Clinicopathological Characterization in Poultry of Three Strains of Newcastle Disease Virus Isolated From Recent Outbreaks

Abstract

Newcastle disease is a severe threat to the poultry industry and is caused by Newcastle disease virus, a member of the genus Avulavirus, family Paramyxoviridae. The virus is rapidly evolving, and several new genotypes have been discovered in the past few years. Characterization of these strains is important to evaluate field changes, anticipate new outbreaks, and develop adequate control measures. Three Newcastle disease isolates (APMV-1/duck/Vietnam, Long Bien/78/2002, APMV-1/chicken/ Australia/9809-19-1107/1998, and APMV-1/double-crested cormorant/USA, Nevada/19529-04/2005) from recent outbreaks were investigated via clinicopathological assessment, immunohistochemistry (IHC), in situ hybridization, virus isolation, and serology in experimentally infected 4-week-old chickens. Phylogenetic studies showed that Australia isolate belongs to class II genotype I, Long Bien to class II genotype VIId, and Nevada cormorant to class II genotype V. Even though all 3 viruses had a virulent fusion protein cleavage site and ICPI values greater than 1.5, they all differed in their ability to cause clinical signs, in their lesions, and in their viral distribution in body tissues. The Long Bien isolate showed the most severe clinicopathological picture and the most widespread viral distribution. The Australia and Nevada cormorant isolates had a milder pathological phenotype, with viral replication restricted to only a few organs. The variability in clinicopathological characteristics despite the similarity in ICPI suggests that full clinicopathological assessment is necessary to fully characterize new isolates and that there are differences in pathogenesis among viruses of different genotypes.

Outbreak investigation of Newcastle disease virus from vaccinated chickens in Eritrea

“…Though signs and gross lesions associated with the virulent pathotypes will give rise to strong suspicion of the disease, they do not present a reliable basis for diagnosis of ND (OIE, 2012). Absolute identification is dependent upon the isolation and identification of the causative virus (Terregino and Capua, 2009;Susta et al, 2010). The preferred method for diagnosis of Newcastle disease involves mainly conventional viral isolation in embryonated chicken eggs with subsequent identification by haemagglutination inhibition test and molecular techniques like PCR (RT-PCR) (Alexander, 1991;Terregino and Capua, 2009).…”

Isolation, Identification and Molecular Characterization of Highly Pathogenic Newcastle Disease Virus From Field Outbreaks

“…In various developing countries, ND is an endemic and thus have a high economic impact. Due to this disease, poultry industry is facing losses of billions of Rupees annually in Pakistan [14] and millions of dollars worldwide [15]. ND is a serious threat to the poultry industry [16].…”

Molecular Pathotyping of Newcastle Disease Virus from Naturally Infected Chickens by RT-PCR and RFLP Methods

“…Based on the phylogenetic distance, NDV can be classified into two classes, namely class 1 and class 2. Class 2 NDV are further subclassed into nine genotypes (Susta et al, 2011).…”