-ILT (2020) (original) (raw)
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Archives of Virology, 2020
Infectious laryngotracheitis (ILT) is a respiratory disease that causes significant economic losses in the poultry industry worldwide. In this study, ILT outbreaks were reported on 30 farms located in eight Egyptian governorates between January 2018 and May 2019. Gross examination of diseased chickens revealed congestion and hemorrhage of laryngeal and tracheal mucosa with fibrinohemorrhagic casts and/or caseous material in the lumens. Histopathological examination showed epithelial sloughing, syncytium formation, heterophilic exudation, and development of eosinophilic intranuclear inclusion bodies. Infectious laryngotracheitis virus (ILTV) antigen was detected in the tracheal epithelium, infiltrated inflammatory cells, and syncytial cells, using immunohistochemistry. PCR targeting a portion of the thymidine kinase gene was further utilized to confirm the presence of ILTV DNA. The complete coding sequences of three envelope glycoprotein genes, gG, gD, and gJ, and a partial sequence of the infected cell polypeptide 4 (ICP4) gene from samples representing all of the farms and disease outbreaks were determined. Five prototype strains with unique sequences were chosen for detailed molecular characterization. Sequence comparisons and phylogenetic analysis of the partial ICP4 gene revealed that two strains were chicken embryo origin (CEO)-vaccine-like strains, and three were tissue culture origin (TCO)-vaccine-like strains. Analysis of the gJ gene sequence indicated that all of the strains were CEO vaccine-like strains. It was predicted that the latter three strains were recombinants of CEO- and TCO-vaccine-like strains. In conclusion, immunohistochemistry coupled with multigenomic PCR sequencing proved to be efficient for identification and typing of ILTV strains during disease outbreaks. Both CEO-vaccine-like and recombinant virus strains were circulating in Egypt during the 2018 and 2019 outbreaks.
Benha Veterinary Medical Journal
Infectious Laryngotracheitis (ILT) is an acute highly contagious respiratory disease of chickens. It has significant economic importance due to mortalities and the drop in egg production. In this study, seventy samples from different layer farms were collected from the outbreaks that occurred in Qalyubia province, Egypt, at the period from February 2018 till May 2019 to detect ILTV by molecular characterization through polymerase chain reaction assay (PCR) as well as isolation on the specific pathogen free-embryonated chicken eggs (SPF-ECEs) through chorioallantoic membrane (CAM) route. Post mortem examination of infected chickens revealed hemorrhagic tracheitis with fibrino-hemorrhagic casts and caseated materials. The PCR revealed amplification of a 688bp fragment of Infected Cell Protein 4 (ICP4) gene. Following that, seven samples were sequenced and phylogenetically analyzed. Sequence analysis of the ICP4 gene of these samples revealed complete identity with TCO (tissue culture origin) vaccines and the vaccine-related strains, which were previously isolated from Giza, Sharqia, Kafr El Sheikh, and Faiyum provinces through the years 2007 to 2018. Inoculation of ILTV PCR positive samples on SPF-ECE appeared as yellowish-white pock lesions on the inoculated CAM from the first passage. From these results, we can say that ILTV circulating in Egypt is a vaccinal strain that regains its virulence from the back passage in birds and causes outbreaks all over the country.
Avian Diseases Digest, 2008
Infectious laryngotracheitis (ILT) is an acute viral respiratory disease, primarily of chickens. Economic losses attributable to ILT affect many poultry-producing areas throughout the United States (US) and the world. Despite efforts to control the disease by vaccination, prolonged epidemics of ILT remain a threat to the poultry industry. Earlier epidemiological and molecular evidence indicated that outbreaks in the US are caused by vaccine-related strains. In this study, polymerase chain reaction and restriction fragment polymorphism (PCR-RFLP) of four genome regions was utilized to characterize 25 isolates from commercial poultry and backyard flocks from the US. Combinations of PCR-RFLP patterns classified the ILT virus isolates into nine groups. Backyard flock isolates were categorized in three separate groups. The ILT virus US Department of Agriculture (USDA) reference strain and the tissue culture origin (TCO) vaccine strain were categorized into two separate groups. Twenty-two isolates from commercial poultry were categorized into four groups: one group, of six isolates, showed patterns identical to the chicken embryo origin (CEO) vaccines; a second group, of nine isolates, differed in only one pattern from the CEO vaccines; a third group, of two isolates, differed in only one pattern from the TCO vaccine; a fourth group, of five isolates, differed in six and nine patterns from the CEO and TCO vaccines, respectively. Results obtained from this study clearly demonstrated that most of the commercial poultry isolates (17 of 22 isolates) were closely related to the vaccine strains. However, isolates different to the vaccine strains were also identified in commercial poultry.
