PMID- 32352307 OWN - NLM STAT- MEDLINE DCOM- 20210315 LR - 20210315 IS - 1465-3338 (Electronic) IS - 0307-9457 (Linking) VI - 49 IP - 4 DP - 2020 Aug TI - Latency characteristics in specific pathogen-free chickens 21 and 35 days after intra-tracheal inoculation with vaccine or field strains of infectious laryngotracheitis virus. PG - 369-379 LID - 10.1080/03079457.2020.1754331 [doi] AB - Latency is an important feature of infectious laryngotracheitis virus (ILTV) yet is poorly understood. This study aimed to compare latency characteristics of vaccine (SA2) and field (CL9) strains of ILTV, establish an in vitro reactivation system and examine ILTV infection in peripheral blood mononuclear cells (PBMC) in specific pathogen-free chickens. Birds were inoculated with SA2 or CL9 ILTV and then bled and culled at 21 or 35 days post-inoculation (dpi). Swabs (conjunctiva, palatine cleft, trachea) and trigeminal ganglia (TG) were examined for ILTV DNA using PCR. Half of the TG, trachea and PBMC were co-cultivated with cell monolayers to assess in vitro reactivation of ILTV infection. ILTV DNA was detected in the trachea of approximately 50% of ILTV-inoculated birds at both timepoints. At 21 dpi, ILTV was detected in the TG only in 29% and 17% of CL9- and SA2-infected birds, respectively. At 35 dpi, ILTV was detected in the TG only in 30% and 10% of CL9- and SA2-infected birds, respectively. Tracheal organ co-cultures from 30% and 70% of CL9- and SA2-infected birds, respectively, were negative for ILTV DNA at cull but yielded quantifiable DNA within 6 days post-explant (dpe). TG co-cultivation from 30% and 40% of CL9-and SA2-infected birds, respectively, had detectable ILTV DNA within 6 dpe. Latency characteristics did not substantially vary based on the strain of virus inoculated or between sampling timepoints. These results advance our understanding of ILTV latency and reactivation. RESEARCH HIGHLIGHTS Following inoculation, latent ILTV infection was detected in a large proportion of chickens, irrespective of whether a field or vaccine strain was inoculated. In vitro reactivation of latent ILTV was readily detected in tracheal and trigeminal ganglia co-cultures using PCR. ILTV latency observed in SPF chickens at 21 days post-infection was not substantially different to 35 days post-infection. FAU - Thilakarathne, Dulari S AU - Thilakarathne DS AD - Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, The University of Melbourne, Parkville, Australia. FAU - Hartley, Carol A AU - Hartley CA AUID- ORCID: 0000-0002-1927-8040 AD - Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, The University of Melbourne, Parkville, Australia. FAU - Diaz-Mendez, Andres AU - Diaz-Mendez A AUID- ORCID: 0000-0003-3004-8518 AD - Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, The University of Melbourne, Parkville, Australia. FAU - Quinteros, Jose A AU - Quinteros JA AD - Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, The University of Melbourne, Parkville, Australia. FAU - Fakhri, Omid AU - Fakhri O AD - Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, The University of Melbourne, Parkville, Australia. FAU - Coppo, Mauricio J C AU - Coppo MJC AD - Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, The University of Melbourne, Parkville, Australia. FAU - Devlin, Joanne M AU - Devlin JM AD - Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, The University of Melbourne, Parkville, Australia. LA - eng PT - Journal Article DEP - 20200602 PL - England TA - Avian Pathol JT - Avian pathology : journal of the W.V.P.A JID - 8210638 SB - IM MH - Animals MH - Chickens/*virology MH - Herpesviridae Infections/*veterinary/virology MH - Herpesvirus 1, Gallid/*immunology/physiology MH - Leukocytes, Mononuclear/immunology MH - Male MH - Polymerase Chain Reaction/veterinary MH - Poultry Diseases/*virology MH - Specific Pathogen-Free Organisms MH - Trachea/virology MH - Trigeminal Ganglion/virology MH - Virus Latency OTO - NOTNLM OT - in vitro reactivation OT - Chickens OT - infectious laryngotracheitis virus OT - latency EDAT- 2020/05/01 06:00 MHDA- 2021/03/16 06:00 CRDT- 2020/05/01 06:00 PHST- 2020/05/01 06:00 [pubmed] PHST- 2021/03/16 06:00 [medline] PHST- 2020/05/01 06:00 [entrez] AID - 10.1080/03079457.2020.1754331 [doi] PST - ppublish SO - Avian Pathol. 2020 Aug;49(4):369-379. doi: 10.1080/03079457.2020.1754331. Epub 2020 Jun 2.