Thermostability and Immunogenicity of Genotype II Avian Orthoavulavirus (AOaV-1) Isolates from Duck (Anas platyrhynchos) and Parrot (Eclectusroratus).

Newcastle disease (ND) is a highly contagious viral disease of poultry causing significant economic losses worldwide. Vaccination is considered the most reliable approach to curb the economic menace that is ND, but the thermolabile nature of Newcastle disease virus (NDV) vaccination poses a significant threat to its protective efficacy. This study aimed to profile the thermostability of NDV isolates from duck (As/Km/19/44) and parrot (As/WB/19/91) and evaluate their immunogenic potential in chicks. Fusion protein cleavage site (FPCS) and phylogenetic analysis demonstrated the lentogenic nature of both the isolates/strains and classified them as class II genotype II NDV. The characterized NDV isolates were adapted in specific-pathogen-free (SPF) chicks by serially passaging. Biological pathogenicity assessment of chicken-adapted As/Km/19/44 (PSD44C) and As/WB/19/91 (PSP91C) revealed both the isolates to be avirulent with a mean death time (MDT) of more than 90 h and an intracerebral pathogenicity index (ICPI) ranging from 0.2 to 0.4. Both of the NDV isolates displayed varied thermostability profiles. PSD44C was the most thermostable strain as compared to PSP91C and the commercially available LaSota vaccine strain. The immunogenicity of PSD44C and LaSota was significantly higher than PSP91C. Based on these results, it is concluded that NDV isolate PSD44C is more thermostable and immunogenic when administered intraocularly without any adverse effects. Therefore, PSD44C is suitable for further research and vaccine development.

Co-circulation of different genotype, sub-genotype and serotypes of hepatitis B virus (HBV) and its epidemiology in Assam: A north-eastern state of India.

PURPOSE: Hepatitis B virus (HBV) infection is a global health problem. HBV has different genotypes and subgenotypes with geographical distinctiveness. AIMS: To study the molecular epidemiology and distribution pattern of HBV in Assam; a distinct state of India that may have different genotypic divergence. SETTINGS AND DESIGN: Patients attending a tertiary care hospital susceptive of Hepatitis B were included, irrespective of age and sex in different agro-climatic zones of Assam. METHODS: Samples positive for Hepatitis B surface antigen test and COBAS®TaqMan® HBV tests were further confirmed by PCR and sequencing followed by phylogenetic analysis. STATISTICAL ANALYSIS USED: Chi-square test was used to determine whether there was a significant difference among the results in this study. RESULTS: An increase trend of HBV positive cases has been observed in the state. The incidence in female was lower than that of male and age group 26-35 years was most vulnerable. Genotype D, subgenotype D2 and serotype ayw3 were predominant genotype, subgenotype and serotype. The prevalence of subgenotype C3 was a new finding. Phylogenetic analysis showed that the genotypes of HBV prevailing in the state have close relationship with neighboring countries of India which may be due to increased cross border migration of population CONCLUSIONS: This comprehensive study of HBV in Assam described the distribution of HBV genotypes and subgenotypes and serotypes in different agro-climatic zones of Assam. These findings will help to formulate the roadmap for prevention and control of the disease as well as targeted therapy of HBV in this State.

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.

Isolation and molecular characterization of Orf virus from natural outbreaks in goats of Assam.

Outbreaks of contagious ecthyma (caused by a Parapox virus) in goats were investigated in 6 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. Four representative isolates from different places were selected for phylogenetic analysis. The major envelop protein (B2L) of Orf virus was targeted for molecular analysis. The sequencing and phylogenetic analysis of the selected sequences at nucleotide level revealed that the Orf virus isolates were closely related to each other (97.6-100 %) and showed highest similarity to the Orf virus isolate 82/04 (98.4 %), reported from Shahjahanpur, India. The data will provide an insight in transmission of the virus from northern to North eastern part of the country.