Genetic diversity of the genotype VII Newcastle disease virus: identification of a novel VIIj sub-genotype

Transcriptome-wide N6-methyladenosine modification profiling of mRNAs during infection of Newcastle disease virus in chicken macrophages

N6-methyladenosine (m6A) modification, the most prevalent post-transcriptional modification of eukaryotic mRNAs, is reported to play a crucial role in viral infection. However, the role of m6A modification during Newcastle disease virus (NDV) infection has remained unclear. In this study, we performed MeRIP-seq to investigate the transcriptome-wide m6A methylome and m6A-modified genes in NDV-infected chicken macrophages. A total of 9496 altered peaks were identified, of which 7015 peaks were significantly upregulated across 3320 genes, and 2481 peaks were significantly down-regulated across 1264 genes. Combined analysis of m6A peaks and mRNA expression showed that 1234 mRNAs had significantly altered levels of methylation and expression after NDV infection, and m6A modification tended to have a negative relationship with mRNA expression, suggesting that m6A modification may regulate the process of NDV infection by regulating gene expression, particularly of the genes important in the innate immune response. To the best of our knowledge, this is the first comprehensive characterization of m6A patterns in chicken macrophage mRNA after NDV infection, providing a valuable basis for further exploring the role of m6A modification mechanisms during the course of NDV infection.

Current situation and future direction of Newcastle disease vaccines

Newcastle disease (ND) is one of the most economically devastating infectious diseases affecting the poultry industry. Virulent Newcastle disease virus (NDV) can cause high mortality and severe tissue lesions in the respiratory, gastrointestinal, neurological, reproductive and immune systems of poultry. Tremendous progress has been made in preventing morbidity and mortality caused by ND based on strict biosecurity and wide vaccine application. In recent decades, the continual evolution of NDV has resulted in a total of twenty genotypes, and genetic variation may be associated with disease outbreaks in vaccinated chickens. In some countries, the administration of genotype-matched novel vaccines in poultry successfully suppresses the circulation of virulent NDV strains in the field. However, virulent NDV is still endemic in many regions of the world, especially in low- and middle-income countries, impacting the livelihood of millions of people dependent on poultry for food. In ND-endemic countries, although vaccination is implemented for disease control, the lack of genotype-matched vaccines that can reduce virus infection and transmission as well as the inadequate administration of vaccines in the field undermines the effectiveness of vaccination. Dissection of the profiles of existing ND vaccines is fundamental for establishing proper vaccination regimes and developing next-generation vaccines. Therefore, in this article, we provide a broad review of commercial and experimental ND vaccines and promising new platforms for the development of next-generation vaccines.

Molecular Characterization of Velogenic Newcastle Disease Virus (Sub-Genotype VII.1.1) from Wild Birds, with Assessment of Its Pathogenicity in Susceptible Chickens

Simple Summary

Newcastle disease virus (NDV) is a highly contagious viral disease affecting a wide range of avian species. The disease can be particularly virulent in chickens, resulting in high mortality and morbidity. In this study, we characterized velogenic NDV sub-genotype VII.1.1 from wild birds and assessed its pathogenicity in susceptible chickens. One hundred wild birds from the vicinity of poultry farms with a history of NDV infection were examined clinically. Pooled samples from the spleen, lung, and brain were screened using real-time reverse transcriptase polymerase chain reaction (RRT-PCR) and reverse transcriptase polymerase chain reaction (RT-PCR) to detect the NDV F gene fragment, and phylogenetic analysis was carried out for identification of the genetic relatedness of the virus. Chickens were infected with the strains identified, and the major histopathological changes were assessed. Interestingly, NDV was detected in 44% of cattle egret samples and 26% of house sparrow samples by RRT-PCR, while RT-PCR detected NDV in 36% of cattle egrets examined and 20% of house sparrow samples. Phylogenetic analysis revealed close identity, of 99.7–98.5% (0.3–1.5% pairwise distance), between the isolates used in our study and other Egyptian class II, sub-genotype VII.1.1 NDV strains. Histopathological examination identified marked histopathological changes that are consistent with NDV. These findings provide interesting data in relation to the detection of NDV sub-genotype VII.1.1 in wild birds and reveal the major advantages of the combined use of molecular and histopathological methods in the detection and characterization of the virus. More research is needed to determine the characteristics of this contagious disease in the Egyptian environment.

