Compare and contrast infection with Taenia saginata and Echinococcus granulosus in humans, including the consequences of the infections
What will be an ideal response?
Both of these parasites are cestodes (tapeworms) that are acquired by ingestion. Humans are the definitive host for T. saginata and become infected when they consume undercooked beef containing the immature larvae in the form of cysticerci. The larvae emerge in the intestine, attach to the wall, begin feeding, and mature into self-fertilizing adults. The humans pass the eggs in their feces. Intestinal infection with the adult tapeworm may be asymptomatic, but patients may experience diarrhea, nausea, abdominal pain, and weight loss.
Humans are accidental intermediate hosts of E. granulosus, a parasite of canines. Humans become infected when they ingest the tapeworm eggs, which hatch in the intestine. The larvae then burrow out of the intestine and take up residence in a variety of organs ranging from the liver to the brain. The larvae of E. granulosus are capable of asexual reproduction in intermediate hosts, so the cysts established by the larvae continue to increase in size (and number of larvae) throughout the lifetime of the host. Eventually, the expanding cyst damages the organ in which it resides, and the condition may progress to organ failure. As a consequence, the human hosts experience a range of symptoms determined by the organ(s) being damaged (e.g., declining liver function to the point of failure or brain damage may mimic a tumor). Humans are considered dead-end hosts for E. granulosus because their flesh is rarely consumed by the definitive host.
You might also like to view...
The first successful outcome of gene therapy was in a case of a young girl suffering from ____________________,
who was supplied with normal copies of the ADA gene. Fill in the blank(s) with the appropriate word(s).
After dinosaurs became extinct, the number of mammal species increased greatly. What process applies to this example?
A) adaptive radiation B) endosymbiosis C) competition D) eukaryotic development
Tawny owls (Strix aluco) pair-bond for life, with both members of a pair living and hunting in adjacent, well-defined
territories. Their reproduction is regulated in accordance with the resources, especially the food supply, present in their territories. Tawny owls can best described as: a. r strategists. b. K strategists. c. fecundists. d. life historists. e. scramblers.
Cholera toxin polypeptide A binds to surface gangliosides on target cells. If the gangliosides were removed,
A) polypeptide A would bind to target cells. B) polypeptide A would enter the cells. C) polypeptide B would not be able to enter the cells. D) Vibrio would not produce cholera toxin. E) Vibrio would bind to target cells.