Nagendra Nath Barman

Identification and phylogenetic analysis of orf viruses isolated from outbreaks in goats of Assam, a northeastern state of India

Two outbreaks of orf virus (ORFV) (a parapoxvirus) infection in goats, which occurred in Golaghat and Kamrup districts of Assam, a northeastern part of India, were investigated. The disease was diagnosed by standard virological and molecular techniques. The entire protein-coding region of B2L gene of two isolates were cloned and sequenced. Phylogenetic analysis based on B2L amino acid sequences showed that the ORFVs identified in these outbreaks were closely related to each other and both were closer to ORFV-Shahjahanpur 82/04 isolate from north India. The present study revealed that the precise characterization of the genomic region (B2L gene) might provide evidence for the genetic variation and movement of circulating ORFV strains in India.

Molecular characterization of Newcastle disease virus strains isolated from different outbreaks in Northeast India during 2014–15

Newcastle disease virus (NDV) isolates recovered from different outbreaks in chicken flocks in Assam during 2014-15 were genotypically and pathotypically characterized. Nucleotide sequence analysis of fusion (F) and hemagglutinin protein genes showed a close similarity with genotype XIII strains of NDV. Amino acid sequence of F protein showed a virulent cleavage site (112)R-R-Q-K-R-F(117). Furthermore, pathogenicity test in one-day-old chicks and embryonated chicken eggs showed a virulent pathotype of the isolated NDV strains. The study will help us to understand the biology of circulating strains of NDV in Northeastern part of India.

Development of single dilution immunoassay to detect E2 protein specific classical swine fever virus antibody

Classical swine fever virus (CSFV) is the causative agent of a highly contagious disease in swine. The disease is endemic in different parts of the world and vaccination is the only way to protect pigs from CSFV infection. The virus surface protein E2 is the major immunogenic protein eliciting protective immunity against CSFV infection in swine. The whole virus antigen cannot differentiate CSFV from other pestiviruses as it cross reacts with border disease and bovine viral diarrhoea viruses. Commercial available ELISA is based on the whole CSFV particle and can lead to false positive results. Moreover, the available commercial ELISA is not cost effective. In the present study, a recombinant E2 protein based single serum dilution ELISA was developed which showed enhanced sensitivity, specificity and accuracy as compared to commercial CSFV detection ELISA. The recombinant E2 protein based ELISA could be an alternate to existing diagnostics against CSFV infection in pigs.

Seroprevalence of contagious ecthyma in goats of Assam: An analysis by indirect enzyme-linked immunosorbent assay.

Aim: The objective of this study was to screen the prevalence of contagious ecthyma (CE) among the goat population of Assam owing to its high prevalence rate. Materials and Methods: In this study, a total of 231 serum samples were collected from 12 districts of Assam during September 2013 to July 2014. The serum samples were tested for the presence of antibodies against Orf virus (ORFV) by indirect enzyme-linked immunosorbent assay (ELISA). Indirect ELISA was standardized using purified Orf reference virus produced in bulk in primary lamb testes cells. Results: Studies on seroprevalence showed 76.62% of goats were seropositive. The total number of animals were divided into different age groups starting from 0-2 months, 2-4 months, 4-6 months, and above 8 months and accordingly highest prevalence of antibodies against ORFV was recorded in the age-group above 8 months of age. Significantly, lower rates of infection were observed in goats of age group 2-4 months. This study recorded that seropositivity from naturally infected animals and in contact apparently healthy animals to be 53.67% and 46.32%, respectively. Conclusion: The results indicated that CE is a prevalent infection in goats of Assam, and the healthy population is at increased risk of infection.

Molecular characterization of E2 glycoprotein of classical swine fever virus: adaptation and propagation in porcine kidney cells.