Abstract

Newcastle disease (ND) is considered to be one of the most economically significant avian viral diseases. It has a worldwide distribution and a continuous diversity of genotypes. Despite its limited zoonotic potential, Newcastle disease virus (NDV) outbreaks in Egypt occur frequently and result in serious economic losses in the poultry industry. In this study, we investigated and characterized NDV in wild cattle egrets and house sparrows. Fifty cattle egrets and fifty house sparrows were collected from the vicinity of chicken farms in Kafrelsheikh Governorate, Egypt, which has a history of NDV infection. Lung, spleen, and brain tissue samples were pooled from each bird and screened for NDV by real-time reverse transcriptase polymerase chain reaction (RRT-PCR) and reverse transcriptase polymerase chain reaction (RT-PCR) to amplify the 370 bp NDV F gene fragment. NDV was detected by RRT-PCR in 22 of 50 (44%) cattle egrets and 13 of 50 (26%) house sparrows, while the conventional RT-PCR detected NDV in 18 of 50 (36%) cattle egrets and 10 of 50 (20%) of house sparrows. Phylogenic analysis revealed that the NDV strains identified in the present study are closely related to other Egyptian class II, sub-genotype VII.1.1 NDV strains from GenBank, having 99.7–98.5% identity. The pathogenicity of the wild-bird-origin NDV sub-genotype VII.1.1 NDV strains were assessed by experimental inoculation of identified strains (KFS-Motobas-2, KFS-Elhamoul-1, and KFS-Elhamoul-3) in 28-day-old specific-pathogen-free (SPF) Cobb chickens. The clinical signs and post-mortem changes of velogenic NDV genotype VII (GVII) were observed in inoculated chickens 3 to 7 days post-inoculation, with 67.5–70% mortality rates. NDV was detected in all NDV-inoculated chickens by RRT-PCR and RT-PCR at 3, 7, and 10 days post-inoculation. The histopathological findings of the experimentally infected chickens showed marked pulmonary congestion and pneumonia associated with complete bronchial stenosis. The spleen showed histocytic cell proliferation with marked lymphoid depletion, while the brain had malacia and diffuse gliosis. These findings provide interesting data about the characterization of NDV in wild birds from Egypt and add to our understanding of their possible role in the transmission dynamics of the disease in Egypt. Further research is needed to explore the role of other species of wild birds in the epidemiology of this disease and to compare the strains circulating in wild birds with those found in poultry.

Insights into Genomic Epidemiology, Evolution, and Transmission Dynamics of Genotype VII of Class II Newcastle Disease Virus in China

Newcastle disease virus (NDV) is distributed worldwide and has caused significant losses to the poultry industry. Almost all virulent NDV strains belong to class II, among which genotype VII is the predominant genotype in China. However, the molecular evolution and phylodynamics of class II genotype VII NDV strains in China remained largely unknown. In this study, we identified 13 virulent NDV including 11 genotype VII strains and 2 genotype IX strains, from clinical samples during 1997 to 2019. Combined NDV sequences submitted to GenBank, we investigate evolution, and transmission dynamics of class II NDVs in China, especially genotype VII strains. Our results revealed that East and South China have the most genotypic diversity of class II NDV, and East China might be the origin of genotype VII NDVs in China. In addition, genotype VII NDVs in China are presumably transmitted by chickens, as the virus was most prevalent in chickens. Furthermore, codon usage analysis revealed that the F genes of genotype VII NDVs have stronger adaptation in chickens, and six amino acids in this gene are found under positive selection via selection model analysis. Collectively, our results revealed the genetic diversity and evolutionary dynamics of genotype VII NDVs in China, providing important insights into the epidemiology of these viruses in China.

Sequence analysis and pathogenicity of Avian Orthoavulavirus 1 strains isolated from poultry flocks during 2015-2019

Background

Newcastle disease (ND) causes severe economic losses in poultry industry worldwide. Egyptian poultry industry suffered from severe economic losses since the isolation of Velogenic Newcastle disease virus (vNDV) genotype VIId in 2011 and up till now despite the use of different vaccination programs. So, this study aimed to isolate and characterize the vNDV from a total of 120 poultry flocks from ten provinces in the Egyptian Delta region with a history of respiratory manifestation, high mortalities or a decrease in egg production between 2015 and 2019. Seventy-three samples’ allantoic fluid (73/120, 60.8%) were positive for hemagglutination with chicken RBCs. These samples were submitted to molecular examination using qRT-PCR specific primers for AOAV-1, highly pathogenic avian influenza (HPAI-H5), low pathogenic avian influenza (LPAI-H9) and infectious bronchitis virus (IBV).

