Chpt 4a (Pg.93-107) Parasitic Nematodes

Question 1

21. Hookworms that are of clinical importance in the tropics belong to which genera a) Ascaris and Enterobius b) Trichuris and Strongyloides c) Ancylostoma and Necator d) None of the above

Answer 1

Answer: c) Ancylostoma and Necator Explanation: The two main genera of hookworms that cause significant health concerns in tropical regions are Ancylostoma and Necator

Question 2

22. Which species of hookworm is referred to as the “Old World” hookworm a) Necator americanus b) Ancylostoma braziliense c) Ancylostoma duodenale d) Strongyloides stercoralis

Answer 2

Answer: c) Ancylostoma duodenale Explanation: Ancylostoma duodenale is known as the “Old World” hookworm due to its prevalence in regions like Europe and the Mediterranean

Question 3

23. How does a human typically become infected with hookworms a) Ingestion of contaminated food or water b) Penetration of the skin by infective larvae in soil c) Inhalation of airborne eggs d) Direct contact with an infected individual

Answer 3

Answer: b) Penetration of the skin by infective larvae in soil Explanation: Hookworm infection occurs when filariform larvae present in the soil come into contact with human skin and penetrate it

Question 4

24. How do hookworms primarily cause harm to their host a) By consuming blood from the intestinal wall b) By blocking the intestinal tract c) By migrating through the lungs and causing respiratory distress d) By laying eggs that cause tissue damage

Answer 4

Answer: a) By consuming blood from the intestinal wall Explanation: Adult hookworms attach to the intestinal mucosa and feed on the host’s blood potentially leading to anemia and other complications

Question 5

25. What is the most common symptom of a hookworm infection a) Fever and chills b) Skin rash c) Anemia and fatigue d) Abdominal pain and diarrhea

Answer 5

Answer: c) Anemia and fatigue Explanation: Anemia resulting from blood loss is a hallmark symptom of hookworm infection leading to fatigue and weakness

Question 6

26. Diagnosis of hookworm infection is typically made by a) Identifying the characteristic eggs in a stool sample b) Performing a blood test c) Taking a skin biopsy d) Conducting a chest X-ray

Answer 6

Answer: a) Identifying the characteristic eggs in a stool sample Explanation: Hookworm infection is diagnosed through the detection of characteristic hookworm eggs in the patient’s stool

Question 7

27. What is the drug of choice for treating hookworm infections a) Mebendazole b) Albendazole c) Ivermectin d) Both a and b

Answer 7

Answer: d) Both a and b Explanation: Mebendazole and albendazole are both effective treatments for hookworm infections

Question 8

28. Which of the following is NOT a preventive measure for hookworm infection a) Wearing shoes in areas where hookworm is prevalent b) Proper disposal of human feces c) Consuming a balanced diet d) Washing hands thoroughly after contact with soil

Answer 8

Answer: c) Consuming a balanced diet Explanation: While a balanced diet is important for overall health it doesn’t directly protect against hookworm infection Preventing hookworm focuses on avoiding contact with contaminated soil

Question 9

29. What is the common name for Strongyloides stercoralis a) Pinworm b) Whipworm c) Threadworm d) Hookworm

Answer 9

Answer: c) Threadworm Explanation: Strongyloides stercoralis is referred to as the threadworm

Question 10

30. Strongyloides stercoralis has a unique life cycle What is it called a) Direct life cycle b) Heterogeneous life cycle c) Monoxenic life cycle d) Indirect life cycle

Answer 10

Answer: b) Heterogeneous life cycle Explanation: Strongyloides stercoralis stands out due to its complex life cycle that involves both free-living and parasitic stages termed a heterogeneous life cycle

Question 11

31. What are the two main life cycles of Strongyloides stercoralis a) Direct and indirect b) Free-living and parasitic c) Larval and adult d) Sexual and asexual

Answer 11

Answer: b) Free-living and parasitic Explanation: The life cycle of Strongyloides stercoralis alternates between a free-living phase in the soil and a parasitic phase within a human host

Question 12

32. How can Strongyloides stercoralis larvae infect a human host a) By penetrating the skin b) By being ingested with contaminated food or water c) By being inhaled d) All of the above

Answer 12

Answer: d) All of the above Explanation: Strongyloides stercoralis larvae can infect humans through various routes skin penetration ingestion of contaminated substances and potentially inhalation

Question 13

33. What is autoinfection in the context of Strongyloides stercoralis a) When larvae in the intestine develop into adult worms without leaving the host b) When an individual is infected multiple times by different strains of the parasite c) When the parasite spreads to different organs within the same host d) When the parasite is transmitted from mother to child during pregnancy

Answer 13

Answer: a) When larvae in the intestine develop into adult worms without leaving the host Explanation: Autoinfection in Strongyloides stercoralis involves rhabditiform larvae transforming into filariform larvae within the host’s intestine leading to a continued infection cycle

Question 14

34. What is a serious complication that can arise from Strongyloides stercoralis infection especially in immunocompromised individuals a) Hyperinfection syndrome b) Meningitis c) Liver failure d) Kidney failure

