title: Differences in aerosolization of Rift Valley fever virus resulting from choice of inhalation exposure chamber: implications for animal challenge studies.
abstract: The aerosol characteristics of Rift Valley fever virus (RVFV) were evaluated to achieve reproducible infection of experimental animals with aerosolized RVFV suitable for animal efficacy studies. Spray factor (SF), the ratio between the concentrations of the aerosolized agent to the agent in the aerosol generator, is used to compare performance differences between aerosol exposures. SF indicates the efficiency of the aerosolization process; a higher SF means a lower nebulizer concentration is needed to achieve a desired inhaled dose. Relative humidity levels as well as the duration of the exposure and choice of exposure chamber all impacted RVFV SF. Differences were also noted between actual and predicted minute volumes for different species of nonhuman primates. While NHP from Old World species (Macaca fascicularis, M. mulatta, Chlorocebus aethiops) generally had a lower actual minute volume than predicted, the actual minute volume for marmosets (Callithrix jacchus) was higher than predicted (150% for marmosets compared with an average of 35% for all other species examined). All of these factors (relative humidity, chamber, duration, and minute volume) impact the ability to reliably and reproducibly deliver a specific dose of aerosolized RVFV. The implications of these findings for future pivotal efficacy studies are discussed.
authors: Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA, USA.
authors: Douglas S
authors: DS
authors: Reed
authors: Laura M
authors: LM
authors: Bethel
authors: Diana S
authors: DS
authors: Powell
authors: Amy L
authors: AL
authors: Caroline
authors: Amy L
authors: AL
authors: Hartman
mesh_terms: D000336:Aerosols; D000391:Air Microbiology; D000818:Animals; D035843:Biomedical Research / Q000379:methods / Q000592:standards*; D004195:Disease Models, Animal; D006813:Humidity; D019570:Inhalation Exposure / Q000592:standards*; D011323:Primates; D015203:Reproducibility of Results; D012295:Rift Valley Fever / Q000473:pathology* / Q000821:virology*; D012296:Rift Valley fever virus; D013997:Time Factors
chemical_list: D000336:Aerosols
keywords: aerosol; infection; respiratory