Advances in research on genetic relationships of waterfowl parvoviruses

Derzsy’s disease and Muscovy duck parvovirus disease have become common diseases in waterfowl culture in the world and their potential to cause harm has risen. The causative agents are goose parvovirus (GPV) and Muscovy duck parvovirus (MDPV), which can provoke similar clinical symptoms and high mortality and morbidity rates. In recent years, duck short beak and dwarfism syndrome has been prevalent in the Cherry Valley duck population in eastern China. It is characterised by the physical signs for which it is named. Although the mortality rate is low, it causes stunting and weight loss, which have caused serious economic losses to the waterfowl industry. The virus that causes this disease was named novel goose parvovirus (NGPV). This article summarises the latest research on the genetic relationships of the three parvoviruses, and reviews the aetiology, epidemiology, and necropsy characteristics in infected ducks, in order to facilitate further study.

Taraxacum assemanii represents a new section: A revision of the misinterpreted Taraxacum primigenium, and the elucidation of the enigmatic Taraxacum section Primigenia (Compositae, Crepidinae)

On the basis of new gatherings at the type locality, Taraxacum primigenium was evaluated taxonomically. Its achenes differ substantially from the protologue description that is based on achenes of T. assemanii. Taraxacum primigenium, also on the basis of an nrDNA analysis, is close to T. sect. Piesis, and represents a narrow endemic confined to the Lalezar Mts., SE Iran. Taraxacum assemanii, newly typified, is known from mountains of SE Anatolia and Lebanon, and from the Zagros in SW Iran. It is characterized by large, almost or totally smooth achenes with indistinct cone and a very gradual achene body/beak transition, a thick short beak and a short, slightly brownish pappus. It represents a single member of a newly described section, T. sect. Pristina. The name of T. sect. Primigenia, although with a diagnosis corresponding to the characters of T. assemanii, is to be interpreted according to its type, T. primigenium, and is understood as a synonym of T. sect. Piesis. Another taxon evaluated, T. cylleneum, endemic to several mountain ranges in of Peloponnesos, Greece, is similar to T. primigenium, and very close to the core taxa of T. sect. Piesis. All the species dealt with reproduce sexually.

Immunogenicity of an Inactivated Novel Duck Parvovirus Vaccine for Short Beak and Dwarf Syndrome in Cherry Valley Ducks

Duck short beak and dwarf syndrome (SBDS) is a viral infectious disease caused by novel duck parvovirus (NDPV). It has brought serious economic losses to the Chinese duck industry in recent years. Currently, there exists no effective vaccine against this disease. In this study, we developed an inactivated virus vaccine based on NDPV-DS15 for SBDS. Immune efficacy was evaluated in 112 ducks, which were randomly divided into vaccination, challenge control, vaccination-challenge, and blank control groups (n = 28 each). Clinical characteristics, antibodies, viral excretion, viremia, and pathological changes were monitored and analyzed. No morbidity or death was observed in the immunized ducks, which showed normal weight and good mental state. High levels of serum antibodies (OD450 nm: ~0.63) were detected in ducks immunized with inactivated vaccine at 7 days post-vaccination (dpv), and the amount of virus neutralizing antibodies increased from 1:23 to 1:28.5 from 7 dpv to 42 dpv. The anal swab, serum, and tissue viral load tests showed that vaccination could significantly inhibit the replication of NDPV in immunized ducks. Moreover, NDPV could not be isolated from the spleens of immunized or vaccination-challenged ducks. Our results show that the developed inactivated NDPV vaccine, administered in an oil emulsion adjuvant, possesses good immunogenicity and represents a potentially powerful tool for SBDS prevention and control.

Molecular Characteristics and Phylogenetic Analysis of Short Beak and Dwarfism Syndrome-Related Novel Goose Parvovirus

Short beak and dwarfism syndrome (SBDS) emerged in cherry valley duck flocks in China in 2015, and novel goose parvovirus (NGPV) was proved to be the etiological agent of SBDS. To date, whether SBDS-related NGPV isolates possess common molecular characteristics remains unknown. In this study, three new NGPV strains (namely, SDHT16, SDJN19, and SDLC19) were isolated from diseased ducks showing typical SBDS and successfully passaged in embryonated goose or cherry valley duck embryo. The whole genomes of three NGPV strains shared 98.9%–99.7% homologies between each other but showed slightly lower homologies (95.2%–96.1%) with the classical GPV strains. A total of 16 common amino acid point mutations were produced in the VP1 proteins of six NGPV strains (SDHT16, SDJN19, SDLC19, QH, JS1, and SDLC01) compared with the classical Chinese GPV strains, among which nine amino acid sites were identical to the European GPV strain B. The non-structural protein Rep1 of the six NGPV strains generated 12 common amino acid mutations compared with the classical GPV strains. The phylogenetic analysis indicated that the Chinese NGPV strains clustered with the European SBDS-related NGPV strains, forming a separate branch, distinct from the group formed by the classical GPV strains. Taken together, the present study unveils the common molecular characteristics of the NGPV isolates and directs the conclusion that the Chinese NGPV isolates probably originate from a common ancestor with the European SBDS-related NGPV.

A ROR2 coding variant is associated with craniofacial variation in domestic pigeons

SummaryVertebrate craniofacial morphogenesis is a highly orchestrated process that is directed by evolutionarily conserved developmental pathways 1,2. Within species, canalized developmental programs typically produce only modest morphological variation. However, as a result of millennia of artificial selection, the domestic pigeon (Columba livia) displays radical variation in craniofacial morphology within a single species. One of the most striking cases of pigeon craniofacial variation is the short beak phenotype, which has been selected in numerous breeds. Classical genetic experiments suggest that pigeon beak length is regulated by a small number of genetic factors, one of which is sex-linked (Ku2 locus) 3–5. However, the molecular genetic underpinnings of pigeon craniofacial variation remain unknown. To determine the genetic basis of the short beak phenotype, we used geometric morphometrics and quantitative trait loci (QTL) mapping on an F2 intercross between a short-beaked Old German Owl (OGO) and a medium-beaked Racing Homer (RH). We identified a single locus on the Z-chromosome that explains a majority of the variation in beak morphology in the RH x OGO F2 population. In complementary comparative genomic analyses, we found that the same locus is also strongly differentiated between breeds with short and medium beaks. Within the differentiated Ku2 locus, we identified an amino acid substitution in the non-canonical Wnt receptor ROR2 as a putative regulator of pigeon beak length. The non-canonical Wnt (planar cell polarity) pathway serves critical roles in vertebrate neural crest cell migration and craniofacial morphogenesis 6,7. In humans, homozygous ROR2 mutations cause autosomal recessive Robinow syndrome, a rare congenital disorder characterized by skeletal abnormalities, including a widened and shortened facial skeleton 8,9. Our results illustrate how the extraordinary craniofacial variation among pigeons can reveal genetic regulators of vertebrate craniofacial diversity.

Genetic characterization and phylogenetic analysis of Novel Duck-Origin Goose Parvovirus in Anhui Province, Eastern China

Recently, a novel duck-origin goose parvovirus (N-GPV) was reported to cause short beak and dwarfism syndrome in ducks. In this study, we performed complete genome sequencing and analyzed three different duck-derived parvoviruses that infected different breeds of ducks. Phylogenetic trees based on gene sequences indicated that they were classical goose parvovirus (C-GPV), Muscovy duck parvovirus (MDPV), and N-GPV, respectively. Furthermore, potential recombination events were found. These results improve our understanding of the diversity of duck-derived parvoviruses in the Anhui province, eastern China, and provide a reference for the prevention of associated diseases.

Short Beak and Dwarfism Syndrome in Ducks in Poland Caused by Novel Goose Parvovirus

Short beak and dwarfism syndrome (SBDS), which was previously identified only in mule ducks, is now an emerging disease of Pekin ducks in China and Egypt. The disease is caused by the infection of ducks with a genetic variant of goose parvovirus—novel goose parvovirus (nGPV). In 2019, SBDS was observed for the first time in Poland in eight farms of Pekin ducks. Birds in the affected flock were found to show growth retardation and beak atrophy with tongue protrusions. Morbidity ranged between 15% and 40% (in one flock), while the mortality rate was 4–6%. Co-infection with duck circovirus, a known immunosuppressive agent, was observed in 85.7% of ducks. The complete coding regions of four isolates were sequenced and submitted to GenBank. The phylogenetic analysis revealed a close relationship of Polish viral sequences with the Chinese nGPV. Genomic sequence alignments showed 98.57–99.28% identity with the nGPV sequences obtained in China, and 96.42% identity with the classical GPV (cGPV; Derzsy’s disease). The rate of amino acid mutations in comparison to cGPV and Chinese nGPV was higher in the Rep protein than in the Vp1 protein. To our knowledge, this is the first report of nGPV infection in Pekin ducks in Poland and Europe. It should be emphasized that monitoring and sequencing of waterfowl parvoviruses is important for tracking the viral genetic changes that enable adaptation to new species of waterbirds.

Detection of Novel Goose Parvovirus Disease Associated with Short Beak and Dwarfism Syndrome in Commercial Ducks

Derzsy’s disease causes disastrous losses in domestic waterfowl farms. A genetically variant strain of Muscovy duck parvovirus (MDPV) and goose parvovirus (GPV) was named novel goose parvovirus (NGPV), which causes characteristic syndrome in young ducklings. The syndrome was clinically characterized by deformity in beaks and retarded growth, called short beaks and dwarfism syndrome (SBDS). Ten mule and pekin duck farms were investigated for parvovirus in three Egyptian provinces. Despite low recorded mortality rate (20%), morbidity rate was high (70%), but the economic losses were remarkable as a result of retarded growth and low performance. Isolation of NGPV was successful on primary cell culture of embryonated duck liver cells with a clear cytopathic effect. Partial gene sequence of the VP1 gene showed high amino acids identity among isolated strains and close identity with Chinese strains of NGPV, and low identity with classic GPV and MDPV strains. To the best of our knowledge, this can be considered the first record of NGPV infections in Egypt.