Nematodes Multiple Choice Question & Answers

Question 1. What is the most common clinical manifestation when larvae of Ascaris, hookworm, and Strogyloides migrates through the body?

1. Asymptomatic
2. Pneumonitis
3. Acute dermal reaction
4. Anemia

Answer. (1) (Asymptomatic)

Most infected individuals with Ascaris, hookworm, and Strogyloides are asymptomatic.

Read And Learn More: Micro Biology And Immunology Multiple Choice Question And Answers

Question 2. Autoinfection not seen in:

1. Ascaris
2. Hymenolepis
3. Tenia solium
4. Enterobius

Answer. (1) (Ascaris)

• Autoinfection is seen by: CHEST (Cryptosporidium parvum, Hymenolepis nana,
• Enterobius vermicularis, Strongyloides stercoralis and Taenia solium)

Question 3. All the following parasites enter the human body by penetrating the skin except:

1. Ancylostoma duodenale
2. Necator americanus
3. Strongyloides stercoralis
4. Trichinella spiralis

Answer. (4) (Trichinella spiralis)

Trichinella spiralis is transmitted by consumption of contaminated pig’s meat containing L1 stage larvae.

Question  4. Small intestine helminths are:

1. Ascaris
2. Necator
3. Trichuris
4. Enterobius
5. Ancyclostoma

Answer. (1, 2, 5) (Ascaris, Necator, Ancylostoma)

Question  5. Autoinfection is seen with:

1. Cryptosporidium
2. Strongyloides
3. Giardia
4. Gnathostoma

Answer. (2) (Strongyloides)

Question  6. Microcytic hypochromic anemia found in infestation of:

1. Ancylostoma
2. Ascaris
3. Necator
4. Diphyllobothrium

Answer. (1, 3) (Ancylostoma, Necator)

7. Which of the following is viviparous?

1. Strongyloidis stercoralis
2. Trichinella spiralis
3. Enterobius
4. Ascaris

Answer. (2) (Trichinela spiralis)

• Viviparous: Worms that lay Larva directly, without egg formation, e.g. Filarial worms, Trichinella, and Dracunculus

Question 8. Patient with a history of Kidney transplantation presenting with diarrhea (video of worms given). The motility of the worms is given in the figure. The correct statement about the organism is:

1. Monoecious and the organism is related with parthenogenesis.
2. Transmitted by intake of contaminated food and water
3. Loffler’s pneumonia is caused by the same organism.
4. Body gets this infection through filariform larvae

Answer. (4) (The body gets this infection through filariform larvae)

• Larva in stool specimen of a transplant patient with diarrhea-suggestive of the larva of Strongyloides
• Strongyloides is dioecious, but exhibit parthenogenesis.
• Transmitted by skin penetration through filariform larvae, not by intake of contaminated food and water
• Loffler’s pneumonia is caused by Ascaris

Question  9. Larva in stool can be seen in?

1. Echinococcus granulosus
2. Ancylostoma duodenale
3. Ascaris lumbricoides
4. Strongyloides stercoralis
5. Trichinella spiralis

Answer. (2, 4) (Ancylostoma duodenale, Strongyloides stercoralis)

• Detection of rhabditiform larvae is the method of diagnosis for Strongyloidiasis.
• In hookworm infection, though eggs are in diagnostic form, in a stool sample that is not fresh, the eggs may hatch out to release rhabditiform larvae.

Question  10. The patient had bronchopneumonia and gastroenteritis stool examination showed motile larvae diagnosis is:

1. Ascaris
2. Enterobius
3. Strongyloides
4. Trichinella

Answer. (3) (Strongyloides) Ref: Apurba Sastry’s Essentials of Medical Parasitology 1/e p241,2/e p191

Question  11. Swollen belly syndrome is caused by:

1. Ascaris lumbricoid
2. Strongyloides fuelleborni
3. Strongyloides stercoralis
4. Wuchereria bancrofti

Answer. (2) (Strongyloides fuelleborni)

• Swollen belly syndrome
• It is caused by Strongyloides fuelleborni.
• It is a serious life-threatening condition characterized by diarrhea, respiratory distress, and protein-losing enteropathy that leads to hypoalbuminemia and edema
• It is seen commonly in infants of Western Papua and New Guinea
• It is diagnosed by detecting the eggs but not larvae in the stool (different from S.stercoralis).

