Email updates

Keep up to date with the latest news and content from Virology Journal and BioMed Central.

Open Access Research

Genetic characterization of type 2a canine parvoviruses from Taiwan reveals the emergence of an Ile324 mutation in VP2

Chao-Nan Lin12*, Chi-Hsien Chien12, Ming-Tang Chiou1, Ling-Ling Chueh3, Meng-Yu Hung1 and Han-Siang Hsu14

Author Affiliations

1 Department of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan

2 Veterinary Hospital, National Pingtung University of Science and Technology, Pingtung, Taiwan

3 Graduate Institute of Veterinary Medicine, National Taiwan University, Taipei, Taiwan

4 Don-Da Animal Hospital, Taichung, Taiwan

For all author emails, please log on.

Virology Journal 2014, 11:39  doi:10.1186/1743-422X-11-39


The electronic version of this article is the complete one and can be found online at: http://www.virologyj.com/content/11/1/39


Received:10 December 2013
Accepted:19 February 2014
Published:25 February 2014

© 2014 Lin et al.; licensee BioMed Central Ltd.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Abstract

Background

Canine parvovirus 2 (CPV 2) is a major infectious cause of mortality in puppies. The characteristic symptom of CPV 2 disease is intestinal hemorrhage with severe bloody diarrhea. Soon after CPV was first recognized in the late 1970s, the original virus, CPV 2, was replaced in the canine population by strains carrying minor antigenic variants (termed 2a, 2b, and 2c) of the VP2 gene that could be distinguished using monoclonal antibodies and molecular analyses. Here, we provide an updated molecular characterization of the CPV 2 circulating in Taiwan.

Methods

In this study, 28 isolates of CPV 2 from 144 dogs with suspected CPV infection were obtained from northern, central, and southern Taiwan from 2008 to 2012 and screened by PCR. The 28 isolates were sequenced, and a phylogenetic analysis of the VP2 gene was performed.

Results

Of the 28 Taiwanese CPV 2 isolates, 15 were identified as new CPV 2a, and 13 were identified as new CPV 2b. Compared to the reference CPV 2a, all 15 of the CPV 2a sequences collected in this study contain an Ile324 mutation caused by a TAT to ATT mutation at nucleotides 970–972 of the VP2 gene.

Conclusion

Our VP2 sequence data revealed that both types are currently prevalent CPV 2 field strains circulating in Taiwan, and a unique Ile324 VP2 mutation was found in our Taiwanese CPV 2a isolates and recent Asian isolates. CPV 2c was not observed in this study.

Keywords:
Canine parvovirus; Genotype; VP2; Sequence analysis

Background

Canine parvovirus (CPV) enteritis is characterized by intestinal hemorrhage with severe bloody diarrhea [1]. The causative agent, CPV 2, was first identified in the late 1970s [2]. CPV is a non-enveloped, linear, single-stranded DNA virus with a genome of approximately 5 kb, and it belongs to the genus Parvovirus, together with feline panleukopenia virus (FPV), mink enteritis virus, raccoon parvovirus, and porcine parvovirus [3]. Indeed, CPV 2 is believed to have originated from FPV [4,5], and various hypotheses for how this may have occurred have been suggested, including direct mutation from FPV and contact between cats and dogs kept as companion animals within the same home [5].

An antigenic variant, CPV 2a, developed within a few years after the emergence of CPV 2 [6,7], and another CPV 2 variant, CPV 2b, began appearing in the canine population in the mid-1980s [8]. In 2000, a new antigenic variant, CPV 2c, was first detected in Italy [9]. New antigenic types of CPV 2 have been found in epidemics worldwide and are replacing the original CPV 2. The antigenic variant CPV 2a shows the following substitutions within the VP2 protein: Met87Leu, Ile101Thr, Ala300Gly, and Asp305Tyr. Furthermore, CPV 2b has been confirmed to contain an additional substitution, Asn426Asp [10,11]. These two variants further evolved into new 2a and 2b types, with substitutions of Ser297Ala, during the 1990s [12]. Antigenic variant CPV 2c was identified with a substitution Asp426Glu [9]. Different antigenic variants of CPV 2 predominate in different countries [12-42].