Results

Fifty samples (50/120: 41.6%) were confirmed positive for AOAV-1, based on genetic analysis of matrix and fusion protein. The co-infection rate of other respiratory viral diseases examined was 1.6, 14.1, and 4.1%, for HPAI-H5, LPAI-H9, and IBV, respectively. Biologically, the intracerebral pathogenicity index of ten selected AOAV-1 isolates ranged from 1.70 to 1.98, which indicated the velogenic nature of these isolates. All the sixteen sequenced isolates were AOAV-1 genotype VII.1.1. The full F gene sequence of six examined AOAV-1 VII.1.1 isolates contained the seven neutralizing epitopes, and the glycosylation motif of six-potential sites for N linked glycosylation at residues 85, 191, 366, 447, 471, and 541.

Conclusion

It could be concluded that the high prevalence of AOAV-1 genotype VII.1.1 in the Egyptian chicken flocks despite the intensive vaccination with live and killed ND vaccines, as all the 16 isolates tested were belonged to this genotype. Homologous vaccination is badly needed to control and reduce the spread of AOAV-1 genotype VII.1.1infection in Egyptian poultry flocks.

Reverse Genetics Assembly of Newcastle Disease Virus Genome Template Using Asis-Sal-Pac BioBrick Strategy

Background

The BioBrick construction as an approach in synthetic biology provides the ability to assemble various gene fragments. To date, different BioBrick strategies have been exploited for assembly and cloning of a variety of gene fragments. We present a new BioBrick strategy, here referred as Asis-Sal-Pac BioBrick, which we used for the assembly of NDV as a candidate for single-stranded non-segmented, negative-sense RNA genome viruses.

Results

In the present study, we isolated three NDVs from clinical samples which were classified into the VIId genotype based on their pathogenicity and phylogenetic analyses. Then, SalI, AsisI, and PacI enzymes were used to design and develop a novel BioBrick strategy, which enabled us to assemble the NDV genome, adopting the “rule of six”. In this method, in each assembly step, the restriction sites in the newly formed destination plasmid are reproduced, which will be used for the next insertion. In this study using two overlapping PCRs, the cleavage site of the F gene was also modified from ¹¹²RRQKRF¹¹⁷to ¹¹²GRQGRL¹¹⁷ in order to generate the attenuated recombinant NDV. Finally, in order to construct the recombinant NDV viruses, the plasmids harboring the assembled full-length genome of the NDV and the helper plasmids were co-transfected into T7-BHK cells. The rescue of the recombinant NDVwas confirmed by RT-PCR and HA tests.

Conclusions

These findings suggest that the combination of reverse genetic technology and BioBrick assembly have the potential to be applied for the development of novel vaccine candidates. This promising strategy provides an effective and reliable approach to make genotype-matched vaccines against specific NDV strains or any other virus.

Chimeric Newcastle Disease Virus-like Particles Containing DC-Binding Peptide-Fused Haemagglutinin Protect Chickens from Virulent Newcastle Disease Virus and H9N2 Avian Influenza Virus Challenge

Newcastle disease virus (NDV) and H9N2 subtype Avian influenza virus (AIV) are two notorious avian respiratory pathogens that cause great losses in the poultry industry. Current inactivated commercial vaccines against NDV and AIV have the disadvantages of inadequate mucosal responses, while an attenuated live vaccine bears the risk of mutation. Dendritic cell (DC) targeting strategies are attractive for their potent mucosal and adaptive immune-stimulating ability against respiratory pathogens. In this study, DC-binding peptide (DCpep)-decorated chimeric virus-like particles (cVLPs), containing NDV haemagglutinin-neuraminidase (HN) and AIV haemagglutinin (HA), were developed as a DC-targeting mucosal vaccine candidate. DCpep-decorated cVLPs activated DCs in vitro, and induced potent immune stimulation in chickens, with enhanced secretory immunoglobulin A (sIgA) secretion and splenic T cell differentiation. 40 μg cVLPs can provide full protection against the challenge with homologous, heterologous NDV strains, and AIV H9N2. In addition, DCpep-decorated cVLPs could induce a better immune response when administered intranasally than intramuscularly, as indicated by robust sIgA secretion and a reduced virus shedding period. Taken together, this chimeric VLPs are a promising vaccine candidate to control NDV and AIV H9N2 and a useful platform bearing multivalent antigens.

