Dr. Man Sokchea (Parasitology)
You are allowed to choose ONE answer you believe is the best.
Questions and Answers
- 1.
The roundworms constitute an unusual group of organisms in the phylum Nematoda, in that they all live a part of their lives as intracellular parasites.
- A.
Ancylostoma duodenale
- B.
Strongyloides sterocoralis
- C.
Trichinella species
- D.
Capillaria species
Correct Answer
C. Trichinella speciesExplanation
The given answer, Trichinella species, is correct because it is a type of roundworm that belongs to the phylum Nematoda. Trichinella species are known for their unique life cycle as intracellular parasites, meaning they live inside the cells of their host organisms. This distinguishes them from other roundworms mentioned in the options, such as Ancylostoma duodenale, Strongyloides sterocoralis, and Capillaria species, which may be parasites but do not necessarily live intracellularly.Rate this question:
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- 2.
Trichuris species have a direct life cycle, and mature in a single host. The host becomes infected when it:
- A.
Penetrates thru the skin.
- B.
Ingests embryonated eggs from the environment.
- C.
Inhales the sporocyst.
- D.
Breasts the baby.
Correct Answer
B. Ingests embryonated eggs from the environment.Explanation
Trichuris species have a direct life cycle, meaning they do not require intermediate hosts to complete their life cycle. The correct answer is that the host becomes infected when it ingests embryonated eggs from the environment. This means that the eggs of Trichuris species are passed in the feces of an infected individual and can contaminate the environment. If another host ingests these eggs, they can hatch and develop into adult worms within the intestines of the new host, causing infection.Rate this question:
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- 3.
Trichuriasis is caused by various species of Trichuris, nematode parasites in the family Trichuridae. These parasites are also known as whipworms. Both larval and adult whipworms are normally found:
- A.
Only in the intestines.
- B.
In the intestine.
- C.
In the liver parenchyma.
- D.
In the gallbladder.
Correct Answer
A. Only in the intestines.Explanation
The correct answer is "only in the intestines" because Trichuriasis is a condition caused by whipworms, which are nematode parasites that primarily inhabit the intestines of their host. These parasites do not typically reside in the liver parenchyma or the gallbladder. Therefore, the correct answer is that both larval and adult whipworms are found only in the intestines.Rate this question:
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- 4.
The larvae hatch in the digestive tract, migrate into the mucosa, and return to the intestinal lumen. There the adult stages develop and remain with their slender anterior ends anchored in the mucosa.
- A.
S. stercoralis
- B.
Capillaria species
- C.
E. vermicularis
- D.
T. trichiura
Correct Answer
D. T. trichiuraExplanation
T. trichiura is the correct answer because the explanation provided describes the life cycle of this parasite. The larvae of T. trichiura hatch in the digestive tract, migrate into the mucosa, and then return to the intestinal lumen. In the lumen, the larvae develop into adult stages and remain anchored in the mucosa with their slender anterior ends. This life cycle is specific to T. trichiura and distinguishes it from the other parasites mentioned.Rate this question:
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- 5.
Parasite buries a thin, threadlike anterior half into the intestinal mucosa and feeds on tissue secretion.
- A.
S. stercoralis
- B.
Capillaria species
- C.
E. vermicularis
- D.
T. triciura
Correct Answer
D. T. triciuraExplanation
The correct answer is T. triciura because it is a known intestinal parasite that buries its thin, threadlike anterior half into the intestinal mucosa and feeds on tissue secretion.Rate this question:
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- 6.
These histological findings were typical of acute disease. he patient recovered well after surgery and mebendazole has been prescribed for him as well as his close family members.
- A.
S. stercoralis
- B.
Capillaria species
- C.
E. vermicularis
- D.
A. lambricoides
Correct Answer
C. E. vermicularisExplanation
The given histological findings being typical of acute disease suggest that the patient had an acute infection. The patient's recovery after surgery and the prescription of mebendazole for him and his close family members indicate that the infection was likely caused by a parasitic worm. Among the options provided, E. vermicularis, also known as pinworm, is the most common parasitic worm that infects humans and is associated with acute disease. Therefore, E. vermicularis is the most likely cause of the infection in this case.Rate this question:
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- 7.