Question  12. A 40-year HIV-positive male patient comes with odynophagia and watery diarrhea endoscopy reveals esophageal and gastric candidiasis. A wet mount of the stool of the patient reveals the following picture: What is true about this helminth?

• Filariform larvae is infective for humans were. as shown in the diagram
• Usually transmitted through contaminated food and water
• Females of these species show parthenogenesis
• The drug of choice is Triclabendazole

Answer. (3) (Females of these species show parthenogenesis)

• The stool mount above is showing severe infestation with Strongyloides Rhabditiform Larvae.
• The infective stage is Filariform larvae only.
• It is usually transmitted through the skin (skin penetration)
• In the human intestine, male Strongyloides do not exist, only females exist who reproduce asexually by parthenogenesis.
• The drug of choice for strongyloidiasis is Ivermectin.

Question  13. Larvae which pass through lung during its life cycle:

1. Strongyloides stercoralis
2. Ascaris lumbricoides
3. Necator
4. Trichuris trichiura
5. Wuchereria bancrofti microfilarae

Answer. (1, 2, 3, 5) (Strongyloides stercoralis, Ascaris lumbricoides, Necator, Wuchereria bancrofti microfilarae)

• Pulmonary migration is seen in the life cycle of:
• Ascaris: Causes Loffler’s pneumonia
• Hookworm: Causes mild pneumonitis
• Strongyloides: Causes mild pneumonitis
• Wuchereria bancrofti microfilariae: Cause Tropical pulmonary eosinophilia

Question  14. Ova in stool is not of diagnostic significance in:

1. Strongyloides
2. Entrobius
3. Ankylostoma
4. Trichuris

Answer. (1) (Strongyloides)

• Strongyloides is ovoviviparous, hence the eggs hatch out immediately to produce rhabditiform larva which is the diagnostic form found in stool.

Question  15. The cause of larva currens:

1. Strongyloides stercoralis
2. Necator americanus
3. Ankylostoma duodonale
4. H. nana

Answer. (1) (Strongyloides stercoralis)

• Strongyloides larva produces a condition in an individual who has been already sensitized called larva currens.
• This is caused by external auto-infection and local allergic reactions to the larvae penetrating skin.
• Migrating filariform larva moves rapidly in a short line at the rate of 3-4 cm in an hour, hence is termed as larva currens.

Question  16. Identify the organism from its egg in the picture.

1. Enterobius vermicularis
2. Trichuris trichiura
3. Ascaris lumbricoides
4. Necator americanus

Answer. (4) (Necator americanus)

• Non-bile stained oval eggs containing segmented ovum with four blastomeres- suggestive of Hookworm (Ancylostoma and Necator).

Question  17. Parasites not transmitted through soil:

1. Whipworm
2. Hookworm
3. Tapeworm
4. Roundworm

Answer. (3) (Tapeworm)

• Soil-transmitted helminths include Ascaris (roundworm), Trichuris (whipworm), hookworm

Question  18. Chandler’s index is used for:

1. Guinea worm
2. Pinworm
3. Hookworm
4. Roundworm

Answer. (3) (Hookworm)

Chandler’s index is used in the epidemiological studies of hookworm disease to estimate the morbidity and mortality in the community due to hookworm infection (which depends much upon the worm load).

