• Plague, a zoonotic disease caused by the gram-negative bacterium Yersinia pestis , is transmitted to humans by the bites of infected fleas (eg, Xenopsylla cheopis ), scratches from infected animals, inhalation of aerosols, or consumption of food contaminated with Y pestis . (medscape.com)
  • Plague is a bacterial disease of rodents and is generally transmitted to humans through the bites of infected fleas but can also be transmitted by direct contact with infected animals, including rodents, wildlife and pets. (outbreaknewstoday.com)
  • Northern rat fleas are external parasites, living by hematophagy off the blood of rodents. (wikipedia.org)
  • The rat flea is widespread due to their relationship to rodents and other vertebrates. (wikipedia.org)
  • Though the northern rat flea primarily parasitizes the Norway rat, Rattus norvegicus, it has occasionally been observed feeding on humans and wild rodents. (wikipedia.org)
  • Rodents acts as the primary host for flea species and parasitized rodents account for 25% of all mammals. (wikipedia.org)
  • Fleas from sylvatic rodents feed on humans only reluctantly. (medscape.com)
  • In Lushoto District, it has been suggested that the fleas Xenopsylla cheopis , X. brasiliensis , and Dinopsyllus lypusus are plague vectors among sylvatic rodents, but Pulex irritans , the human flea, has received little attention ( 9 ). (cdc.gov)
  • Sylvatic cycle consists of transmission among mild rodents by flea. (howmed.net)
  • Pets that are allowed to roam and hunt can bring infected fleas from dead rodents back into the home, putting household members at risk. (outbreaknewstoday.com)
  • Plague activity in New Mexico is usually highest during the summer months, so it is especially important now to take precautions to avoid rodents and their fleas which can expose you to plague. (outbreaknewstoday.com)
  • Hinnebusch BJ, Rudolph AE, Cherepanov P, Dixon JE, Schwan TG, Forsberg A. Role of Yersinia murine toxin in survival of Yersinia pestis in the midgut of the flea vector. (medscape.com)
  • Within the blocked flea model, Yersinia murine toxin (Ymt) has been shown to be important for facilitating colonization of the midgut within the flea . (bvsalud.org)
  • One proposed mechanism of EPT is the regurgitation of infectious material from the flea midgut during feeding . (bvsalud.org)
  • 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. (bvsalud.org)
  • This blockage is caused by a mass formation in the proventriculus. (wikipedia.org)
  • However, a study revealed that a simultaneous Salmonella infection inhibits the formation of this blockage. (wikipedia.org)
  • At its next attempt to feed, unable to swallow due to the blockage, the flea regurgitates plague bacilli into the bite wound. (medscape.com)
  • 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 . (bvsalud.org)
  • This digitally colorized scanning electron microscopic image depicts yellow colored Yersinia pestis bacteria, which had gathered on the proventricular spines of a Xenopsylla cheopis flea. (cdc.gov)
  • However, the Oriental rat flea ( Xenopsylla cheopis ) is an effective vector because of its tendency to regurgitate and to feed on nonrodent hosts (see the image below). (medscape.com)
  • Male Xenopsylla cheopis (oriental rat flea) engorged with blood. (medscape.com)
  • Diseases that can be spread through fleas include the plague and typhus. (wikipedia.org)
  • However, fleas simultaneously infected by the plague and Salmonella died within 2-3 days due to bloody diarrhea. (wikipedia.org)
  • Plague is a rare but fatal infection found throughout much of the world, including northwestern Uganda and neighboring Democratic Republic of the Congo. (cdc.gov)
  • Competency of the flea to serve as vector for transmission of plague to humans depends on its willingness to feed on a human host and its tendency to regurgitate intestinal contents during a blood meal. (medscape.com)
  • This flea is the primary vector of plague in most large plague epidemics in Asia, Africa, and South America. (medscape.com)
  • The density of P. irritans, but not of other domestic fleas, was significantly higher in villages with a higher plague frequency or incidence. (cdc.gov)
  • These observations suggest that in Lushoto District human fleas may play a role in plague epidemiology. (cdc.gov)
  • We report differences between plague-affected and plague-free villages in the numbers of free domestic fleas present in mud houses and consider whether this variation can be linked to house plastering as an antiflea measure. (cdc.gov)
