title: Yersinia murine toxin is not required for early-phase transmission of Yersinia pestis by Oropsylla montana (Siphonaptera: Ceratophyllidae) or Xenopsylla cheopis (Siphonaptera: Pulicidae).
abstract: Plague, caused by Yersinia pestis, is characterized by quiescent periods punctuated by rapidly spreading epizootics. The classical 'blocked flea' paradigm, by which a blockage forms in the flea's proventriculus on average 1-2 weeks post-infection (p.i.), forces starving fleas to take multiple blood meals, thus increasing opportunities for transmission. Recently, the importance of early-phase transmission (EPT), which occurs prior to blockage formation, has been emphasized during epizootics. Whilst the physiological and molecular mechanisms of blocked flea transmission are well characterized, the pathogen-vector interactions have not been elucidated for EPT. Within the blocked flea model, Yersinia murine toxin (Ymt) has been shown to be important for facilitating colonization of the midgut within the flea. One proposed mechanism of EPT is the regurgitation of infectious material from the flea midgut during feeding. Such a mechanism would require bacteria to colonize and survive for at least brief periods in the midgut, a process that is mediated by Ymt. Two key bridging vectors of Y. pestis to humans, Oropsylla montana (Siphonaptera: Ceratophyllidae) or Xenopsylla cheopis (Siphonaptera: Pulicidae), were used in our study to test this hypothesis. Fleas were infected with a mutant strain of Y. pestis containing a non-functional ymt that was shown previously to be incapable of colonizing the midgut and were then allowed to feed on SKH-1 mice 3 days p.i. Our results show that Ymt was not required for EPT by either flea species.
authors.affiliation: Bacterial Diseases Branch, Division of Vector-borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.
authors.forename: Tammi L
authors.initials: TL
authors.lastname: Johnson
authors.affiliation: Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.
authors.forename: B Joseph
authors.initials: BJ
authors.lastname: Hinnebusch
authors.affiliation: Bacterial Diseases Branch, Division of Vector-borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.
authors.forename: Karen A
authors.initials: KA
authors.lastname: Boegler
authors.affiliation: Bacterial Diseases Branch, Division of Vector-borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.
authors.forename: Christine B
authors.initials: CB
authors.lastname: Graham
authors.affiliation: Bacterial Diseases Branch, Division of Vector-borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: MacMillan
authors.affiliation: Bacterial Diseases Branch, Division of Vector-borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.
authors.forename: John A
authors.initials: JA
authors.lastname: Montenieri
authors.affiliation: Bacterial Diseases Branch, Division of Vector-borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.
authors.forename: Scott W
authors.initials: SW
authors.lastname: Bearden
authors.affiliation: Bacterial Diseases Branch, Division of Vector-borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Gage
authors.affiliation: Bacterial Diseases Branch, Division of Vector-borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Eisen
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000378:metabolism*; D006801:Humans; D007303:Insect Vectors / Q000382:microbiology* / Q000502:physiology; D051379:Mice; D010930:Plague / Q000382:microbiology / Q000635:transmission*; D051381:Rats; D017207:Rats, Sprague-Dawley; D005423:Siphonaptera / Q000382:microbiology* / Q000502:physiology; D014774:Virulence; D058260:Xenopsylla / Q000382:microbiology* / Q000502:physiology; D015010:Yersinia pestis / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity
chemical_list: D001427:Bacterial Toxins