Fowl adenovirus 8a isolated from chickens with runting and stunting syndrome induces inclusion body hepatitis and hepatitis-hydropericardium syndrome in chicken embryos

Vet World Vol.17 November-2024 Article - 15

Research Article

Veterinary World, 17(11): 2556-2566

https://doi.org/10.14202/vetworld.2024.2556-2566

Luis Nuñez^1,2, Silvana Santander-Parra^1,3, Marcia Catroxo⁴, Claudete Serrano Astolfi-Ferreira³, Anthony Loor-Giler^5,6, and Antonio Piantino Ferreira³

1. Facultad de Ciencias de la Salud, Carrera de Medicina Veterinaria, Universidad de Las Américas (UDLA), Antigua Vía a Nayón S/N, Quito EC 170124, Ecuador.
2. One Health Research Group, Universidad de Las Américas (UDLA), Antigua Vía a Nayón S/N, Quito EC 170124, Ecuador.
3. Laboratory of Avian Diseases, School of Veterinary Medicine and Animal Science, Department of Pathology, University of São Paulo, São Paulo, Brazil.
4. Laboratory of Electron Microscopy, Center for Research and Development of Animal Health, Instituto Biologico, Av. Cons. Rodrigues Alves, 1252, 04014-002, São Paulo, SP, Brazil.
5. Laboratorios de Investigación, Dirección general de Investigación, Universidad de las Américas (UDLA), Antigua Vía a Nayón S/N, Quito EC 170124, Ecuador.
6. Facultad de Ingeniería y Ciencias Aplicadas, Carrera de Ingeniería en Biotecnología, Universidad de Las Américas (UDLA), Antigua Vía a Nayón S/N, Quito EC 170124, Ecuador.

Background and Aim: Fowl adenovirus (FAdV) is the etiological agent of inclusion body hepatitis (IBH) and hepatitis-hydropericardium syndrome (HHS) in poultry. It is also detected in chickens with runting and stunting syndrome (RSS). FAdV has been detected worldwide, and genotypes 8a, 8b, and 11 have been identified in chickens with enteric problems in Brazil. Nevertheless, none of them have been isolated; therefore, these viruses propagate; thus, the viral behavior and pathogenicity are unknown in Brazil. This study aimed to isolate FAdV from the enteric content of chickens affected by RSS.

Materials and Methods: Enteric content samples from chickens affected with RSS and a positive polymerase chain reaction (PCR) test for FAdV were inoculated into specific pathogen-free chicken embryonated eggs (CEEs) through the yolk and chorioallantoic membrane routes on 8 and 10 days of age, respectively and the eggs were incubated for five days for viral isolation.

Results: The embryos exhibited dwarfism, beak atrophy, and pale claws. In addition, some embryos displayed edema and gelatin-like characteristics. The liver exhibited hepatomegaly and multiple necrotic foci, resembling the appearance of nutmeg. In addition, the kidneys appeared enlarged and pale. After 8 days of incubation, the hearts of the inoculated embryos showed hydropericardium. Microscopic evaluation revealed the presence of hepatitis, which was characterized by the presence of intranuclear inclusion bodies and cellular necrosis. Viral FAdV particles were observed in kidney cells using electron microscopy. Viral DNA was detected in the embryos in all three passages, and viral gene copies were also measured in some organs, with high FAdV gene copies detected in the spleen and bursa beyond the liver.

Conclusion: The molecular characterization of FAdV revealed that the isolated strain belonged to genotype 8a of FAdV. Here, FAdV-8a from chickens infected with RSSs produced IBH/HHS in CEE, and FAdV-8a detected in RSS outbreaks, in addition to producing IBH/HHS in chicken embryos, could be a possible viral agent that causes IBH/HHS in chickens.

Keywords: chicken embryonated eggs, fowl adenovirus, hepatitis-hydropericardium syndrome, inclusion body hepatitis, runting and stunting syndrome.

How to cite this article: Nuñez L, Santander-Parra S, Catroxo M, Astolfi-Ferreira CS, Loor-Giler A, and Ferreira AP (2024) Fowl adenovirus 8a isolated from chickens with runting and stunting syndrome induces inclusion body hepatitis and hepatitis-hydropericardium syndrome in chicken embryos, Veterinary World, 17(11): 2556-2566.

Received: 2024-06-20 Accepted: 2024-10-10 Published online: 2024-11-13

Corresponding author: Luis Nuñez E-mail: fabiann7@yahoo.es

DOI: 10.14202/vetworld.2024.2556-2566

Copyright: Nuñez, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/ by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.