Enterobius vermicularis or pinworm is one of the most common parasites in humans affecting mainly children. The stage can be identified for diagnosis in:
- A.
Eggs
- B.
Cysts
- C.
Trophozoites
- D.
Sporozoites
Correct Answer
A. EggsExplanation
The correct answer is "Eggs". Enterobius vermicularis or pinworm can be diagnosed by identifying its eggs. This parasite is commonly found in humans, especially in children. By examining the eggs under a microscope, it is possible to confirm the presence of pinworm infection. Other stages mentioned in the options, such as cysts, trophozoites, and sporozoites, are not relevant to the diagnosis of Enterobius vermicularis.Rate this question:
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- 8.
In the lumen of some female parasites, many oval eggs were seen in their gravid genital tract. The eggs can be identified for diagnosis in:
- A.
Biopsy
- B.
Perianal folds
- C.
Autopsy
- D.
Stool specimens
Correct Answer
D. Stool specimensExplanation
Stool specimens are the most appropriate for identifying the oval eggs in the lumen of female parasites. This is because when parasites are present in the gastrointestinal tract, their eggs are often passed out in the feces. By examining stool specimens under a microscope, the eggs can be detected and identified, allowing for a diagnosis to be made. Biopsy, perianal folds, and autopsy may not be as effective in identifying the eggs as they may not directly sample the area where the eggs are present.Rate this question:
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- 9.
Enterobius vermicularis or pinworms is one of the most common parasite in humans affecting mainly children, depositing their eggs:
- A.
In the liver parenchyma.
- B.
In the alveolar space.
- C.
On perianal folds.
- D.
In the lumen of the intestine.
Correct Answer
C. On perianal folds.Explanation
Pinworms, also known as Enterobius vermicularis, are a common parasite that primarily affects children. They deposit their eggs on perianal folds, which are the skin folds around the anus. This is because the adult female pinworms migrate to the perianal area at night to lay their eggs. The eggs can then be easily transferred to the surrounding environment, leading to further infection. Therefore, the correct answer is "On perianal folds."Rate this question:
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- 10.
Enteriobius vermicularis or pinworm is one of the most common parasite in humans affecting mainly in children. The following statements humans get infected are correct except:
- A.
By the fecal-oral route.
- B.
By ingesting the parasite's eggs.
- C.
From contaminated foods or water.
- D.
By penetrating thru the skin.
Correct Answer
D. By penetrating thru the skin.Explanation
Enterobius vermicularis, or pinworm, is primarily transmitted through the fecal-oral route. This means that individuals become infected by ingesting the parasite's eggs, which are present in contaminated food or water. The eggs are typically ingested accidentally, often by touching contaminated surfaces and then putting hands or fingers in the mouth. The parasite does not penetrate through the skin as a mode of transmission.Rate this question:
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- 11.
The disease is often asymptomatic but can sometimes manifest classically as nocturnal anal pruritus especially in children.
- A.
Ancylostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
Enterobius vermicularis
Correct Answer
D. Enterobius vermicularisExplanation
Enterobius vermicularis is a parasitic worm that causes the condition known as pinworm infection. This infection is often asymptomatic, meaning that it does not cause any noticeable symptoms. However, in some cases, especially in children, it can cause nocturnal anal pruritus, which is itching around the anus at night. This symptom is considered a classic manifestation of Enterobius vermicularis infection. The other options listed, Ancylostoma duodenale, Trichinella species, and Capillaria species, do not typically cause this specific symptom.Rate this question:
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- 12.
Acute appendicitis is the most common abdominal emergency worldwide. Several pathological mechanisms leading to appendiceal wall inflammation and luminal obstruction are thought to be responsible for the disease.
- A.
Ancylostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
B. Trichinella speciesExplanation
Trichinella species are parasitic worms that can infect humans and cause a condition called trichinellosis. These worms are typically acquired by consuming undercooked or raw meat, particularly pork. In the context of the given question, it is likely that Trichinella species are being mentioned as a possible cause of appendiceal wall inflammation and luminal obstruction, leading to acute appendicitis. While more commonly associated with gastrointestinal symptoms such as diarrhea and abdominal pain, it is possible for trichinellosis to lead to appendicitis in some cases.Rate this question:
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- 13.
Self-infection occurs by transferring infective eggs to the mouth with hands that have scratched the perianal area.
- A.
Ancylostoma duodenale
- B.
Trichinella speies
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
D. E. vermicularisExplanation
Self-infection refers to the transmission of an infection from one part of the body to another. In the case of E. vermicularis, also known as pinworm, self-infection occurs when infective eggs are transferred to the mouth through the hands after scratching the perianal area. This can happen when a person with a pinworm infection scratches the itchy area around the anus, inadvertently picking up the eggs under their fingernails. If the person then touches their mouth or food without washing their hands properly, they can ingest the eggs, leading to self-infection.Rate this question:
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- 14.
Gravid females migrate nocturnally outside the anus and oviposit while crawling on the skin of the perianal area.
- A.
Ancyclostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
D. E. vermicularisExplanation
This answer is correct because E. vermicularis, also known as pinworm, is a parasitic worm that commonly infects humans. The given statement describes the behavior of gravid females, which refers to pregnant female worms, migrating outside the anus and laying eggs while crawling on the skin around the anus. This behavior is characteristic of E. vermicularis. The other options, Ancyclostoma duodenale, Trichinella species, and Capillaria species, do not exhibit this specific behavior.Rate this question:
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- 15.
In households where more than one member is infected or where repeated, symptomatic infections occur, it is recommended that all household members be treated at the same time.
- A.
Ancylostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
D. E. vermicularisExplanation
In households where more than one member is infected or where repeated, symptomatic infections occur, it is recommended that all household members be treated at the same time. This is because E. vermicularis, also known as pinworm, is highly contagious and can easily spread from person to person within a household. Treating all household members simultaneously helps to prevent reinfection and the spread of the parasite to others.Rate this question:
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- 16.
A person infected with parasitic infection is often asymptomatic, but itching around the anus is a common symptom of:
- A.
Ancylostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
D. E. vermicularisExplanation
E. vermicularis is the correct answer because it is commonly known as pinworm and it is the most common parasitic infection in humans. Although many infected individuals do not show symptoms, itching around the anus is a common symptom of pinworm infection. Ancylostoma duodenale is a hookworm that typically causes symptoms such as anemia and abdominal pain. Trichinella species are responsible for trichinellosis, which causes muscle pain and swelling. Capillaria species can cause infections in various parts of the body, but itching around the anus is not a common symptom.Rate this question:
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- 17.
Often the patient will complain of teeth grinding and insomnia due to disturbed sleep, or even abdominal pain or appendicitis.
- A.
Ancylostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
D. E. vermicularisExplanation
E. vermicularis, also known as pinworm, is a parasitic worm that commonly infects the human intestines. One of the symptoms associated with this infection is teeth grinding, which can lead to disturbed sleep and insomnia. Additionally, abdominal pain or appendicitis can also be experienced by the patient. Therefore, E. vermicularis is the most likely answer based on the symptoms described.Rate this question:
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- 18.
Gravid females migrate nocturnally outside the anus and oviposit while crawling on the skin of the perianal area.
- A.
Ancylostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
D. E. vermicularisExplanation
The given statement describes the behavior of gravid females, which means pregnant females, migrating outside the anus and laying eggs while crawling on the skin around the anus. This behavior is characteristic of E. vermicularis, also known as pinworm. Ancylostoma duodenale, Trichinella species, and Capillaria species do not exhibit this specific behavior, making E. vermicularis the correct answer.Rate this question:
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- 19.
