Use of Live and Inactivated Vaccines in the Control of West Nile Fever in Domestic Geese

Abstract

The recent epizootic of West Nile fever in Israel affected predominantly young domestic geese between three and eight weeks old. Clinically, the birds presented paralytic signs while morbidity and mortality were severe in affected flocks. The condition was encountered from early September through late November on goose farms located throughout the country. Losses incurred by goose flocks were sufficiently great as to warrant investigation of ways to protect young geese against the neurological form of the disease. We have conducted a series of vaccination trials in which three‐week old geese were immunized with an attenuated, commercial flavivirus vaccine derived from Israel turkey meningoencephalitis virus (TME). Birds were challenged two weeks later with a low Vero cell passage of West Nile virus by the intracerebral route. In a second group of experiments, inactivated and live TME vaccines were given in tandem at an interval of two weeks and challenged two weeks later. The third vaccination trial was based on West Nile virus (WNV) harvested from infant mouse brain, inactivated with formalin and oil adjuvanted. A single injection given either subcutaneously or intramuscularly resulted in 75% protection of the vaccinated groups, while two injections spaced two weeks apart resulted in 94% protection. Groups of geese, vaccinated at the farms and challenged under controlled conditions in the laboratory, showed levels of protection ranging from 39% to 72% for TME vaccine and 52% and 80% for WNV vaccine. The lower levels of protection are attributable to flocks being affected with intercurrent infections at the time of vaccination.

Risk Factors Associated With West Nile Virus Mortality in American Crow Populations in Southern Quebec

“…Previous studies have explored the impact of age on sensitivity to WNV. Two studies have shown that sensitivity to WNV increases with age: one on geese with an Israeli strain (McLean et al, 2002) and another on chickens with an Egyptian strain (Malkinson et al, 2001). Although both the Egyptian and Israeli strains closely resemble the NY99 strain present in North American, neither geese nor chickens are passerines (Ludwig et al, 2002;Meulen et al, 2005), which limits the comparability of these results to our findings.…”

The relative contribution of antibody and CD8+ T cells to vaccine immunity against West Nile encephalitis virus

“…An analogously high titer of WNVspecific IgG was achieved after immunization and boost with the same formalin-inactivated virus preparation in baboons [55]. A comparable prime-boost strategy with formalininactivated WNV also protected the majority of domestic geese from IC challenge [13,14] and induced neutralizing antibodies in horses [17]. Another caveat of our studies is that lower doses of the formalin-inactivated vaccine induced a less robust antibody response with decreased protection from IC challenge.…”

“…Although attenuated and inactivated viral vaccines currently protect horses and birds against WNV infection, no vaccine is approved for human use. Formalin-treated WNV protects geese, hamsters, and horses from lethal experimental WNV challenge [13][14][15][16][17][18], and horses in field trials [16,19,20]. Although inactivated vaccines may be useful for immunocompromised individuals, repeated dosing may be required to induce durable protection.…”

Complex Adenovirus-Mediated Expression of West Nile Virus C, PreM, E, and NS1 Proteins Induces both Humoral and Cellular Immune Responses

“…A number of approaches for the development of a WNV vaccine have been investigated, such as the use of an inactivated virus (35,52,61,62), subunit particles (47,84,85), naked DNA (24,35,48,70,71,91), cross-protection immunity induced by Japanese encephalitis virus vaccination (1,77,88), live-, attenuated virus (51,78,79,89), recombinant virus (3,25,39,50,58,74,78,79,86), and virus replicons (2). Currently, only ChimeriVax-WNV, a vaccine based on a recombinant virus that expresses the preM and E proteins of WNV in an attenuated yellow fever virus backbone, has completed phase I clinical trials (58;Acambis, 2007), and others are in preclinical development (34,70,71).…”