1.
Most cyclophyllidean tapeworms are thought to be apathogenic in the definitive host. However, recent data suggests that adults of this tapeworm may be associated with some cases of colic in horses:
Correct Answer
B. Anoplocephala perfoliata
Explanation
Anoplocephala perfoliata is the correct answer because recent data suggests that adults of this tapeworm may be associated with some cases of colic in horses. This indicates that this specific tapeworm species can cause colic in horses, contradicting the general belief that most cyclophyllidean tapeworms are apathogenic in the definitive host.
2.
Cats and dogs become infected with adults of Spirometra when they ingest:
Correct Answer
C. Non-fish vertebrates containing fully developed plerocercoid larvae
Explanation
Cats and dogs become infected with adults of Spirometra when they ingest non-fish vertebrates containing fully developed plerocercoid larvae. This means that the larvae of Spirometra develop into a specific stage called plerocercoid larvae inside non-fish vertebrates. When cats and dogs consume these infected vertebrates, the larvae develop into adults within their bodies, causing the infection.
3.
Which of the following tapeworm larvae in the intermediate host grows rapidly and aggressively, is invasive, and is impossible to completely remove at surgery?
Correct Answer
C. Strobilocercus of Taenia taeniaeformis
Explanation
The strobilocercus of Taenia taeniaeformis is the correct answer because it is a tapeworm larva that grows rapidly and aggressively in the intermediate host. It is also invasive and cannot be completely removed through surgery. The other options, such as the hydatid cysts of Echinococcus multilocularis and Echinococcus granulosus, and the cysticercus of Taenia saginata, do not exhibit the same characteristics of rapid growth, invasiveness, and surgical removal difficulty.
4.
Taenia solium infects humans as a definitive host and pigs as an intermediate host. However, in some cases humans can become aberrantly infected with cysticerci of this tapeworm. What system is most severely affected in humans due to cysticerci of Taenia solium?
Correct Answer
D. Hepatic
Explanation
Cysticerci of Taenia solium most severely affect the hepatic system in humans.
5.
Prevention of re-infection of a dog with Taenia pisiformis requires:
Correct Answer
D. Restricting access to rabbit prey
Explanation
Restricting access to rabbit prey is necessary for preventing re-infection of a dog with Taenia pisiformis because rabbits can serve as intermediate hosts for the tapeworm. By preventing the dog from consuming rabbits, which may be infected with the tapeworm larvae, the risk of re-infection is significantly reduced. This measure is important alongside other preventive measures such as flea and tick control, as well as avoiding feeding the dog raw or undercooked beef, which can also be a source of infection.
6.
Humans become infected with Echinococcus granulosus when they:
Correct Answer
A. Ingest eggs from the feces of an infected dog
Explanation
The correct answer is "ingest eggs from the feces of an infected dog" because Echinococcus granulosus is a tapeworm that primarily infects dogs as the definitive host. The adult tapeworms live in the intestines of infected dogs and produce eggs that are passed in the feces. Humans can become infected by accidentally ingesting these eggs, typically through contaminated food or water. Once ingested, the eggs hatch in the small intestine and the larvae migrate to various organs, forming cysts, most commonly in the liver and lungs.
7.
Ruminants become infected with Moneiza when they ingest cysticercoid laravae that have developed within:
Correct Answer
E. Orbatid mites
Explanation
Ruminants become infected with Moneiza when they ingest cysticercoid larvae that have developed within orbatid mites. Orbatid mites are a type of mite commonly found in soil and vegetation. These mites can become infected with Moneiza larvae and when ingested by ruminants, the larvae can develop into adult parasites in the animal's intestines. This can lead to health issues and disease in the ruminant population.
8.
Cyclophyllidean tapeworms _____________ whereas Pseudophyllidean tapeworms __________.
Correct Answer
B. Have a scolex with suckers/ have a scolex with bothria
Explanation
Cyclophyllidean tapeworms have a scolex with suckers, while Pseudophyllidean tapeworms have a scolex with bothria.
9.
Hydatid cysts are found in a variety of wild and domestic animals that serve effectively as intermediate hosts. In some of these species the cysts are often sterile. Dogs become infected with the adult tapeworms only if the cysts contain viable _______________, and, in the pastoral cycle, the normal intermediate hosts are __________.
Correct Answer
B. Hexacanth embryos/ sheep
Explanation
In this question, the correct answer is "hexacanth embryos/ sheep". This answer is supported by the information provided in the question. It states that dogs become infected with the adult tapeworms only if the cysts contain viable hexacanth embryos, and in the pastoral cycle, the normal intermediate hosts are sheep. This suggests that hexacanth embryos are found in the cysts of sheep, and dogs become infected through this intermediate host.
10.
Tapeworms have sexually immature stages called "metacestodes." The infective metacestode found only in the cyclophyllidean family Mesocestoididae is termed a " _______" and the adults of these tapeworms are mainly found in ___________?
Correct Answer
C. Cycticercus/ omnivores
11.
A ______________ is not a stage in the life cycle of a pseudophllidean tapeworm?
Correct Answer
D. Sparganum
Explanation
The options tetrathryidium, coracidium, and procercoid are all stages in the life cycle of a pseudophyllidean tapeworm. However, sparganum is not a stage in the life cycle of a pseudophyllidean tapeworm.
12.
Of the following tapeworms, only ____________ correctly matches the statement attached to it.
Correct Answer
D. Thysanoma actinioides: The cysticercoides are transmitted by fleas
13.