A retrospective analysis has revealed that the oldest CPV 2c strain was identified in 1996 in Germany [18], and the results from European epidemiological surveys show that CPV 2c is now predominant in Italy, Germany, and Spain and is also widely co-distributed with CPV 2a or CPV 2b in Portugal, France, and Belgium [18,43-47]. Outside of Europe, CPV 2a and 2b isolates are common in the United States [19,41], whereas CPV 2c is more widespread in Uruguay [20,32], Brazil [33], and Argentina [30,48]. Surprisingly, either CPV 2a or CPV 2b is the predominant variant in Asian countries [12,13,15,21,22,24-26,28,29],[35,37,38] and Australia [42], though a few CPV 2c strains have been isolated in India [26]. Interestingly, a new amino acid substitution, Tyr324Ile, was identified in Korea [21,24], China [29], Thailand [28], Uruguay [32], Japan [38], Taiwan [35], and India [37,49].

In Taiwan, as in other Asian countries, variants CPV 2a and 2b have predominated since the first outbreak [13,15,35]. However, few recent studies have included a genetic analysis of Taiwanese CPV 2 strains. Therefore, the aim of this study was to clarify the evolution of CPV 2 isolated from northern, central, and southern Taiwan during the 2008–2012 period.

Results

PCR amplification and genotype analysis

A total of 28 cases from 144 dogs showed positive results for CPV 2. All of the CPV 2 isolates were clearly separated into two genotypes (Figure 1). Of the 28 Taiwanese CPV 2 strains, 15 were identified as new CPV 2a, and 13 were identified as new CPV 2b. Of the 15 new CPV 2a isolates, 3 (20%), 2 (13.3%), and 10 (66.7%) isolates were collected from northern, central, and southern Taiwan, respectively (Table 1). Of the 13 new CPV 2b isolates, 3 (23.1%), 10 (76.9%), and 0 (0%) isolates were collected from northern, central, and southern Taiwan, respectively (Table 1). Taken together, our results show that both types are currently prevalent CPV 2 field strains circulating in Taiwan.

thumbnailFigure 1. Phylogenetic relationships based on the partial VP2 gene of CPV 2 between Taiwanese isolates and reference strains. The analysis was performed employing the maximum likelihood method based on 1,000 replicates using MEGA 5 software. N: Northern Taiwan, C: Central Taiwan, S, Southern Taiwan. Light grey underlay: CPV 2 isolates in the present study. Italic: the Ile324 mutation in VP2.

Table 1. The genotypes of 28 canine parvovirus type 2 isolates collected from Taiwanese dogs

DNA sequence analysis

The partial VP2 nucleotide sequences were analyzed using DNASTAR software, revealing 99.4-100, 99.7-100, and 99–99.4% homology within the local CPV 2a isolates, within the local CPV 2b isolates, and between the local CPV 2a and 2b isolates, respectively (Table 2). In comparison to the low nucleotide sequence similarity between reference Taiwanese CPV 2a and our CPV 2a (99.4-99.5%), the homology levels between our analyzed CPV 2a isolates (99.7-99.8%) and Korean CPV 2 K026 (EU009204) appeared to be much higher (data not shown).

Table 2. Sequence homology of local new CPV 2a and 2b isolates and reference strains

Amino acid sequence analysis

Amino acid comparisons among the 28 isolates and the 12 reference strains revealed a major region of great diversity at amino acids 297–324 (Figure 2). We also examined the 2 amino acids (positions 297 and 426) within this partial VP2 gene identified by Ohshima [12] et al. and Buonavoglia et al. [9] that were proposed to distinguish CPV 2a/2b from new CPV 2a/2b and CPV 2a/2b/2c, respectively. Our alignment revealed that all of our new CPV 2a and 2b strains contained Ala297 (Figure 2). The amino acid Glu426, which is unique to strain CPV 2c, was no observed in any strain in this study. Four nonsynonymous mutations were observed in our CPV 2a and/or 2b strains (TGT to TGC, CTA to CTG, AAT to AAC and CAA to CAG). One unique amino acid substitution was found in the all of our CPV 2a isolates (Tyr324Ile), caused by the mutation of TAT to ATT at nucleotide positions 970–972 of the VP2 gene. Our CPV 2a isolates were more closely related to the Ile324 isolates from other countries than to the prototype Taiwanese CPV 2a Taiwan 9 (Figure 1).

thumbnailFigure 2. Multiple amino acid sequence alignment of the partial VP2 gene of CPV 2. Only those amino acid sequences differing from the FPV sequence are shown. The heterogenic region is boxed.

