Characterization of a Newcastle disease virus isolated from apparently normal guinea fowl (Numida melagridis)

Recombinase polymerase amplification-nucleic acid lateral flow immunoassays for Newcastle disease virus and infectious bronchitis virus detection

Newcastle disease virus (NDV) and infectious bronchitis virus (IBV) are two poultry pathogens affecting the respiratory tract of chickens, and cause major economic losses in the industry. Rapid detection of these viruses is crucial to inform implementation of appropriate control measures. The objective of our study is developing a simple, rapid and field applicable recombinase polymerase amplification (RPA)–nucleic acid lateral flow (NALF) immunoassay for detection of NDV and IBV. Isothermal amplification of the matrix protein (M) gene of NDV and the nucleoprotein (N) gene of IBV was implemented via recombinase polymerase amplification at 38 °C for 40 min and 20 min, respectively using modified labeled primers. NALF device used in this study utilizes antibodies for detection of labeled RPA amplicons. The results revealed that RPA-NALF immunoassays can detect both viruses after 40 min at 38 °C and only NDV after 20 min. The limit of detection (LOD) was 10 genomic copies/RPA reaction. The assays results on clinical samples collected from diseased chicken farms demonstrated a good performance in comparison with quantitative real time reverse transcription polymerase chain reaction (qRT-PCR). The assays established in this study can facilitate rapid, on-site molecular diagnosis of suspected cases of ND and IB viral infections as the results can be detected by the naked eye without the need for measuring fluorescence. Furthermore, the NALF device could be adapted to detect other infectious agents.

Genetic characterization and pathogenicity assessment of Newcastle disease virus isolated from wild peacock

The continued spread and occurrence of Newcastle disease virus (NDV) has posed potential threat to domestic poultry industry around the globe. Mainly, wild avian species has always been implicated for the natural reservoir for virus and spread of the disease. In the present study, we report the isolation of Newcastle disease virus (NDV/Peacock/India/2012) in necropsy brain tissue sample of wild peacock from North India. Complete genome of the virus was found to be 15,186 nucleotides (nts) with six genes in order of 3'-N-P-M-F-HN-L-5', which was limited by 55-nts leader region at the 3' end and a 114-nts trailer sequence at 5' end. Sequence analysis of fusion protein revealed the dibasic amino acid cleavage site (112)R-R-Q-K-R-F(117), a characteristic motif of virulent virus. Phylogenetic analysis placed the isolate in genotype II of Newcastle disease virus showing the lowest mean percent divergence (6 %) with other genotype II counterparts. The isolate was characterized as mesogenic (intermediate pathotype) based on the mean death time (63 h) in embryonated chicken eggs and the intra-cerebral pathogenicity index (1.40) in day-old chicks. The report emphasizes the dynamic ecology of NDV strains circulating in a wild avian host during the outbreak of 2012 in North India. Further the genotypic and pathotypical characterizations of the isolate could help in development of homologous vaccine against NDV strain circulating in avian population.

Detection and molecular characterization of Newcastle disease virus in peafowl (Pavo cristatus) in Haryana State, India

Present study was undertaken to investigate the cause of deaths of peafowls in Haryana State. In total, 145 birds were sick and 28 birds were reported dead during July to September 2012. Some of the sick birds were showing signs of shaking of heads, torticollis and paresis. Blood and cloacal swab samples from sick birds along with brain and intestinal tissues from dead birds were collected for further investigation. Although post-mortem examination showed no typical lesions of Newcastle disease virus (NDV) yet raised HI tires against NDV in some serum samples and clinical signs indicated the presence of NDV. One of the brain tissues (NDV/IND2012/01) from the field case was processed and adapted to Vero cell line for virus isolation. The fusion (F) gene based nested RT-PCR (RT-nPCR) confirmed the presence of NDV in all field samples and cell culture isolate. Sequencing of the partial F gene amplicons (216 bp) using the PCR primers as sequencing primers confirmed the PCR results. The deduced amino acid sequences of partial F gene were found to have the amino acid motif (111)GRRQKR/F(117) in the fusion protein cleavage site (FPCS). This amino acid motif is indicative of the velogenic nature of these NDVs. Phylogenetic studies have shown that the virus belonged to class II genotype VII very closely related to virus isolates originated from outbreaks in Western Europe, Israel, Indonesia, Taiwan and India. Phylogenetic grouping of the virus and sequence of FPCS is indicative of pathogenic potential of virus strain circulating in peacocks in Haryana.

