title: Pneumonic tularemia in rabbits resembles the human disease as illustrated by radiographic and hematological changes after infection.
abstract: BACKGROUND
  Pneumonic tularemia is caused by inhalation of the gram negative bacterium, Francisella tularensis. Because of concerns that tularemia could be used as a bioterrorism agent, vaccines and therapeutics are urgently needed. Animal models of pneumonic tularemia with a pathophysiology similar to the human disease are needed to evaluate the efficacy of these potential medical countermeasures.
  
  
  RESULTS
  Rabbits exposed to aerosols containing Francisella tularensis strain SCHU S4 developed a rapidly progressive fatal pneumonic disease. Clinical signs became evident on the third day after exposure with development of a fever (>40.5°C) and a sharp decline in both food and water intake. Blood samples collected on day 4 found lymphopenia and a decrease in platelet counts coupled with elevations in erythrocyte sedimentation rate, alanine aminotransferase, cholesterol, granulocytes and monocytes. Radiographs demonstrated the development of pneumonia and abnormalities of intestinal gas consistent with ileus. On average, rabbits were moribund 5.1 days after exposure; no rabbits survived exposure at any dose (190-54,000 cfu). Gross evaluation of tissues taken at necropsy showed evidence of pathology in the lungs, spleen, liver, kidney and intestines. Bacterial counts confirmed bacterial dissemination from the lungs to the liver and spleen.
  
  
  CONCLUSIONS
  The pathophysiology of pneumonic tularemia in rabbits resembles what has been reported for humans. Rabbits therefore are a relevant model of the human disease caused by type A strains of F. tularensis.
authors.affiliation: Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America. dsreed@pitt.edu
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Reed
authors.forename: Le'kneitah
authors.initials: L
authors.lastname: Smith
authors.forename: Tammy
authors.initials: T
authors.lastname: Dunsmore
authors.forename: Anita
authors.initials: A
authors.lastname: Trichel
authors.forename: Luis A
authors.initials: LA
authors.lastname: Ortiz
authors.forename: Kelly Stefano
authors.initials: KS
authors.lastname: Cole
authors.forename: Eileen
authors.initials: E
authors.lastname: Barry
mesh_terms: D000818:Animals; D018826:CD13 Antigens / Q000097:blood; D004435:Eating; D006801:Humans; D045823:Ileus / Q000382:microbiology; D007422:Intestines / Q000382:microbiology; D007668:Kidney / Q000382:microbiology; D008099:Liver / Q000382:microbiology; D008168:Lung / Q000382:microbiology; D008231:Lymphopenia / Q000382:microbiology; D010976:Platelet Count; D011014:Pneumonia / Q000097:blood / Q000000981:diagnostic imaging* / Q000382:microbiology*; D011817:Rabbits; D011859:Radiography; D013154:Spleen / Q000382:microbiology; D014406:Tularemia / Q000097:blood / Q000000981:diagnostic imaging* / Q000382:microbiology*
chemical_list: D018826:CD13 Antigens