Virulence, Swine, Molecular Sequence Data, Quebec, Genetic Variation, Articles, Sequence Analysis, DNA, Viral Load, Immunohistochemistry, Severity of Illness Index, Disease Outbreaks, Animals, Female, Circoviridae Infections, Phylogeny, Polymorphism, Restriction Fragment Length
Abstract

In the late fall of 2004 more severe lesions of porcine circovirus-2 associated disease (PCVAD) than usual occurred during an outbreak of porcine circovirus-2 (PCV-2) infection in Ontario nursery and grower/finisher pigs. The lesions were of unprecedented severity and included diffuse bronchointerstitial pneumonia, granulomatous enteritis, vasculitis, interstitial nephritis, and new lesions of splenic infarction. Some affected herds had up to 50% mortality. The outbreak correlated with the sudden emergence of a variant PCV-2, with PCR restriction fragment length polymorphism (RFLP) type 321. Phylogenetic comparison of ORF2 sequences and full genome sequences showed the new variant to be different from the previously dominant RFLP type 422 viruses, and similar to viruses that had occurred in France and other European and Asian countries. A subsequent retrospective study showed a statistically significant increase in the frequency of histological lesions in lymph node, spleen, lung, small intestine, colon and kidney, for pigs spontaneously infected with RFLP type 321, compared with the older RFLP type 422 strain. Viral burden, based on IHC staining in lymph node, also showed a statistically significant increase in pigs infected with the newer variant RFLP type 321, compared with the older RFLP type 422 strain. This enhanced virulence in pigs infected with PCV-2 RFLP type 321 strain may be related to the genetic differences in this new strain of PCV-2. This virus is now the dominant strain of PCV-2 virus found in Ontario and Quebec swine.

Published
2008

2. The emergence of a new strain of porcine circovirus-2 in Ontario and Quebec swine and its association with severe porcine circovirus associated disease--2004-2006.

Author

Carman S, Cai HY, DeLay J, Youssef SA, McEwen BJ, Gagnon CA, Tremblay D, Hazlett M, Lusis P, Fairles J, Alexander HS, and van Dreumel T

Subjects
Animals, Circoviridae Infections epidemiology, Circoviridae Infections pathology, Circoviridae Infections virology, Circovirus genetics, Female, Genetic Variation, Immunohistochemistry veterinary, Male, Molecular Sequence Data, Ontario epidemiology, Phylogeny, Quebec epidemiology, Sequence Analysis, DNA, Severity of Illness Index, Swine, Swine Diseases epidemiology, Swine Diseases virology, Viral Load veterinary, Virulence genetics, Circoviridae Infections veterinary, Circovirus pathogenicity, Disease Outbreaks veterinary, Polymorphism, Restriction Fragment Length, Swine Diseases pathology
Abstract

In the late fall of 2004 more severe lesions of porcine circovirus-2 associated disease (PCVAD) than usual occurred during an outbreak of porcine circovirus-2 (PCV-2) infection in Ontario nursery and grower/finisher pigs. The lesions were of unprecedented severity and included diffuse bronchointerstitial pneumonia, granulomatous enteritis, vasculitis, interstitial nephritis, and new lesions of splenic infarction. Some affected herds had up to 50% mortality. The outbreak correlated with the sudden emergence of a variant PCV-2, with PCR restriction fragment length polymorphism (RFLP) type 321. Phylogenetic comparison of ORF2 sequences and full genome sequences showed the new variant to be different from the previously dominant RFLP type 422 viruses, and similar to viruses that had occurred in France and other European and Asian countries. A subsequent retrospective study showed a statistically significant increase in the frequency of histological lesions in lymph node, spleen, lung, small intestine, colon and kidney, for pigs spontaneously infected with RFLP type 321, compared with the older RFLP type 422 strain. Viral burden, based on IHC staining in lymph node, also showed a statistically significant increase in pigs infected with the newer variant RFLP type 321, compared with the older RFLP type 422 strain. This enhanced virulence in pigs infected with PCV-2 RFLP type 321 strain may be related to the genetic differences in this new strain of PCV-2. This virus is now the dominant strain of PCV-2 virus found in Ontario and Quebec swine.

Published
2008

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