Phylogenetic analysis of Newcastle disease viruses isolated from asymptomatic guinea fowls (Numida meleagris) and Muscovy ducks (Cariana moscata) in Nigeria

Four Newcastle disease virus isolates were recovered from asymptomatic guinea fowl (Numida meleagris galeata) and Muscovy ducks (Cariana moscata). For the purpose of molecular identification and phylogeny, phylogenetic characterization was performed to identify the pathotypes. All four viruses had a cleavage motif (112)RRQKRF(117) which is characteristic of virulent strains. The isolates grouped with viruses previously reported as sub-lineage 5 g from chickens in Nigeria. This study report for the first time the identification of the virulent sub-lineage 5 g Newcastle disease virus from apparently healthy guinea fowl and domestic ducks in Nigeria, and since infections were sub-clinical, it suggest that these species could play a role in the spread and transmission of virulent Newcastle disease virus that can infect other poultry. The isolation and identification of virulent Newcastle disease virus in these unusual hosts and the high sequence similarity (99.3-100 %) between viruses in this study with strains reported for Niger and Cameroun gives insights into the ecology of virulent Newcastle disease viruses and suggests some cross-border movement and trade in live poultry.

Pathotyping of a Newcastle disease virus isolated from peacock (Pavo cristatus)

This report describes Newcastle disease in peacock and the isolation and characterization of the virus. The virus had an intracerbral pathogenicity index of 1.71 and mean death time of 47 h. The isolate had multiple basic amino acids at the fusion protein cleavage site sequence ((110)GGRRQRRFIG(119)) with a phenylalanine at residue 117. Biological and molecular characterization revealed that the virus is velogenic. Phylogenetic analysis placed the isolate in genotype II.

ESTUDIO DE LA VACUNACIÓN EXPERIMENTAL EN GALLINA DE GUINEA (NUMIDA MELEAGRIS) CONTRA LA ENFERMEDAD DE NEWCASTLE E INVESTIGACIÓN DEL ESTADO DEL PORTADOR DE VIRUS

RESÚMEN El trabajo tuvo como objetivo estudiar la importancia de la vacunación contra la enfermedad de Newcastle en pintadas (Numida meleagris galeata), como tanbién investigar el estado de portador del virus en esta especie. Fueron usadas 300 gallina de guinea, distribuidas, aleatoriamente, en 5 grupos vacunados o no. A las 5 y 12 semanas, todos los grupos fueron desafiados con una suspensión de virus patogénico (NVD), EID50 = 10 8,15/0,1 mL. Para aislamiento viral, realizado en huevos embrionados LPE, después de 5, 10, 15, 20 y 30 días (5 colectas) para el grupo testigo y 15 días (colecta única) después de cada desafío para los demás grupos, fueron usados hisopados de cloaca. Las gallina de guinea de todos los grupos no demostraron síntomas de la enfermedad de Newcastle. Las gallina de guinea entonces se mostraron refractarias a la enfermedad clínica con el NVD. En las gallina de guinea del grupo testigo, el aislamiento viral se obtuvo de 5 hasta 30 días después de cada desafío. Quedó demostrado así el estado de portador de NVD de la gallina de guinea. En las pintadas de los grupos vacunados, el aislamiento viral fue nulo. Quedó demostrado también así la importancia de la vacunación en la supresión del estado de portador del NVD de la gallina de guinea.