Discussion

CPV 2, which causes intestinal hemorrhage with severe bloody diarrhea in dogs, is distributed worldwide, and genetic variation among CPV 2 isolates could be used to further classify the viruses into four genotypes (2, 2a, 2b, and 2c) that differ in their amino acid sequence and VP2 gene phylogenetic relationships [10]. CPV 2a and 2b are the predominant variants in Asia [12,13,15,21,22,24-26,28,29],[35,37,38], whereas CPV 2c is recently distributed on several continents, including Europe (Italy, Germany, Spain, Portugal, France, Belgium, UK, Greece, and Bulgaria) [18,43], Africa (Tunisia) [23], North America (USA) [19,41], South America (Brazil [33], Uruguay [20,32], Argentina [30,48], and Ecuador [34]), and Asia (India) [26]. The first case of CPV 2c was identified in 1996 in Germany [18]. Although a few CPV 2c cases have been reported in Asia (India) [26], no CPV 2c was observed in the present study.

This is the first study to investigate the genotype prevalence of CPV 2 in northern, central, and southern Taiwan in recent years. Our results indicate that both types are currently prevalent CPV 2 field strains circulating in Taiwan. Surprisingly, all of the CPV 2a isolates contain a unique amino acid substitution (Tyr324Ile). Our review of the GenBank database and sequence analyses showed that this Ile324 variant of CPV 2a is also found in Korea [21,24], China [29], Thailand [28], Uruguay [32], Japan [38], Taiwan [35], and India [37,49]. Interestingly, with the exception of Uruguay, this Ile324 CPV 2a variant is only distributed in Asian countries, and our data revealed that this variant was first found in Taiwan in 2009. We believe that the Ile324 CPV 2a variant emerged a few years ago. Taken together, our results suggest that the Ile324 CPV 2a variant may be present due to i) importation from abroad or ii) evolution from existing CPV 2a genotypes. An ongoing investigation is aimed at distinguishing between these possibilities.

VP2 encodes a viral capsid protein that is the major structural protein of CPV 2 and is involved in the host immune response [50]. Therefore, a small number of mutations may result in increased pathogenicity [34], and the effectiveness of commercial vaccines against the Ile324 variant of CPV 2a requires further evaluation. Among all carnivore parvoviruses, residue 324 of VP2 is subject to positive selection [51] and is adjacent to a residue (amino acid 323) known to be involved in host range and tropism via canine transferrin receptor binding [52]. The mutation of CPV 2 residue 323 may influence interactions between residues in neighboring loops of either the same VP2 molecule or the threefold-related VP2, greatly decreasing replication in canine cells [53]. Although the function of residue 324 remains to be elucidated, using SYBR Green-based real-time PCR, our previous study detected the viral shedding of the Ile324 CPV 2 variant for up to 63 days in naturally infected dogs [54]. The pathogenesis of this new variant requires further investigation.

The first CPV 2 infection in Taiwan was recorded in 1980 and was attributed to CPV 2, which was later replaced by CPV 2a and 2b [13]. Previous studies have shown that the predominant genotypes of CPV 2 in northern, central, and southern Taiwan were CPV 2a [13], CPV 2b [15], and CPV 2a [35], respectively, in agreement with our results. Thus, both genotypes (CPV 2a and CPV 2b) constitute the prevalent CPV 2 field strains circulating in Taiwan in the last two decades. However, CPV 2 is constantly mutating, leading to the evolution of novel CPV 2 variants. For example, the CPV 2a Ile324 variant and CPV 2c Glu426 variant have emerged worldwide. Additional CPV 2 cases need to be investigated using continuous surveillance and sequence analysis.

Conclusion

Our VP2 sequence data revealed that both types are currently prevalent CPV 2 field strains circulating in Taiwan, and a unique Ile324 VP2 mutation was found in our Taiwanese CPV 2a isolates and in recent Asian isolates. CPV 2c was not observed in this study.

