Molecular Epidemiology of Outbreak-Associated and Wild-Waterfowl-Derived Newcastle Disease Virus Strains in Finland, Including a Novel Class I Genotype

Abstract

e Newcastle disease (ND) is a highly contagious, severe disease of poultry caused by pathogenic strains of Newcastle disease virus (NDV; or avian paramyxovirus-1). NDV is endemic in wild birds worldwide and one of the economically most important poultry pathogens. Most of the published strains are outbreak-associated strains, while the apathogenic NDV strains that occur in wild birds, posing a constant threat to poultry with their capability to convert into more virulent forms, have remained less studied. We screened for NDV RNA in cloacal and oropharyngeal samples from wild waterfowl in Finland during the years 2006 to 2010: 39 of 715 birds were positive (prevalence, 5.5%). The partial or full-length F genes of 37 strains were sequenced for phylogenetic purposes. We also characterized viruses derived from three NDV outbreaks in Finland and discuss the relationships between these outbreak-associated and the wild-bird-associated strains. We found that all waterfowl NDV isolates were lentogenic strains of class I or class II genotype I. We also isolated a genetically distinct class I strain (teal/Finland/13111/2008) grouping phylogenetically together with only strain HIECK87191, isolated in Northern Ireland in 1987. Together they seem to form a novel class I genotype genetically differing from other known NDVs by at least 12%.

Prevalence of avian paramyxovirus type 1 in Mallards during autumn migration in the western Baltic Sea region

“…Co-infections involving APMV-1 and IAV have been observed previously in North America and Europe [16,34]. In this study, more than half of the APMV-1 infected Mallard were simultaneously infected with IAV and statistical analyses suggest, although barely significant in this limited dataset, that the frequency of co-infection might be higher than expected.…”

Empirical analysis suggests continuous and homogeneous circulation of Newcastle disease virus in a wide range of wild bird species in Africa

“…The biological material collected and the RNA extraction method are the same for AIV and for NDV, and several research groups tested their samples for both NDV and AIV. The extension of NDV studies to new geographical areas and new species confirmed the global pattern that had been described since the 1970s: a large range of species are susceptible to NDV infection, with LPNDV mostly isolated in waterfowl [18][19][20] and specific genotypes of vNDV persisting in certain species such as pigeons [21] and cormorants [22]. These studies also showed a high variability in the NDV infection rate of wild bird populations depending on the site, the period, the species and the methods used.…”

Characterization of Newcastle Disease Viruses in Wild and Domestic Birds in Luxembourg from 2006 to 2008

“…In this scenario, the detection of similar strains in 2007 and 2008 would indicate that avirulent viruses could be maintained in the local bird population throughout the year. However, their relationship with NDV isolates recently identified in migratory species in Finland (23,26) could not be further clarified on the basis of the short Finnish sequences. Wild Anatidae, such as Eurasian teals, mallards, and northern shovelers, have different migratory routes, which mainly depend on weather conditions and the availability of food resources.…”