Detection and Genomic Characterization of Senecavirus from Indian Pigs

Background: Senecavirus A (SVA), is a positive sense small non-enveloped RNA virus which belongs to Picornaviridae family and is responsible for porcine vesicular disease. The disease has been reported in many countries since late 2014, 2015 and 2016 like USA, Canada, Brazil, China and Thailand. Methods: In this study, the metagenomic study was performed on faecal samples of pigs/piglets suffering from diarrhea in Haryana, India with the help of next generation sequencing. The cDNA library was prepared from the faecal samples and run on the Illumina MiSeq instrument followed by identification and genomic characterization. Result: This study revealed the presence of SVA in the samples. The characterization of complete genome sequence of this strain showed complete nucleotide identity (100%) with SVA genomes reported from Canada, however, the polyprotein shares 98-99% amino acid sequence similarity with the genomes currently available in the GenBank. To the best of our knowledge this is the first report of SVA infection in pigs/piglets of Haryana, India. It demonstrates that an active and urgent surveillance of the swine population is required in the region. Additionally, the veterinarians must pay immediate attention to this vesicular disease and adopt preventive measures for its control.

Identification of a Conserved Neutralizing Epitope in Seneca Valley Virus VP2 Protein: New Insight for Epitope Vaccine Designment

Background Seneca Valley virus (SVV) is a picornavirus that causes vesicular disease in swine. Clinical characteristics of the disease is similar to common viral diseases such as foot-and-mouth disease virus, porcine vesicular disease virus, and vesicular stomatitis virus, which can cause vesicles in the nose or hoof of pigs. Therefore, developing tools for detecting SVV infection is critical and urgent. Methods The neutralizing antibodies were produced to detect the neutralizing epitope. Results Five SVV neutralizing monoclonal antibodies (mAb), named 2C8, 3E4, 4C3, 6D7, and 7C11, were generated by immunizing mouses with ultra-purified SVV-LNSY01-2017. All five monoclonal antibodies exhibited high neutralizing titers to SVV. The epitopes targeted by these mAbs were further identified by peptide scanning using GST fusion peptides. The 153QELNEE158 peptide is defined as the smallest linear neutralizing epitope. The antibodies showed no reactivity to VP2 single mutants E157A. Furthermore, the antibodies showed no neutralizing activity with the recombinant virus (SVV-E157A). Conclusion The five monoclonal antibodies and identified epitopes may contribute to further research on the structure and function of VP2 and the development of diagnostic methods for detecting different SVV strains. Additionally, the epitope recognized by monoclonal antibodies against VP2 protein may provide insights for novel SVV vaccines and oncolytic viruses development.

Construction and Generation of a Recombinant Senecavirus a Stably Expressing the NanoLuc Luciferase for Quantitative Antiviral Assay

Senecavirus A (SVA), also known as Seneca Valley virus, is a recently emerged picornavirus that can cause swine vesicular disease, posing a great threat to the global swine industry. A recombinant reporter virus (rSVA-Nluc) stably expressing the nanoluciferase (Nluc) gene between SVA 2A and 2B was developed to rapidly detect anti-SVA neutralizing antibodies and establish a high-throughput screen for antiviral agents. This recombinant virus displayed similar growth kinetics as the parental virus and remained stable for more than 10 passages in BHK-21 cells. As a proof-of-concept for its utility for rapid antiviral screening, this reporter virus was used to rapidly quantify anti-SVA neutralizing antibodies in 13 swine sera samples and screen for antiviral agents, including interferons ribavirin and interferon-stimulated genes (ISGs). Subsequently, interfering RNAs targeting different regions of the SVA genome were screened using the reporter virus. This reporter virus (rSVA-Nluc) represents a useful tool for rapid and quantitative screening and evaluation of antivirals against SVA.

