Description: Scanning Electron Micrograph of a Flea. See PHIL 11436 for a colorized version of this image. Fleas are known to carry a number of diseases that are transferable to human beings through their bites. Included in this infections is the plague, caused by the bacterium Yersinia pestis.
Fleas, like other holometabolous insects, have a four-part life cycle consisting of eggs, larvae, pupae, and adults. Eggs are shed by the female in the enviroment . Eggs hatch into larvae in about 3-4 days and feed on organic debris in the environment. The number of larval instars varies among the species. Larvae eventually form pupae , which are in cocoons that are often covered with debris from the environment (sand, pebbles, etc). The larval and pupal stages take about 3-4 weeks to complete. Afterwards, adults hatch from pupae and seek out a warm-blooded host for blood meals.
The primary hosts for Ctenocephalides felis and C. canis are cats and dogs, respectively, although other mammals, including humans, may be fed upon. The primary hosts for Xenopsylla cheopis are rodents, especially rats. In North America, plague (Yersinia pestis) is cycled between X. cheopis and prairie dogs. Humans are the primary host for Pulex irritans.
 | Content Providers(s): CDC Creation Date: Photo Credit: Janice Haney Carr. By CDC/Janice Haney Carr [Public domain], via Wikimedia Commons None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image. This image or file is a work of an employee of the United States Federal Government (Centers for Disease Control and Prevention), taken or made during the course of the person's official duties. As a work of the U.S. federal government, the image or file is in the public domain. Generally speaking, works created by U.S. Government employees are not eligible for copyright protection in the United States. See Circular 1 "COPYRIGHT BASICS" PDF from the U.S. Copyright Office. |
TEXT CREDIT: Centers for Disease Control and Prevention
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