Updated unified phylogenetic classification system and revised nomenclature for Newcastle disease virus

Several Avian paramyxoviruses 1 (synonymous with Newcastle disease virus or NDV, used hereafter) classification systems have been proposed for strain identification and differentiation. These systems pioneered classification efforts; however, they were based on different approaches and lacked objective criteria for the differentiation of isolates. These differences have created discrepancies among systems, rendering discussions and comparisons across studies difficult. Although a system that used objective classification criteria was proposed by Diel and co-workers in 2012, the ample worldwide circulation and constant evolution of NDV, and utilization of only some of the criteria, led to identical naming and/or incorrect assigning of new sub/genotypes. To address these issues, an international consortium of experts was convened to undertake in-depth analyses of NDV genetic diversity. This consortium generated curated, up-to-date, complete fusion gene class I and class II datasets of all known NDV for public use, performed comprehensive phylogenetic neighbor-Joining, maximum-likelihood, Bayesian and nucleotide distance analyses, and compared these inference methods. An updated NDV classification and nomenclature system that incorporates phylogenetic topology, genetic distances, branch support, and epidemiological independence was developed. This new consensus system maintains two NDV classes and existing genotypes, identifies three new class II genotypes, and reduces the number of sub-genotypes. In order to track the ancestry of viruses, a dichotomous naming system for designating sub-genotypes was introduced. In addition, a pilot dataset and sub-trees rooting guidelines for rapid preliminary genotype identification of new isolates are provided. Guidelines for sequence dataset curation and phylogenetic inference, and a detailed comparison between the updated and previous systems are included. To increase the speed of phylogenetic inference and ensure consistency between laboratories, detailed guidelines for the use of a supercomputer are also provided. The proposed unified classification system will facilitate future studies of NDV evolution and epidemiology, and comparison of results obtained across the world.

Catalytic inactivation of influenza virus by iron oxide nanozyme

Influenza poses a severe threat to human health in the world. However, developing a universal anti-viral strategy has remained challenging due to the presence of diverse subtypes as well as its high mutation rate, resulting in antigenic shift and drift. Here we developed an antiviral strategy using iron oxide nanozymes (IONzymes) to target the lipid envelope of the influenza virus. Methods: We evaluated the antiviral activities of our IONzymes using a hemagglutination assay, together with a 50% tissue culture infectious doses (TCID₅₀) method. Lipid peroxidation of the viral envelope was analyzed using a maleic dialdehyde (MDA) assay and transmission electron microscopy (TEM). The neighboring viral proteins were detected by western blotting. Results: We show that IONzymes induce envelope lipid peroxidation and destroy the integrity of neighboring proteins, including hemagglutinin, neuraminidase, and matrix protein 1, causing the inactivation of influenza A viruses (IAVs). Furthermore, we show that our IONzymes possess a broad-spectrum antiviral activity on 12 subtypes of IAVs (H1~H12). Lastly, we demonstrate that applying IONzymes to a facemask improves the ability of virus protection against 3 important subtypes that pose a threat to human, including H1N1, H5N1, and H7N9 subtype. Conclusion: Together, our results clearly demonstrate that IONzymes can catalyze lipid peroxidation of the viral lipid envelope to inactivate enveloped viruses and provide protection from viral transmission and infection.

A comparative genomic and evolutionary analysis of circulating strains of Avian avulavirus 1 in Pakistan

Newcastle disease, caused by Avian avulavirus 1 (AAvV 1), is endemic to many developing countries around the globe including Pakistan. Frequent epidemics are not uncommon even in vaccinated populations and are largely attributed to the genetic divergence of prevailing isolates and their transmission in the environment. With the strengthening of laboratory capabilities in Pakistan, a number of genetically diverse AAvV 1 strains have recently been isolated and individually characterized in comparison with isolates reported elsewhere in the world. However, there lacks sufficient comparative genomic and phylogenomic analyses of field circulating strains that can elucidate the evolutionary dynamics over a period of time. Herein, we enriched the whole genome sequences of AAvV reported so far (n = 35) from Pakistan and performed comparative genomic, phylogenetic and evolutionary analyses. Based on these analyses, we found only isolates belonging to genotypes VI, VII and XIII of AAvV 1 in a wide range of avian and human hosts. Comparative phylogeny revealed the concurrent circulation of avulaviruses representing different sub-genotypes such as VIg, VIm, VIIa, VIIb, VIIe, VIIf, VIIi, XIIIb and XIIId. We found that the isolates of genotype VII were more closely associated with viruses of genotype XIII than genotype VI. An inter-genotype comparative residue analysis revealed a few substitutions in structurally and functionally important motifs. Putative recombination events were reported for only one of the captive-wild bird (pheasant)-origin isolates. The viruses of genotype VII had a high genetic diversity as compared to isolates from genotypes VI and XIII and, therefore, have more potential to evolve over a period of time. Taken together, the current study provides an insight into the genetic diversity and evolutionary dynamics of AAvV 1 strains circulating in Pakistan. Such findings are expected to facilitate better intervention strategies for the prevention and control of ND in disease-endemic countries across the globe particularly Pakistan.

