Canine parvovirus in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Veterinary Studies in Virology at Massey University, Turitea, Palmerston North, New Zealand

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dc.contributor.authorOhneiser, Sylvia Anna
dc.date.accessioned2014-06-30T02:08:48Z
dc.date.available2014-06-30T02:08:48Z
dc.date.issued2013
dc.description.abstractSince the initial global emergence of canine parvovirus type 2 (CPV-2) in the early 1980s the virus has continued to evolve in its new host. As a result, the original CVP-2 was replaced by newly emerged subtypes designated CPV-2a and CPV-2b. Recently, a third antigenic subtype CPV-2c has emerged in several countries. In New Zealand the evolution of CVP-2 has not been monitored since its emergence in the early 1980s, largely because of the high efficacy of the vaccines available on the market. This lack of monitoring of CPV-2 has left a dearth of knowledge regarding the epidemiological features of CPV-2 in New Zealand. Hence, the aim of this study was to determine what subtypes of CPV-2 circulate in New Zealand and to investigate the phylogenetic relationships between CPV-2 from New Zealand and from other parts of the world. As part of this project, a virological survey was conducted across New Zealand. A total of 79 faecal samples were collected from dogs suspected to be infected with CPV-2, as judged by submitting veterinarians. Of those, 70 tested positive for CPV-2 DNA. All but one of the CPV-2 sequences were subtyped as CPV-2a. The remaining sequence was subtyped as CPV- 2, and most likely represented a vaccine strain of the virus. The majority (74.3%) of CPV-2 positive samples originated from dogs six months of age and younger, with 70% of samples collected from dogs considered not fully vaccinated (unvaccinated dogs or those with only single vaccination), a further 17% of samples originated from dogs with an unknown vaccination history. Two separate phylogenetic analyses were performed. Seventy one CPV-2 positive sequences originated from New Zealand (61 survey samples, six historic samples, two vaccine sequences and one parvovirus sequence obtained from a cat) and the reference sequence were trimmed to produce contiguous sequences of equal length. These 72 sequences were used to investigate the genetic structure of CPV-2 within New Zealand. Haplotype network analyses revealed that Cook-straight [i.e. Cook Strait] is not an effective geographical barrier to CVP-2 gene flow with an equal distribution of genotypes in the North and South Islands. Translocation of the virus between the islands is likely occurring by transportation of sub-clinically infected animals and fomites. Additional CPV-2 VP2 sequences (n=95) originating from various countries were obtained from the National Centre for Biotechnology Information (NCBI) database. The selection of 27 samples originating from New Zealand for which a full length contiguous sequence of VP-2 gene was available were aligned with sequences obtained from the NCBI database. The resulting dataset of 123 CPV-2 sequences was used to assess the New Zealand CPV-2 sequences in the context of the worldwide radiation of CPV-2. Phylogenetic analyses of this dataset revealed that New Zealand has a closed monophyletic population of CPV-2 sequences. This suggests that CPV-2 is not being continuously introduced to New Zealand from overseas, but has evolved following a limited number of introductions in the past. Phylogenetic analysis also revealed that CPV-2 subtypes from around the world have emerged independently of one another. This work has contributed to our understanding of molecular epidemiology of CPV-2 in New Zealand. The knowledge of predominant CPV-2 subtypes circulating in this country is important for evidence driven recommendations with regard to CPV-2 vaccination. Understanding of the genetic structure of the current CPV-2 circulating in New Zealand is also crucial for timely recognition, detection and management of any novel antigenic subtypes that may emerge in the future.en_US
dc.identifier.urihttp://hdl.handle.net/10179/5507
dc.language.isoenen_US
dc.publisherMassey Universityen_US
dc.rightsThe Authoren_US
dc.subjectCanine parvovirusen_US
dc.subjectDog diseasesen_US
dc.subjectInfectious diseases in dogsen_US
dc.subjectMolecular epidemiologyen_US
dc.subjectResearch Subject Categories::VETERINARY MEDICINE::Veterinary epidemiologyen_US
dc.titleCanine parvovirus in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Veterinary Studies in Virology at Massey University, Turitea, Palmerston North, New Zealanden_US
dc.typeThesisen_US
massey.contributor.authorOhneiser, Sylvia Annaen_US
thesis.degree.disciplineVirologyen_US
thesis.degree.grantorMassey Universityen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Veterinary Studies (M.V.S.)en_US
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