Original Research

Thermostability study of virulent Newcastle disease viruses isolated in Southern Angola

António Neto, Ana M. Henriques, Teresa Fagulha, Miguel Fevereiro
Onderstepoort Journal of Veterinary Research | Vol 91, No 1 | a2147 | DOI: https://doi.org/10.4102/ojvr.v91i1.2147 | © 2024 António Neto, Ana M. Henriques, Teresa Fagulha, Miguel Fevereiro | This work is licensed under CC Attribution 4.0
Submitted: 20 October 2023 | Published: 15 April 2024

About the author(s)

António Neto, Laboratory of Virology, National Institute of Agricultural and Veterinary Research, Oeiras, Portugal Laboratory for the Production of Veterinary Vaccines, Veterinary Research Institute, Lubango, Angola
Ana M. Henriques, Laboratory of Virology, National Institute of Agricultural and Veterinary Research, Oeiras, Portugal
Teresa Fagulha, Laboratory of Virology, National Institute of Agricultural and Veterinary Research, Oeiras, Portugal
Miguel Fevereiro, Laboratory of Virology, National Institute of Agricultural and Veterinary Research, Oeiras, Portugal

Abstract

Newcastle disease (ND) is endemic in Angola. Several outbreaks of ND occurred in small backyard flocks and village chickens with high mortality in the southern provinces of the country, Cunene, Namibe and Huíla, in 2016 and 2018. In those years, 15 virulent ND virus (NDV) strains were isolated and grouped within subgenotype 2 of genotype VII (subgenotype VII.2). We now present a study on the thermostability of the isolates, aiming at the selection of the most thermostable strains that, after being genetically modified to reduce their virulence, can be adapted to the production of vaccines less dependent on cold chain and more adequate to protect native chickens against ND. Heat-inactivation kinetics of haemagglutinin (Ha) activity and infectivity (I) of the isolates were determined by incubating aliquots of virus at 56 °C for different time intervals. The two isolates from Namibe province showed a decrease in infectivity of 2 log10 in ≤ 10 min, therefore belonging to the I-phenotype, but while the NB1 isolate from 2016 maintained the Ha activity up to 30 min and was classified as thermostable virus (IHa+), the Ha activity of the 2018 NB2 isolate decreased by 2 log2 in < 30 min, being classified as a thermolabile virus (IHa). Of the 13 NDV isolates from Huíla province, 10 isolates were classified as thermostable, eight with phenotype I+Ha+ and 2 with phenotype IHa+. The other three isolates from this province were classified as thermolabile viruses (IHa).

Contribution: This study will contribute to the control and/or eradication of Newcastle disease virus in Angola. The thermostable viral strains isolated from chickens in the country can be genetically manipulated by reverse genetic technology in order to reduce their virulence and use them as a vaccine in the remote areas of Angola.


Keywords

Angola; haemagglutinin activity; infectivity; Newcastle disease virus; thermostability

Sustainable Development Goal

Goal 1: No poverty

Metrics

Total abstract views: 289
Total article views: 278


Crossref Citations

No related citations found.