  • Role of the Yersinia pestis hemin storage (hms) locus in the transmission of plague by fleas. (medscape.com)
  • Early-phase transmission of Yersinia pestis by unblocked fleas as a mechanism explaining rapidly spreading plague epizootics. (medscape.com)
  • Transmission of Yersinia pestis from an infectious biofilm in the flea vector. (medscape.com)
  • Humans are the accidental hosts (bitten by a flea that is a part of sylvatic cycle). (howmed.net)
  • Although evidence of infection with Y. pestis has been observed in several wild rodent and flea species, the actual reservoir in which the infection survives between epidemics has not yet been identified, and the ecology of the infection and the source from which humans acquire infection are poorly understood ( 4 - 8 ). (cdc.gov)
  • Y. pestis causes diseases through a bite of an infected rat or flea, but can also be transmitted by air. (kenyon.edu)
  • The major defense against Y pestis infection is the development of specific anti-envelope (F1) antibodies, which serve as opsonins for the virulent organisms, allowing their rapid phagocytosis and destruction while still within the initial infectious locus. (kenyon.edu)
  • When the flea takes a blood meal from an infected rodent, stomach enzymes cause a clot to form, blocking the flea's proventricularis. (medscape.com)
  • Nosopsyllus fasciatus, the northern rat flea, is a species of flea found on domestic rats and house mice. (wikipedia.org)
  • Like other fleas, this species plays a role in spreading zoonotic diseases. (wikipedia.org)
  • Pulex irritans , known as the human flea, was the predominant flea species (72.4%) in houses. (cdc.gov)
  • Our results show that Ymt was not required for EPT by either flea species. (bvsalud.org)
  • Avian Trichomonas is a parasitic organism that infests the upper gastro-intestinal tract (esophagus, crop and proventriculus), mouth, oropharynx (throat region) and upper respiratory tract of a range of different bird species. (pet-informed-veterinary-advice-online.com)
  • The classic mode of transmission to humans is a flea bite (see the image below). (medscape.com)
  • Whilst the physiological and molecular mechanisms of blocked flea transmission are well characterized, the pathogen-vector interactions have not been elucidated for EPT. (bvsalud.org)
  • In nature, this flea would develop a ravenous hunger because of its inability to digest the fibrinoid mass of blood and bacteria. (medscape.com)
  • If this flea were to bite a mammal, the proventriculus would be cleared, and thousands of bacteria would be regurgitated into the bite wound. (medscape.com)
  • Fleas can become infected by taking the blood of other infected animals. (kenyon.edu)
  • Therefore, parasitism by fleas can affect the population of the hosts. (wikipedia.org)
  • Studies in gerbil hosts have found that flea infestation reduced Gerbillus dasyurus body mass and immune defences. (wikipedia.org)
  • In common vole hosts, it has also been found that flea infestation reduces body mass and immune defences and also induces an iron deficiency. (wikipedia.org)
  • The rat flea contributes to the reemergence and cycles of some diseases, as previously mentioned. (wikipedia.org)
  • Domestic fleas were collected in 12 villages in the western Usambara Mountains in Tanzania. (cdc.gov)
  • Plastering a mud house is recommended in the area as a way of keeping the house free of fleas ( 9 ) and involves mixing soil (without manure) with water and rubbing the mixture over the floors with a piece of cloth. (cdc.gov)
  • The rat flea has three instar stages in its development. (wikipedia.org)
  • Fleas from sylvatic rodents feed on humans only reluctantly. (medscape.com)
  • Remarkably, only four minor changes in the bacterial progenitor, representing one gene gain and three gene losses, enabled transmission by flea vectors. (nih.gov)
  • When the flea takes a blood meal from an infected rodent, stomach enzymes cause a clot to form, blocking the flea's proventricularis. (medscape.com)
  • The true glandular stomach is called the proventriculus where hydrochloric acid and digestive enzymes are secreted. (safarivet.com)
  • If the infection is not contained at this site, the organisms may be further spread via the bloodstream to organs such as lungs, spleen, liver, kidneys, and meninges. (medscape.com)
  • Although this patient is much older than usual for D. caninum infection, the appearance of these proglottids is classic, with the small size and shape resembling "grains of rice. (blogspot.com)