Peste des petits ruminants (PPR) is a highly contagious, economically important viral disease of small ruminants, targeted for global eradication by the year 2030. The recent geographic surge in PPR virus distribution, economic implications, the success of the rinderpest eradication campaign, and ongoing national/regional efforts convinced the FAO and OIE to initiate a global PPR control and eradication strategy. Since its discovery, a series of diagnostic tools have been developed for detecting PPR virus and virus-specific antibodies. Furthermore, it is understood that diagnostic and vaccine-monitoring tools are inevitable components of the four-stage strategy of global PPR eradication from assessment to the post-eradication phase. However, these tools may not be suitable for all stages of PPR control and eradication. For instance, diagnostics such as ELISA could be used for mass screening of clinical and serum samples, whereas immunochromatographic tests can be used at the field level as a pen-side test. Yet, assays with higher sensitivity, such as RT-PCR, RT-PCR ELISA, real-time RT-PCR and LAMP are important for early diagnosis of PPR and also, theoretically, during the late stages of eradication or when sampling non-natural hosts. Moreover, during the later stages of any control program, suspected/doubtful outbreaks will have to be reconfirmed using multiple laboratory tests. Hence, diagnostics can and should be efficiently applied at different stages of the PPR control and eradication campaign based on available resources and the number of samples to be tested. This article provides an overview of the various PPR diagnostic tools and suggests where and how they should be logically applied during the different phases of global PPR control and eradication.

Sheeppox and goatpox are economically important diseases of small ruminants caused by sheeppox virus (SPPV) and goatpox virus (GTPV), respectively. Although SPPV and GTPV have host preference, some strains may infect both sheep and goats. As capripox viruses (SPPV, GTPV and LSDV) are antigenically related but genetically distinct, their differentiation requires analysis at molecular level. In the present study, RPO30 and GPCR genes of eight Indian SPPV and GTPV isolates were PCR amplified, cloned and sequences are genetically and phylogenetically analyzed. The RPO30 gene of SPPV and GTPV had lineage-specific signatures, and deletion of 21-nucleotide exclusively present in SPPV. Similarly, GPCR gene also had lineage-specific signatures for SPPV and GTPV. Phylogenetic analysis of capripox viruses based on RPO30 and GPCR genes revealed three distinct lineage-specific clusters as per their host origin. Our study supports that both RPO30 and GPCR genes could be used for differentiation of SPPV and GTPV as well as for molecular epidemiological studies. The study also highlights the distinct lineage specificities of the Indian SPPV and GTPV isolates including vaccine strains.

Aim: To detect and differentiate Capripox virus (sheeppox virus and goatpox virus) infections by using 30 kDa RNA polymerase subunit (RPO30) gene based PCR.Materials and Methods: Two capripox viruses' viz., sheep pox virus (SPPV) and goatpox virus (GTPV) from clinical samples of different outbreaks were detected and differentiated using capri pox virus (CaPVs) genotyping PCR targeting the CaPV RPO30 gene. By using the above PCR assay, a total of 54 scab samples from pox disease outbreaks occurred in goats (n=21) and sheep (n=33) were screened. Results: Out of 54 clinical samples, 43 [17 out of 21 (80.95%) goat scabs and 26 out of 33 sheep (78.78%)] were found positive for capripox virus infection. All positive samples yielded expected amplicon sizes of 172 bp for goatpox virus and 152 bp for sheep pox virus. Conclusion:The current study demonstrated that RPO30 gene based PCR assay could be used for molecular epidemiology of capripox virus infection and differentiation of causative agent viz., sheep pox virus and goatpox virus.

Generally, capripoxvirus infections are host specific in nature and occasionally infect more than one species. In this study, an investigation was carried out from an outbreak of capripox in a mixed flock of sheep and goats which occurred in 2013 in the State of Jammu & Kashmir. The genetic analysis of P32, RPO30 and GPCR genes revealed that both goats and sheep were infected with goatpox virus.

Recent developments in molecular biology shed light on cross-species transmission of SPPV and GTPV. The present study was planned to characterize the capripoxviruses which were circulating in the field condition among sheep and goats using RPO30 gene-based viral lineage (SPPV/GTPV) differentiating PCR and sequencing of RPO30 and GPCR genes from clinical samples. Out of 58 scabs (35 sheep and 23 goats) screened, 27 sheep and 18 goat scabs were found positive for capripox virus infections. With the exception of one sheep and one goat scabs, all the positive samples yielded amplicon size according to host origin, i.e. SPPV in sheep and GTPV in goats. In the above two exceptional cases, goat scab and sheep scab yielded amplicon size as that of SPPV and GTPV, respectively. Further, sequencing and phylogenetic analyses of complete ORFs of RPO30 and GPCR genes from six sheep and three goat scabs revealed that with the exception of above two samples, all had host-specific signatures and clustered according to their host origin. In case of cross-species infecting samples, sheep scab possessed GTPV-like signatures and goat scab possessed SPPV-like signatures. Our study identifies the circulation of cross-infecting SPPV and GTPV in the field and warrants the development of single-strain vaccine which can protect the animals from both sheeppox and goatpox diseases.

Development of a cost effective quality vaccine is a key issue in rabies control programme in developing countries. With this perspective, in the present study, challenge virus standard (CVS)-11 strain of rabies virus was adapted to grow in BHK-21 cells, characterized, compared with other viruses including global vaccine strains and field isolates from Indian subcontinent and China at molecular level. This cell adapted virus was evaluated for the production of cost effective veterinary vaccine. The maximum virus titre achieved was 10 7 fluorescent focus unit (FFU)/mL at 10th passage level. There was no nucleotide difference in the nucleoprotein (N) and glycoprotein (G) genes after adaptation in cell line. Phylogenetic analysis showed that adapted virus was grouped with global vaccine strains, closest being with other CVS strains but distinct from the Indian field isolates. Global vaccine strains including cell adapted CVS-11 virus have 83-87 % identity at nucleotide level of G gene with Indian field viruses. Growth kinetics of cell culture adapted virus showed that the optimum virus titer (around 10 7 FFU/mL) could be obtained at around 48 h post infection by cocultivation method using 0.1 multiplicity of infection inoculums at 37°C. These findings can be used for up scaling of vaccine production. The protective efficacy of test vaccine produced using 10 6.95 FFU/mL cell culture harvest showed 1.17 IU/mL relative potency by NIH test. Further, adapted virus was found to be suitable for use in rapid fluorescent focus inhibition test.

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