Indian Journal of Animal Research, Volume 57 Issue 6: 770-776 (June 2023)
Background: Infectious laryngotracheitis (ILT) is an economically important viral respiratory disease in poultry. Recently, re-emergence of Infectious laryngotracheitis virus (ILTV) has been reported in several countries including India. The current study aimed to evaluate the poultry flocks of Tamil Nadu with circulating GaHV-1 and to elucidate the origin of the virus involved in the outbreak. Methods: In this study, a molecular based survey on the overall occurrence of natural cases of Infectious laryngo-tracheitis in poultry flocks from Tamil Nadu, India were performed. Pathological findings in respiratory and secondary lymphoid organs like caecal tonsils and harderian gland was carried out. The PCR technique targeting Infected Cell Protein-4 (ICP4) gene along with molecular characterization was performed. Result: The overall prevalence rate in the outbreak was 42.86% with highest incidence in layer flocks (62.85%) than the broiler flocks (22.85%). The highest susceptible age groups were between 20-30 weeks old. Tracheal pathology revealed epithelial sloughing, syncytial cell formation, eosinophilic intranuclear inclusion bodies and heterophilic exudation microscopically. Partial genome sequencing and Phylogenetic analysis of ICP4 gene revealed high genetic homology between field isolates and the virulent strains from Turkey, Germany, China and Brazil. In the present study, along with pathological findings, a rapid and sensitive PCR assay was used for detection of ILT virus specific ICP4 gene in commercial poultry farms in the region.
African Journal of Microbiology Research, 2011
Avian infectious laryngotracheitis (ILT) is a severe clinical respiratory disease of chickens and causes the clinical symptoms of difficulty in breathing and bloody coughing and as if involves laying hens affect the egg production. Two different regions of the infected cell protein 4 (ICP4) gene of infectious laryngotrucheitis virus (ILTV) were amplified and sequenced for characterization of field isolates and tissue culture-origin (TCO) and chicken embryo-origin (CEO) vaccine strains. Phylogenetic analysis of the two regions showed no differences in nucleotide and amino acid sequences between Iranian field isolates with high morbidity and nearly 30% mortality and CEO attenuated vaccines. These findings suggest that modified-Live (ML) ILT vaccine viruses may increase in virulence after bird-to-bird passages.
Suez Canal Veterinary Medical Journal. SCVMJ, 2019
Newcastle disease virus (NDV), Infectious bronchitis virus (IBV) and avian influenza virus (AIV) are the most important respiratory viruses. Many outbreaks have been reported in Egypt in spite of the intensive use of vaccination due to the wide variations in the serotypes, the highly contagious nature, the evolution of specific tissue tropism and the mutations due to simultaneous infection of multiple virus types and use of live vaccines. In this study, 10 broiler flocks in Ismailia, Sharkeia, Gharbia, Dakahleia and Matrooh suffered of severe respiratory illness with high mortalities were examined. A total of 138 nasal swabs and 144 tissue pools (brain, trachea, lung, liver, proventriculus, spleen, kidney, intestine and cecal tonsils) were collected from affected chickens and tested with Real Time RT-PCR (qRT-PCR) assay. Total positivity percentages of each virus in chickens were 23.46% for NDV, 18.08% for IBV and 31.20% for AIV. Three NDV, three IBV and four AIV sequences out of 208 positive samples were selected for sequence analysis of F, S1 and M gene respectively. The sequence analysis of F gene of NDV revealed that all isolates were clustered in genotype VII and exhibited the cleavage site (112 RRQKRF 117) of virulent velogenic NDVs. The S1 gene of IBV showed that the three isolates were closely related to variant II IBV strains. The M gene sequence analysis revealed that two AI isolates belonged to H9N2 and two AI isolates belonged to H5N8 subtypes. 200 Marwa Salem et al.
Pakistan Veterinary Journal, 2014
Infectious laryngotracheitis virus (ILTV) is a worldwide cause of acute respiratory disease in chickens. In this study, an outbreak of laryngotracheitis in commercial layers flock, Sharkia Province, Egypt in 2011 was investigated by sequencing of thymidine kinase (TK) and glycoprotein G (gG) genes. The chickens showed clinical ILTV infection, histopathological examination revealed epithelial sloughing, development of syncytical cells, heterophilic exudation with presence of eosinophilic intranuclear inclusion bodies. The virus was isolated on chorioallantoic membrane (CAM) of embryonated chicken eggs (ECE), and it induced typical pock lesions after two passages. The obtained 647 amplicon by PCR confirmed the presence of ILTV genome. Gene sequencing of TK and gG showed high genetic homology between field isolate from commercial layer flock (Sharkia-11) and vaccine strains. To our knowledge, this is the first documented ILTV outbreak attributed to vaccination with live modified ILT vaccine in Sharkia, Egypt based on sequence analysis of TK and gG genes. To Cite This Article: Ali AMA, SMG Mansour, MHA Mohamed, H Ali and A Shahin, 2014. Molecular characterization of thymidine kinase and glycoprotein G genes from a possible vaccine induced infectious laryngotracheitis outbreak in Egypt. Pak Vet J, 34(3): 381-385.