Methods

Specimen collection and DNA extraction

Clinical samples (whole blood and/or rectal swab) were collected from 144 dogs in northern, central, and southern Taiwan between 2008 and 2012. These samples were mainly acquired from dogs with diarrhea and/or bloody diarrhea. The year of sampling, age, clinical history, and CPV types of the sampled dogs are summarized in Table 1.

Sample preparation and CPV 2 screening

Viral DNA was extracted from the clinical samples (either whole blood or rectal swab) using a Genomic DNA Mini Kit (Geneaid Biotech, Ltd., Taipei, Taiwan) according to the manufacturer’s protocol. All of the clinical specimens were screened for CPV 2 by polymerase chain reaction (PCR) as described by Lin et al. [54].

VP2 gene amplification and sequencing

Samples showing positive PCR results from either type of specimen were included in this study. The partial VP2 gene of CPV 2 was amplified by PCR as described by Buonavoglia et al. [9]. The DNA fragments were purified (Geneaid Biotech, Ltd., Taipei, Taiwan), and the target nucleotide sequences were determined in both orientations using an auto-sequencer (ABI 3730XL, Foster City, CA, USA).

Sequence and phylogenetic analyses

The VP2 DNA sequences of our samples were compared to those of reference FPV (M38246), CPV 2 (M38245), CPV 2a (M24003), CPV 2b (M74849, AY742941), new CPV 2a (AY742953, AB054213, AB054215, DQ340434, EF011664, EF189717, EU009204, EU145955, FJ005259, FJ197841, FJ197842, FJ435343, FJ435345, FJ435346, FJ435347, FJ869138, GQ379043, GQ379048, GU569936, GU569942, HQ602978, HQ602995, JF346754, JF906788, JN403045, JX048605, JX048606, KC196114, KF149978), new CPV 2b (AY742955, AY869724, EU009205, EU145954, FJ005260, FJ005264, JF414817, JN867603, KF149985), and CPV 2c (FJ005235, FJ005237, FJ222821, GQ865518, GU380303, JF414818, KC196099, KF149962). Multiple alignments of the nucleic acid and amino acid sequences were performed with the Clustal W method using the MegAlign program (DNASTAR, Madison, WI, USA). The phylogenetic analyses were conducted by the maximum likelihood method using MEGA 5, version 5.05.

Abbreviations

CPV: Canine parvovirus; PCR: Polymerase chain reaction.

Competing interests

The authors declare that they have no competing interests.

Authors’ contributions

CNL designed and analyzed the experimental data and wrote the manuscript. CHC, MTC, and LLC managed the study, provided materials and reagents, contributed to the interpretation of the data, and co-wrote the manuscript. MYH and HSH contributed to the DNA extraction and PCR. All of the authors read and approved the final manuscript.

Acknowledgement

We thank Dr. Li-En Hsieh, Dr. Ya-Ling Lin, and Dr. Ya-Min Xu for sample collection.

References

  1. MacLachlan NJ, Dubovi EJ: Parvoviridae. In Fenner’s Veterinary virology. 4th edition. Edited by MacLachlan NJ, Dubovi EJ. London: Academic; 2011:507. OpenURL

  2. Appel MJ, Scott FW, Carmichael LE: Isolation and immunisation studies of a canine parco-like virus from dogs with haemorrhagic enteritis.

    Vet Res 1979, 105:156-159. OpenURL

  3. Hoelzer K, Parrish CR: The emergence of parvoviruses of carnivores.

    Vet Res 2010, 41:39-51. OpenURL

  4. Allison AB, Harbison CE, Pagan I, Stucker KM, Kaelber JT, Brown JD, Ruder MG, Keel MK, Dubovi EJ, Holmes EC, Parrish CR: Role of multiple hosts in the cross-species transmission and emergence of a pandemic parvovirus.

    J Virol 2012, 86:865-872. OpenURL

  5. Truyen U: Evolution of canine parvovirus-a need for new vaccines?

    Vet Microbiol 2006, 117:9-13. OpenURL

  6. Parrish CR, O’Connell PH, Evermann JF, Carmichael LE: Natural variation of canine parvovirus.

    Science 1985, 230:1046-1048. OpenURL

  7. Parrish CR, Have P, Foreyt WJ, Evermann JF, Senda M, Carmichael LE: The global spread and replacement of canine parvovirus strains.