All of the following tapeworms infect human beings but only ________ and ______ can do so by autoinfection
Correct Answer
B. Echinococcus granulosus/ Vampirolepis nana
Explanation
Echinococcus granulosus and Vampirolepis nana are the only tapeworms among the given options that can infect human beings through autoinfection. Autoinfection refers to the ability of a parasite to complete its life cycle within the same host without the need for an intermediate host. This means that the tapeworm larvae can develop into adult worms within the human host, leading to a continuous cycle of infection. The other tapeworms listed in the options may infect humans, but they do not have the ability to undergo autoinfection.
14.
Spirometra mansonoides is a pseudophyllidean tapeworm that causes sparganosis in human beings, dogs and cats. Considering that plerocercoids become adult tapeworms and procercoids become plerocercoids, developmental stages acquired by ingestion of infected __________ would be the most likely source of such infections.
Correct Answer
D. Rodents
Explanation
Developmental stages acquired by ingestion of infected rodents would be the most likely source of sparganosis infections caused by Spirometra mansonoides. This is because plerocercoids, which are the larval stage of the tapeworm, develop into adult tapeworms within the definitive host (human beings, dogs, and cats). The procercoids, another larval stage, are acquired by ingesting infected copepods. However, since the question specifically mentions developmental stages that become adult tapeworms, the correct answer is rodents, as they serve as intermediate hosts for the tapeworm.
15.
In infections with cestodes of the family Taeniidae, the __________ causes the greater damage, and always in the ___________.
Correct Answer
C. Adult/ definitive host
Explanation
In infections with cestodes of the family Taeniidae, the adult cestode causes the greater damage, and always in the definitive host. The adult stage of the cestode is the mature form that resides in the definitive host, which is the host where the cestode reaches sexual maturity and reproduces. This stage is responsible for causing the most harm to the host's tissues and organs. The definitive host is typically the organism in which the cestode completes its life cycle. Therefore, the adult cestode in the definitive host is the correct answer.
16.
Adults tapeworms of Mesocestoides spp. often infect dogs, although certain wildlife species are preferred hosts. Dogs sometimes become infected with a larval stage of Mesocestoides. In such infection, __________ are typicaly found in the ___________.
Correct Answer
D. Coenuri/ muscles
Explanation
In cases of infection with the larval stage of Mesocestoides, coenuri are typically found in the muscles. The coenuri are the larval stage of the tapeworm and they form cysts in the muscles of the infected host. This is a common occurrence in dogs, although certain wildlife species are preferred hosts for the adult tapeworms.
17.
Tapeworms have sexually immature stages called "metacestodes." Which of the following metacestodes is the transmission stage of the Family Anoplocephalidae?
Correct Answer
D. Cysticercoid
18.
In infections with cestodes of the family Taeniidae, the _________ stage causes the least damage, and is always found in the __________.
Correct Answer
C. Adult/ definitive host
Explanation
In infections with cestodes of the family Taeniidae, the adult stage causes the least damage, and is always found in the definitive host.
19.
Thysanoma actinoides is a tapeworm that
Correct Answer
D. Is found in the small intestine and bile ducts and has fringed proglottids
Explanation
Thysanoma actinoides is a tapeworm that is found in the small intestine and bile ducts and has fringed proglottids. This means that the tapeworm lives in the small intestine and bile ducts of the host organism. The fringed proglottids are segments of the tapeworm that contain reproductive organs. This information helps to identify the specific characteristics of Thysanoma actinoides and distinguish it from other tapeworm species.
20.
Hydatid cysts of Echinococcus granulosus are found in a wide variety of animals. The infective cysts of this tapeworm contain __________, and the normal intermediate hosts are ___________.
Correct Answer
C. Protscolices/ sheep
Explanation
The correct answer is protoscolices/ sheep. Hydatid cysts of Echinococcus granulosus are found in various animals, but the normal intermediate hosts for this tapeworm are sheep. The infective cysts contain protoscolices, which are small worm-like structures that can develop into adult tapeworms in the definitive host, which is typically a dog.
21.
The infective stage of a pseudophyllidean tapeworm is a _____________.
Correct Answer
C. Plerocercoid
Explanation
The infective stage of a pseudophyllidean tapeworm is the plerocercoid. Plerocercoids are the intermediate stage of the tapeworm life cycle, found in the body cavity or muscles of the second intermediate host. They are infective to the final host, where they develop into adult tapeworms. This stage allows the tapeworm to complete its life cycle and continue its reproductive cycle.
22.
Considering specific habits and behaviors, which of the following definitive hosts would most likely become infected with a pseudophyllidean tapeworm?
Correct Answer
C. Grizzly bear
Explanation
Grizzly bears are more likely to become infected with a pseudophyllidean tapeworm compared to the other options. This is because grizzly bears are known to consume fish, which are common intermediate hosts for pseudophyllidean tapeworms. Fish are an important part of the grizzly bear's diet, increasing their chances of being infected with this type of tapeworm.
23.
The tapeworm with a metacestode that produces a condition referred to as "sparganosis" belongs to the genus _________ and the metacestode is the __________.
Correct Answer
B. Spirometra/ plerocercoid
24.
The condition in cattle referred to as "measly beef" is caused by _______ of ________.
Correct Answer
A. Cysticerci/ Taenia saginata
Explanation
The condition in cattle referred to as "measly beef" is caused by the presence of cysticerci of Taenia saginata. Cysticerci are the larval stage of the tapeworm Taenia saginata, which can infect cattle when they consume contaminated food or water. These cysticerci can develop in the muscles of the infected cattle, leading to the formation of small cysts. When humans consume undercooked or raw beef containing these cysts, they can become infected with the adult tapeworm, causing a condition known as taeniasis.
25.
The extremely large tapeworms found in the small intestines of cattle and sheep belong to the genus ___________.
Correct Answer
B. Moniezia
Explanation
The correct answer is Moniezia. Moniezia is a genus of tapeworms that are commonly found in the small intestines of cattle and sheep. These tapeworms can grow to be extremely large in size.