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Hong X, Zhang H, Zhang X, Zhang XP, Zhang T. A meta-analysis for prevalence of infectious laryngotracheitis in chickens in mainland China in 1981-2022. BMC Vet Res 2024; 20:142. [PMID: 38594649 PMCID: PMC11344410 DOI: 10.1186/s12917-024-03991-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 03/26/2024] [Indexed: 04/11/2024] Open
Abstract
BACKGROUND Infectious laryngotracheitis (ILT) is a highly infectious upper respiratory tract disease of chickens caused by infectious laryngotracheitis virus or Gallid herpesvirus 1 (GaHV-1). ILT is an important respiratory disease of chickens and annually causes significant economic losses in the chicken industry. Although numerous relevant studies have been published, the overall prevalence of ILT infection among chicken in mainland China is still unknown, and associated risk factors need to be evaluated to establish preventive measures. RESULTS The present study reviewed the literature on the prevalence of ILT in chickens in China as of December 20, 2022, retrieved from six databases-CNKI, Wanfang, VIP, PubMed, Web of Science, and ScienceDirect-were used to retrieve relevant studies published between January 1, 1981 and December 20, 2022. The literature quality of studies was assessed, and 20 studies with a total of 108,587 samples were included in the meta-analysis. Results of the meta-analysis showed that the overall prevalence of ILT was 10% (95% confidence interval: 8 -12%) through the random-effects model, which showed high heterogeneity, I2 = 99.4%. Further subgroup analyses showed that the prevalence of ILT decreased over time; furthermore, the prevalence in Northwest China was slightly lower than that in North China and South China, and the prevalence estimated using the diagnostic technique AGP was higher than that reported using other diagnostic techniques. CONCLUSIONS ILT is prevalent to some extent in mainland China. Given that the ILT attenuated live vaccine has a certain level of virulence and the prevalence differences between regions, we recommend controlling breeding density, improving immunization programs and continuously monitoring viruses and to prevent ILT prevailing in mainland China.
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Affiliation(s)
- Xingping Hong
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | | | - Xiaorong Zhang
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Xue Ping Zhang
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China
| | - Tangjie Zhang
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China.
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China.
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Gowthaman V, Kumar S, Koul M, Dave U, Murthy TRGK, Munuswamy P, Tiwari R, Karthik K, Dhama K, Michalak I, Joshi SK. Infectious laryngotracheitis: Etiology, epidemiology, pathobiology, and advances in diagnosis and control - a comprehensive review. Vet Q 2021; 40:140-161. [PMID: 32315579 PMCID: PMC7241549 DOI: 10.1080/01652176.2020.1759845] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Infectious laryngotracheitis (ILT) is a highly contagious upper respiratory tract disease of chicken caused by a Gallid herpesvirus 1 (GaHV-1) belonging to the genus Iltovirus, and subfamily Alphaherpesvirinae within Herpesviridae family. The disease is characterized by conjunctivitis, sinusitis, oculo-nasal discharge, respiratory distress, bloody mucus, swollen orbital sinuses, high morbidity, considerable mortality and decreased egg production. It is well established in highly dense poultry producing areas of the world due to characteristic latency and carrier status of the virus. Co-infections with other respiratory pathogens and environmental factors adversely affect the respiratory system and prolong the course of the disease. Latently infected chickens are the primary source of ILT virus (ILTV) outbreaks irrespective of vaccination. Apart from conventional diagnostic methods including isolation and identification of ILTV, serological detection, advanced biotechnological tools such as PCR, quantitative real-time PCR, next generation sequencing, and others are being used in accurate diagnosis and epidemiological studies of ILTV. Vaccination is followed with the use of conventional vaccines including modified live attenuated ILTV vaccines, and advanced recombinant vector vaccines expressing different ILTV glycoproteins, but still these candidates frequently fail to reduce challenge virus shedding. Some herbal components have proved to be beneficial in reducing the severity of the clinical disease. The present review discusses ILT with respect to its current status, virus characteristics, epidemiology, transmission, pathobiology, and advances in diagnosis, vaccination and control strategies to counter this important disease of poultry.
