Pulex irritans
From Felipedia
Pulex irritans, the human flea, is primarily a worldwide parasite that infests humans but has been recorded sporadically in cats.
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Parasitology
Human blood is the preferred food of Pulex irritans, but it will feed on other mammals. Today, this species is most often found on pigs. Individuals that work with swine are some of the most likely people to become infested. In societies where personal hygiene is important, infestations by human fleas are not as common. Human fleas were extremely common before the development of modern standards in both hygiene and laundering. Most fleas, during that time, were found in a person’s bedding. In an attempt to decrease infestation, the Chinese placed warmed flea traps made of ivory or bamboo between the sheets before going to bed at night. During the Renaissance period, ladies frequently wore fur collars, called cravats, to catch the pestering fleas. The cravat could then be removed and shaken out to decrease the chance of coming in contact with any fleas. Pulex irritans is mainly a nuisance to humans. The flea's saliva contains enzymes and histamine-like substances, which may cause an allergic reaction in some of their victims. These allergic reactions may involve an intense itching sensation. The parasite can also be a vector of a variety of diseases. Even though Pulex irritans was not the primary species responsible for spreading the bubonic plague throughout Europe during the Middle Ages, it is capable of transmitting it.
Zoonosis
Pulex irritans may also transmit murine typhus, tularemia, and tapeworm, but the chances of this are relatively rare. One disease, in particular, that Pulex irritans is known to transmit is murine typhus. Murine typhus is a mild form of typhus caused by the bacterium Rickettsia typhi. The fleas become infected with the bacterium by feeding on a human who has the disease. The bacteria grow in the epithelial cells lining the flea's gut wall and are excreted in the insect's feces. After approximately twelve to eighteen days, the infection will kill the flea. Scratching of a fleabite will infect a person. Rubbing of the bitten area will spread the flea's infected feces into the wound. An infected person will experience headaches, marked prostration, malaise, chills, loss of appetite, nausea, and a rapid rise in temperature with fever after an incubation period of one to two weeks. Within four to six days after the initial symptoms appear a rash will form over most of the body[1].
Morphology
The adults are approximately 1.5 to 4 mm in length and are laterally flattened. They are dark brown in color, are wingless, and have mouthparts that aid in both the piercing of the skin and sucking of the host’s blood. Neither genal nor pronotal combs are present. The adult flea may have either a curved or rounded head. Only five percent of living fleas are in adult form at any given time. Most fleas are distributed in the egg, larva, or pupa stages.
Diagnosis
Diagnosis can be readily made on isolation and microscopic examination of the flea. It must be distinguished from other causes of pruritus in cats, including:
