Preliminary testing in turkeys of the safety and efficacy of a putative haemorrhagic enteritis virus vaccine

Hoang, Phuong; Gray, Peter; Walkden-Brown, Stephen W; McMillan, Mary; Gerber, Priscilla F; Reynolds, Paul

doi:10.1111/avj.12841

Author(s)

Hoang, Phuong

Gray, Peter

Walkden-Brown, Stephen W

McMillan, Mary

Gerber, Priscilla F

Reynolds, Paul

Publication Date

2019

Abstract

Haemorrhagic enteritis virus (HEV) causes clinical haemorrhagic enteritis in young poults and/or subclinical immunosuppression which is often associated with colibacillosis. This disease is controlled with live vaccines worldwide, however, importation of HEV vaccines or cells that support HEV propagation are not permitted in Australia. A major experiment in isolators was conducted to test the safety and efficacy of a putative HEV vaccine. The study had a factorial design with four factors namely vaccination age (28 and 42 days of age), vaccine dose (0, 10⁵, 10⁶, 10⁷ genomic copies of HEV vaccine), challenge with HEV (yes, no) and vaccination-challenge interval (7, 21 or 42 days). A total of 315 poults were used providing 6-8 birds per treatment combination. Turkey growth rate, mortality, pathological findings, anti-HEV antibodies and viral load were examined. Vaccination lead to significant increases in anti HEV antibody over the following 2-4 weeks. Overall, vaccination with 10⁶ and 10⁷ was protective against increase in relative splenic weight and splenic viral load in challenged birds. Clinical haemorrhagic enteritis was not induced by any treatment but there was an increased incidence of airsacculitis in groups receiving either HEV vaccine or challenge virus compared to the negative control birds (25.8-29.3% vs. 9.4%, P < 0.05). Growth rate, mortality and relative bursal weight were unaffected by vaccination. This laboratory level study indicates that the putative vaccine is safe and likely to be efficacious, but may cause elevated levels of airsacculitis. These findings require confirmation in larger scale field trials.

Citation

Australian Veterinary Journal, 97(9), p. 323-332

ISSN

1751-0813

0005-0423

Pubmed ID

31328258

Link

https://hdl.handle.net/1959.11/27434

Language

en

Publisher

Wiley-Blackwell Publishing Ltd

Title

Preliminary testing in turkeys of the safety and efficacy of a putative haemorrhagic enteritis virus vaccine

Type of document

Journal Article

Entity Type

Publication

Author(s)	Hoang, Phuong Gray, Peter Walkden-Brown, Stephen W McMillan, Mary Gerber, Priscilla F Reynolds, Paul
Publication Date	2019
Abstract	Haemorrhagic enteritis virus (HEV) causes clinical haemorrhagic enteritis in young poults and/or subclinical immunosuppression which is often associated with colibacillosis. This disease is controlled with live vaccines worldwide, however, importation of HEV vaccines or cells that support HEV propagation are not permitted in Australia. A major experiment in isolators was conducted to test the safety and efficacy of a putative HEV vaccine. The study had a factorial design with four factors namely vaccination age (28 and 42 days of age), vaccine dose (0, 10⁵, 10⁶, 10⁷ genomic copies of HEV vaccine), challenge with HEV (yes, no) and vaccination-challenge interval (7, 21 or 42 days). A total of 315 poults were used providing 6-8 birds per treatment combination. Turkey growth rate, mortality, pathological findings, anti-HEV antibodies and viral load were examined. Vaccination lead to significant increases in anti HEV antibody over the following 2-4 weeks. Overall, vaccination with 10⁶ and 10⁷ was protective against increase in relative splenic weight and splenic viral load in challenged birds. Clinical haemorrhagic enteritis was not induced by any treatment but there was an increased incidence of airsacculitis in groups receiving either HEV vaccine or challenge virus compared to the negative control birds (25.8-29.3% vs. 9.4%, P < 0.05). Growth rate, mortality and relative bursal weight were unaffected by vaccination. This laboratory level study indicates that the putative vaccine is safe and likely to be efficacious, but may cause elevated levels of airsacculitis. These findings require confirmation in larger scale field trials.
Citation	Australian Veterinary Journal, 97(9), p. 323-332
ISSN	1751-0813 0005-0423
Pubmed ID	31328258
Link	https://hdl.handle.net/1959.11/27434
Language	en
Publisher	Wiley-Blackwell Publishing Ltd
Title	Preliminary testing in turkeys of the safety and efficacy of a putative haemorrhagic enteritis virus vaccine
Type of document	Journal Article
Entity Type	Publication

Preliminary testing in turkeys of the safety and efficacy of a putative haemorrhagic enteritis virus vaccine

Files: