title: Haemorrhagic enteritis of turkeys - current knowledge.
abstract: Haemorrhagic enteritis virus (HEV), an adenovirus associated with acute haemorrhagic gastro-intestinal disease of 6-11-week old turkeys predominantly hampers both humoral and cellular immunity. Affected birds are more prone to secondary complications (e.g. colibacillosis and clostridiosis) and failure to mount an effective vaccine-induced immune response. HEV belongs to the new genus Siadenovirus. Feco-oral transmission is the main route of entry of the virus and it mainly colonizes bursa, intestine and spleen. Both naturally occurring virulent and avirulent strains of HEVs are serologically indistinguishable. Recent findings revealed that ORF1, E3 and fib genes are the key factors affecting virulence. The adoption of suitable diagnostic tools, proper vaccination and biosecurity measures have restrained the occurrence of disease epidemics. For diagnostic purposes, the best source of HEV is either intestinal contents or samples from spleen. For rapid detection highly sensitive and specific tests such as quantitative real-time PCR based on Taq man probe has been designed. Avirulent strains of HEV or MSDV can be effectively used as live vaccines. Novel vaccines include recombinant hexon protein-based subunit vaccines or recombinant virus-vectored vaccines using fowl poxvirus (FPV) expressing the native hexon of HEV. Notably, subunit vaccines and recombinant virus vectored vaccines altogether offer high protection against challenge or field viruses. Herein, we converse a comprehensive analysis of the HEV genetics, disease pathobiology, advancements in diagnosis and vaccination along with appropriate prevention and control strategies.
authors.affiliation: a Avian Diseases Section, Division of Pathology , ICAR-Indian Veterinary Research Institute , Izatnagar , India.
authors.forename: Kuldeep
authors.initials: K
authors.lastname: Dhama
authors.affiliation: b Poultry Disease Diagnosis and Surveillance Laboratory , Veterinary College and Research Institute , Namakkal , Tamil Nadu, India.
authors.forename: Vasudevan
authors.initials: V
authors.lastname: Gowthaman
authors.affiliation: c Central University Laboratory, Tamil Nadu Veterinary and Animal Sciences University , Chennai , India.
authors.forename: Kumaragurubaran
authors.initials: K
authors.lastname: Karthik
authors.affiliation: d Department of Microbiology , DUVASU , Mathura , India.
authors.forename: Ruchi
authors.initials: R
authors.lastname: Tiwari
authors.affiliation: a Avian Diseases Section, Division of Pathology , ICAR-Indian Veterinary Research Institute , Izatnagar , India.
authors.forename: Swati
authors.initials: S
authors.lastname: Sachan
authors.affiliation: a Avian Diseases Section, Division of Pathology , ICAR-Indian Veterinary Research Institute , Izatnagar , India.
authors.forename: M Asok
authors.initials: MA
authors.lastname: Kumar
authors.affiliation: a Avian Diseases Section, Division of Pathology , ICAR-Indian Veterinary Research Institute , Izatnagar , India.
authors.forename: M
authors.initials: M
authors.lastname: Palanivelu
authors.affiliation: e Division of Biological Standardization , ICAR-Indian Veterinary Research Institute , Izatnagar , India.
authors.forename: Yashpal Singh
authors.initials: YS
authors.lastname: Malik
authors.affiliation: f Director, ICAR-Indian Veterinary Research Institute , Izatnagar , India.
authors.forename: Raj Kumar
authors.initials: RK
authors.lastname: Singh
authors.affiliation: g Avian Viral Diseases Programme Compton Laboratory , Berkshire , UK.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Munir
mesh_terms: D000257:Adenoviridae Infections / Q000175:diagnosis / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D000818:Animals; D004751:Enteritis / Q000662:veterinary; D011201:Poultry Diseases / Q000175:diagnosis / Q000517:prevention & control / Q000821:virology; D046809:Siadenovirus / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D014422:Turkeys; D014611:Vaccination / Q000662:veterinary*; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D014765:Viral Vaccines
keywords: Turkey; control; diagnosis; haemorrhagic enteritis virus; pathobiology; review; vaccine