Question  19. The average blood loss in Ancylostomiasis per worm is:

1. 0.2 ml/day
2. 2 ml/day
3. 0.33 ml/day
4. 1 ml/day

Answer. (1) (0.2 ml/day)

Question  20. Chandler’s index:

1. No. of hookworm eggs/gm of stool
2. No. of hookworm larva/gm of stool
3. No. of E.coli in a water sample
4. No. of failure of contraception for 100 women years exposure

Answer. (1) (No. of hookworm eggs/gm…)

Question  21. Parasites penetrating through the skin for entry into the body are:

1. Ancylostoma duodenale
2. Stronglyoides
3. Roundworm
4. Trichuris trichura

Answer. (1, 2) (Ancy…, Strong…)

• Parasites enter through penetration of skin:
• From Soil-Hookworm, Strongyloides
• From Water-Acanthamoeba, Schistosoma spp.

Question  22. Chandler’s index. All are true except:

1. It is average no of hookworm eggs per gram of feces for the entire community
2. < 200 eggs/gm indicates hookworm infection is of not much significance
3. > 300 indicate hookworm infection is an important public health problem
4. Can be used for monitoring treatment response

Answer. (4) (Can be used for monitoring treatment response)

• Chandler’s index is an endemicity marker of hookworm infection in the community, it is not a prognostic marker and, hence cannot be used for monitoring treatment response.

Question  23. A child with 3 years of age presents with weakness with Hb level <5 g/dL. A history of blood loss in stool was present. What would be the causative organism?

1. Hookworm
2. Roundworm
3. Whipworm
4. Pinworm

Answer. (1) (Hookworm)

• Among the given options, Hookworms cause chronic intestinal blood loss that results in iron deficiency anemiBlood loss may also be seen following whipworm infection but NOT severe.

Question  24. The nematode that resides in the cecum and appendix is?

1. Ascaris lumbricoides
2. Mansonellaozzardi
3. Enterobius vermicularis
4. All of these

Answer. (3) (Enterobius vermicularis)

• Ascaris lumbricoides: Resides in small intestine
• Mansonella ozzardi: Resides in the serous cavity
• Enterobius vermicularis: Resides in large intestine.

Question 25. Eggs of which of the following parasites cause intense pruritus in perianal skin:

1. Ascaris
2. Hookworm
3. Enterobius vermicularis
4. Trichuris

Answer. (3) (Enterobius vermicularis)

Question 26. Which of the following has barrel-shaped eggs?

1. E. vermicularis
2. Ascaris lumbricoides duodenale
3. N. americanus
4. Trichuris trichiura

Answer. (5) (Trichuris trichiura)

• Barrel-shaped eggs with mucus plug at the end are suggestive of Trichuris trichiura eggs.
• Note: Capillaria philippinensis also possesses eggs similar to Trichuris.

Question 27. The following are images of an intestinal nematode. Which of these are true about it?

1. Filariform larvae is infective for humAnswer. as shown in the diagram
2. Transmitted usually through contaminated food and water
3. Females of these species show parthenogenesis
4. Triclabendazole is the drug of choice

Answer. (2) (Transmitted usually through contaminated food and water )

• This is a picture of adult male and female worms of Trichuris.
• Trichuris is transmitted by the consumption of food and water contaminated with eggs.
• Mebendazole or albendazole is safe and moderately effective for the treatment of trichuriasis.

Question 28. Which is the mode of transmission and infective form of the parasite whose egg picture is given below?

1. Ingestion of uncooked/raw beef
2. Ingestion of egg contaminated in water
3. Penetration by the filariform larva
4. Penetration by rhabditiform larva

Answer. (2) (Ingestion of egg contaminated in water)

This is the egg of Trichuris trichiurIt spreads by ingestion of egg contaminated in water.

Question 29. Unsegmented eggs are seen in which parasite:

1. Trichuris trichura
2. Necator americanus
3. Ancylostoma
4. Dracunculus

Answer. (1) (Trichuris…)

• Trichuris trichura has unsegmented, barrel-shaped eggs with mucus plugs at the ends.
• Eggs of Hookworm (Necator americanus and Ancylostoma) are segmented and oval.
• Dracunculus does not have an egg stage.

