Genetic diversity of avian avulavirus 1 (Newcastle disease virus genotypes VIg and VIIb) circulating in wild birds in Kazakhstan

Abstract

In order to improve current understanding of the molecular epidemiology of avian avulavirus 1 (AAvV-1, formerly avian paramyxovirus 1) in wild birds in Kazakhstan, 860 cloacal swab samples were evaluated. Samples were collected from 37 families of wild birds in nine different regions in the years 2011 and 2014. Overall, 54 positive samples (4.2%) were detected from 17 different families of wild birds, and 16 AAvV-1 isolates were characterized. Three of the isolates contained the fusion protein cleavage site motif RRQKR, and 13 contained KRQKR, which is typical for pathogenic strains of AAvV-1. The AAvV-1 isolates were found to belong to the genotypes VIg and VIIb.

Cormorants as a Potentially Important Reservoir and Carrier of Newcastle Disease Virus on the Asian Continent

“…This finding shows the presence of an important NDV focus in the wild nature of Central Asia, which can pose a potential threat to poultry farms in the southern regions of the continent during seasonal migrations of cormorants. The proof of this statement is the outbreak of NDV that close to Lake Alakol around the cormorant nesting grounds in southeastern Kazakhstan and Kyrgyzstan (GenBank: MK423875), where outbreaks with massive mortality of domestic chickens occurred in poultry farms, caused by 99% phylogenetically close NDV strains of sub-genotype VIIb (8,10). So, the connection between NDV cases in wild and domestic birds become apparent in Central Asia.…”

“…-NDV outbreaks with mortality were recorded during the nesting period in the summer. -Besides the cormorants, mortality was observed among sympatric gulls and pelicans (8,9). -Highly pathogenic for domestic birds -Outbreaks do not occur every year, but after two or more years.…”

“…For the first time in Asia, NDV isolates were isolated directly from cormorants in 2014 at Lake Alakol ( 8 ). Juveniles of up to 3 weeks of age were affected and the disease was accompanied with significant mortality.…”

“…In 1974, strains of velogenic NDV were isolated from cormorants in the northern Caspian ( 7 ), but mortality among cormorants was not recorded at that time. Then, in 2014 and 2016, mortality was recorded among juvenile cormorants in Central Asia at Lake Alakol ( 8 , 9 ). Simultaneously with the detection of the velogenic NDV in cormorants, epizootic outbreaks with high mortality in local poultry farms were registered.…”

Genome Sequences of Newcastle Disease Virus Strains from Two Outbreaks in Indonesia

“…NDV is a single-stranded, nonsegmented, negative-sense, and enveloped RNA virus with six major structural proteins in the order 3=-NP-P-M-F-HN-L-5= (2,3). NDV has been divided into two classes; class I represents avirulent strains, while class II represents virulent and nonvirulent strains (4)(5)(6). Recent ND outbreaks have appeared in commercial chickens, even vaccinated flocks, leading to mortality rates of 70 to 80%, and are caused mainly by highly virulent genotype VII NDVs (6,7).…”