DNA Vaccine for West Nile Virus Infection in Fish Crows (Corvus ossifragus)

Department of Vector Assessment, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702-5011, USA.
Emerging infectious diseases (Impact Factor: 6.75). 10/2003; 9(9):1077-81. DOI: 10.3201/eid0909.030025
Source: PubMed


A DNA vaccine for West Nile virus (WNV) was evaluated to determine whether its use could protect fish crows (Corvus ossifragus) from fatal WNV infection. Captured adult crows were given 0.5 mg of the DNA vaccine either orally or by intramuscular (IM) inoculation; control crows were inoculated or orally exposed to a placebo. After 6 weeks, crows were challenged subcutaneously with 105 plaque-forming units of WNV (New York 1999 strain). None of the placebo inoculated-placebo challenged birds died. While none of the 9 IM vaccine-inoculated birds died, 5 of 10 placebo-inoculated and 4 of 8 orally vaccinated birds died within 15 days after challenge. Peak viremia titers in birds with fatal WNV infection were substantially higher than those in birds that survived infection. Although oral administration of a single DNA vaccine dose failed to elicit an immune response or protect crows from WNV infection, IM administration of a single dose prevented death and was associated with reduced viremia.

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    • "It was also noted that the birds did not show any unusual behaviors, health changes or side effects post-vaccination (Chang et al., 2007). This vaccine has also demonstrated efficacy in other bird species such as the American robins (Turdus migratorius) (Kilpatrick et al., 2010) and the fish crows (Corvus ossifragus; Turell et al., 2003). The first two DNA vaccines for veterinary use were granted US approval in 2005 for West Nile virus vaccine for horses and haematopoietic necrosis vaccine for farm-reared Atlantic salmon (Chalmers, 2006). "
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    • "Subunit vaccines, inactivated vaccines and DNA vaccines against WNV infections were used with variable success in birds. Vaccine efficacy in these studies was determined by experimental WNV challenge of the birds [13-21] or by determination of neutralizing antibody response [22-24]. "
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    • "Because of the difficulty of capturing and vaccinating free-ranging Island Scrub-Jays more than once per year (Boyce et al. 2011), we chose to evaluate the efficacy of a single inoculation with one of three vaccines to protect Western Scrub-Jays from experimental infection with WNV. Although some of the evaluated vaccines have been tested in other corvids, including Fish Crows (Corvus ossifragus ) (Turell et al. 2003) and American Crows (Corvus brachyrhynchos ) (Bunning et al. 2007), this is the first evaluation of these vaccines in the genus Aphelocoma. "
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