Question  30. Chronic dysentery, abdominal pain, and rectal prolapse in children is caused by:

1. Trichuris
2. Ascariasis
3. Enterobius
4. Trichinella

Answer. (1) (Trichuris)

• Clinical features of Trichuriasis:
• Heavy infections may result in abdominal pain, anorexia, and bloody or mucoid diarrhea resembling inflammatory bowel disease.
• Rectal prolapse can result from massive infections with Trichuris in children, who often suffer from malnourishment and other diarrheal illnesses.
• Moderately heavy Trichuris burdens also contribute to growth retardation.

Question 31. Specific diagnosis of Ascaris is made by:

1. Adult worm in stool
2. Egg detection
3. Antigen detection
4. Antibody detection
5. Skin test

Answer. (1, 2, 4) (Adult worm in stool, Egg detection, and Antibody detection)

• Laboratory diagnosis of Ascariasis
• Parasitic diagnosis:
• Demonstration of characteristic Ascaris eggs in the stool: Eggs are passed in large numbers.
• The concentration of stool by Salt floatation and Formalin-ether method- light infections
• Demonstration of egg in bile (duodenal intubation)
• Demonstration of adult worm in stool/vomitus- after treatment with antihelminthics.
• Demonstration of larvae in gastric aspirate, sputum, or bronchial aspirates – pulmonary infections
• Serodiagnosis- In case extraintestinal Ascarisis
• Antibody detection by
• Microprecipitation on the larvae
• Indirect hemagglutination test
• Immunofluorescent antibody test.

Question 32. Ascaris causes:

1. Bile duct obstruction
2. Intestinal obstruction
3. Appendicitis
4. All of the above

Answer. (4) (All of the above)

Features of Ascariasis

• Lung phase of larval migration: Causes eosinophilic pneumonitis (Löffler’s syndrome) and fever
• Intestinal phase: In heavy infections, particularly in children:
• A large bolus of entangled worms can cause pain and small bowel obstruction, sometimes complicated by perforation, intussusception, or volvulus.
• A large worm can enter and occlude the biliary tree, causing biliary colic, cholecystitis, cholangitis, pancreatitis, or (rarely) intrahepatic abscesses.
• In highly endemic areas, intestinal and biliary ascariasis can induce acute appendicitis and gallstones as causes of surgical acute abdomen.

Question 33. The image depicted below belongs to which of the following?

1. Brugia malayi
2. Wuchereria bancrofti
3. Loa loa
4. Onchocerca

Answer. (1) (Brugia malayi)

Question 34. Lymphatic filariasis is caused by?

1. Loa Joa
2. Wuchreria bancrofti
3. Brugia malayi
4. Brugia timori
5. Onchocerca volvulus

Answer. (2, 3, 4) (Wuchreria bancrofti, Brugia malayi, Brugia timori)

Lymphatic filariasis is caused by Wuchreria bancrofti, Brugia malayi, Brugia timori

Question 35. Lymphatic obstruction occurs with which worm?

1. Filarial worm
2. Hookworm
3. Pinworm

Answer. (1) (Filarial worm)

Question 36. Wuchereria bancrofti all are true except:

1. DEC provocation test is used to demonstrate microfilaria during the day
2. Two nuclei in the tail region
3. Microfilaria is a major diagnostic form

Answer. (2) (Two nuclei in the tail region)

• The tail tip of the microfilaria of Brugiya malayi is blunt and has two nuclei; whereas the tail tip of Wuchereria bancrofti is pointed without nuclei.
• Microfilaria is the diagnostic form for lymphatic filariasis, but not for occult filariasis.
• DEC provocation test is used to demonstrate microfilaria during the day- microfilaria comes to peripheral blood within 30 minutes of DEC intake.

Question 37. Which does not cause lymphatic filariasis?

