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Newcastle disease is an avian pathogen causing severe economic losses to the Indian poultry industry due to recurring outbreaks in vaccinated and unvaccinated flocks. India being an endemic country, advocates vaccination against the virus using lentogenic and mesogenic strains. Two virus strains which are commonly used for vaccination are strain F (a lentogenic virus) and strain R2B (a mesogenic virus). Strain F is given to 0–7 days old chicks and R2B is given to older birds which are around 6–8 weeks old. To understand the genetic makeup of these two strains, a complete genome study and phylogenetic analysis of the F, HN genes of these vaccine strains were carried out. Both the viral strains had a genome length of 15,186 nucleotides and consisted of six genes with conserved complimentary 3' leader and 5' trailer regions. The fusion protein cleavage site of strain F is GGRQGRL and strain R2B is RRQKRF. Although both the viral strains had different virulence attributes, the length of the HN protein was similar with 577 amino acids. Phylogenetic analysis of F, HN and complete genome sequences grouped these two strains in genotype II category which are considered as early genotypes and corroborated with their years of isolation. [ABSTRACT FROM AUTHOR]

Egg Drop Syndrome-76 (EDS-76) is a recognized disease of chickens and Japanese Quails, which is of high economic importance due to its drastic negative effects on egg production in laying birds. The aim of the present study was to better understand the EDS-76 viral disease process in Japanese quails (Coturnix coturnix japonica), since very limited studies have been conducted in this species of birds. For this purpose, an experimental study was conducted with infection of EDS-76 virus in laying Japanese quails to reveal pathology, effect on egg production/quality and immune responses of this virus in these birds. By 7, 9 and 13-15 Days Post Infection (DPI), drop as well as aberrant egg production and lower mean egg quality were observed compared to control birds. Significant histopathological changes were observed in genitalia and spleen. Haemagglutination Inhibition (HI) and Enzyme Linked Immunosorbent Assay (ELISA) titres rose rapidly by 2nd week when it became maximum; thereafter declined and maintained at low levels up to 10 week post infection. The mean total protein values in infected quail gradually increased to 4.10±0.05/100 mL without any change in mean albumen value at 12 DPI. In conclusion, the course of the EDS-76 is significant not only in chickens but also in quails even though it occurs occasionally in quails. Explorative pathological, blood biochemical and immunological studies are suggested during EDS-76 viral disease course in quails. This would aid in formulating effective disease prevention and control measures for this economically important disease of poultry.