Molecular epidemiology of hydropericardium syndrome outbreak-associated serotype 4 fowl adenovirus isolates in central China

Abstract

In several parts of China, there have been a large number of hydropericardium syndrome (HPS) outbreaks caused by serotype 4 fowl adenovirus (FAdV­4) in broiler chickens since 2015. These outbreak-associated FAdV-4 strains were distinct from previous circulating strains which did not lead to severe HPS outbreaks. To better understand the molecular epidemiology of the currently circulating FAdV strains for effective diagnosis and treatment of HPS, we isolated 12 HPS outbreak-associated FAdV-4 strains from different regions in central China and investigated their molecular characteristics by performing phylogenetic analyses based on the hexon genes. Our results indicated the FAdV-4 strains in this study all belonged to serotype FAdV-4, species FAdV-C. And in comparison with ON1, KR5, MX-SHP95, PK-01, PJ-06 strains within the cluster where outbreak-associated FAdV-4 strains were located, the nucleotide sequence divergence were 1.31, 1.10, 1.42, 2.77 and 2.84%, respectively. Phylogenetic analyses revealed the hexon genes of the 12 outbreak-associated strains clustered to a relatively independent branch of the tree, and evolved from the same ancestor and we suggested that these outbreak-associated FAdV-4 strains originate from earlier strains in India.

Identification of four serotypes of fowl adenovirus in clinically affected commercial poultry co‐infected with chicken infectious anaemia virus in Trinidad and Tobago

“…In a similar way to the majority of more recent FAdV screenings studies (Changjing et al., ; De la Torre et al., ; Zhang et al., ), we have applied molecular typing based on the hexon loop‐1 for classification of the detected FAdV strains, replacing the traditional methods of serological cross‐neutralization assays and restriction fragment length polymorphism (Hess, ). Although these tests have served as the basis for typing of isolates, these methods of characterization are costly, require reference sera and are sometimes unable to differentiate between serotypes (Changjing et al., ; Hess, ).…”

Isolation and molecular characterization of prevalent Fowl adenovirus strains in southwestern China during 2015–2016 for the development of a control strategy

“…In recent years, outbreaks of FAdVs have been frequently reported worldwide. Over the past 5 years, epidemics with mixed serotypes have been observed in different regions, such as FAdV-2, -11, -7 and -8 in Europe and North America, 7 , 35 , 36 , 37 FAdV-4 in Asia 5 , 38 , 39 , 40 , 41 and FAdV-2 and -8b in South Africa. 42 , 43 The most notable diseases associated with FAdV infection in chickens are IBH, HHS and GE.…”

“… 38 , 39 Phylogenetic analysis of the hexon gene has revealed that strains circulating in China before 2014 and after 2015 had different ancestors, and that new strains circulating in China were derived from earlier Indian strains. 39 The genome sequences of the contemporary strains have also been analyzed and clustered. This new pandemic FAdV-4 strain virus can be characterized by the notable nucleotide deletions in ORFs 19 and 27.…”

Pathogenic, Phylogenetic, and Serological Analysis of Group I Fowl Adenovirus Serotype 4 SDSX Isolated From Shandong, China

“…Since 2015, severe outbreaks of HHS have occurred in commercial duck farms in Jiangsu, Anhui, Hubei, Jiangxi, Shandong, and Henan Provinces, China, resulting in high mortalities, pericardial effusion, and stunted growth among ducks (Chen et al, 2016 ; Yu et al, 2018 ). Several previous studies have focused on the epidemiology (Liu et al, 2015 ; Zhang et al, 2016 ; Li et al, 2017 ), gene structure (Mase et al, 2009 ; Griffin and Nagy, 2011 ; Shah et al, 2016 ), diagnostic detection (Günes et al, 2012 ; Junnu et al, 2014 ; Niczyporuk et al, 2015 ; Wang et al, 2017 ), and vaccine strategies (Schonewille et al, 2010 ; Shah et al, 2012 , 2017 ) for the disease. Unfortunately, little is known about the pathogenicity of this virus in Cherry Valley meat ducks, except that intracerebral infection caused a 15% mortality rate (Chen et al, 2016 ) and oral infection showed no clinical signs (Pan et al, 2017 ); therefore, to complete the pathogenicity of the virus, Cherry Valley meat ducks were infected with FAdV-4 in this study.…”