Dr. Man Sokchea (Parasitology)

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.

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.

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.

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.

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.

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.

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.

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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.

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.

A parasite is an organism that lives on or in a host and obtains its nutrients from the host, often at the host's expense. This can include protozoa or helminths, which are types of parasites. The other options, vector, agent, and arthropod, do not specifically refer to organisms that obtain their food from or at the expense of a host.

Enterobius vermicularis, also known as pinworm, is a parasitic worm that commonly infects humans. The most typical symptom of Enterobius vermicularis infection is perianal pruritus, which refers to itching around the anus, especially at night. This itching can be so severe that it leads to excoriations (skin abrasions) and bacterial superinfection. In some cases, the female genital tract can also be affected, leading to vulvovaginitis. Additionally, invasion of the pelvic or peritoneal area can result in the formation of granulomas.

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.

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.

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.

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."

The correct answer is 4 nuclei. Entamoeba histolytica is a parasite that causes amoebic dysentery. It has a unique life cycle that involves different stages, including the infective stage. This infective stage, known as the cyst, is passed out of the human host through fecal matter. The cyst can remain alive for about 10 days outside the host. When the cyst is ingested by a new human host through contaminated food or water, it undergoes a process called excystation. During excystation, the cyst breaks open and releases four nuclei, which eventually develop into new amoebic organisms.

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.

The correct answer is filarform larvae. Ancylostoma duodenale is a parasitic worm that causes hookworm infection in humans. The infective stage of this worm is the filarform larvae, which are tiny, elongated, and have a hook-like mouthpart. These larvae are found in contaminated soil and can penetrate the skin of humans, leading to infection. Once inside the body, the larvae migrate to the small intestine and develop into adult worms, causing symptoms such as abdominal pain, anemia, and diarrhea.

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.

Enterobius vermicularis, also known as pinworm, is a common intestinal parasite that primarily affects children. The eggs of Enterobius vermicularis are elongate-oval and slightly flattened on one side. They are usually partially-embryonated when shed, which means that they are in an early stage of development. One way to diagnose an Enterobius vermicularis infection is by applying cellulose tape to the anus of a suspect patient, especially in the morning before their first bowel movement. The tape can collect any eggs that may be present around the anus, which can then be examined under a microscope for confirmation of the infection.

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.

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.

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.

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.

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.

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.

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.

Mature cysts with 4 nuclei are responsible for spreading the infections caused by G. lumblia. These cysts are fully developed and contain four nuclei, which are the reproductive structures of the parasite. When these cysts are excreted in stool, they can contaminate the environment and spread the infection to others. The presence of four nuclei in the mature cysts indicates that they are capable of reproducing and causing further infection.

Cryptosporidium is a protozoan parasite that primarily affects the gastrointestinal tract. It is shed in the feces of infected individuals in the form of oocysts. Oocysts are the infective stage of the parasite and are resistant to environmental conditions, allowing them to survive outside the host and spread the infection to others. Therefore, the correct answer is oocyte, which refers to the oocyst stage of Cryptosporidium.

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.

Entamoeba histolytica is a parasite that feeds on various elements to grow and multiply, but it does not feed on bacteria. This means that it does not rely on bacteria as a food source for its growth and reproduction. Instead, it feeds on other substances such as the host's tissue, blood, and nutrition.

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.

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.

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.

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.

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.

A definitive host is a host in which a parasite reaches maturity and sexually reproduces. This means that the parasite completes its life cycle and can produce offspring within the definitive host. Other hosts may also play a role in the life cycle of the parasite, but the definitive host is the one where the parasite reaches its final stage of development.

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.

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.

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.

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.

An intermediate host is a host that harbors a parasite only for a short transition period, usually allowing for the completion of a developmental stage. This means that the parasite uses the intermediate host to undergo a specific phase of its life cycle before moving on to its definitive host, where it will reach sexual maturity and reproduce. The intermediate host is not the permanent host for the parasite, but rather serves as a temporary environment for its development.

The correct answer is "Its larval and adult stage". Ascaris lumbricoides is a parasitic roundworm that infects humans. The life cycle of Ascaris involves both larval and adult stages. The larval stage begins when the eggs are ingested, usually through contaminated food or water. The larvae then hatch in the intestines and migrate through the bloodstream to the lungs. In the lungs, they mature into adults and eventually travel back to the intestines, where they reproduce and lay eggs. Therefore, both the larval and adult stages of Ascaris lumbricoides contribute to its pathology.

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.

The adult stage of Ascaris lumbricoides may cause effects due to its mechanical effects. It can cause blockage of the intestine.

The correct answer is the cystic stage. Entamoeba is a genus of parasitic amoebas that can cause diseases in humans, such as amoebic dysentery. The cystic stage is a dormant and resistant form of the parasite that allows it to survive outside the host and be transmitted to new hosts. In this stage, the amoeba is enclosed in a protective cyst wall and is not actively feeding or causing disease.

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.

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.

The correct answer is "Larval stage". The life cycle of Entamoeba histolytica includes three stages: trophozoite stage, pre-cystic stage, and cystic stage. The larval stage is not a part of the life cycle of Entamoeba histolytica.