1. Loa loa
2. Wuchereria bancrofti
3. Brugia malai
4. Brugia timori

Answer. (1) (Loa loa)

Agents of lymphatic filariasis: Wuchereria bancrofti, Brugia malai and Brugia timori

Question 38. Which of the following diseases is transmitted by all of these mosquitoes like Anopheles,

1. Aedes and Culex?
2. Japanese Encephalitis
3. Malaria
4. Filariasis
5. Yellow Fever

Answer. (3) (Filariasis)

• Wuchereria bancrofti: Transmitted by
• Nocturnal strains-Culex, Anopheles (mosquitoes),
• Subperiodic strains-Aedes (mosquitoes)
• Japanese Encephalitis: Transmitted by Culex tritaeniorhynchus
• Malaria: Transmitted by Female Anopheles mosquito
• Yellow Fever: Transmitted by Aedes.

Question 39. Which among the following does not affect eyes?

1. Onchocerca volvulus
2. Trypanosoma
3. Loa loa
4. Trichuris

Answer. (4) (Trichuris)

• Onchocerca volvulus – Causes River blindness, Punctate keratitis and Sclerosing keratitis
• Trypanosoma cruzi- Romana’s sign (periorbital edema)
• Loa loa: Causes Calabar swelling.

Question 40. Life cycle of Wuchereria bancrofti in the mosquito is described as:

1. Cyclopropanation
2. Cyclodevelopmental
3. Propagative
4. None

Answer. (2) Cyclodevelopmental)

• Propagative transmission- the multiply extensively without change of form, e.g. Arboviruses,
• Cyclopropagative transmission: The Pathogen undergoes a developmental cycle (changes from one stage to another) as well as multiplication in the body of the arthropod, e.g. Malaria
• Cyclodevelopmental transmission: The pathogen undergoes developmental changes from one stage to another, but does not multiply, e.g. Filaria.

Question 41. Sheathed microfilaria is/are:

1. W. bancrofti
2. Loa loa
3. M. perstans
4. M. malayi

Answer. (1, 2) (W. bancrofti and Loa loa)

• Sheathed microfilaria is covered by a hyaline sheath, in which larva moves backward and forwards within the sheath, e.g. Wuchereria, Brugia and Loa loa

Question 42. In which stage of filariasis is microfilaria seen in peripheral blood?

• Tropical eosinophilia
• Early adenolymphangitis stage
• Late adenolymphangitis stage
• Elephantiasis

Answer. (2) (Early adeadenolymphangitis stage)

• Microfilaria is also demonstrated in peripheral blood in the early stages of filariasis:
• Acute filariasis (lymphangitis, lymphadenitis)
• Asymptomatic stage
• Microfilariae are not found in the peripheral blood:
• Occult filariasis such as tropical pulmonary eosinophilia
• Chronic filariasis (Elephantiasis)
• Wrong time collection

Question 43. Kallu a 30-year-old man, presented with subcutaneous itchy nodules over the left iliac crest. On examination, they are firm, nontender, and mobile. Skin scrapping contains microfilaria and adult worms of:

1. Loa loa
2. Onchocerca volvulus
3. Brugia malayi
4. Mansonella perstans

Answer. (2) (Onchocerca volvulus)

• Clue for diagnosis
• Subcutaneous firm, nontender, and mobile, itchy nodules over the left iliac crest.
• Skin scrapping contains microfilaria and adult worms

Question 44. Calabar swelling is produced by:

1. Onchocerca volvulus
2. Loa loa
3. Burgia malayi
4. Wuchereria bancrofti

Answer. (2) (Loa loa)

• Calabar Swelling: Localized angioedema and erythema usually on the extremities, characterized by fugitive, swollen lumps of subcutaneous tissue caused by a parasitic filarial worm (Loa loa) endemic to Central and West Africa.
• The swollen areas migrate with the worm through the body at a speed of about 1 cm per minute and may become as large as a small egg.