REPLICATION AND TRANSMISSION OF LIVE ATTENUATED INFECTIOUS LARYNGOTRACHEITIS VIRUS (ILTV) VACCINES
Avian Diseases Digest, 2007
Infectious laringotracheitis virus (ILTV) is associated with serious economic losses due to clinical signs, mortality, decreased egg production, and predisposition to other avian pathogens. The virus is a member of family herpesviridae, subfamily Alphaherpesvirinae, and it is taxonomically classified as Gallid herpesvirus 1. Although it was the first poultry pathogen controlled by vaccination, ILTV is still a major problem in areas where dense bird populations exist. Currently, there are two main types of ILTV live vaccines commercially available, those attenuated by sequential passages in chicken embryos (CEO) or by sequential passages in tissue culture (TCO). The replication, transmission, and protection of the CEO and TCO vaccines were evaluated using vaccinated, contact-exposed, and sentinel specific pathogen free chickens. No differences were observed in the ability of the CEO and TCO vaccines to replicate in the upper respiratory tract, to transmit to contact-exposed birds, and to induce protection against the challenge virus. However, chickens contact-exposed to vaccinates were not protected against challenge. iv DEDICATION Dedico este trabajo a las personas más importantes de mi vida, mis padres. Por medio de la educación y el cariño que me brindaron es que he llegado tan lejos en mi vida. También quiero dedicar este trabajo a mi hermano Alejandro y su esposa Gilma, quienes han creído en mí siempre y sin dudarlo me han apoyado para lograr mis sueños. "I dedicate this thesis to the most important persons in my life, my parents. Because of the education and love that they provided to me, I have come so far in my life. As well, I would like to dedicate this journey to my brother Alejandro and his wife Gilma, who have always believed in me, and unconditionally have supported me in the road to achieve my dreams." v ACKNOWLEDGMENTS First of all, I would like to thanks my major professor Dr. Maricarmen García, for believing in me, give me the opportunity to reach my dreams and for teaching me with all her patience and knowledge. You are my mentor and friend, and I will be everlastingly thankful.
Veterinary World, 2019
Background and Aim: Infectious laryngotracheitis (ILT) of chickens is a substantial issue to be studied in Iraq because this disease is one of the most highly contagious respiratory diseases in the world caused by a herpesvirus. However, in Iraq, the ILT virus (ILTV) infection and disease have yet not been confirmed in layers, so farm owners do not vaccinate these layers. The current study aimed to document the detection and characterization of ILTV in layer hens from Al-Diwaniyah city, for the first time in Iraq, using molecular techniques like polymerase chain reaction (PCR) and sequencing. Materials and Methods: Four layer farms (15,000 unvaccinated layers/farm) in Al-Diwaniyah province, Iraq, suffered a severe ILT outbreak, was diagnosed and reported by clinical and PCR tests. This disease has been reported in Iraq, and more recently, it began to show outbreaks in Al-Diwaniyah city. The current work opted to investigate the ILTV using PCR and DNA sequencing techniques. The study targeted the p32 gene of ILTV using pooled tracheal swabs and organs including the trachea, lung, and kidneys which were collected from dead and clinically infected chickens. Results: The analyses revealed that four of six suspected field samples showed positive results by PCR. The DNA sequencing results showed the homology of the amplified fragments with the studied gene. Conclusion: This study confirmed the presence of ILTV in hens with respiratory signs during the outbreak.
Viruses, 2021
Infectious laryngotracheitis (ILT) is an infectious upper respiratory tract disease that impacts the poultry industry worldwide. ILT is caused by an alphaherpesvirus commonly referred to as infectious laryngotracheitis virus (ILTV). Vaccination with live attenuated vaccines is practiced regularly for the control of ILT. However, extensive and improper use of live attenuated vaccines is related to vaccine viruses reverting to virulence. An increase in mortality and pathogenicity has been attributed to these vaccine revertant viruses. Recent studies characterized Canadian ILTV strains originating from ILT outbreaks as related to live attenuated vaccine virus revertants. However, information is scarce on the pathogenicity and transmission potential of these Canadian isolates. Hence, in this study, the pathogenicity and transmission potential of two wildtype ILTVs and a chicken embryo origin (CEO) vaccine revertant ILTV of Canadian origin were evaluated. To this end, 3-week-old specific...