title: Protection provided by a recombinant ALVAC(®)-WNV vaccine expressing the prM/E genes of a lineage 1 strain of WNV against a virulent challenge with a lineage 2 strain.
abstract: The emergence of lineage 2 strains of WNV in Europe as a cause of clinical disease and mortality in horses raised the question whether the existing WNV vaccines, all based on lineage 1 strains, protect against circulating lineage 2 strains of WNV. In the present paper we have determined the level of cross protection provided by the recombinant ALVAC(®)-WNV vaccine in a severe challenge model that produces clinical signs of WNV type 2 disease. Ten horses were vaccinated twice at 4 weeks interval with one dose of the ALVAC-WNV vaccine formulated at the minimum protective dose. A further 10 horses served as controls. Two weeks after the second vaccination, all horses were challenged intrathecally with a recent neurovirulent lineage 2 strain of WNV. The challenge produced viraemia in 10 out of 10 and encephalitis in 9 out of 10 control horses. Three horses had to be euthanized for humane reasons. In contrast, none of the vaccinated horses developed WNV disease and only 1 vaccinated horse became viraemic at a single time point at low titre. The prevalence of WNV disease and viraemia were significantly lower in the vaccinated horses than in the control horses (P<0.0001 for both). Based on these results, the ALVAC-WNV vaccine will provide veterinarians with an effective tool to control infections caused by lineage 1 and 2 strains of WNV.
authors.affiliation: Merial S.A.S., 254 rue Marcel Mérieux, 69007 Lyon, France. jules.minke@merial.com
authors.forename: J M
authors.initials: JM
authors.lastname: Minke
authors.forename: L
authors.initials: L
authors.lastname: Siger
authors.forename: L
authors.initials: L
authors.lastname: Cupillard
authors.forename: B
authors.initials: B
authors.lastname: Powers
authors.forename: T
authors.initials: T
authors.lastname: Bakonyi
authors.forename: S
authors.initials: S
authors.lastname: Boyum
authors.forename: N
authors.initials: N
authors.lastname: Nowotny
authors.forename: R
authors.initials: R
authors.lastname: Bowen
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D056738:Cross Protection; D005260:Female; D006734:Horse Diseases / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D006736:Horses; D008297:Male; D016896:Treatment Outcome; D014611:Vaccination / Q000662:veterinary; D014614:Vaccines, Synthetic / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D014765:Viral Vaccines / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology; D014901:West Nile Fever / Q000276:immunology / Q000517:prevention & control* / Q000662:veterinary / Q000821:virology; D053060:West Nile Virus Vaccines / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology; D014902:West Nile virus / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*
chemical_list: C078788:ALVAC vaccine; D000914:Antibodies, Viral; D014614:Vaccines, Synthetic; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; D053060:West Nile Virus Vaccines; C074932:prM protein, Flavivirus