A genotype VII Newcastle disease virus-like particles confer full protection with reduced virus load and decreased virus shedding

Newcastle disease (ND) is one of the most severe avian infectious disease inflicting a great loss on poultry industry worldwide. The control of ND relies on proper vaccination strategies. The vaccine strains of Newcastle disease virus (NDV) mainly belong to genotype I, II or III, which cannot fully prohibit virus shedding against the prevalent genotype VII virulent strain attack. To develop a safe, genotype matched vaccine candidate, we employed a bac-to-bac expression system and constructed a genotype VII NDV strain based virus-like particles (NDV VLPs). It was constructed with NDV M protein as the skeleton, and protective antigen F and HN proteins displayed on the surface. The NDV VLPs exhibited a similar appearance to the live NDV particles, but with denser F and HN proteins displayed on the surface. The immunization assay indicated that NDV VLPs stimulated a longer protection period, less tissue virus loading and shorter virus shedding period than the commercialized LaSota-formulated vaccine when challenged with genotype VII NDV strain. These results proposed the potential role of NDV VLPs as an alternative to current live genotype unmatched vaccine for the control and eliminate NDV in the avian flocks.

Genotype Diversity of Newcastle Disease Virus in Nigeria: Disease Control Challenges and Future Outlook

Newcastle disease (ND) is one of the most important avian diseases with considerable threat to the productivity of poultry all over the world. The disease is associated with severe respiratory, gastrointestinal, and neurological lesions in chicken leading to high mortality and several other production related losses. The aetiology of the disease is an avian paramyxovirus type-1 or Newcastle disease virus (NDV), whose isolates are serologically grouped into a single serotype but genetically classified into a total of 19 genotypes, owing to the continuous emergence and evolution of the virus. In Nigeria, molecular characterization of NDV is generally very scanty and majorly focuses on the amplification of the partial F gene for genotype assignment. However, with the introduction of the most objective NDV genotyping criteria which utilize complete fusion protein coding sequences in phylogenetic taxonomy, the enormous genetic diversity of the virus in Nigeria became very conspicuous. In this review, we examine the current ecological distribution of various NDV genotypes in Nigeria based on the available complete fusion protein nucleotide sequences (1662 bp) in the NCBI database. We then discuss the challenges of ND control as a result of the wide genetic distance between the currently circulating NDV isolates and the commonest vaccines used to combat the disease in the country. Finally, we suggest future directions in the war against the economically devastating ND in Nigeria.

Biological and phylogenetic characterization of a novel hemagglutination-negative avian avulavirus 6 isolated from wild waterfowl in China

Up to now only nine whole genome sequences of avian avulavirus 6 (AAvV‐6) had been documented in the world since the first discovery of AAvV‐6 (AAvV‐6/duck/HongKong/18/199/77) at a domestic duck in 1977 from Hong Kong of China. Very limited information is known about the regularities of transmission, genetic and biological characteristics of AAvV‐6 because of the lower isolation rate and mild losses for poultry industry. To better further explore the relationships among above factors, an AAvV‐6 epidemiological surveillance of domestic poultry and wild birds in six provinces of China suspected of sites of inter‐species transmission and being intercontinental flyways during the year 2013–2017 was conducted. Therefore, 9,872 faecal samples from wild birds and 1,642 cloacal and tracheal swab samples from clinically healthy poultry of live bird market (LBM) were collected respectively. However, only one novel hemagglutination‐negative AAvV‐6 isolate (AAvV‐6/mallard/Hubei/2015) was isolated from a fresh faecal sample obtained from mallard at a wetland of Hubei province. Sequencing and phylogenetic analyses of this AAvV‐6 isolate (AAvV‐6/mallard/Hubei/2015) indicated that this isolate grouping to genotype I were epidemiological intercontinentally linked with viruses from the wild birds in Europe and America. Meanwhile, at least two genotypes (I and II) are existed within serotype AAvV‐6. In additional, this novel hemagglutination‐negative AAvV‐6 isolate in chicken embryos restored its hemagglutination when pre‐treated with trypsin. These findings, together with data from other AAvV‐6, suggest potential epidemiological intercontinental spreads among AAvV‐6 transmission by wild migratory birds, and reveal potential threats to wild birds and domestic poultry worldwide.