Answer 14

Answer: a) Hyperinfection syndrome Explanation: Hyperinfection syndrome is a dangerous complication of Strongyloides stercoralis where there’s an accelerated multiplication of the parasite within the host often seen in those with weakened immune systems

Question 15

35. What is the best method for diagnosing Strongyloides stercoralis infection a) Stool examination for larvae b) Blood test c) Chest X-ray d) Skin biopsy

Answer 15

Answer: a) Stool examination for larvae Explanation: Diagnosis of Strongyloides stercoralis usually relies on finding rhabditiform or filariform larvae in a stool sample

Question 16

36. What is the primary drug of choice for treating Strongyloides stercoralis a) Mebendazole b) Albendazole c) Ivermectin d) Pyrantel pamoate

Answer 16

Answer: c) Ivermectin Explanation: While other medications might be used ivermectin is often the preferred drug for treating Strongyloides stercoralis infections

Question 17

37. Which of the following parasitic nematodes can cause significant pulmonary symptoms during their larval migration stage a) Ascaris lumbricoides b) Strongyloides stercoralis c) Hookworms d) All of the above

Answer 17

Answer: d) All of the above Explanation: The larval stages of Ascaris lumbricoides Strongyloides stercoralis and hookworms can migrate through the lungs leading to respiratory symptoms like cough and pneumonitis

Question 18

38. Which of these nematodes primarily infects children a) Ascaris lumbricoides b) Enterobius vermicularis c) Trichuris trichiura d) All of the above

Answer 18

Answer: d) All of the above Explanation: These nematode infections are commonly found in children often due to factors like hygiene practices and exposure in school or play environments

Question 19

39. Which of the following is a common symptom of many intestinal nematode infections a) Abdominal pain and discomfort b) Loss of appetite and weight loss c) Fatigue and weakness d) All of the above

Answer 19

Answer: d) All of the above Explanation: Intestinal nematode infections share many symptoms including abdominal discomfort appetite changes weight loss and general fatigue

Question 20

40. Improving sanitation and hygiene practices is a key strategy for preventing which nematode infections a) Ascaris lumbricoides b) Enterobius vermicularis c) Trichuris trichiura d) All of the above

Answer 20

Answer: d) All of the above Explanation: Proper sanitation and hygiene are essential for breaking the transmission cycles of these nematode infections by reducing contamination and exposure to infective stages

Question 21

1. Which of the following is NOT a characteristic feature of nematodes? a) Triploblastic b) Possess three body layers c) Bilaterally symmetrical d) Possess a true coelom

Answer 21

Answer: d) Possess a true coelom Explanation: Nematodes are pseudocoelomates meaning they have a body cavity that is not completely lined with mesoderm. This distinguishes them from true coelomates which have a body cavity fully lined with mesoderm.

Question 22

2. What is the common name for Ascaris lumbricoides? a) Pinworm b) Whipworm c) Hookworm d) Roundworm

Answer 22

Answer: d) Roundworm Explanation: Ascaris lumbricoides is commonly known as the roundworm due to its round body shape.

Question 23

3. Which of these statements about the morphology of Ascaris lumbricoides is INCORRECT? a) Adult females are generally larger than males. b) The male has a curved tail with a copulatory spicule. c) The worms are white in color. d) The head region has three lips with papillae.

Answer 23

Answer: c) The worms are white in color. Explanation: Ascaris lumbricoides are described as being “elastic and yellow to pink” in color not white.

Question 24

4. Ascaris lumbricoides exhibits a simple monoxenic life cycle. What does this mean? a) The parasite requires two hosts to complete its life cycle. b) The parasite requires only one host to complete its life cycle. c) The parasite can reproduce both sexually and asexually. d) The parasite has a complex life cycle with multiple larval stages.

Answer 24

Answer: b) The parasite requires only one host to complete its life cycle. Explanation: A monoxenic life cycle signifies that a parasite completes its entire life cycle within a single host species.

Question 25

5. How does a human typically get infected with Ascaris lumbricoides? a) By ingesting embryonated eggs from contaminated food water or soil. b) Through skin penetration by infective larvae. c) By inhaling airborne eggs. d) Through the bite of an infected mosquito.

Answer 25

Answer: a) By ingesting embryonated eggs from contaminated food water or soil. Explanation: Humans are infected by consuming embryonated Ascaris lumbricoides eggs which are typically found in contaminated sources like food water or soil.

Question 26

6. Which of the following is NOT a common symptom of ascariasis? a) Abdominal discomfort b) Loss of appetite c) Skin rash d) Cough and dyspnea

Answer 26

Answer: c) Skin rash Explanation: While abdominal discomfort appetite loss and respiratory issues (cough dyspnea) are common in ascariasis skin rashes are not characteristic of this infection.

Question 27

7. What is the primary diagnostic method for ascariasis? a) Blood test b) Stool examination for eggs c) Chest X-ray d) Sputum analysis

Answer 27

Answer: b) Stool examination for eggs Explanation: Diagnosing ascariasis primarily involves identifying Ascaris lumbricoides eggs in a patient’s stool sample.