    J Gen Virol 1988, 69(Pt 5):1111-1116. OpenURL

  8. Parrish CR, Aquadro CF, Strassheim ML, Evermann JF, Sgro JY, Mohammed HO: Rapid antigenic-type replacement and DNA sequence evolution of canine parvovirus.

    J Virol 1991, 65:6544-6552. OpenURL

  9. Buonavoglia C, Martella V, Pratelli A, Tempesta M, Cavalli A, Buonavoglia D, Bozzo G, Elia G, Decaro N, Carmichael L: Evidence for evolution of canine parvovirus type 2 in Italy.

    J Gen Virol 2001, 82:3021-3025. OpenURL

  10. Martella V, Decaro N, Buonavoglia C: Evolution of CPV-2 and implication for antigenic/genetic characterization.

    Virus Genes 2006, 33:11-13. OpenURL

  11. Decaro N, Desario C, Parisi A, Martella V, Lorusso A, Miccolupo A, Mari V, Colaianni ML, Cavalli A, Di Trani L, Buonavoglia C: Genetic analysis of canine parvovirus type 2c.

    Virology 2009, 385:5-10. OpenURL

  12. Ohshima T, Hisaka M, Kawakami K, Kishi M, Tohya Y, Mochizuki M: Chronological analysis of canine parvovirus type 2 isolates in Japan.

    J Vet Med Sci 2008, 70:769-775. OpenURL

  13. Chang WL, Chang AC, Pan MJ: Antigenic types of canine parvoviruses prevailing in Taiwan.

    Vet Rec 1996, 138:447. OpenURL

  14. Battilani M, Ciulli S, Tisato E, Prosperi S: Genetic analysis of canine parvovirus isolates (CPV-2) from dogs in Italy.

    Virus Res 2002, 83:149-157. OpenURL

  15. Wang HC, Chen WD, Lin SL, Chan JP, Wong ML: Phylogenetic analysis of canine parvovirus VP2 gene in Taiwan.

    Virus Genes 2005, 31:171-174. OpenURL

  16. Chinchkar SR, Mohana Subramanian B, Hanumantha Rao N, Rangarajan PN, Thiagarajan D, Srinivasan VA: Analysis of VP2 gene sequences of canine parvovirus isolates in India.

    Arch Virol 2006, 151:1881-1887. OpenURL

  17. Doki M, Fujita K, Miura R, Yoneda M, Ishikawa Y, Taneno A, Kai C: Sequence analysis of VP2 gene of canine parvovirus isolated from domestic dogs in Japan in 1999 and 2000.

    Comp Immunol Microbiol Infect Dis 2006, 29:199-206. OpenURL

  18. Decaro N, Desario C, Addie DD, Martella V, Vieira MJ, Elia G, Zicola A, Davis C, Thompson G, Thiry E, Truyen U, Buonavoglia C: The study molecular epidemiology of canine parvovirus, Europe.

    Emerg Infect Dis 2007, 13:1222-1224. OpenURL

  19. Kapil S, Cooper E, Lamm C, Murray B, Rezabek G, Johnston L 3rd, Campbell G, Johnson B: Canine parvovirus types 2c and 2b circulating in North American dogs in 2006 and 2007.

    J Clin Microbiol 2007, 45:4044-4047. OpenURL

  20. Perez R, Francia L, Romero V, Maya L, Lopez I, Hernandez M: First detection of canine parvovirus type 2c in South America.

    Vet Microbiol 2007, 124:147-152. OpenURL

  21. Jeoung SY, Ahn SJ, Kim D: Genetic analysis of VP2 gene of canine parvovirus isolates in Korea.

    J Vet Med Sci 2008, 70:719-722. OpenURL

  22. Kang BK, Song DS, Lee CS, Jung KI, Park SJ, Kim EM, Park BK: Prevalence and genetic characterization of canine parvoviruses in Korea.

    Virus Genes 2008, 36:127-133. OpenURL

  23. Touihri L, Bouzid I, Daoud R, Desario C, El Goulli AF, Decaro N, Ghorbel A, Buonavoglia C, Bahloul C: Molecular characterization of canine parvovirus-2 variants circulating in Tunisia.