Classical swine fever virus (CSFV) is the causative agent of a highly contagious disease, hog cholera in pigs. The disease is endemic in many parts of the world, and vaccination is the only way to protect the animals from CSFV infection. The lapinized vaccine strains are occasionally not protective because of animal to animal passage, inadequate vaccination strategy, suboptimal vaccine dose, and emergence of new variants. The surface glycoprotein E2 of CSFV is a major antigenic determinant and can modulate the disease outcome in pigs. In the present study, we characterized the CSFV in porcine kidney cells. The CSFV vaccine strains showed enhanced replication following 15 passages in porcine kidney cells. Nucleotide sequence analysis of the E2 protein gene of the cell culture-adapted vaccine strain of CSFV showed a mutation in putative amino acid sequences that are identical to its virulent counterpart. The study suggests the possibility of exaltation in vaccine strains following its adaptation in host cells and paves the way for a further exploration of the biology of its outbreak.

Identification of swinepox virus from natural outbreaks in pig population of Assam

Outbreaks of swinepox [caused by a swinepox virus (SWPV)] in pigs were investigated in 3 districts of Assam, a north eastern state of India. Diagnosis of the disease was carried out employing both standard virological as well as molecular methods. Three representative isolates from different places were selected for inoculation into confluent monolayers of Porcine Kidney-15 (PK-15) cell line. The cytopathic effects were characterized by cell rounding, nuclear vacuolation, cell fusion, granulation of cells and finally detachment from third blind passage onwards. The three genes viz., SPV18–20 and P42 of SWPV was targeted for confirmation of the virus. Swinepox virus was successfully adapted to the PK-15 cell line from seventh passage onwards. The isolated viruses were characterized by sequencing and phylogenetic analysis of P42 gene (extracellular envelope protein), a homologue of vaccinia virus F13L gene. In India, studies on swine pox are very limited. This is the first report on successful isolation of swinepox virus from north eastern region of India. Assam and the other north-eastern states of India being a hub for pig husbandry, isolation of swinepox virus will help in developing and formulating control strategies against the disease.

Goatpox outbreak at a high altitude goat farm of Mizoram: possibility of wild life spill over to domestic goat population

In this study, pox-like outbreaks in goat population was investigated that occurred in a high altitude goat farm located in Mizoram, a hilly state of North eastern India. The outbreak initially involved the serows, an wild animal belonging to the family Bovidae, subfamily Caprinae and genus Capricornis, the state animal of Mizoram. Later, the disease affected the domestic goat population. The disease was diagnosed on the basis of gross lesions and PCR amplification of partial P32 gene of capripox virus. The virus was isolated in vero cells. The full length P32 gene was sequenced and phylogenetic tree was constructed. It was revealed that the capripox virus isolated from the outbreak was closely related to the Chinese strain of goatpox virus at both amino acid and nucleotide level. To the authors’ knowledge, this is the first report on isolation and characterization of capripoxvirus from north eastern region of India.

Incidence of elephant endotheliotropic herpesvirus in Asian elephants in India

Elephant endotheliotropic herpesviruses (EEHVs) are the cause of acute hemorrhagic disease in endangered Asian and African elephants. In the present study, we report the incidence of EEHV infection and associated mortality in the captive elephant of Assam, India. Our result showed the gross morphology and histopathological changes of EEHV infection in the elephant. Moreover, the phylogenetic analysis of the polymerase, helicase, and GPCR genes from the infected tissue samples suggested the presence of EEHV1A virus.

Scanning Electron Microscopic Study of Caprine Intestine with Special Reference to Gut-Associated Lymphoid Tissues

The intestine of adult indigenous goat of Assam (Capra hircus) was studied by scanning electron microscopy (SEM) for elucidating the morphology of intestinal mucosa as well as the morphology of gutassociated lymphoid tissue including Peyer’s patches (PP) and solitary lymphoid nodule. SEM of intestines revealed the presence of villi in the small intestinal mucosa. Goblet cells were noticed as white pinheads on the villus surface between the enterocytes. The large intestinal mucosa of adult Assam local goat was devoid of villi. SEM of small intestinal mucosa revealed leaf or finger-like absorptive villi covering PP. Even the dome villi were completely covered by absorptive villi and were shorter than the absorptive villi. The absorptive villi in all segments of the small intestine had numerous microvilli. The interfollicular region had high endothelial venules. Propria nodules were lymphoid nodules predominantly in lamina propria and covered by distinct follicle-associated epithelium which lacked goblet cells and openings to deep invaginations into the mucosa.