Molecular detection and phylogenetic tree of infectious laryngotracheitis virus in layers in Al-Diwaniyah province, Iraq

Abstract

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.

Molecular detection and characterization of infectious laryngotracheitis virus in backyard chickens in Turkey

“…Countries including USA, Canada, Brazil, Europe, Australia, China, Egypt, South Asia, Lebanon and Saudi Arabia have notified ILT outbreaks (Gowthaman et al 2020). Lastly, the disease have been reported in Iraq (Alaraji et al 2019) and Namibia (Molini et al 2019). In Turkey, the frequency of the disease that determined in present study is lower than other countries.…”

“…The positivity rates of backyards were quite lower than Aras et al (2018) and this difference may be related with the sensitivity of ELISA tests. Virus isolation and serological tests (fluorescent antibody technique, enzyme-linked immunosorbent assay, serum neutralization, and agar gel immunodiffusion) have been used for diagnoses but, these methods are laborious, time consuming and the sensitivities of serological tests are lower than PCR (Alaraji et al 2019). ILT continue to keep its importance throughout the world.…”

Infectious laryngotracheitis: Etiology, epidemiology, pathobiology, and advances in diagnosis and control – a comprehensive review

“…During the period of 2000-2013, the disease had been reported at least in 100 countries (Menendez et al 2014). Recently, ILTV was confirmed by molecular techniques in Al-Diwaniyah province, Iraq which was the first report from the country (Alaraji et al 2019). In 2018, three outbreaks of ILT were reported in Windhoek, Namibia causing huge mortality in commercial layers and broilers (Molini et al 2019).…”

“…The disease has been reported from several Asian (China, Georgia, India, Japan, Lebanon, Myanmar, Philippines, Sabah, Sarawak, Taiwan, Iraq and Uzbekistan), African (Cameroon, Uganda, Namibia, Egypt, Nigeria), North American (Canada, Delaware, Georgia, Mexico, Maryland, New Brunswick, North Carolina, Ontario, Pennsylvania and Virginia), Central American and Caribbean (Costa Rica, Trinidad and Tobago), South American (Argentina, Brazil, Chile, Peru, Suriname and Uruguay), European (Austria, Belgium, Denmark, Germany, Italy, Moldova, Norway, the Netherlands, Poland, Sweden, Switzerland and UK) and Oceania countries (Australia, Cook Islands, French Polynesia, Guam, Kiribati and New Zealand (Hidalgo 2003;Chac on and Ferreira 2009;OIE 2014;Magouz et al 2018;Alaraji et al 2019;Molini et al 2019). Very recently, it was reported that recombinant ILT virus and CEO vaccine-like virus are causing outbreaks in Eygpt (Bayoumi et al 2020).…”

Multilocus analysis of Gallid herpesvirus 1 in layer chickens in Iraq

“…A vaccination program immunizing against ILTV has not officially been adopted by the federal government of Iraq [15] because of the political and economical disturbances. However, some farmers import the live-attenuated vaccine illegally from neighboring countries such as Syria, Turkey, Iran, Saudi Arabia, and Jordan (Figure -1).…”