A total of 85 samples (58.0 %) were found to be positive for Canine parvovirus (CPV) by PCR assay (Hfor/Hrev primers) out of 158 suspected faecal samples of dogs collected from various states/union territories of India. Nine CPV isolates could be obtained in A-72 cell line. The sequencing of the partial VP2 gene of CPV identified the predominant CPV strain as CPV-2a (Ser297Ala) with one CPV-2b (Ser297Ala) and another CPV-2a variant strain (Ser297Gly). Several non-synonymous and synonymous mutations were also recorded in this study. The phylogenetic tree revealed that most of the CPV sequences from Tamil Nadu (Southern India) and Maharashtra (Western India) obtained during 2011 and few sequences from Northern India obtained during 2012 were grouped together along with CPV-2a (Ser297Ala) strains from China and India and followed the same evolution; although there was definitive indication of separate lineages too by few other sequences.

Aim: The present study was conducted to isolate and characterize canine parvovirus circulating in Southern India by genetic analysis of VP2 capsid protein gene. Materials and Methods:In this study, 128 samples were collected from nine different locations covering five Southern Indian states (Pondicherry, Tamil Nadu, Kerala, Andhra Pradesh and Karnataka) . Out of 128 samples, 69 samples were found to be positive by PCR assay. Out of 69 positive samples, 36 were randomly selected and processed for virus isolation. Twenty viruses could be isolated successfully and 18 randomly selected isolate were subjected to VP2 gene sequence analysis along with 6 random clinical samples.Result: Seventeen isolates and 5 clinical samples were characterized as New CPV-2a (CPV2a with 297-Ser Ala). But one isolate and one clinical sample had amino acids variations which were characteristics of New CPV-2b. The phylogenetic analysis revealed that one of the field isolates was found to be phylogenetically closely related to New CPV-2b strains of India; rest other sequences was found to share ancestral origins with New CPV-2a reference strains of Japan, China, Thailand and India.

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Comparative efficacy of faecal culture and IS900 Polymerase chain reaction (PCR) assay of faecal samples was investigated in 40 clinically suspected cases of Johne's disease in dairy cattle. The sensitivity of faecal culture and PCR assay in this study was 52.5% (21/40) and 90% (36/40) respectively. All isolates appeared only on the mycobactin J supplemented Herrold's egg yolk medium (HEYM) at 8-16 weeks post-inoculation, were acid-fast and were positive for IS900 PCR yielding a single amplicon of 217 bp. A total of 28 faecal samples out of 40 were positive by IS900 primary PCR assay for Mycobacterium avium subsp. paratuberculosis (Map) yielding an expected product of size 217 bp. Twelve faecal samples, which gave negative results in the primary PCR, were subjected to secondary PCR assay. Of the 12 samples, 8 gave positive results in the IS900 nested PCR (nPCR), which yielded a PCR product of 167 bp, proving better sensitivity of nPCR assay than single amplification PCR. PCR could detect additionally 15 samples as positive which were negative by faecal culture. The chi-square analysis showed a highly significant difference between the tests (P< 0.01). This study suggests that IS900-PCR-based detection of Map could be used as a potential diagnostic tool for rapid and effective Johne's disease surveillance.

Aims:  To develop a specific and highly sensitive loop‐mediated isothermal amplification (LAMP) technique for the rapid detection of canine parvovirus (CPV) DNA directly in suspected faecal samples of dogs by employing a simple method of template preparation. Methods and Results:  LAMP reaction was developed by designing two sets of outer and inner primers, which target a total of six distinct regions on VP2 gene of CPV. The template DNA was prepared by a simple boiling and chilling method. Of the 140 faecal samples screened by the developed LAMP and the conventional PCR assays, 104 samples (74·28%) were found positive by LAMP, whereas 81 samples (57·85%) were found positive by PCR. The specificity of the LAMP assay was tested by cross‐examination of common pathogens of dogs and further confirmed by sequencing. The detection limit of the LAMP was 0·0001 TCID50 ml−1, whereas the detection limit of the PCR was 1000 TCID50 ml−1. Conclusions:  The developed LAMP assay detects CPV DNA in faecal specimens directly within an hour by following a simple and rapid boiling and chilling method of template preparation. The result also shows that the developed LAMP assay is specific and highly sensitive in detecting CPV. Significance and Impact of the Study:  The result indicates the potential usefulness of LAMP which is a simple, rapid, specific, highly sensitive and cost‐effective field‐based method for direct detection of CPV from the suspected faecal samples of dogs.

The canine parvovirus (CPV) infection is a highly contagious and serious enteric disease of dogs with high fatality rate. The present study was taken up to characterize the full-length viral polypeptide 2 (VP2) gene of CPV of Indian origin along with the commercially available vaccines. The faecal samples from parvovirus suspected dogs were collected from various states of India for screening by PCR assay and 66.29% of samples were found positive. Six CPV-2a, three CPV-2b, and one CPV-2c types were identified by sequence analysis. Several unique and existing mutations have been noticed in CPV types analyzed indicating emergence of newer variants of CPV in India. The phylogenetic analysis revealed that all the field CPV types were grouped in different subclades within two main clades, but away from the commercial vaccine strains. CPV-2b and CPV-2c types with unique mutations were found to be establishing in India apart from the prevailing CPV-2a type. Mutations and the positive selection of the mutants were found to be the major mechanism of emergence and evolution of parvovirus. Therefore, the incorporation of local strain in the vaccine formulation may be considered for effective control of CPV infections in India.

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The present study was aimed at molecular typing of Canine parvovirus (CPV) occurring in Pondicherry using PCR based assays. CPV-2a and CPV-2b types were detected by PCR in 68 (53.12%) out of 128 faecal samples/rectal swabs. All the 68 samples found positive by PCR assay were subjected to multiplex PCR assay with CPV-2ab and CPV-2b primer pairs. Sixty-seven (98.52%) samples were characterized as CPV-2b type and one sample (1.47%) was categorized as CPV-2a type. Sixty clinical samples found negative by CPV-2ab primers were subjected to another PCR assay with CPV-555 primer pair for detecting CPV-2c. Though three samples (5%) responded to this PCR, subsequent RFLP of these PCR products with MboII did not show any cleavage indicating the absence of CPV-2c in Pondicherry. It was inferred that CPV-2b was the most prevalent CPV type in Pondicherry. It was further concluded that the CPV-2 variants (CPV-2a, CPV-2b and CPV-2c) currently circulating in the field worldwide could be diagnosed by employing multiplex PCR and PCR-RFLP assays.