Molecular analysis of Newcastle disease virus isolates reveals a novel XIId subgenotype in Vietnam

Eight Vietnamese Newcastle disease virus field isolates from 2008-2015 and 3 vaccine specimens were genotyped based on their full F gene sequences and compared to 80 reference strains representing all 18 genotypes. Three isolates formed a novel subgenotype XIId, identified for the first time in Vietnam; while the others clustered as follows: four in subgenotypes VIId and VIIh; two in Genotype I; and two in Genotype II. Evolutionary distance calculations confirmed the Vietnamese XIId isolates were distinct from XIIa and XIIb by 0.062-0.070; and from other genotypes by 0.089-0.245. This data demonstrated that a novel XIId subgenotype emerged in Vietnam indicating considerable genetic diversity, thus highlighting the need to implement antigenic matching during vaccination against NDVs.

Molecular evolution and epidemiological links study of Newcastle disease virus isolates from 1995 to 2016 in Iran

In the case of Newcastle disease virus, multiple factors such as host adaptation, immune response evasion, and selective pressures have been suggested to result in evolution of viruses and the emergence of genetic variants. Multiple studies on virus classification and global epidemiological links have yielded consistent data. Here, we have performed a molecular analysis study of circulating Newcastle disease viruses in Iran (1995-2016). According to evolutionary divergences, subgenotype VIg, VIj, VIIj, VIId, XIIIa and XIIId isolates have been circulating in the country during a 21-year period. Based on data analysis, VIg isolates shared highest sequence identity with Russian and Polish isolates of the VIg subgenotype, while VIj subgenotype isolates (2012) were most similar to a virus isolated in 2015 in India. Analysis of the evolutionary divergence of subgenotype VIIj suggests that Chinese and Ukrainian viruses may have played a crucial role in the emergence of VIIj isolates. Evolutionary difference studies also indicated that XIIIa isolates circulating in Iran may have caused the emergence of adapted variants of subgenotype XIIId. Therefore, we propose that the evolutionary and epidemiological study of virulent Newcastle disease viruses could help to provide accurate molecular data about variants circulating in the region, thus aiding in the design of more efficient recombinant vaccines.

First genetic characterization of newcastle disease viruses from Namibia: identification of a novel VIIk subgenotype

The complete sequences of the fusion (F) protein genes of six Newcastle disease virus (NDV) isolates from backyard poultry in Namibia in 2016 have been determined. The F gene cleavage site motif for all of the isolates was ¹¹²RRQKRF¹¹⁷, indicating that the viruses are virulent. A phylogenetic analysis using the full F gene sequence revealed that the viruses belong to a novel subgenotype, VIIk. This is the first genetic characterization of NDV isolates from Namibia, and the findings have important implications for Newcastle disease management and control in the region.

Characterization of Colombian serotype 1 avian paramyxoviruses, 2008-2010

Newcastle disease (ND) still remains one of the most important diseases affecting domestic poultry in Colombia. Here, for the first time, we report on the molecular characterization of 12 virulent and 12 avirulent or lentogenic avian paramyxovirus type 1 (APMV-1) strains that were isolated from commercial, backyard, and game poultry in Colombia from 2008 to 2010. The 12 virulent isolates had a fusion (F) protein cleavage site with basic amino acids at positions 113, 115, and 116 and a phenylalanine at position 117 (¹¹²RRQKR*F¹¹⁷), characteristic of virulent strains. The remaining 12 isolates had the F protein cleavage sites ¹¹²GKQGR*L¹¹⁷ or ¹¹²GRQGR*L¹¹⁷ typical of avirulent or lentogenic APMV-1 strains. Phylogenetic analysis of full-length F genes of all isolates was performed, and based on the recently proposed criteria for classification of APMV-1 strains, the 24 Colombian isolates were found to belong to class II viruses and clustered into four different genotypes. Ten virulent isolates clustered with genotype VII (sub-genotype VIId), seven lentogenic strains within genotype II, five lentogenic strains with genotype I (sub-genotype Ia), and two virulent isolates within genotype XII. Our data provide essential information on the genetic diversity of AMPV-1 isolates circulating in Colombia.