. Public health and preventive medicine. ach possessingtwo central sexual openings (Fig. 26, c). The head is ova] (Fig. 26, a) ; liastwo suctorial grooves, one on either side (Fig. 26, h), but does not possess arostellum or booklets. The eggs are oval in shape, each with a brown shellclosed at one end by an operculum (Fig. 26, d and e). Released from thesegments, Avhich are expelled in lengths of from 2 to 4 ft., they are immature, Fk;. 25.—Taenia cucumerina, natural ^ize. (After Leuckart.) hut after immersion in water fur a varying time, according to temperature,they become fully developed in
. Public health and preventive medicine. ach possessingtwo central sexual openings (Fig. 26, c). The head is ova] (Fig. 26, a) ; liastwo suctorial grooves, one on either side (Fig. 26, h), but does not possess arostellum or booklets. The eggs are oval in shape, each with a brown shellclosed at one end by an operculum (Fig. 26, d and e). Released from thesegments, Avhich are expelled in lengths of from 2 to 4 ft., they are immature, Fk;. 25.—Taenia cucumerina, natural ^ize. (After Leuckart.) hut after immersion in water fur a varying time, according to temperature,they become fully developed into sixdiooked ciliated embryos. Forcing backthe opercula, they escape from their shells and swim about till they encounterthe necessary mollusc, which they enter, and through it reach the fish. Theirpiscatorial pursuits being thus ended, they undergo changes, passing through amodified cysticercal stage, in which they lose their cilia and booklets, elongateand develop their heads, tails, and suckers. At this stage they lie free, or are. Fig. 26. BotkHocephaZus latus. , Head, liat surface, x 8diameters, b, Head, edge, x S diameters, c, Segment, 8 diameters. , Egg, surface shell, x 300 diameters. feebly encysted in the viscera or muscles, and, when the tish is eaten raw orinsufficiently cooked or smoked, gain access to the human intestine. Geographical Distribution.—It is endemic in Switzerland, Russia, andJapan, and, owing to exportation of fish, may appear hi other countries. Method of Transmission.—From the ingestion of raw or insufficientlycooked, cured, or smoked fish. Prevention of Origin and Spread.—Condemnation of infected fish. ALIMENTARY SYSTEM 35 Efficient cooking or preservation of fish. Cleanliness on the part of the use of anthelmintics. Other Bothriocephalada found in the human intestine are— Name. Intermediate Host. Definitive Host in additionto Man. B. cordatus ....B. eristatus .... Tapeworms may cause n
Size: 1556px × 1606px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectprevent, bookyear1902