Self-infection occurs by transferring infective eggs to mouth with hands that have scratched the perianal area.
- A.
Ancylostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
D. E. vermicularisExplanation
E. vermicularis, also known as pinworm, is a common intestinal parasite that can cause self-infection. The female pinworm lays eggs in the perianal area, causing itching. When a person scratches the area, the eggs can be transferred to their hands. If the person then touches their mouth or food without washing their hands, they can ingest the eggs, leading to self-infection. This cycle of transmission is common in households and institutions, especially among children.Rate this question:
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- 20.
The eggs are generally flat on one side and rounded on the other.
- A.
Ancylostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
D. E. vermicularisExplanation
E. vermicularis, also known as pinworm, is the correct answer because it is the only parasite listed that matches the description given in the question. Pinworm eggs are typically flat on one side and rounded on the other, which is a characteristic feature of this particular parasite. Ancylostoma duodenale, Trichinella species, and Capillaria species do not exhibit this specific egg shape.Rate this question:
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- 21.
Method of choice for recovery in "Pinworm Paddle" or a properly prepared scotch tape preparation.
- A.
Ancylostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
D. E. vermicularisExplanation
The correct answer is E. vermicularis. "Pinworm Paddle" or a properly prepared scotch tape preparation is a method used for the recovery of E. vermicularis. This method involves pressing a transparent adhesive tape against the perianal area, which allows the collection of pinworm eggs or adult worms for microscopic examination. Ancylostoma duodenale, Trichinella species, and Capillaria species are not typically recovered using this method.Rate this question:
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- 22.
People who are infected with pinworm can transfer the parasite to others for as long as there is a female pinworm depositing eggs on the perianal skin.
- A.
Ancylostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
D. E. vermicularisExplanation
E. vermicularis, also known as pinworm, is the correct answer because the statement in the question specifically mentions that people infected with pinworm can transfer the parasite to others as long as there is a female pinworm depositing eggs on the perianal skin. This aligns with the characteristics and behavior of E. vermicularis, making it the correct answer choice.Rate this question:
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- 23.
Once mature, the adult female pinworm migrates to the colon and lays eggs when many of their hosts are asleep.
- A.
In the feces
- B.
In the liver
- C.
In the intestine
- D.
Around the anus at night
Correct Answer
D. Around the anus at nightExplanation
The adult female pinworm migrates to the area around the anus at night to lay eggs. This behavior is typical for pinworms, as they have a nocturnal activity pattern. By laying eggs around the anus, the pinworm ensures that the eggs are in close proximity to their next host, as the eggs can easily be transferred to the fingers or undergarments of the host during scratching or movement while sleeping. This facilitates the transmission of pinworm infection to others.Rate this question:
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- 24.
Once someone has ingested pinworm eggs, there is an incubation period of 1 to 2 months or longer for the adult gravid female to mature.
- A.
In the small intestine
- B.
In the large intestine
- C.
In the liver
- D.
In the lungs
Correct Answer
A. In the small intestineExplanation
After ingesting pinworm eggs, they need time to develop and mature into adult gravid females. This process takes about 1 to 2 months or even longer. During this incubation period, the eggs hatch in the small intestine and the larvae continue to develop into adult worms. Therefore, the correct answer is "In the small intestine."Rate this question:
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- 25.
These eggs are deposited around the anus by the worm and can be carried to common surfaces such as hands, toys, bedding, clothing, and toilet seats.
- A.
Ancyclostoma duodenalis
- B.
Trichinella species
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
D. E. vermicularis -
- 26.
A person is infected with pinworms by ingesting parasitic stage either directly or indirectly.
- A.
Cysts
- B.
Sporocysts
- C.
Eggs
- D.
Larvae
Correct Answer
C. EggsExplanation
Pinworms are a type of parasitic worm that infects the human intestinal tract. The correct answer is "Eggs" because pinworm infection occurs when a person ingests the eggs of the pinworm. These eggs are typically found in contaminated food, water, or surfaces that have been touched by someone with a pinworm infection. Once ingested, the eggs hatch in the small intestine, and the larvae mature into adult worms in the large intestine. Therefore, the ingestion of pinworm eggs is the primary mode of transmission for this parasitic infection.Rate this question:
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- 27.
