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Show i"""-",i" -," Threadworms Parasites Infesting the Gullet of Sheep and Cattle Caused by Swallowing Insects Sheep and 'cattle very frequently liave threadworms In tho gullet. These worms aro Been in tho lining of tho gullet beneath tho surface In a rather striking wavy pattern similar simi-lar to that formed by a snaka as It travels oter a smooth surface Tho worms aro slender and threadlike, jVl but as they measure from over an J- inch to almost 6 Inches In length mid raise up tho surface of the lining of tho gullet to form slender wavy ridges ridg-es they are readily located when an infested gullet Is sflt open and examined. exam-ined. So far ag known, ths damage occasioned by the presenco of theso parasites in sheep and cattlo Is rather ra-ther slight, though It has been determined deter-mined that a closely related paraslto Is Intimately associated with If not tho casual agent of cancer In tho stomach of rats. It has been shown by Investigation and experiments In the Zoological Division of tho Dureau of Animal Industry In-dustry that various species of dung beetles aro tho sources from which sheep and cattlo becomo Infested with tho gullet worm. Theso dung beetles may bo found In almost any manure deposit, except during the winter In cold climates. Tho beetles usually crawl under tho manure deposit, de-posit, enter from tho bottom, and feed on the Inner portion of tho deposit de-posit as long as It remains moist. When tho beetles cat tho manuro thoy swallow tho gullet worm eggs which have passed down tho esophagus esoph-agus through tho stomach nnd intestine in-testine and out In tho manuro of tho infested sheep or cow. As soon as tho manuro becomes too dry and hard to work tho dung beetles abandon It and crawl into tho ground or fly to other and fresher fresh-er deposits. In about a month tho eggs which were eaten by the beetles beet-les have hatched and developed Into an encysted stage in tho body of the beetle, ready to contlnuo their development de-velopment when tho Infested beetle ia swallowed by a cow or sheep, Tho opportunity for sheep and cattlo cat-tlo to swallow these beetles comes when tho beetles fly from one manure ma-nure doposlt to another. Tho flight usually ends by tho beetles landing on the pasture somewhere near n manure deposit, and aB they crawl about through tho grass toward tho )Ql manuro, attracted by tho odor, thoy aro commonly swallowed by grazing animals. Tho beetles aro no doubt eaten unconsciously as a rule, but as sheep and cattle eat largo numbers of Insects, slnco practically every plant Is tho permanent homo or tho temporary resting place of a number ot Insects, It is perhaps a matter of more or lesB lndlfforenco to them even If they aro conscious of tho presence of insects in a mouthful of food,. This Is especially! truo of cattle, slnco cattle aro noted for eating foreign for-eign objects, such as nails, wlro, bolts, knives, rubbers, etc. Among "tho various kinds of insects picked up by sheep and cattlo during tho courso of a day dung beetles' aro llko-ly llko-ly to bo moro or less numerous and of theso soino aro likely to harbor larval stages of the gullet worm, now ready for tho next step In development. develop-ment. In tho digestive tract of tho cow or sheep tho beetles undorgo partial par-tial digestion, releasing tho larval worms, which make their way to thy gullet and burrow Into Its lining. Hero tho worms becomo maturo and in tlmo tho femalo deposits eggs that pass down tho gullet and out In tho manuro to carry on tho Hfo cycle. It was found that under experimental experi-mental conditions tho eggs of tho gullet worm would develop to an Infective In-fective larva In croton bugs as well as in. dung beetles; but slnco croion bugs 'do not breed In manuro and r.ro house dwellers, It Is evident that thoy do not play nny part In tho nnt: nral transmission o,f tho paraslto. It Is interesting to nolo, howover, that Danish scientists havo found a worm similar to tho gullet worm of sheep and cattlo, which develops as a larva lar-va In creton bugs, cockroaches, and mealworms, and which occurs in nature na-ture inytho gullet, mouth, tonguo and llrst portion of tho stomach of rats. This worm is extremely interesting from the fact nlready montloned that I A its development In tho rat is follow. 'V cd by tho nppearanco of cantor of tho stomach, a fact of great Importance Import-ance from n scientific and medical standpoint. Tho samo paraslto will also develop in mlco, rabbits and guinea pigs, but apparently does not causo cancer In theso animals. While thcro Is now a general roc-ognltlon roc-ognltlon of tho Importance of biting Insects as carriers of such diseases as malaria and yellow fovor, nnd of such Insects as tho ily as carriers of tho gorms of typhoid fover and othor bacterial diseases, tho facts cited I abovo show that insects have an Im-rortanco Im-rortanco not yet generally recognized recogniz-ed as carriers of parasites. From such parasitic Infection man himself Is not immune. It has long been known that infestation with a certain kind of tapeworm only occurs as tho result of eating tho fleas or llco of dogs, and tho list of cases of tho occurrence oc-currence of this tapeworm In man, and especially In children indicates only too well that dog nea8 and Hco are swallowed by human beings not altogether rarely. In the caso of sheep and cattlo tho swallowing of Insects Is practically unavoidable, but man can guard himself against swallowing swal-lowing dog fleas and llco and Its rather unpleasant as well as dangerous danger-ous consequences of observing greater great-er caro in his rtlatlojis with pet animals, an-imals, particularly by oxcludlng them from his household, which Is tho only cortaln way of preventing tho scattering scat-tering of their oxternal parasites in places from which children and even grown persons aro llablo to swallow them. |