Question 28

8. What is the drug of choice for treating ascariasis? a) Pyrantel pamoate b) Ivermectin c) Mebendazole d) Praziquantel

Answer 28

Answer: c) Mebendazole Explanation: Mebendazole is the preferred medication for treating ascariasis though other options like pyrantel pamoate can also be used.

Question 29

9. Enterobius vermicularis is commonly known as: a) Whipworm b) Hookworm c) Pinworm d) Threadworm

Answer 29

Answer: c) Pinworm Explanation: Enterobius vermicularis is commonly referred to as the pinworm or threadworm.

Question 30

10. Which of the following environments is most conducive to the spread of Enterobius vermicularis? a) Rural farms b) Crowded living conditions like boarding schools c) Tropical rainforests d) Areas with poor sanitation

Answer 30

Answer: b) Crowded living conditions like boarding schools Explanation: Pinworm infections are highly contagious and often spread in crowded environments particularly those with close contact and shared facilities.

The correct answer is b) Crowded living conditions like boarding schools.

Why:

Enterobius vermicularis (pinworm) is most commonly spread in environments where people are in close contact with each other, especially in settings where hygiene practices are not optimal. Crowded living conditions, such as boarding schools, are conducive to the spread of the parasite because:

Pinworm eggs are highly contagious and can spread quickly through contaminated hands, bedding, clothing, and shared surfaces in crowded environments.

Children are particularly susceptible because they tend to have close physical contact, may have poor hygiene habits, and may scratch the perianal area, spreading eggs.

While poor sanitation (option d) can also contribute to the spread of pinworms, crowded conditions are particularly significant in facilitating the transmission due to the high frequency of human-to-human contact.

Question 31

11. What is a unique characteristic of the life cycle of Enterobius vermicularis? a) The larvae migrate through the lungs. b) The females lay eggs in the perianal region. c) The eggs require a period of maturation in the soil. d) Infection occurs through skin penetration.

Answer 31

Answer: b) The females lay eggs in the perianal region. Explanation: The life cycle of Enterobius vermicularis notably involves gravid females migrating to the perianal region to deposit eggs.

Question 32

12. What symptom is MOST characteristic of pinworm infection? a) Abdominal pain b) Bloody diarrhea c) Perianal itching especially at night d) Weight loss

Answer 32

Answer: c) Perianal itching especially at night Explanation: The most distinctive symptom of a pinworm infection is intense itching around the anus primarily during the nighttime hours.

Question 33

13. What diagnostic method is used to detect pinworm infection? a) Stool examination b) Blood test c) Cellophane tape test d) Urine analysis

Answer 33

Answer: c) Cellophane tape test Explanation: The cellophane tape test is the most effective method for diagnosing pinworm infection as it involves applying tape to the perianal region to collect eggs.

Question 34

14. What is the recommended treatment for pinworm infection? a) Mebendazole b) Albendazole c) Ivermectin d) Both a and b

Answer 34

Answer: d) Both a and b Explanation: Mebendazole and albendazole are both effective medications for treating pinworm infections.

Question 35

15. What does the name Trichuris trichiura refer to? a) The worm’s whip-like shape b) The location of the worm in the host’s body c) The worm’s mode of transmission d) The severity of the infection

Answer 35

Answer: a) The worm’s whip-like shape Explanation: Trichuris trichiura commonly called whipworm derives its name from the worm’s resemblance to a whip. The thinner anterior end represents the “lash” and the thicker posterior the “handle.”

Question 36

16. Which group of people is MOST commonly infected with Trichuris trichiura? a) Children in developed countries b) Adults living in urban areas c) Individuals in the tropics with poor sanitary habits d) People who consume undercooked pork

Answer 36

Answer: c) Individuals in the tropics with poor sanitary habits Explanation: Trichuris trichiura is more prevalent in tropical regions where sanitation is inadequate.

Question 37

17. Trichuris trichiura eggs are characterized by their: a) Round shape with a thick shell b) Oval shape with a thin shell c) Barrel shape with terminal plugs d) Elongated shape with a pointed end

Answer 37

Answer: c) Barrel shape with terminal plugs Explanation: The eggs of Trichuris trichiura are distinctive for their barrel-like shape with prominent plugs at both ends.

Question 38

18. Where do adult Trichuris trichiura worms typically reside in the human host? a) Small intestine b) Large intestine (cecum and colon) c) Liver d) Lungs

Answer 38

Answer: b) Large intestine (cecum and colon) Explanation: Adult Trichuris trichiura worms primarily inhabit the cecum and colon sections of the large intestine.

Question 39

19. What is the primary mode of transmission for Trichuris trichiura? a) Ingestion of contaminated food or water b) Skin penetration by infective larvae c) Inhalation of airborne eggs d) Direct contact with an infected individual

Answer 39

Answer: a) Ingestion of contaminated food or water Explanation: Infection with Trichuris trichiura occurs through the consumption of food or water contaminated with embryonated eggs.

Question 40

20. Which of the following is a potential complication of a heavy Trichuris trichiura infection? a) Rectal prolapse b) Anemia c) Growth retardation in children d) All of the above

Answer 40

Answer: d) All of the above Explanation: Severe Trichuris trichiura infections can lead to complications including rectal prolapse anemia and stunted growth in children.