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Affiliation(s)
- Vasudevan Gowthaman
- Poultry Disease Diagnosis and Surveillance Laboratory, Tamil Nadu Veterinary and Animal Sciences University, Namakkal, Tamil Nadu, India
| | - Sachin Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Monika Koul
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Urmil Dave
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - T R Gopala Krishna Murthy
- Poultry Disease Diagnosis and Surveillance Laboratory, Tamil Nadu Veterinary and Animal Sciences University, Namakkal, Tamil Nadu, India
| | - Palanivelu Munuswamy
- Division of Pathology, ICAR - Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India
| | - Ruchi Tiwari
- Department of Veterinary Microbiology and Immunology, College of Veterinary Sciences, UP Pandit Deen Dayal Upadhayay Pashu Chikitsa Vigyan Vishwavidyalay Evum Go-Anusandhan Sansthan (DUVASU), Mathura, Uttar Pradesh, India
| | - Kumaragurubaran Karthik
- Central University Laboratory, Tamil Nadu Veterinary and Animal Sciences University, Chennai, Tamil Nadu, India
| | - Kuldeep Dhama
- Division of Pathology, ICAR - Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India
| | - Izabela Michalak
- Faculty of Chemistry, Department of Advanced Material Technologies, Wrocław University of Science and Technology, Wrocław, Poland
| | - Sunil K Joshi
- Department of Microbiology & Immunology, Department of Pediatrics, Division of Hematology, Oncology and Bone Marrow Transplantation, University of Miami School of Medicine, Miami, Florida, USA
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Aras Z, Yavuz O, Sanioğlu Gölen G. Occurrence of infectious laryngotracheitis outbreaks in commercial layer hens detected by ELISA. J Immunoassay Immunochem 2018; 39:190-195. [PMID: 29424631 DOI: 10.1080/15321819.2018.1428991] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Infectious laryngotracheitis (ILT) is an acute respiratory disease of chickens and a cause of great economic loss in commercial layers. The aims of this study were to investigate the prevalence of ILT in the field outbreaks and to compare the characteristics of ILT-infected and free flocks of commercial layers. A total of 625 blood serum samples were collected from 25 different layer flocks. The presence of antibodies against infectious laryngotracheitis virus (ILTV) in each sample was determined by ELISA. Of the 625 serum samples, 266 (42.56%) were found to be positive for ILTV antibodies. A total of 16 (64%) flocks were detected ILT positive by ELISA method. The mortality of infected flocks was statistically higher (P < 0.05) than uninfected flocks. The egg production of positive flocks was lower than that of the free flocks, but this difference was not statistically significant. The average live weight of hens in infected flocks was lower (P > 0.05) than hens in free flocks. In conclusion, the results of this study indicated a high prevalence of ILT infection in the commercial layer flocks in Konya region, Turkey. In outbreaks, ILT significantly increased the mortality rate and decreased the average live weight in layer hens.
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Affiliation(s)
- Zeki Aras
- a Department of Microbiology, Faculty of Veterinary Medicine , Aksaray University , Aksaray , Turkey
| | - Orhan Yavuz
- b Department of Pathology, Faculty of Veterinary Medicine , Aksaray University , Aksaray , Turkey
| | - Gökçenur Sanioğlu Gölen
- a Department of Microbiology, Faculty of Veterinary Medicine , Aksaray University , Aksaray , Turkey
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Roy P, Fakhrul Islam AFM, Burgess SK, Hunt PW, McNally J, Walkden-Brown SW. Real-time PCR quantification of infectious laryngotracheitis virus in chicken tissues, faeces, isolator-dust and bedding material over 28 days following infection reveals high levels in faeces and dust. J Gen Virol 2016; 96:3338-3347. [PMID: 26294959 DOI: 10.1099/jgv.0.000268] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Infectious laryngotracheitis (ILT) is an important disease of chickens caused by ILT virus (ILTV). We used the Australian SA2 and A20 vaccine strains of ILTV to determine tissue distribution and excretion characteristics of ILTV in specific-pathogen-free chickens and to determine whether ILTV is readily detectable in environmental samples such as faeces, bedding material and dust using real-time quantitative PCR. Three groups of 10 freshly hatched chicks were placed in isolators and infected orally with high doses of the two strains of vaccine virus or left unchallenged as controls. Over a 28-day post-infection (p.i.) period, faecal and serum samples were collected at frequent intervals from six individually identified chickens in each group. Dust and litter samples from the isolators were collected less frequently. Tissue samples were collected from three to four sacrificed or dead/euthanized birds at 6, 14 and 28 days p.i. Infection resulted in clinical ILT, a pronounced antibody response and sustained qPCR detection of the viral genome in the trachea, Harderian gland, lung and kidney up to 28 days p.i. A high level of the viral genome was also detected in faeces between 2 and 7 days p.i., declining by about approximately four orders of magnitude to low, but detectable, levels at 21 and 28 days p.i. The finding of high-level shedding of ILTV in faeces warrants further investigation into the epidemiological role of this, and the sustained high levels of ILTV observed in dust suggest that it may be a useful sample material for monitoring ILTV status in flocks.
