Haemorrhagic enteritis of turkeys and related infections of pheasants and domestic fowl: a review

Chandra, Rajesh; Kumar, Ashok

doi:10.1079/wps19980017

Cited by 4 publications

(1 citation statement)

References 76 publications

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“…HEV is the etiological agent of hemorrhagic enteritis (HE), a disease characterized by immunosuppression in turkeys of >4-weeks of age. The disease has two presentations: (1) clinical disease consisting of depression, gastrointestinal hemorrhages, and transient immunosuppression followed by increased mortality (up to 80% for highly virulent strains due to blood loss and secondary infection with opportunists like Escherichia coli ) [ 6 , 7 , 8 ]; and (2) subclinical infection, consisting in immunosuppression and causing economical losses because of secondary bacterial infection, especially from Escherichia coli , and processing plant condemnations [ 7 , 9 , 10 ]. The immunosuppression caused by the subclinical infection increases the birds susceptibility to secondary bacterial infections which poses a problem for the judicious antibiotic use in farm animals, both being important problems for the turkey industry [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

Molecular Characterization of Hemorrhagic Enteritis Virus (HEV) Obtained from Clinical Samples in Western Canada 2017–2018

Palomino-Tapia

Mitevski²,

Inglis³

et al. 2020

Viruses

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Hemorrhagic enteritis virus (HEV) is an immunosuppressive adenovirus that causes an acute clinical disease characterized by hemorrhagic gastroenteritis in 4-week-old turkeys and older. Recurrent incidence of secondary infections (e.g., systemic bacterial infections, cellulitis, and elevated mortality), may be associated with the presence of field-type HEV in Canadian turkey farms. We speculate that field-type HEV and vaccine/vaccine-like strains can be differentiated through analysis of the viral genomes, hexon genes, and the specific virulence factors (e.g., ORF1, E3, and fib knob domain). Nine out of sixteen spleens obtained from cases suspected of immunosuppression by HEV were analyzed. The limited data obtained showed that: (1) field-type HEV circulates in many non-vaccinated western Canadian flocks; (2) field-type HEV circulates in vaccinated flocks with increased recurrent bacterial infections; and (3) the existence of novel point mutations in hexon, ORF1, E3, and specially fib knob domains. This is the first publication showing the circulation of wild-type HEV in HEV-vaccinated flocks in Western Canada, and the usefulness of a novel procedure that allows whole genome sequencing of HEV directly from spleens, without passaging in cell culture or passaging in vivo. Further studies focusing more samples are required to confirm our observations and investigate possible vaccination failure.

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Section: Introductionmentioning

confidence: 99%

Molecular Characterization of Hemorrhagic Enteritis Virus (HEV) Obtained from Clinical Samples in Western Canada 2017–2018

Palomino-Tapia

Mitevski²,

Inglis³

et al. 2020

Viruses

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Chronologic Analysis of Gross and Histologic Lesions Induced by Field Strains of FAdV-1, FAdV-8b, and FAdV-11 in Six-Week-Old Chickens

et al. 2017

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Inclusion body hepatitis (IBH) is a disease affecting broiler chicken flocks worldwide. Several serotypes of fowl adenovirus (FAdV) have been implicated in disease outbreaks, with and without immunosuppression as a predisposing factor. IBH usually occurs in flocks up to 30 days of age; it is seldom seen in older birds. The objective of this study was to determine whether the pathogenicity for older birds of three FAdV field strains, belonging to serotypes 1, 8b, and 11, in the absence of immunosuppressive factors, was akin to that for younger birds, and to establish an effective and economical disease model for assessing cross-protection between serotypes. To achieve this objective, the gross pathology, histopathology, and dissemination of virus were examined at multiple time points after inoculation of 6-wk-old, specific-pathogen-free chickens via intraperitoneal injection. Both FAdV-8b and FAdV-11 generated lesions typical of those associated with outbreaks of IBH, and they were shown to be primary pathogens. The presence and severity of hepatic lesions were used to define two disease stages: degeneration (1-5 days postinoculation) and convalescence (6-14 days postinoculation). During the degenerative stage, FAdV-8b was detected in the liver, kidney, and gizzard of most birds, whereas FAdV-11 was predominantly detected in the liver, and both viruses persisted in the gizzard into convalescence. The pathogenesis of two IBH-associated FAdV strains in 6-wk-old chickens confirms their high level of virulence and also provides an effective experimental model for investigation of cross-protection between FAdVs. It also demonstrates persistence of the virus in the gizzard long after infection, supporting the notion that it is a site of viral shedding.

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Avian adenovirus infections: diversity of pathogens, hazard to poultry industry and problems of immunoprophylaxis (review)

Zelenskiy,

Volkov,

Komarov

et al. 2024

Veterinariâ segodnâ

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The data on diversity of adenovirus pathogens in nature and the role of the main representatives of the Adenoviridae family in poultry infectious pathology are presented. Special attention is paid to problematic issues of immunoprophylaxis due to lack of cross-immunity between different virus serotypes. There is no single and effective approach in the global strategy of immunoprophylaxis of avian adenoviruses, therefore, improving the means of avian adenovirus disease control is an urgent and important task. Avian adenovirus infections are represented by different nosological units: egg drop syndrome, hydropericardium syndrome, adenoviral gizzard erosion, marbled spleen disease of pheasants, hemorrhagic enteritis of turkeys, inclusion body hepatitis and many unclassified diseases. The paper provides data on the main nosological forms of adenovirus infections that pose a threat to cost-effective poultry farming, and highlights test results obtained by foreign authors on the effectiveness of some vaccines against adenovirus infection. Most vaccines have been developed to prevent avian hydropericardium syndrome, however, occurrence of many virus serotypes requires effective means of prevention and diagnosis in order to control other infections caused by adenoviruses. There is no registered vaccine against adenovirus infections that cause inclusion body hepatitis and adenoviral gizzard erosion. At the same time, inclusion body hepatitis alone accounts for 2.9% of all recorded avian infectious diseases. Vaccines registered in the Russian Federation are not enough to fully control these infections, and that requires a timely solution to the problem. The variety of avian adenoviruses determines the problems of their differential diagnosis and specific prevention.

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Haemorrhagic enteritis of turkeys and related infections of pheasants and domestic fowl: a review

Cited by 4 publications

References 76 publications

Molecular Characterization of Hemorrhagic Enteritis Virus (HEV) Obtained from Clinical Samples in Western Canada 2017–2018

Molecular Characterization of Hemorrhagic Enteritis Virus (HEV) Obtained from Clinical Samples in Western Canada 2017–2018

Chronologic Analysis of Gross and Histologic Lesions Induced by Field Strains of FAdV-1, FAdV-8b, and FAdV-11 in Six-Week-Old Chickens

Avian adenovirus infections: diversity of pathogens, hazard to poultry industry and problems of immunoprophylaxis (review)

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