Chapters authored
Adenoviruses and Their Diversity in Poultry
An investigation into the aetiology of fowl adenovirus strains and their distribution worldwide in populations of poultry flocks industry has been conducted. Pathogenic role of the viruses is not always clear. They can cause latent infection or several diseases and are the reason of economic losses in poultry flock industry. Ubiquity of adenovirus strains was commonly described, and stand-alone pathogenicity for a long time has been disputed. A globally emerging trend of adenoviruses and adenovirus-associated diseases has been increasing from year to year in all over the world. Mainly, type FAdV-4 is responsible for hydropericardium hepatitis syndrome (HP), type FAdV-1 for gizzard erosion and ulceration (GEU), and types FAdV-2, 8a, 8b, and 11 seem to be responsible for inclusion body hepatitis (IBH). Defining the spreading of the avian adenovirus strains in different types of fowl profile production, recognising their property and determining their types and molecular characterisation are very important from the epidemiological point of view and are considered as excellent basis for vaccine development and gene therapy implementation. This chapter provides a comprehensive review of FAdVs, including their epidemiology, pathogenesis, diagnostic, detection, and molecular characterisation. This comprehensive review is needed to better understand the latest progress in study of the viruses and prospects regarding disease control and implementation of gene therapy.
Part of the book: Application of Genetics and Genomics in Poultry Science
Marek’s Disease Is a Threat for Large Scale Poultry Production
Marek’s disease (MD) is one of the widespread infectious diseases that causes huge losses in large-scale poultry production. This is due to weight loss, poorer feed conversion and an increased number of deaths among infected birds. The etiological agent is a Marek’s disease virus (MDV) belonging to the Herpesviridae family. It is mainly described in poultry, however, it is also found in geese. There are three MDV serotypes, and four patotypes within serotype 1. Currently, Marek’s disease is very rare in its classical form. There are non-specific clinical symptoms, and anatomopathological changes are mainly observed in the liver, spleen and the reproductive system. This may be due to the evolution in the pathogenicity of MDV field strains over the past several decades. The presence of MDV and number of molecular diagnostic tests based on the detection of viral nucleic acids and viral proteins is already found in birds that have several weeks old. Laboratory diagnostics are based mainly on molecular biology (mainly PCR) methods. The only relatively effective method instead of biosecurity measures, of preventing MD is prophylactic vaccination of 1-day-old chickens or in ovo vaccination. Nevertheless, Marek’s disease is still recorded in poultry flocks around the world, with estimated losses reaching several million dollars.
Part of the book: Updates on Veterinary Anatomy and Physiology