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Affiliation(s)
- Parimal Roy
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia.,Central University Laboratory, Tamilnadu Veterinary and Animal Sciences University, Chennai 600051, India
| | - A F M Fakhrul Islam
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia
| | - Susan K Burgess
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia
| | - Peter W Hunt
- CSIRO FD McMaster Laboratory, Locked Bag 1, Armidale, NSW 2351 Australia
| | - Jody McNally
- CSIRO FD McMaster Laboratory, Locked Bag 1, Armidale, NSW 2351 Australia
| | - Stephen W Walkden-Brown
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia
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Ou SC, Giambrone JJ. Infectious laryngotracheitis virus in chickens. World J Virol 2012; 1:142-9. [PMID: 24175219 PMCID: PMC3782274 DOI: 10.5501/wjv.v1.i5.142] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 06/12/2012] [Accepted: 09/07/2012] [Indexed: 02/05/2023] Open
Abstract
Infectious laryngotracheitis (ILT) is an important respiratory disease of chickens and annually causes significant economic losses in the poultry industry world-wide. ILT virus (ILTV) belongs to alphaherpesvirinae and the Gallid herpesvirus 1 species. The transmission of ILTV is via respiratory and ocular routes. Clinical and post-mortem signs of ILT can be separated into two forms according to its virulence. The characteristic of the severe form is bloody mucus in the trachea with high mortality. The mild form causes nasal discharge, conjunctivitis, and reduced weight gain and egg production. Conventional polymerase chain reaction (PCR), nested PCR, real-time PCR, and loop-mediated isothermal amplification were developed to detect ILTV samples from natural or experimentally infected birds. The PCR combined with restriction fragment length polymorphism (RFLP) can separate ILTVs into several genetic groups. These groups can separate vaccine from wild type field viruses. Vaccination is a common method to prevent ILT. However, field isolates and vaccine viruses can establish latent infected carriers. According to PCR-RFLP results, virulent field ILTVs can be derived from modified-live vaccines. Therefore, modified-live vaccine reversion provides a source for ILT outbreaks on chicken farms. Two recently licensed commercial recombinant ILT vaccines are also in use. Other recombinant and gene-deficient vaccine candidates are in the developmental stages. They offer additional hope for the control of this disease. However, in ILT endemic regions, improved biosecurity and management practices are critical for improved ILT control.
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Affiliation(s)
- Shan-Chia Ou
- Shan-Chia Ou, Joseph J Giambrone, Department of Poultry Science, Auburn University, Auburn, AL 36849, United States
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Dufour-Zavala L. Epizootiology of infectious laryngotracheitis and presentation of an industry control program. Avian Dis 2008; 52:1-7. [PMID: 18459288 DOI: 10.1637/8018-051007-review] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Despite improved biosecurity and vaccination programs in recent years, infectious laryngotracheitis continues to emerge in the field on a regular basis in poultry producing states. Evidence is mounting that most field outbreaks are caused by viruses indistinguishable from chicken-embryo-origin vaccine strains and, for that reason, broiler outbreaks are often referred to in the field as "vaccinal laryngotracheitis" (VLT). Cooperative industry programs are described, in which the poultry industry, along with government, laboratories, and other sectors involved with poultry live production work together to control and contain VLT outbreaks. These programs take into account many epizootiologic aspects of the disease and, when diligently followed, are successful in most instances at keeping the numbers of cases low and the outbreaks under control. The programs include the rapid diagnosis of the disease, the use of geographic information system technology, biosecurity, vaccination, and communications between all stakeholders.
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Raggi L, Brownell J, Stewart G. Effects of Infectious Laryngotracheitis Virus on Egg Production and Quality. Poult Sci 1961. [DOI: 10.3382/ps.0400134] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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