    Virus Genes 2009, 38:249-258. OpenURL

  24. Yoon SH, Jeong W, Kim HJ, An DJ: Molecular insights into the phylogeny of canine parvovirus 2 (CPV-2) with emphasis on Korean isolates: a Bayesian approach.

    Arch Virol 2009, 154:1353-1360. OpenURL

  25. Mohan Raj J, Mukhopadhyay HK, Thanislass J, Antony PX, Pillai RM: Isolation, molecular characterization and phylogenetic analysis of canine parvovirus.

    Infect Genet Evol 2010, 10:1237-1241. OpenURL

  26. Nandi S, Chidri S, Kumar M, Chauhan RS: Occurrence of canine parvovirus type 2c in the dogs with haemorrhagic enteritis in India.

    Res Vet Sci 2010, 88:169-171. OpenURL

  27. Ntafis V, Xylouri E, Kalli I, Desario C, Mari V, Decaro N, Buonavoglia C: Characterization of Canine parvovirus 2 variants circulating in Greece.

    J Vet Diagn Invest 2010, 22:737-740. OpenURL

  28. Phromnoi S, Sirinarumitr K, Sirinarumitr T: Sequence analysis of VP2 gene of canine parvovirus isolates in Thailand.

    Virus Genes 2010, 41:23-29. OpenURL

  29. Zhang R, Yang S, Zhang W, Zhang T, Xie Z, Feng H, Wang S, Xia X: Phylogenetic analysis of the VP2 gene of canine parvoviruses circulating in China.

    Virus Genes 2010, 40:397-402. OpenURL

  30. Gallo Calderon M, Wilda M, Boado L, Keller L, Malirat V, Iglesias M, Mattion N, La Torre J: Study of canine parvovirus evolution: comparative analysis of full-length VP2 gene sequences from Argentina and international field strains.

    Virus Genes 2012, 44:32-39. OpenURL

  31. Panzera Y, Calderon MG, Sarute N, Guasco S, Cardeillac A, Bonilla B, Hernandez M, Francia L, Bedo G, La Torre J, Perez R: Evidence of two co-circulating genetic lineages of canine distemper virus in South America.

    Virus Res 2012, 163:401-404. OpenURL

  32. Perez R, Bianchi P, Calleros L, Francia L, Hernandez M, Maya L, Panzera Y, Sosa K, Zoller S: Recent spreading of a divergent canine parvovirus type 2a (CPV-2a) strain in a CPV-2c homogenous population.

    Vet Microbiol 2012, 155:214-219. OpenURL

  33. Pinto LD, Streck AF, Goncalves KR, Souza CK, Corbellini AO, Corbellini LG, Canal CW: Typing of canine parvovirus strains circulating in Brazil between 2008 and 2010.

    Virus Res 2012, 165:29-33. OpenURL

  34. Aldaz J, Garcia-Diaz J, Calleros L, Sosa K, Iraola G, Marandino A, Hernandez M, Panzera Y, Perez R: High local genetic diversity of canine parvovirus from Ecuador.

    Vet Microbiol 2013, 166:214-219. OpenURL

  35. Chou SJ, Lin HT, Wu JT, Yang WC, Chan KW: Genotyping of canine parvovirus type 2 VP2 gene in southern Taiwan in 2011.

    Taiwan Vet J 2013, 39:81-92. OpenURL

  36. Dogonyaro BB, Bosman AM, Sibeko KP, Venter EH, van Vuuren M: Genetic analysis of the VP2-encoding gene of canine parvovirus strains from Africa.

    Vet Microbiol 2013, 165:460-465. OpenURL

  37. Mukhopadhyay HK, Matta SL, Amsaveni S, Antony PX, Thanislass J, Pillai RM: Phylogenetic analysis of canine parvovirus partial VP2 gene in India.

    Virus Genes 2013, 48:89-95. OpenURL

  38. Soma T, Taharaguchi S, Ohinata T, Ishii H, Hara M: Analysis of the VP2 protein gene of canine parvovirus strains from affected dogs in Japan.

    Res Vet Sci 2013, 94:368-371. OpenURL

  39. Castro TX, Costa EM, Leite JP, Labarthe NV, Cubel Garcia RC: Monitoring of canine parvovirus (CPV) strains detected in vaccinated puppies in Brazil.