Biological properties of swine vesicular disease virus strain 2348 Italy/2008

Swine vesicular disease (SVD) is a viral infectious disease, which, if acute, is manifested by the clinical pattern similar to a number of vesicular diseases including foot-and-mouth disease. In case of subclinical disease, there are no evident clinical signs, therefore the diagnosis is problematic, and there can be the risk of the disease introduction into the Russian Federation with the infected pigs. The key measure for the prevention of SVD introduction involves control diagnostic testing of all animals imported in the country that makes it necessary to keep updated the currently used methods and tools for the disease laboratory diagnosis. The paper demonstrates data on experimental infection of pigs with SVDV strain 2348 Italy/2008 that belongs to the most recent one of the four known phylogenetic groups. The virus was kindly provided by the World Reference Laboratory for Foot-and-Mouth Disease (Pirbright, Great Britain), and it was adapted to the monolayer continuous cell cultures of porcine origin (IB-RS-2 and PGSK-30). The pigs were intradermally infected with concentrated cultured virus at a dose of 109 TCID50. The infected animals demonstrated clinical signs typical for the acute disease. There was evidence that the virus was not transmitted to the intact animal in case husbandry conditions were met that allowed to avoid the infection transmission by the fecal-oral and contact mechanisms. As a result of the experiment, reference sera were collected at different time intervals post infection and their activity was determined using virus microneutralization test in cell culture and ELISA. Aphthae collected from the infected animals were deposited into the Strain collection of the Reference Laboratory for Foot-and-Mouth Disease, FGBI “ARRIAH”.

A case report on pemphigus foliaceus

Pemphigus Foliaceus (PF) is second most common autoimmune vesicular disease in the pemphigus family characterized by superficial blisters of the skin and rarely mucous membranes which rupture to produce scaly, crusted lesions. A 54 year old female patient admitted in female derma ward in tertiary care hospital, with the chief complaints of painful ruptured blisters all over the body with crusty, scaly patches associated with serous discharge and itching since 15 days. A positive Nikolsky’s sign is when the skin shears off easily when the surface is wiped sideways with a cotton swab or a finger. Based on both subjective and objective evidence, this case is assessed as Pemphigus Foliaceus. The plan incudes Corticosteroids, Immunosuppressants, Antibiotics, Vitamin A & D supplements, IV fluids, calcium and aminoacids supplements, antivirals and antifungals (if needed), proper wound management and finally plasmapheresis.

Retrospective Characterization of the 2006–2007 Swine Vesicular Disease Epidemic in Northern Italy by Whole Genome Sequence Analysis

Advances in the epidemiological tracing of pathogen transmission have been largely driven by the increasing characterisation of whole-genome sequence data obtained at a finer resolution from infectious disease outbreaks. Dynamic models that integrate genomic and epidemiological data further enhance inference on the evolutionary history and transmission dynamics of epidemic outbreaks by reconstructing the network of ‘who-infected-whom’. Swine Vesicular Disease (SVD) was present in Italy from 1966 until 2015, and since the mid-1990s, it has mainly been circulating within Italy’s central-southern regions with sporadic incursions to the north of the country. However, a recrudescence of SVD in northern Italy was recorded between November 2006 and October 2007, leading to a large-scale epidemic that significantly affected the intensive pig industry of the Lombardy region. In this study, by using whole-genome sequence data in combination with epidemiological information on disease occurrences, we report a retrospective epidemiological investigation of the 2006–2007 SVD epidemic, providing new insights into the transmission dynamics and evolutionary mode of the two phases that characterised the epidemic event. Our analyses support evidence of undetected premises likely missed in the chain of observed infections, of which the role as the link between the two phases is reinforced by the tempo of SVD virus evolution. These silent transmissions, likely resulting from the gradual loss of a clear SVD clinical manifestation linked to sub-clinical infections, may pose a risk of failure in the early detection of new cases. This study emphasises the power of joint inference schemes based on genomic and epidemiological data integration to inform the transmission dynamics of disease epidemics, ultimately aimed at better disease control.