Parasitic infections are more common within families with school-aged children.
- A.
Ancylostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
Option 4
Correct Answer
D. Option 4Explanation
Option 4 is the correct answer because Capillaria species are known to cause parasitic infections in humans, particularly in the intestines. These infections are more common within families with school-aged children because children are more likely to come into contact with the parasites through contaminated soil or food. Ancylostoma duodenale and Trichinella species are also parasites that can cause infections in humans, but they are not specifically associated with being more common within families with school-aged children.Rate this question:
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- 28.
Parasitic infection is caused by a small, thin, white roundworms called:
- A.
Ancylostoma duodenale
- B.
Trichinella species
- C.
Capillaria species
- D.
E. vermicularis
Correct Answer
D. E. vermicularisExplanation
E. vermicularis is the correct answer because it is a small, thin, white roundworm that causes parasitic infection. Ancylostoma duodenale is a hookworm that causes a different type of infection. Trichinella species and Capillaria species are also types of roundworms, but they cause different types of infections and are not specifically associated with parasitic infection.Rate this question:
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- 29.
Capillaria hepatica (C. hepatica) is a nematide parasite of wild rodents and other mammals and has worldwide distribution. Adult worms colonize:
- A.
The muscle of the host
- B.
The lumen of intestine of the host
- C.
The lungs of the host
- D.
The liver of the host
Correct Answer
D. The liver of the hostExplanation
C. hepatica is a nematode parasite that primarily colonizes the liver of its host. This parasite has a worldwide distribution and infects various mammals, including wild rodents. By colonizing the liver, C. hepatica can cause hepatomegaly and liver damage, leading to various clinical manifestations. The other options mentioned, such as the muscle, intestine, and lungs, are not the primary sites of colonization for C. hepatica.Rate this question:
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- 30.
C. henpatica: these parasites could be accidentally transmitted to humans by: ingesting of embryonated eggs.
- A.
Ingestion of eggs in fecal-contaminated food
- B.
Ingestion of cysts in the muscle of fish
- C.
Ingestion of sporocysts in the muscle of fish
- D.
Penetration of larvae thru the skin
Correct Answer
A. Ingestion of eggs in fecal-contaminated foodExplanation
The correct answer states that C. henpatica parasites can be accidentally transmitted to humans by ingesting eggs in fecal-contaminated food. This means that if the food is contaminated with feces that contain the eggs of the parasites, and a person consumes this contaminated food, they can become infected with the parasites.Rate this question:
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- 31.
The adults of Capillaria philippinensis (males: 2.3 to 3.2mm; females: 2.5 to 4.3mm) reside in the human:
- A.
Small intestine
- B.
Large intestine
- C.
Blood stream
- D.
Muscle
Correct Answer
A. Small intestineExplanation
Capillaria philippinensis is a type of parasitic worm that infects humans. The given information states that the adults of this worm reside in the human body. The sizes of the males and females are also provided. Based on this information, it can be inferred that Capillaria philippinensis resides in the small intestine of humans.Rate this question:
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- 32.
Capillaria philippinensis is a parasitic disease in humans caused by eating:
- A.
Raw or undercooked fish
- B.
Raw or undercooked pork
- C.
Raw or undercooked beef
- D.
Raw or undercooked vegetable
Correct Answer
A. Raw or undercooked fishExplanation
Capillaria philippinensis is a parasitic disease in humans that is caused by consuming raw or undercooked fish. This parasite is commonly found in the intestines of infected fish, and when humans consume these infected fish, the parasite can enter their digestive system and cause infection. Therefore, it is important to ensure that fish is properly cooked before consumption to prevent the transmission of this parasitic disease.Rate this question:
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- 33.
Capillaria spp. Parasitic stage passed in the human stool.
- A.
Cysts
- B.
