Epidemiological, Pathological, and Molecular Studies on Sheeppox Disease Outbreaks in Karnataka, India.

An epidemiological study spanning twelve years has revealed that sheeppox disease is both widespread and endemic, predominantly surging during the winter and summer seasons. This investigation focused on sheeppox across 11 field outbreaks, involving 889 animals from non-migratory flocks across six districts in Karnataka, in the southern peninsula of India. Among these, 105 animals exhibited clinical signs suggestive of sheeppox, such as lesions on the body, and 95 cases were confirmed through PCR testing. The overall positivity rate for sheeppox stood at 10.68% (95 out of 889 animals). The incidence of sheeppox was notably higher in animals aged between 1 and 2 years and was more prevalent in females. Affected animals displayed symptoms including respiratory distress, weakness, fever, loss of appetite, depression, and various skin lesions ranging from papular to pock lesions across their bodies. There was a significant increase in total leukocyte count, while hemoglobin levels, red blood cell counts, and hematocrit values significantly decreased. On gross examination, sheeppox lesions, varying from vesicular to nodular forms, were predominantly found on hairless areas of the body. Microscopic examination of skin lesions revealed extensive changes, such as hyperkeratosis, parakeratosis, acanthosis, hydropic degeneration, and necrosis of epithelial cells, along with characteristic intracytoplasmic viral inclusions. The lungs exhibited type-II pneumocyte hyperplasia and proliferative bronchiolitis, also with intracytoplasmic inclusions. Confirmation of the sheeppox virus was achieved through PCR and subsequent sequence analysis. Phylogenetic analysis of the full-length P32 and RPO30 gene demonstrated homology with sheeppox isolates from various parts of India and neighboring countries, indicating that Indian sheeppox viruses are highly lineage-specific and correlate with the host of origin. Based on these findings, it is recommended to implement a homologous vaccination strategy, utilizing selective host/viral strains to enhance protection in susceptible animals.

Structural and sequence analysis of the RPO30 gene of sheeppox and goatpox viruses from India.

Sheeppox and goatpox are transboundary viral diseases of sheep and goats that cause significant economic losses to small and marginal farmers worldwide, including India. Members of the genus Capripoxvirus (CaPV), namely Sheeppox virus (SPPV), Goatpox virus (GTPV), and Lumpy skin disease virus (LSDV), are antigenically similar, and species differentiation can only be accomplished using molecular approaches. The present study aimed to understand the molecular epidemiology and host specificity of SPPV and GTPV circulating in India through sequencing and structural analysis of the RNA polymerase subunit-30 kDa (RPO30) gene. A total of 29 field isolates from sheep (n = 19) and goats (n = 10) belonging to different geographical regions of India during the period: Year 2015 to 2023, were analyzed based on the sequence and structure of the full-length RPO30 gene/protein. Phylogenetically, all the CaPV isolates were separated into three major clusters: SPPV, GTPV, and LSDV. Multiple sequence alignment revealed a highly conserved RPO30 gene, with a stretch of 21 nucleotide deletion in all SPPV isolates. Additionally, the RPO30 gene of the Indian SPPV and GTPV isolates possessed several species-specific conserved signature residues/motifs that could act as genotyping markers. Secondary structure analysis of the RPO30 protein showed four α-helices, two loops, and three turns, similar to that of the E4L protein of vaccinia virus (VACV). All the isolates in the present study exhibited host preferences across different states of India. Therefore, in order to protect vulnerable small ruminants from poxviral infections, it is recommended to take into consideration a homologous vaccination strategy.

Lumpy Skin Disease (LSD) in Yak (Bos grunniens): An Evidence of Species Spillover from Cattle in India.

Lumpy skin disease (LSD), caused by the lumpy skin disease virus (LSDV), is a global concern that affects cattle and buffalo. Recently, the disease has been reported in new species such as the Indian Gazelle, Camel, Banteng, Gaur, and Giraffe from various parts of the world. This report provides an insight into the occurrence of LSD in Yak from Sikkim, a North-Eastern state of India. During the investigation, both cattle and yak exhibited typical clinical signs of LSD, including skin nodular lesions. The morbidity, mortality, and case fatality rates for cattle were 9.08%, 1.84%, and 20.24%, respectively. Similarly, the morbidity, mortality, and case fatality rates in yak were 7.57%, 1.24%, and 16.33%, respectively. The virus isolation and amplification of LSDV-specific genes confirmed the presence of LSDV in cattle, yak, and vectors. Further, demonstrated antibodies in randomly collected sera from naïve and unvaccinated cattle and yak using indirect Enzyme Linked Immuno-sorbent Assay (iELISA) and Serum Neutralisation test (SNT) from this region. Sequencing and phylogenetic analysis of P32, GPCR, and RPO30 genes revealed that the virus isolated from both species was 100% identical to each other and also closely related to the field LSDV isolates circulating in the Indian subcontinent. The study highlighted the emergence of LSDV in unconventional hosts and underscored the need to include other bovine species in national disease control programs, encompassing disease surveillance initiatives.