    Res Vet Sci 2011, 90:336-340. OpenURL

  40. Majer-Dziedzic B, Jakubczak A, Zietek J: Phylogenetic analysis of canine parvovirus CPV-2 strains and its variants isolated in Poland.

    Pol J Vet Sci 2011, 14:379-384. OpenURL

  41. Hong C, Decaro N, Desario C, Tanner P, Pardo MC, Sanchez S, Buonavoglia C, Saliki JT: Occurrence of canine parvovirus type 2c in the United States.

    J Vet Diagn Invest 2007, 19:535-539. OpenURL

  42. Meers J, Kyaw-Tanner M, Bensink Z, Zwijnenberg R: Genetic analysis of canine parvovirus from dogs in Australia.

    Aust Vet J 2007, 85:392-396. OpenURL

  43. Decaro N, Buonavoglia C: Canine parvovirus- a review of epidemiological and diagnostic aspects, with emphasis on type 2c.

    Vet Microbiol 2012, 155:1-12. OpenURL

  44. Decaro N, Desario C, Amorisco F, Losurdo M, Elia G, Parisi A, Ventrella G, Martella V, Buonavoglia C: Detection of a canine parvovirus type 2c with a non-coding mutation and its implications for molecular characterisation.

    Vet J 2013, 196:555-557. OpenURL

  45. Decaro N, Desario C, Billi M, Mari V, Elia G, Cavalli A, Martella V, Buonavoglia C: Western European epidemiological survey for parvovirus and coronavirus infections in dogs.

    Vet J 2011, 187:195-199. OpenURL

  46. Decaro N, Elia G, Campolo M, Desario C, Lucente MS, Bellacicco AL, Buonavoglia C: New approaches for the molecular characterization of canine parvovirus type 2 strains.

    J Vet Med B Infect Dis Vet Public Health 2005, 52:316-319. OpenURL

  47. Decaro N, Elia G, Martella V, Campolo M, Desario C, Camero M, Cirone F, Lorusso E, Lucente MS, Narcisi D, Scalia P, Buonavoglia C: Characterisation of the canine parvovirus type 2 variants using minor groove binder probe technology.

    J Virol Methods 2006, 133:92-99. OpenURL

  48. Calderon MG, Romanutti C, DA A, Keller L, Mattion N, La Torre J: Evolution of canine parvovirus in Argentina between years 2003 and 2010: CPV2c has become the predominant variant affecting the domestic dog population.

    Virus Res 2011, 157:106-110. OpenURL

  49. Mittal M, Chakravarti S, Mohapatra JK, Chug PK, Dubey R, Narwal PS, Kumar A, Churamani CP, Kanwar NS: Molecular typing of canine parvovirus strains circulating from 2008–2012 in an organized kennel in India reveals the possibility of vaccination failure.

    Infect Genet Evol 2014.

    http://dx.doi.org/10.1016/j.meegid.2014.01.015 webcite

    OpenURL

  50. de Turiso JA L, Cortes E, Ranz A, Garcia J, Sanz A, Vela C, Casal JI: Fine mapping of canine parvovirus B cell epitopes.

    J Gen Virol 1991, 72(Pt 10):2445-2456. OpenURL

  51. Hoelzer K, Shackelton LA, Parrish CR, Holmes EC: Phylogenetic analysis reveals the emergence, evolution and dispersal of carnivore parvoviruses.

    J Gen Virol 2008, 89:2280-2289. OpenURL

  52. Hueffer K, Parrish CR: Parvovirus host range, cell tropism and evolution.

    Curr Opin Microbiol 2003, 6:392-398. OpenURL

  53. Chang SF, Sgro JY, Parrish CR: Multiple amino acids in the capsid structure of canine parvovirus coordinately determine the canine host range and specific antigenic and hemagglutination properties.

    J Virol 1992, 66:6858-6867. OpenURL

  54. Lin CN, Chien CH, Chiou MT, Wang JW, Lin YL, Xu YM: Development of SYBR green-based real-time PCR for the detection of canine, feline and porcine parvoviruses.

    Taiwan Vet J 2014.

    Accepted

    OpenURL