Question 45. Mayer Kouwenaar syndrome is a synonym for:

1. Tropical pulmonary eosinophilia
2. Occult filariasis
3. Cutaneous Larva migrans
4. Visceral Larva migrans

Answer. (1) (Tropical pulmonary eosinophilia )

• Occult filariasis: Also called as Weingarten’s Syndrome.
• Tropical Pulmonary Eosinophilia- Also called as Meyers- Kouwenaar Syndrome.

Question 46. Which of the following parasites causes myocarditis?

1. Trichenella spiral
2. Trichuris trichura
3. Ancyclostoma duodenale
4. Tienea solium

Answer. (1) (Trichenella spiralis)

Myocarditis with tachyarrhythmias or heart failure—and, less commonly, encephalitis or pneumonitis—may develop and accounts for most deaths of patients with trichinellosis.

Question 47. Dragon or serpent worm is:

1. Enterobius
2. Trichuris
3. Dracunculus
4. T. solium

Answer. (3) (Dracunculus)

Dracunculus medinensis also called as:

• Guinea worm
• Serpent worm
• Dragon worm
• Medina worm.

Question 48. All of the following regarding dracunculiasis are true except:

1. Eliminated from India
2. Niridazole prevents the transmission of disease
3. Limited to tropics and subtropical region
4. No animal reservoir

Answer. (2) (Niridazole prevents transmission of disease)

• No drug is effective in treating dracunculiasis. Gradual extraction of the worm by winding of a few centimeters on a stick each day remains the common and effective practice. Worms may be excised surgically.
• Dracunculiasis is restricted to the tropics of Africa
• Eliminated from India since 2000 (Last case was seen in July 996)
• No animal reservoir is there for dracunculiasis.

Question 49. Guinea worm was declared eradicated from India in:

1. 1999
2. 2000
3. 2001
4. 2002

Answer. (2) (2000)

• Guinea worm was declared eradicated from India in- 2000
• Last case was detected in India- 1999

Question 50. Cutaneous larva big answer. is caused the following species of hookworm except:

1. Ancylostoma duodenale
2. Ancylostoma caninum
3. Ancylostoma ceylanicum
4. Ancylostoma braziliense

Answer. (1) (Ancylostoma duodenale)

• Cutaneous larva migranswer. is caused by non-human species of Ancylostoma such as
• A.caninum, A.ceylanicum, and A.braziliense.

Question 51. Most common cause of visceral larva migrans:

1. Ancylostoma
2. Visceral leishmaniasis
3. St. stercoralis
4. Toxocara canis

Answer. (4) (Toxocara canis)

Toxocara canis and Toxocara cats are the commonest cause of Visceral larva big answer.

Question 52. Rat lungworm is:

1. Angiostrongylus cantonensis
2. Ascaris suum
3. Ancylostoma caninum
4. Toxocara canis

Answer. (1) (A.cantonensis)

Angiostrongylus cantonensis is known as rat lung worm, rarely infects man; causes eosinophilic meningitis.

Question 53. Parasite causes arthritis include all except:

1. Wuchereria bancrofti
2. Trichuris trichiura
3. Dracunculus
4. Echinococcus

Answer. (2) (Trichuris…)

Trichuris trichiura does not cause arthritis.

Question 54. Protozoa associated with megaesophagus:

1. Trypanosoma
2. Ameba
3. Giardia
4. Gnathostoma

Answer. (4) (Gnathostoma)

Gnathostoma has a mega esophagus, surrounded by four salivary glands.

Question 55. Eggs of all the following helminthic worms float in a saturated salt solution except:

1. Eggs of Necator americans
2. Eggs of Enterobius vermicularis
3. Eggs of Hymenolepis nana
4. Eggs of Taenia solium

Answer. (4) (Eggs of Taenia solium)

• Eggs of all the following helminthic worms float in a saturated salt solution
• ULTO- Unfertilized eggs of Ascaris, Larva of Strongyloides, Taenia eggs and Operculated eggs of trematodes.