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United States Department of Agriculture

Agricultural Research Service

Title: EFFICACY OF THE FOWLPOX VECTORED VACCINE TROVAC-AIV H5 AGAINST HIGHLY PATHOGENIC ASIAN H5N1 AVIAN INFLUENZA CHALLENGE.)

Author
item Bublot, Michel
item Pritchard, Nikki
item Cruz, Julio
item Mickle, Thomas
item Selleck, Paul
item Swayne, David

Submitted to: Avian Influenza Symposium International Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 2/1/2006
Publication Date: 4/3/2006
Citation: Bublot, M., Pritchard, N., Cruz, J., Mickle, T.R., Selleck, P., Swayne, D.E. 2006. Efficacy of the fowlpox vectored vaccine Trovac-AIV H5 against highly pathogenic Asian H5N1 avian influenza challenge [abstract]. Abstracts of the 6th International Symposium on Avian Influenza, April 3-6, 2006, Cambridge, United Kingdom. p. 35.

Interpretive Summary:

Technical Abstract: TROVAC-AIV H5 (TROVAC) is a licensed avian influenza (AI) vaccine that contains a fowlpox recombinant expressing the hemagglutinin of the A/turkey/Ireland/1378/83 H5N8 isolate. TROVAC vaccine was shown to be protective against a panel of HPAI H5 isolated from 1959 to 1997. Recently, Swayne (2004)* showed that TROVAC protected against a recent H5N1 isolate (A/chicken/SouthKorea/03, SK03). Here, we evaluate the efficacy of TROVAC (1) against escalating doses of SK03 and (2) against a 2004 Vietnam H5N1 isolate. In both studies, one-day old SPF chickens were vaccinated by SC route with a field dose of TROVAC and challenged 3 weeks later by the oro-nasal route. In the first study, mortality in the control groups reached 80% and 100% after challenge with 3.5-8.0 log10 EID50 of SK03, respectively. Full and 80% protection against mortality/morbidity was induced by TROVAC after challenge with 3.5-6.5 and 8.0 log10 EID50 of SK03, respectively. A 2-4 log10 and >4 log10 reduction of oral and cloacal shedding were observed in TROVAC vaccinated birds, respectively. TROVAC vaccination induced HI antibodies (7-8 log2) detectable with the homologous H5N8 antigen; the boost in HI titers after challenge was challenge dose-dependent. In the second study, TROVAC-vaccinated chicks were fully protected against morbidity and mortality after challenge with A/chicken/Vietnam/04, whereas unvaccinated chickens died within 2 days after challenge. Altogether, these results confirm the excellent level of protection induced by TROVAC against recent Asian HPAI H5N1 isolates. *Swayne (2004) In “Control of Infectious Animal Diseases by Vaccination” Schudel and Lombard (eds) Dev Biol Basel Karter, 119, pp219-228.

Last Modified: 8/24/2016
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