Enterobius

Abstract: The association of Enterobius vermicularis infestation with acute appendicitis varies from 0.2-41.8% worldwide. Our purpose was to determine the significance of Enterobius-associated appendicitis by retrospective review of appendectomies performed during a 5-year period at a major children's hospital. The Surgical Pathology database at Children's Hospital, Columbus, Ohio, was reviewed for appendiceal specimens found to have Enterobius infestation. Corresponding patient charts were evaluated for age, gender, presenting symptoms, laboratory data, operative findings, and clinical course. Of the 1,549 appendectomies performed from January 1998 through January 2003, 21 specimens (1.4%) were found to contain Enterobius vermicularis. Fifteen of the appendectomies were performed for symptoms of acute appendicitis; the remaining six were incidental appendectomies in conjunction with other operations. The mean age was 8.9 years. Ten patients were male; 11 were female. Of the 15 symptomatic children, nine presented with fever >99.0 degrees F, and 11 had a WBC count >10,000. Intra-operative appearance of the appendix ranged from normal to perforation. Pathologic evaluation showed neutrophil or eosinophil infiltration in 15 of the 21 specimens. Enterobius infestation is an uncommon cause of acute appendicitis in children in the United States. It may be associated with acute appendicitis, "chronic appendicitis," ruptured appendicitis, or with no significant clinical symptoms.

Abstract: Eggs of Enterobius vermicularis (human pinworm) were found in hum coprolites from Hopug and Danger Caves, western Utah. The Caves were inhabitated by man from 10,000 B.C. to A.D. 1400. The oldest coprolite containing dated at 7837 B.C. This represents the earliest known association between man abd this exclusively human parasite.

Abstract: More than thirty years ago Stoll (1947) noted that helminth parasites were amongst the most prevalent of all human infections within many tropical, subtropical and temperate regions of the world. Today the global pattern of infection has changed little. World Health Organization statistics, for example, suggest that approximately one billion people are currently infected with the directly transmitted nematode Ascaris lumbricoides (roundworms). The picture is similar for other nematode parasites such as Trichuris trichiura (whipworms), Enterobius vermicularis (pinworms) and the hookworms Ancylostoma duodenale and Necator americanus (Table 3.1).

Abstract: Cladistic analysis of 13 species of Enterobius based on 31 morphological characters supports the notion that pinworms and primates have co-speciated. A possible exception is the relationship between Enterobius vermicularis and Homo. Enterobius vermicularis is postulated to be the sister-species of E. buckleyi + E. lerouxi + E. anthropopitheci. Thus, if co-speciation has occurred, Homo is the sister-group of Pongo + Gorilla + Pan. Examination of the possibility that E. vermicularis in Homo is the result of host-switching or that Homo has been misclassified demonstrates that the latter possibility is the more parsimonious one. Oxyurid nematodes representing the genera Enterobius Leach, 1853 and Trypan oxyuris Vevers, 1923 parasitize a variety of primate hosts. Their occurrence in primate hosts and their pronounced host specificity in natural conditions has promoted speculation that these pinworms have coevolved with their hosts and thus could serve as markers of primate phylogeny. Cameron (1929) first proposed this notion, stating, "The examination of forms described in this paper suggests that one species restricts itself to one genus of host rather than to one species; in other words the evolution of the parasite is slower than that of the primate. It would seem legitimate to assume, to some extent at least, that the parasite has evolved with the host ... One would expect to find forms most closely related to the human parasites in apes, while those in Old World monkeys would be closer [to] E. vermicularis than those in the new world monkeys and the lories but not so close as in apes, This actually does seem to be the case .... " (pp. 180-181) Sandosham (1950) reported several cases of host transfers occurring in zoo settings such that some species of Enterobius occurred in distantly related hosts. He considered those observations to be evidence refuting Cameron's assertion of host specificity and evolutionary rates. Sandosham further stated, " ... none of the characters of the parasites show a gradation in correspondence with the evolutionary position of the host." (p. 197) Inglis (1961) reexamined the problem based on study of available type material and concluded that Cameron had been correct in his assessment. Inglis responded to Sandosham' s assertions thus, "It should be noted that all the atypical records are from hosts in captivity ... It is reasonable to conclude that "Cameron's Hypothesis"one species of parasite: one genus of host-is a good general guide to the conditions which are likely to be found in the wild." (p. 115) Further, Inglis asserted, "The second suggestion put forward also seems to be, at least in part, correct since, as pointed out above, in the genus Enterobius there is