Xenopsylla Health Dictionary

A severe illness caused by the Gram negative rod, Yersinia pestis. The reservoirs for the infection are various species of rodent and the bacteria are transmitted through the bite of the rat flea, Xenopsylla cheopis. Patients present with enlarged lymph glands (‘buboes’) often in the groin or armpit. Can become septicaemic or develop into a pneumo nia (‘Pneumonic Plague’) and spread by droplet. Also known in the past as “The Black Death”.... bubonic plague

A zoonotic febrile disease caused by the rodent bacterial species, Rickettsia typhi, and transmitted by fleas of the genus Xenopsylla.... murine typhus

This infection – also known as bubonic plague

– is caused by the bacterium Yersinis pestis. Plague remains a major infection in many tropical countries.

The reservoir for the bacillus in urban infection lies in the black rat (Rattus rattus), and less importantly the brown (sewer) rat (Rattus norvegicus). It is conveyed to humans by the rat ?ea, usually Xenopsylla cheopis: Y. pestis multiplies in the gastrointestinal tract of the ?ea, which may remain infectious for up to six weeks. In the pneumonic form (see below), human-to-human transmission can occur by droplet infection. Many lower mammals (apart from the rat) can also act as a reservoir in sylvatic transmission which remains a major problem in the US (mostly in the south-western States); ground-squirrels, rock-squirrels, prairie dogs, bobcats, chipmunks, etc. can be affected.

Clinically, symptoms usually begin 2–8 days after infection; disease begins with fever, headache, lassitude, and aching limbs. In over two-thirds of patients, enlarged glands (buboes) appear – usually in the groin, but also in the axillae and cervical neck; this constitutes bubonic plague. Haemorrhages may be present beneath the skin causing gangrenous patches and occasionally ulcers; these lesions led to the epithet ‘Black Death’. In a favourable case, fever abates after about a week, and the buboes discharge foul-smelling pus. In a rapidly fatal form (septicaemic plague), haematogenous transmission produces mortality in a high percentage of cases. Pneumonic plague is associated with pneumonic consolidation (person-to-person transmission) and death often ensues on the fourth or ?fth day. (The nursery rhyme ‘Ringo-ring o’ roses, a pocketful o’ posies, atishoo! atishoo!, we all fall down’ is considered to have originated in the 17th century and refers to this form of the disease.) In addition, meningitic and pharyngeal forms of the disease can occur; these are unusual. Diagnosis consists of demonstration of the causative organism.

Treatment is with tetracycline or doxycycline; a range of other antibiotics is also e?ective. Plague remains (together with CHOLERA and YELLOW FEVER) a quarantinable disease. Contacts should be disinfected with insecticide powder; clothes, skins, soft merchandise, etc. which have been in contact with the infection can remain infectious for several months; suspect items should be destroyed or disinfected with an insecticide. Ships must be carefully checked for presence of rats; the rationale of anchoring a distance from the quay prevents access of vermin. (See also EPIDEMIC; PANDEMIC; NOTIFIABLE DISEASES.)... plague

A louse-borne febrile illness of humans caused by Rickettsia prowazekii, A similar but milder zoonotic illness is murine typhus, caused by R. typhi harboured by rodents and transmitted by the tropical rat flea, Xenopsylla. The so-called tick typhus group of diseases are better called spotted fevers.... typhus

n. a small wingless bloodsucking insect with a laterally compressed body and long legs adapted for jumping. Adult fleas are temporary parasites on birds and mammals and those species that attack humans (*Pulex, *Xenopsylla, and *Nosopsyllus) may be important in the transmission of various diseases. Their bites are not only a nuisance but may become a focus of infection. Appropriate insecticide powders are used to destroy fleas in the home.... flea