Molecular characteristics and genetic evolutionary analyses of circulating parvoviruses derived from cats in Beijing.

Feline parvovirus (FPV) is a member of the family Parvoviridae, which is a major enteric pathogen of cats worldwide. This study aimed to investigate the prevalence of feline parvovirus in Beijing of China and analyze the genetic features of detected viruses. In this study, a total of 60 (8.5%) parvovirus-positive samples were detected from 702 cat fecal samples using parvovirus-specific PCR. The complete VP2 genes were amplified from all these samples. Among them, 55 (91.7%) sequences were characterized as FPV, and the other five (8.3%) were typed as canine parvovirus type 2 (CPV-2) variants, comprised of four CPV-2c and a new CPV-2b strain. In order to investigate the origin of CPV-2 variants in cats, we amplified full-length VP2 genes from seven fecal samples of dogs infected with CPV-2, which were further classified as CPV-2c. The sequences of new CPV-2b/MT270586 and CPV-2c/MT270587 detected from feline samples shared 100% identity with previous canine isolates KT156833 and MF467242 respectively, suggesting the CPV-2 variants circulating in cats might be derived from dogs. Sequence analysis indicated new mutations, Ala91Ser and Ser192Phe, in the FPV sequences, while obtained CPV-2c carried mutations reported in Asian CPV variants, showing they share a common evolutionary pattern with the Asian 2c strains. Interestingly, the FPV sequence (MT270571), displaying four CPV-specific residues, was found to be a putative recombinant sequence between CPV-2c and FPV. Phylogenetic analysis of the VP2 gene showed that amino acid and nucleotide mutations promoted the evolution of FPV and CPV lineages. Our findings will be helpful to further understand the circulation and evolution of feline and canine parvovirus in Beijing.

Tang Y ，Tang N ，Zhu J ，Wang M ，Liu Y ，Lyu Y ... -  《BMC Veterinary Research》

Analysis of canine parvoviruses circulating in Australia reveals predominance of variant 2b and identifies feline parvovirus-like mutations in the capsid proteins.

Canine parvovirus (CPV) is a major enteric pathogen of dogs worldwide that emerged in the late 1970s from a feline parvovirus (FPV)-like ancestral virus. Shortly after its emergence, variant CPVs acquired amino acid (aa) mutations in key capsid residues, associated with biological and/or antigenic changes. This study aimed to identify and analyse CPV variants and their capsid mutations amongst Australian dogs, to gain insights into the evolution of CPV in Australia and to investigate relationships between the disease and vaccination status of dogs from which viruses were detected. CPV VP2 sequences were amplified from 79 faecal samples collected from dogs with parvoviral enteritis at 20 veterinary practices in five Australian states. The median age at diagnosis was 4 months (range 1-96 months). Only 3.7% of dogs with vaccination histories had completed recommended vaccination schedules, while 49% were incompletely vaccinated and 47.2% were unvaccinated. For the first time, CPV-2b has emerged as the dominant antigenic CPV variant circulating in dogs with parvoviral enteritis in Australia, comprising 54.4% of viruses, while CPV-2a and CPV-2 comprised 43.1% and 2.5%, respectively. The antigenic variant CPV-2c was not identified. Analysis of translated VP2 sequences revealed a vast repertoire of amino acid (aa) mutations. Several Australian CPV strains displayed signatures in the VP2 protein typical of Asian CPVs, suggesting possible introduction of CPV strains from Asia, and/or CPV circulation between Asia and Australia. Canine parvoviruses were identified containing aa residues typical of FPV at key capsid (VP2) positions, representing reverse mutations or residual mutations retained from CPV-2 during adaptation from an FPV-like ancestor, suggesting that evolutionary intermediates between CPV-2 and FPV are circulating in the field. Similarly, intermediates between CPV-2a-like viruses and CPV-2 were also identified. These findings help inform a better understanding of the evolution of CPV in dogs.

Kwan E ，Carrai M ，Lanave G ，Hill J ，Parry K ，Kelman M ，Meers J ，Decaro N ，Beatty JA ，Martella V ，Barrs VR ... -  《-》

Molecular analysis of partial VP-2 gene amplified from rectal swab samples of diarrheic dogs in Pakistan confirms the circulation of canine parvovirus genetic variant CPV-2a and detects sequences of feline panleukopenia virus (FPV).

Ahmed N ，Riaz A ，Zubair Z ，Saqib M ，Ijaz S ，Nawaz-Ul-Rehman MS ，Al-Qahtani A ，Mubin M ... -  《Virology Journal》

Genetic characterization of the parvovirus full-length VP2 gene in domestic cats in Brazil.

Feline parvovirus (FPV) and canine parvovirus (CPV) are over 98% identical in their DNA sequences, and the new variants of CPV (2a/2b/2c) have gained the ability to infect and replicate in cats. The aim of this study was to determine the genetic diversity in the VP2 gene of parvovirus strains circulating in domestic cats in Brazil during a 10-year period (2008-2017). For parvovirus screening, specific PCR was performed, and 25 (34.7%) of 72 cats tested positive. The PCR-positive samples were further subjected to full-length VP2 sequencing (1755 bp), and eight sequences (36%) were characterized as FPV, seven (28%) as CPV-2a and (32%) nine (36%) as CPV-2b. One sequence (RJ1085/11) showing typical CPV amino acid (aa) at residues 80 R, 93 N, 103 A, 232 I, and 323 N could not be characterized at this time. The sequences in this study displayed aa changes previously described for FPV (A14T, A91S, I101T, N564S, and A568G) from cats and CPV-2a/2b (S297N and Y324L) from dogs. However, the Y324L mutation has not yet been reported in any CPV-2a/2b strains from cats. Phylogenetic analysis supported the division of these sequences into two well-defined clades, clade 1 for FPV and clade 2 for CPV2a/2b. Unusually, the sequence RJ1085/11 was grouped separately. Two recombination breakpoints were detected by Bootscan and 3Seq methods implemented in the RDP4. This study is the first report of CPV-2a/2b in cats in Brazil. The detection of FPV strains with mutations characteristic of CPV indicates that Brazilian FPV strains have undergone genetic changes.

Domingues CF ，de Castro TX ，do Lago BV ，Garcia RCNC ... -  《-》

Emergence of canine parvovirus type 2c in domestic dogs and cats from Thailand.

Canine parvovirus type 2 (CPV-2) is an important pathogen causing haemorrhagic enteritis in domestic dogs and wildlife worldwide. In early 2000, canine parvovirus type 2c (CPV-2c) was first reported and subsequently became a predominant subtype circulating in Europe and the Americas. CPV-2c has also been reported in Asia, including cases in China, India, Taiwan and Vietnam. However, CPV-2c has never been reported in Thailand. In this study, we conducted viral enteric disease surveillance in dogs and cats in Thailand during 2016-2018. During 20 months of surveillance, 507 rectal swab samples were collected from dogs (n = 444) and cats (n = 63) with and without clinical signs. The samples were examined for parvovirus by using VP2 gene-specific PCR for parvovirus. Our results showed that the positivity of canine parvovirus (CPV) was 29.95% and that of feline parvovirus (FPV) was 58.73%. In this study, we characterized 34 parvoviruses by VP2 gene sequencing. Moreover, two Thai-CPV-2 (Dog/CU-24 and Cat/CU-21) were characterized by whole genome sequencing. The phylogenetic results showed that Thai-CPV-2 had the highest nucleotide identities and clustered with Asian-CPV-2c but were in separate subclusters from the North American and European CPV-2c. Similarly, whole genome analyses showed that Thai-CPVs are closely related to Asian-CPV-2c, with unique amino acids at positions 297A, 324I, 370R and 426E. In summary, our results demonstrated the emergence of Asian-CPV-2c in dogs and cats in Thailand. Thus, the surveillance of CPV-2 in domestic dogs and cats should be further conducted on a larger scale to determine the dynamics of predominant variants and their distributions in the country and in the Southeast Asia region.

Charoenkul K ，Tangwangvivat R ，Janetanakit T ，Boonyapisitsopa S ，Bunpapong N ，Chaiyawong S ，Amonsin A ... -  《-》