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: 7.33). 10/2003; 9(9):1077-81. DOI: 10.3201/eid0909.030025
Source: PubMed

ABSTRACT 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.

Download full-text


Available from: Nicholas Komar, Aug 09, 2015
  • Source
    • "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. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The devastating effect of West Nile virus (WNV) on the avifauna of North America has led zoo managers and conservationists to attempt to protect vulnerable species through vaccination. The Island Scrub-Jay (Aphelocoma insularis) is one such species, being a corvid with a highly restricted insular range. Herein, we used congeneric Western Scrub-Jays (Aphelocoma californica) to test the efficacy of three WNV vaccines in protecting jays from an experimental challenge with WNV: (1) the Fort Dodge West Nile-Innovator(®) DNA equine vaccine, (2) an experimental DNA plasmid vaccine, pCBWN, and (3) the Merial Recombitek(®) equine vaccine. Vaccine efficacy after challenge was compared with naïve and nonvaccinated positive controls and a group of naturally immune jays. Overall, vaccination lowered peak viremia compared with nonvaccinated positive controls, but some WNV-related pathology persisted and the viremia was sufficient to possibly infect susceptible vector mosquitoes. The Fort Dodge West Nile-Innovator DNA equine vaccine and the pCBWN vaccine provided humoral immune priming and limited side effects. Five of the six birds vaccinated with the Merial Recombitek vaccine, including a vaccinated, non-WNV challenged control, developed extensive necrotic lesions in the pectoral muscle at the vaccine inoculation sites, which were attributed to the Merial vaccine. In light of the well-documented devastating effects of high morbidity and mortality associated with WNV infection in corvids, vaccination of Island Scrub-Jays with either the Fort Dodge West Nile-Innovator DNA vaccine or the pCBWN vaccine may increase the numbers of birds that would survive an epizootic should WNV become established on Santa Cruz Island.
    Vector borne and zoonotic diseases (Larchmont, N.Y.) 03/2011; 11(8):1069-80. DOI:10.1089/vbz.2010.0173 · 2.53 Impact Factor
  • Source
    • "Experimental DNA vaccines have been developed expressing genes encoding the WNV membrane (M) and envelope (E) proteins in eukaryotic expression vectors, and successfully tested in animals and avian species [132] [133] [134]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The emergence and spread of West Nile Virus (WNV) from North through South America during the last decade, and the recent outbreaks of disease in both humans and horses in Europe suggest that the epidemiology of this infection is evolving. WNV is now considered among the emerging threats for both human and veterinary public health in areas like Europe where it was previously regarded to as an exotic agent. Further knowledge has built up from studies investigating the characteristics of the virus and its genome evolution capacity, the adaptation to new avian host species, the changes in vector competence and biology, and the host-pathogen interactions, including the immune response. Also, the new needs for preparedness to future major outbursts of disease have stimulated research on virus detection and characterization, filling the gaps in both specialized diagnostic technology and the need for field rapid assays. This review will present an overview of WNV virology, remarking the impact of virus diversity and evolution on theoretical and practical aspects involved in both risk definition, detection and control of infection.
    The Open Virology Journal 05/2010; 4:42-51. DOI:10.2174/1874357901004020042
  • Source
    • "Unfortunately, the DNA plasmid vaccine we used was ineffective in previous studies when orally administered (Turell et al. 2003, Bunning et al. 2007), suggesting that additional work formulating an orally effective vaccine would be required before a broad-scale field trial could be contemplated . In addition, the effects of vaccination on evolution of the transmissibility and virulence of the virus must be assessed to avoid selection for more virulent strains (Gandon et al. 2001). "
    [Show abstract] [Hide abstract]
    ABSTRACT: West Nile virus (WNV) has caused at least 1150 cases of encephalitis, 100 deaths, and an estimated 30,000-80,000 illnesses in 6 of the last 7 years. Recent evidence from several regions has implicated American robins (Turdus migratorius) as an important host for feeding by Culex mosquitoes, and, when integrated with their host competence for WNV, demonstrates that they are a key WNV amplification host. We evaluated the efficacy of a DNA plasmid vaccine at reducing the viremia and infectiousness of hatch-year American robins. We found that a single dose of vaccine injected intramuscularly resulted in more than a 400-fold (10(2.6)) decrease in average viremia. Although sample sizes were small, these results suggest that vaccinated robins exhibit viremias that are likely to be mostly noninfectious to biting Culex mosquitoes. More broadly, if an orally effective formulation of this vaccine could be developed, new control strategies based on wildlife vaccination may be possible.
    Vector borne and zoonotic diseases (Larchmont, N.Y.) 10/2009; 10(4):377-80. DOI:10.1089/vbz.2009.0029 · 2.53 Impact Factor
Show more