Larvae
- C.
Unembryonated eggs
- D.
Embryonated eggs
Correct Answer
C. Unembryonated eggsExplanation
Unembryonated eggs refer to eggs that have not yet developed into an embryo. In the case of Capillaria spp., a parasitic worm, the unembryonated eggs are passed in the human stool. This means that when the worm reproduces and lays eggs inside the human body, these eggs are excreted in the feces without having developed into embryos. This stage of the parasite's life cycle is crucial for its transmission to other hosts, as the unembryonated eggs need to mature and become embryonated in the environment before they can infect another individual.Rate this question:
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- 34.
Capillaria spp: Ingesting by freshwater fish, larvae hatch, penetrate the intestine and migrate to the tissue.
- A.
Eggs
- B.
Cysts
- C.
Unembryonated eggs
- D.
Embryonated eggs
Correct Answer
D. Embryonated eggsExplanation
Embryonated eggs are the correct answer because the given explanation states that Capillaria spp, a type of parasite, is ingested by freshwater fish. Once ingested, the eggs of Capillaria spp hatch and the larvae penetrate the fish's intestine. From there, the larvae migrate to the fish's tissue. This implies that the eggs of Capillaria spp must be embryonated, meaning they contain an embryo that is ready to hatch. Therefore, the correct answer is embryonated eggs.Rate this question:
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- 35.
Cappilariasis is a parasitic disease in humans caused by 2 different species of capillarids. Fish-eating birds are the usual:
- A.
Intermediate host
- B.
Definitive host
- C.
Reservoir host
- D.
Natural host
Correct Answer
B. Definitive hostExplanation
Cappilariasis is a parasitic disease in humans caused by 2 different species of capillarids. The term "definitive host" refers to the organism in which a parasite reaches sexual maturity and reproduces. In the case of cappilariasis, fish-eating birds are the definitive host, meaning that the parasites reach maturity and reproduce within their bodies. This explains why fish-eating birds are the usual source of infection for humans with cappilariasis.Rate this question:
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- 36.
Trichinella species: Mating takes place in the host:
- A.
Small intestine
- B.
Large intestine
- C.
Blood stream
- D.
Alveolus space
Correct Answer
A. Small intestineExplanation
Trichinella species are parasitic worms that infect mammals, including humans. They have a complex life cycle that involves multiple stages. Mating in Trichinella species occurs in the small intestine of the host. This is where the male and female worms come together to reproduce and produce offspring. The small intestine provides a suitable environment for the mating process to occur, allowing for the continuation of the Trichinella life cycle.Rate this question:
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- 37.
The other Trichinella species cannot be found in encystation, except:
- A.
T. spiralis
- B.
T. pseudospiralis
- C.
T. papuae
- D.
T. zimbabwensis
Correct Answer
A. T. spiralisExplanation
T. spiralis is the only Trichinella species that can be found in encystation. The other species mentioned, T. pseudospiralis, T. papuae, and T. zimbabwensis, do not undergo encystation.Rate this question:
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- 38.
Trichinella spiralis: The larvae in turn, are transported by the blood stream to all parts of the body. The worm grows:
- A.
In the parenchymal cells of the liver
- B.
In the ling parenchyma
- C.
Within the muscle tissue
- D.
In the intestinal wall
Correct Answer
C. Within the muscle tissueExplanation
Trichinella spiralis larvae are transported by the bloodstream to all parts of the body, including the muscle tissue. Once in the muscle tissue, the worm grows and develops. This is an important stage in the life cycle of Trichinella spiralis, as it allows the worm to establish itself in the host and continue its life cycle. The growth of the worm within the muscle tissue can lead to symptoms such as muscle pain and weakness in infected individuals.Rate this question:
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- 39.
Trichinosis is an infestation with larvae of the worm Trichinella spiralis, contracted from eating the inadequate cooking of:
- A.
Pork products
- B.
Fish products
- C.
Beef products
- D.
