title: Infectivity of attenuated poxvirus vaccine vectors and immunogenicity of a raccoonpox vectored rabies vaccine in the Brazilian Free-tailed bat (Tadarida brasiliensis).
abstract: Bats (Order Chiroptera) are an abundant group of mammals with tremendous ecological value as insectivores and plant dispersers, but their role as reservoirs of zoonotic diseases has received more attention in the last decade. With the goal of managing disease in free-ranging bats, we tested modified vaccinia Ankara (MVA) and raccoon poxvirus (RCN) as potential vaccine vectors in the Brazilian Free-tailed bat (Tadarida brasiliensis), using biophotonic in vivo imaging and immunogenicity studies. Animals were administered recombinant poxviral vectors expressing the luciferase gene (MVA-luc, RCN-luc) through oronasal (ON) or intramuscular (IM) routes and subsequently monitored for bioluminescent signal indicative of viral infection. No clinical illness was noted after exposure to any of the vectors, and limited luciferase expression was observed. Higher and longer levels of expression were observed with the RCN-luc construct. When given IM, luciferase expression was limited to the site of injection, while ON exposure led to initial expression in the oral cavity, often followed by secondary replication at another location, likely the gastric mucosa or gastric associated lymphatic tissue. Viral DNA was detected in oral swabs up to 7 and 9 days post infection (dpi) for MVA and RCN, respectively. While no live virus was detected in oral swabs from MVA-infected bats, titers up to 3.88 x 104PFU/ml were recovered from oral swabs of RCN-infected bats. Viral DNA was also detected in fecal samples from two bats inoculated IM with RCN, but no live virus was recovered. Finally, we examined the immunogenicity of a RCN based rabies vaccine (RCN-G) following ON administration. Significant rabies neutralizing antibody titers were detected in the serum of immunized bats using the rapid fluorescence focus inhibition test (RFFIT). These studies highlight the safety and immunogenicity of attenuated poxviruses and their potential use as vaccine vectors in bats.
authors.affiliation: University of Wisconsin - Madison, School of Veterinary Medicine, 1656 Linden Dr., Madison, WI 53706, USA; U.S. Geological Survey, National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI 53711, USA. Electronic address: stading@wisc.edu.
authors.forename: Ben R
authors.initials: BR
authors.lastname: Stading
authors.affiliation: University of Wisconsin - Madison, School of Veterinary Medicine, 1656 Linden Dr., Madison, WI 53706, USA. Electronic address: jorge.osorio@wisc.edu.
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Osorio
authors.affiliation: Centers for Disease Control and Prevention, 1600 Clifton Rd., Atlanta, GA 30333, USA. Electronic address: dly3@cdc.gov.
authors.forename: Andres
authors.initials: A
authors.lastname: Velasco-Villa
authors.affiliation: Texas A&M University, 3258 TAMU, College Station, TX 77843, USA. Electronic address: msmotherman@bio.tamu.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Smotherman
authors.affiliation: University of Wisconsin - Madison, School of Veterinary Medicine, 1656 Linden Dr., Madison, WI 53706, USA. Electronic address: babakke@wisc.edu.
authors.forename: Brock
authors.initials: B
authors.lastname: Kingstad-Bakke
authors.affiliation: U.S. Geological Survey, National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI 53711, USA. Electronic address: trocke@usgs.gov.
authors.forename: Tonie E
authors.initials: TE
authors.lastname: Rocke
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood*; D002685:Chiroptera / Q000276:immunology* / Q000821:virology; D005822:Genetic Vectors; D000071497:Immunogenicity, Vaccine; D008156:Luciferases / Q000235:genetics; D008163:Luminescent Measurements; D008297:Male; D009055:Mouth / Q000821:virology; D018155:Orthopoxvirus / Q000235:genetics / Q000502:physiology; D011212:Poxviridae / Q000276:immunology* / Q000302:isolation & purification / Q000502:physiology; D011818:Rabies / Q000517:prevention & control / Q000662:veterinary; D011819:Rabies Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D011820:Rabies virus / Q000276:immunology*; D014611:Vaccination / Q000379:methods; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic / Q000276:immunology; D014616:Vaccinia virus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000502:physiology; D014765:Viral Vaccines / Q000276:immunology*; D014779:Virus Replication
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D011819:Rabies Vaccines; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D014765:Viral Vaccines; D008156:Luciferases
keywords: Bat; Chiroptera; Poxvirus; Rabies; Vaccine