Question

a) Why can't Taenia Saginata eggs develop in the human gut?

b)What chemical/molecular signals are required for eggs of T.saginta to hatch in the gut of the intermediate host ?

Answer 1

Ans a) Humans are only definitive hosts for Taenia Saginata , Tsaginata eggs can't develop or hatch in the human guts, since it does require certain chemical signals to hatch which is initiated by the gastric juices, intestinal enzymes etc and such an environment is not provided by the human gut. T.saginata can can mature and lay eggs in the human guts, and it also can stay in the human intestine for a long period of time , in some cases it can stay till 25 years .

Ans b) The intermediate host of Taenia Saginata is mostly bovine species like cattles, T.saginata eggs are able to survive many days in harsh conditions and environments, and the eggs hatch only is they do get the proper conditions . The hatching of T.saginata is initiated by the action of gastric juices, intestinal enzymes, and bile on the eggs in the intestine of the cattle. The Bile, gastric juices and intestinal enzymes activates the egg as it provides proper conditions for the eggs to hatch . The liberated embryos do penetrate the intestinal mucosa of cattle and then enters the circulation sysytem and then transported throughout the body. Taenia saginata oncopheres do produce excretory-secretory peptidases, including serine an cysteine endopeptidases, and aminopeptidase, which may play an important role in the invasion of intestinal mucosa.