Fresh vegetable
Correct Answer
A. Pork productsExplanation
Trichinosis is caused by ingesting the larvae of the worm Trichinella spiralis. These larvae are commonly found in undercooked pork products. When pork is not cooked thoroughly, the larvae can survive and cause an infestation when consumed. Therefore, the correct answer is pork products.Rate this question:
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- 40.
Adult stages inhabit the small intestine, where the females produce larve that migrate thru the lymphatics and bloodstream into skeletal musculature, penetrate into muscle cells and encyst.
- A.
Ancylostoma duodenale
- B.
Strongyloides stercoralis
- C.
Trichinella species
- D.
Capillaria species
Correct Answer
C. Trichinella speciesExplanation
Trichinella species is the correct answer because this parasite is known to infect humans and cause trichinellosis. The adult stages of Trichinella inhabit the small intestine, where the females produce larvae. These larvae then migrate through the lymphatics and bloodstream into skeletal musculature. Once in the muscle cells, they penetrate and encyst, forming cysts. This lifecycle is characteristic of Trichinella species, making it the correct answer.Rate this question:
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- 41.
The encapsulated parasitic stages remain viable for years in the host, demonstrated for up to 31 years in humans.
- A.
Ancylostoma duodenale
- B.
Strongyloides stercoralis
- C.
Trichinella species
- D.
Capillaria species
Correct Answer
C. Trichinella speciesExplanation
Trichinella species are known to have encapsulated parasitic stages that can remain viable for long periods of time in the host. This has been demonstrated in humans for up to 31 years.Rate this question:
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- 42.
E. hystolytica: Cysts and trophozoites are passed in feces. Cysts are typically found:
- A.
In unformed or liquid (watery) stool
- B.
In soft formed stool
- C.
In formed (normal shape) stool
- D.
In watery diarrhea
Correct Answer
B. In soft formed stoolExplanation
The correct answer is "In soft formed stool." This is because E. hystolytica cysts are typically found in feces that are soft and have a formed shape. This means that the stool is not watery or liquid, but rather has a consistency that holds its shape. This is important information for diagnosing and identifying the presence of E. hystolytica in a patient's stool sample.Rate this question:
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- 43.
Free-living cycle: The rhabditiform larvae passed in the stool.
- A.
Ancylostoma duodenale
- B.
Strongyloides stercoralis
- C.
Trichinella species
- D.
Capillaria species
Correct Answer
B. Strongyloides stercoralisExplanation
Strongyloides stercoralis is the correct answer because it is the only parasite listed that has a free-living cycle in which the rhabditiform larvae are passed in the stool. Ancylostoma duodenale, Trichinella species, and Capillaria species do not have a free-living cycle and do not pass rhabditiform larvae in the stool.Rate this question:
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- 44.
Pruritus and eruption disappear when larvae enter blood vessels and migrate to intestinal mucosa.
- A.
Ascaris lambricoides
- B.
Ancylostoma duodenale
- C.
Strongyloides stercoralis
- D.
Trichinella species
Correct Answer
C. Strongyloides stercoralisExplanation
When Strongyloides stercoralis larvae enter the blood vessels and migrate to the intestinal mucosa, pruritus (itching) and eruption (skin rash) disappear. This suggests that the symptoms are caused by the larvae in the skin and once they move to the intestines, the symptoms subside. Ascaris lambricoides, Ancylostoma duodenale, and Trichinella species are not known to cause this specific pattern of symptoms, making Strongyloides stercoralis the correct answer.Rate this question:
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- 45.
In such cases sexually mature female worms are also found in the lungs, and less frequently in other organs.
- A.
Ascaris lambricoides
- B.
Ancylostoma duodenale
- C.
Strongyloides stercoralis
- D.
Trichinella species
Correct Answer
C. Strongyloides stercoralisExplanation
In cases where sexually mature female worms are found in the lungs and occasionally in other organs, the most likely culprit is Strongyloides stercoralis. This parasitic worm is known to infect humans and can cause a condition called strongyloidiasis. The female worms of Strongyloides stercoralis can migrate to various organs, including the lungs, leading to respiratory symptoms. Therefore, Strongyloides stercoralis is the correct answer in this context.Rate this question:
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- 46.
