• Fibrin provides the matrix for the lodgement of P. pestis in the flea proventriculus that is required for the blocking process. (ajtmh.org)
  • Thus, it is not surprising that mainly amino acids, in particular the L-glutamate group (e.g., glutamine, histidine, arginine, proline) are catabolized by Y. pestis in the flea vector (Figure 2). (nih.gov)
  • If the flea transfers from its dead host to a human and attempts to feed, the passage of blood into the flea's stomach is obstructed by the blocked proventriculus and so is regurgitated, carrying the plague bacillus into its human host. (gresham.ac.uk)
  • When the biofilm grows large enough that the flea can't feed, they regurgitate it back into the bloodstream of whatever mammal they're feeding on. (labroots.com)
  • To be best prepared to treat soldiers who are plague victims of endemic or biological agent attack by an enemy, military physicians must understand the natural mechanisms by which plague spreads between species, the pathophysiology of disease in fleas and humans, the minimal diagnostic information necessary to begin treatment with effective antibiotics, and the proper use and capabilities of the presently available plague vaccine. (sc-ems.com)
  • Both flea species required about 10(6) Y. pestis cells per flea to be able to transmit to mice. (ajtmh.org)
  • This is because in the pgm (pigmentation) operon there are genes encoding the yersiniabactin (Ybt) siderophore-dependent iron transport system, required for virulence in mice subcutaneously, as well as genes for the Hms phenotype, which is required for cells to colonize and block the proventriculus. (kenyon.edu)
  • Y. pseudotuberculosis strains also varied greatly in their ability to produce biofilms in vitro, but there was no correlation between biofilm phenotype in vitro or on the surface of C. elegans and the ability to colonize or block fleas. (asm.org)
  • Plague is an acute, contagious, febrile illness transmitted to humans by the bite of an infected rat flea. (medscape.com)
  • Y. pestis , on the other hand, is transmitted subcutaneously through a bite of an infected flea or rat (bubonic), but can also be transmitted by air (especially during pandemics of the disease). (kenyon.edu)
  • Metabolic functions and pathogenicity traits upregulated in vivo are illustrated which are considered to be important for colonization of the flea gut (in blue) and the lung or bubo of the mammalian host (in red). (nih.gov)
  • The death of a rodent pressures the living fleas to leave that host and seek other mammals, including humans. (sc-ems.com)
  • Y. pestis maintains its existence by a cycle involving two hosts: a mammal (usually a rodent) and an insect (a flea). (frontiersin.org)
  • On an interesting note, when the temperatures get higher fleas do not have their proventriculus blocked, and only those that are blocked can transmit the disease. (kenyon.edu)
  • For the fleas infected by artificial feeders, they seemed to transmit plague more efficiently to great gerbils than mice. (biomedcentral.com)
  • The Y. pestis nghA ortholog is a pseudogene, and overexpression of functional nghA reduced ECM surface accumulation and inhibited the ability of Y. pestis to produce biofilm in the flea foregut. (asm.org)
  • The flea eventually dies, presumably from starvation and dehydration. (kenyon.edu)
  • It's the flea where the disease actually persists," says Vadyvaloo, 36, an assistant professor in the College of Veterinary Medicine and the first faculty hire in the new School for Global Animal Health. (wsu.edu)
  • The in vivo transcriptome of Y. pestis in the proventriculus of infected fleas revealed numerous metabolic genes involved in the adaptation to the flea gut (Vadyvaloo et al. (nih.gov)
  • Degradation of these amino acids results in an increased flux of the amino acid carbon through the TCA cycle, the enzymatic genes for which are highly induced in the flea (Vadyvaloo et al. (nih.gov)
  • From there, the infected fleas bite us humans, and us humans get the plague. (labroots.com)
  • While Y. pestis is definitely bad for humans, it's not all that nice to fleas either. (labroots.com)
  • It is a facultative anaerobic organism that can infect humans via the oriental rat flea. (wikipedia.org)
  • The pathophysiology of plague basically involves two phases-a cycle within the fleas and a cycle within humans. (medscape.com)
  • In epidemics plague is transmitted to humans by the bite of the Oriental or Indian rat flea and the human flea. (jmvh.org)
  • In the pandemics, the infected fleas were able to spread the plague over long distances as they were carried by rats and by humans travelling along trade routes at sea and overland, and also by infesting rice and wheat grain, clothing, and trade merchandise. (jmvh.org)
  • Biofilm formation in the flea and in vitro is mediated by the Y. pestis hms gene products, which are responsible for an extracellular material produced at growth temperatures of ≤26°C ( 13 , 23 , 29 , 40 ). (asm.org)
  • 2010). Flea meals appear to consist primarily of proteins and lipids with low amounts of carbohydrates. (nih.gov)
  • When held at 30 o C, fleas survive infections in an unblocked state, possibly leading at an explanation of why human bubonic plagues ended after the onset of warmer temperatures. (kenyon.edu)
  • From there, it was most likely carried by Oriental rat fleas living on the black rats that were regular passengers on merchant ships , spreading throughout the Mediterranean Basin and Europe. (wikipedia.org)
  • Ymt, designated murine toxin because the protein is highly lethal for mice, is required for Y. pestis to survive in fleas. (kenyon.edu)
  • Quantitative competitive PCR as a technique for exploring flea-Yersina pestis dynamics. (ajtmh.org)
  • The primary hosts of the fleas are the black urban rat and the brown sewer rat. (jmvh.org)
  • More specifically, fleas become infected after taking blood meals from septicemic animals and becoming infected themselves. (kenyon.edu)
  • Deprived of fibrin matrices, P. pestis are rapidly eliminated from the flea proventriculus. (ajtmh.org)
  • However, both Y. pestis and Y. pseudotuberculosis form biofilms that adhere to the external mouthparts and block feeding of Caenorhabditis elegans nematodes, which has been proposed as a model of Y. pestis -flea interactions. (asm.org)
  • pFra codes for a phospholipase D that is important for the ability of Y. pestis to be transmitted by fleas. (wikipedia.org)