Substantial variation in the virulence of Newcastle disease virus (NDV) isolates means that the detection of NDV or evidence of infection is insufficient for an adequate diagnosis, as control measures for avirulent viruses are very different to those for virulent viruses. Diagnosis therefore requires further characterization, at least as to whether an isolate is virulent or avirulent. Conventional detection and differentiation of ND viruses is perceived as slow, laborious and requiring an undesirable use of in vivo techniques. In addition, further characterization is needed to give greater information on origin and spread. This review concentrates on the application of monoclonal antibody and molecular biological approaches. Panels of monoclonal antibodies were a major advance for the characterization of NDV isolates, although confirmation of virulence for poultry still required in vivo testing. As molecular-based techniques become easier and more reliable, they are likely to supersede the use of monoclonal antibodies, especially for characterizing viruses for epidemiological purposes. The attraction of molecular-based techniques is that they may be able to cover all three aspects of Newcastle disease diagnosis (detection of virus, characterization, including inference of virulence, and epidemiology) quickly, accurately and definitively in a single test. A number of approaches based on the reverse transcriptase polymerase chain reaction have been developed, with subsequent analysis of the product by restriction enzyme analysis, probe hybridization and nucleotide sequencing. Although extensive variation among NDVs still poses technical problems, the real and potential advantages of a molecular biological approach to Newcastle disease diagnosis appear to be overwhelming.

https://www.tandfonline.com/doi/pdf/10.1080/03079450120044515

Detection and differentiation of Newcastle disease virus (avian paramyxovirus type 1).

A review of RT-PCR technologies used in veterinary virology and disease control: sensitive and specific diagnosis of five livestock diseases notifiable to the World Organisation for Animal Health.

Over the past two decades, enormous advances have occurred in the structural and biological characterization of Newcastle disease virus (NDV). As a result, not only the complete sequence of the viral genome has been fully determined, but also a clearer understanding of the viral proteins and their respective roles in the life cycle has been achieved. This article reviews the progress in the molecular biology of NDV with emphasis on the new technologies. It also identifies the fundamental problems that need to be addressed and attempts to predict some research opportunities in NDV that can be realized in the near future for the diagnosis, prevention and treatment of disease(s).

https://www.tandfonline.com/doi/pdf/10.1080/03079450120078626

Newcastle disease virus: macromolecules and opportunities.

Simultaneous detection and differentiation of Newcastle disease and avian influenza viruses using oligonucleotide microarrays.

SUMMARY. Sporadic outbreaks of Newcastle disease (ND) occurred in Taiwan during 1998–2000. In some cases, the disease occurred in broilers less than 2 wk old that originated in a broiler breeder farm, so spread of the ND virus (NDV) from the infected breeder farm to broiler ranches was suspected. The purpose of the present study was to examine the possibility of the transmission of NDV through eggs. Both clinical and experimental evidence were used to prove that this is possible. From epidemiological investigation, the possibility of transmission through eggs was suggested in two separate ND cases from a breeder farm and its progeny because two identical NDVs were isolated from both cases. In order to clarify the possibility of the transmission through eggs, one mean egg lethal dose (ELD50) of NDV was inoculated into the allantoic cavity of 155 9-to-11-day-old specific-pathogen-free (SPF) chicken embryos. Seventy-one hatching chicks from the inoculated embryos were raised for 14 days. The cloacal swabs fr...

https://bioone.org/journals/Avian-Diseases/volume-46/issue-2/0005-2086(2002)046[0461:CEAEEF]2.0.CO;2/Clinical-Epidemiologic-and-Experimental-Evidence-for-the-Transmission-of-Newcastle/10.1637/0005-2086(2002)046[0461:CEAEEF]2.0.CO;2.pdf

Clinical Epidemiologic and Experimental Evidence for the Transmission of Newcastle Disease Virus Through Eggs

To provide information on the epidemiology of Newcastle disease (ND) of poultry in Taiwan, ND virus isolates from chickens and an owl were investigated by restriction site analysis and sequencing of their gene. A 1, 349 base fragment of the F (fusion protein) gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR). The PCR products were analyzed using restriction endonucleases, HinfI, BstOI, and RsaI. Three strains isolated from chickens during the 1995 epidemic outbreak had the same restriction sites as that of a 1994 isolate; the number of the restriction sites of HinfI, BstOI, and RsaI were 4, 2, and 4, respectively. In the F gene of the strain isolated from an owl during the same outbreak an additional restriction site of HinfI was found. The 1991 isolate had only 3 restriction sites. The F gene of the owl isolate was amplified by RT-PCR and followed by direct sequencing. The deduced amino acid sequence at the cleavage site of the F protein was of virulent strains, 112R-R-Q-K-R-F117. The F gene of Ow/Tw/2209/95 was phylogenetically most closely related to that of Ck/Tw/2137/95 isolated from the same outbreak. The present results indicate that the causative virus of the 1995 ND outbreak had already been present in Taiwan.

Yin-Tai Kou

Papers

Restriction Fragment Length Polymorphism Analysis of the F Gene of Newcastle Disease Viruses Isolated from Chickens and an Owl in Taiwan