Parasitic stage can also be occasionally transmitted via mother's milk.
- A.
Ancylostoma duodenale
- B.
Strongyloides stercoralis
- C.
Trichinella speices
- D.
Capillaria species
Correct Answer
B. Strongyloides stercoralisExplanation
Strongyloides stercoralis is a parasitic nematode that can infect humans. It has a unique lifecycle that includes a parasitic stage and a free-living stage. The parasitic stage of Strongyloides stercoralis can infect humans through direct contact with contaminated soil, but it can also be transmitted from mother to child through breastfeeding. This means that if a mother is infected with Strongyloides stercoralis, she can pass the infection to her child through her milk. This mode of transmission is known as vertical transmission. Therefore, the statement that the parasitic stage can occasionally be transmitted via mother's milk is true for Strongyloides stercoralis.Rate this question:
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- 47.
S. stercoralis: True disseminated infection occurs when parasitic stage penetrates tissue and resides in organs atypical of their normal life cycle.
- A.
Eggs
- B.
Trophozoites
- C.
Filariform larvae
- D.
Rhabditiform larvae
Correct Answer
C. Filariform larvaeExplanation
Filariform larvae are the infective stage of S. stercoralis, a parasitic worm. True disseminated infection occurs when these larvae penetrate tissues and reside in organs that are not typical of their normal life cycle. This means that the larvae can migrate to and infect organs such as the liver, lungs, heart, and central nervous system, causing a widespread infection throughout the body.Rate this question:
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- 48.
S. stercoralis: In the current case, only parasitic stage which is unable to penetrate tissue was observed in the biliary fluid, indicative of migration of stage from the intestines to connected organs.
- A.
Eggs
- B.
Trophozoites
- C.
Filariform larvae
- D.
Rhabditiform larvae
Correct Answer
D. Rhabditiform larvaeExplanation
The correct answer is "Rhabditiform larvae." In the given explanation, it is mentioned that only the parasitic stage that is unable to penetrate tissue was observed in the biliary fluid. This indicates that the larvae observed in the fluid were Rhabditiform larvae, as they are the non-infective stage of S. stercoralis that cannot penetrate tissue. This suggests that the larvae migrated from the intestines to connected organs.Rate this question:
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- 49.
Strongyloides stercoralis: Rarely, filariform larvae have been observed to take up residence:
- A.
In the lining of the bronchi
- B.
In the large intestine
- C.
In the lining of the bronchi and trachea
- D.
In the small intestine
Correct Answer
C. In the lining of the bronchi and tracheaExplanation
Strongyloides stercoralis is a parasitic nematode that primarily resides in the small intestine of humans. However, in rare cases, the filariform larvae of Strongyloides stercoralis can migrate to other parts of the body. The given answer states that these larvae can take up residence in the lining of the bronchi and trachea. This means that they can travel to the respiratory system and establish themselves in the airways. This is a possible but uncommon occurrence in cases of Strongyloides stercoralis infection.Rate this question:
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- 50.
S. stercoralis: Filariform larvae transform to adults in:
- A.
Bronchi
- B.
Large intestine
- C.
Bronchi and trachea
- D.
Small intestine
Correct Answer
B. Large intestineExplanation
The correct answer is "large intestine" because S. stercoralis is a parasitic nematode that infects humans and other animals. The filariform larvae of S. stercoralis penetrate the skin and migrate through the bloodstream to the lungs, where they are coughed up and swallowed. From there, they reach the small intestine, where they mature into adults and reproduce. The adult worms then migrate to the large intestine, where they lay eggs and complete their life cycle. Therefore, the transformation from filariform larvae to adults occurs in the large intestine.Rate this question:
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Quiz Review Timeline +
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Jan 23, 2023Quiz Edited by
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Mar 10, 2019Quiz Created by
Byun Nexi
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