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Summary Canine distemper (CD) is one of the highly contagious and invariably fatal viral diseases of dogs and other carnivores. Despite the widespread use of modified live vaccines to control CD, the prevalence of disease has increased at an alarming rate in recent years. Although a number of factors may be ascribed for vaccine failure, antigenic differences among the vaccine and wild‐type strains have gained the interest of researchers. Considering the high genetic variability of haemagglutinin gene (H gene) and its role in eliciting the immune response to canine distemper virus (CDV), we have generated nine full‐length CDV H gene sequences from infected dogs including three vaccinated cases. Bayesian analysis was performed using 102 full‐length H gene nucleotide sequences over a time frame of 76 years (1940–2016) from 18 countries. The time to the most recent common ancestor (tMRCA) of CDV was estimated to be 1696 AD. Phylogenetic reconstruction clustered Indian wild‐type viruses into a distinct monophyletic group clearly separated from the previously established CDV lineages. This signifies the presence of a novel genetic variant (proposed as “Lineage India‐1/Asia‐5”) circulating among dog population in India. To investigate the importance of substitutions at amino acid residues 530 and 549 of CDV H protein in determining the host switches from canid to non‐canid hosts, we analysed 125 H gene sequences including nine sequences generated in this study. Selection pressure analysis and analysis of amino acid sequences revealed a trend towards adaptation of 549H variants in non‐canid hosts although no role of G/E530R/D/N substitution could be identified. This is the first comprehensive study about the nature and ecology of CDV circulating among dog population in India. Outbreaks in vaccinated animals as observed in this study have raised a concern towards the effectiveness of current vaccine strains warranting detailed investigation.

Canine parvovirus-2 (CPV-2), which is ubiquitously distributed worldwide, causes severe and often fatal gastroenteritis in dogs. Accurate, differential and rapid diagnosis of canine parvoviral enteritis remains a challenge for clinicians. A recently developed isothermal amplification technique, polymerase spiral reaction (PSR), was optimized for the first time for a viral pathogen with reference recombinant plasmid standards from different CPV-2 antigenic variants (CPV-2, CPV-2a, CPV-2b and CPV-2c) and subsequently validated using clinical samples. Addition of chromogenic substrate SYBR Green I after the completion of the reaction resulted in bright green fluorescence in positive samples, while negative samples and a no-template control remained orange. These results were further substantiated through visualization of a laddering pattern of the PSR-amplified product in an agarose gel in positive cases and the absence of this pattern in no-template control and negative samples. The PSR assay was found to be highly specific, as it did not react with other putative canine pathogens (canine adenovirus 1 and canine distemper virus). The sensitivity of the newly developed PSR technique was compared with that of conventional PCR, real-time PCR and LAMP, using a serial tenfold dilution of canine parvovirus DNA. The detection limit of PSR was found to be at the femtogram level, which is comparable with that of real-time PCR and LAMP, which are ten times more sensitive than conventional PCR. The assay was validated using 90 clinical samples, of which 54 were found positive, while only 45 samples were positive in conventional PCR. This novel assay, which is fully compliant with the 'ASSURED' concept for disease diagnosis, provides a simple, rapid, specific, sensitive and cost-effective method for diagnosis of canine parvoviral enteritis in veterinary clinics.

Preservation of vaccines, viruses and other biologicals is one of the onerous tasks in maintaining the quality of the products from manufacture until they reach the end users. Live-attenuated viral vaccines, serum immunoglobulins, plasma fractions and clinical samples, including tissues and body fluids, are all materials that usually require cold-chain maintenance during storage and distribution. A number of stabilizers are currently used to help retain the quality of these materials, in particular vaccines, during transit. Deuterium oxide (heavy water; D(2)O) has previously been reported to have a protective effect on biomolecules (proteins and nucleic acids), cells and simple multicellular organisms against thermal shock. Of late, the potential of D(2)O has been demonstrated in stabilization of the oral polio and yellow fever 17D vaccines. This review is the outcome of a thorough search and scan of the literature in a quest to explore the potential use of heavy water in the stabilization of veterinary biologicals. The literature search revealed this potential of heavy water as exemplified by successful stabilization of oral polio and yellow fever vaccines. Through this review, the authors wish to inform animal health researchers and disseminate their knowledge on the use of heavy water in biomolecule stabilization and its potential application in the stabilization of veterinary vaccines and other biologicals.

Summary Peste‐des‐petits‐ruminants (PPR), bluetongue (BT) and goatpox (GP) have been well recognized as causes of significant economic losses in the small ruminant population of Asia and Africa. We describe here the occurrence of these three in an outbreak noticed in non‐descript goats from a subtropical region of central India. An investigation was carried out to confirm the aetiology of the heavy mortality in goats (74.6%, 112/150), with testing of samples from 12 surviving animals exhibiting mixed clinical signs indicative of PPR, BT and GP. Sandwich ELISA was used to detect PPR virus antigen and competition ELISA to detect PPR virus and BT virus antibodies. GP was confirmed on the basis of nodular lesions and an immunodiffusion assay. Eight of the 12 affected animals (66.7%) were positive for PPR virus and BT virus antibodies, and two goats (16.7%, 2/12) exhibiting clinical lesions of pox were also found positive for PPR virus/antibodies and BT virus antibodies, respectively. Although BT virus could not be identified in any sample, detection of BT virus antibodies indicated previous or possibly concurrent infection with BT virus in these goats. The N‐gene‐based RT‐PCR was used to confirm the PPR infection in these goats, and one of the amplicons was sequenced. The sequence and phylogenetic analysis revealed close proximity to PPR virus isolates from Tibet and China, with sequence homology of up to 96.9%. The sequence homology was relatively low with the majority of other Indian isolates (72.7–93.5%). The detection of this new PPR virus sequence indicates the circulation of cross‐border strains in this region of India. It is presumed that the heavy mortality observed in goats is possibly attributable to the occurrence of mixed infection of PPR and GP, or PPR, BT and GP.