Parasitology MCQS Set 2
26. Common tapeworm of dogs is:
A. Taenia solium B. Echinococcus granulosus C. Dipylidium caninum D. Hymenolepis nana
Correct Answer: C. Dipylidium caninum
Explanation: Also known as the “cucumber seed tapeworm,” Dipylidium caninum is the most common cestode of dogs and cats. It is transmitted when the animal ingests fleas containing the larval stage (cysticercoid).
27. Hydatid cyst is formed by:
A. Taenia saginata B. Echinococcus granulosus C. Dipylidium D. Mesocestoides
Correct Answer: B. Echinococcus granulosus
Explanation: Echinococcus granulosus (the Hydatid tapeworm) has a tiny adult stage in dogs, but in the intermediate host (sheep, cattle, humans), it forms a massive Hydatid cyst, often in the liver or lungs.
28. Head of cestode is called:
A. Rostellum B. Proglottid C. Scolex D. Strobila
Correct Answer: C. Scolex
Explanation: The Scolex is the attachment organ (head) of a tapeworm, usually equipped with suckers or hooks. The proglottids are the segments, and the entire chain of segments is the strobila.
29. Six-hooked larva of cestode is called:
A. Cysticercus B. Hydatid C. Hexacanth D. Plerocercoid
Correct Answer: C. Hexacanth
Explanation: The Hexacanth (or oncosphere) is the larval stage found within the tapeworm egg. It is characterized by having three pairs of hooks (six total) used to penetrate the gut wall of the intermediate host.
30. Haemonchus contortus is also called:
A. Lung worm B. Wire worm C. Pin worm D. Thread worm
Correct Answer: B. Wire worm
Explanation: Haemonchus contortus is famously known as the “Barber’s pole worm” or Wire worm. It is a blood-sucking nematode in the abomasum of ruminants, causing severe anemia.
31. Dictyocaulus filaria is found in:
A. Intestine B. Liver C. Bronchi D. Heart
Correct Answer: C. Bronchi
Explanation: Dictyocaulus filaria is the primary lungworm of sheep and goats. Adult worms reside in the bronchi and bronchioles, causing parasitic bronchitis or “husk.”
32. Heart worm of dog is:
A. Dipetalonema B. Strongyloides C. Dirofilaria immitis D. Toxocara
Correct Answer: C. Dirofilaria immitis
Explanation: Dirofilaria immitis is transmitted by mosquitoes. The adult worms live in the right ventricle of the heart and the pulmonary arteries, leading to heart failure.
33. Red mite of poultry is:
A. Sarcoptes B. Dermanyssus gallinae C. Psoroptes D. Otodectes
Correct Answer: B. Dermanyssus gallinae
Explanation: Dermanyssus gallinae is the “Red Mite.” Unlike many mites, it lives in the environment (cracks in the poultry house) and crawls onto birds at night to suck blood.
34. Tongue worm is:
A. Linguatula serrata B. Oestrus ovis C. Hypoderma D. Gastrophilus
Correct Answer: A. Linguatula serrata
Explanation: Linguatula serrata is a pentastomid parasite. Although it looks like a worm, it is phylogenetically related to arthropods. It lives in the nasal passages and sinuses of dogs and other carnivores.
35. Myiasis means:
A. Tick infestation B. Lice infestation C. Infestation with fly larvae D. Mite infestation
Correct Answer: C. Infestation with fly larvae
Explanation: Myiasis is the parasitic infestation of the body of a live mammal by fly larvae (maggots) that grow inside the host while feeding on its tissue.
36. “Blow” refers to:
A. Larval development B. Egg laying by flies C. Adult emergence D. Tissue destruction
Correct Answer: B. Egg laying by flies
Explanation: In entomology, the act of a fly depositing its eggs (or larvae) on a host or organic matter is called blowing.
37. Lucilia is known as:
A. Blue bottle fly B. Green bottle fly C. Flesh fly D. Screw worm
Correct Answer: B. Green bottle fly
Explanation: Lucilia species are the primary Green bottle flies. They are significant causes of “strike” or cutaneous myiasis in sheep.
38. Oestrus ovis causes:
A. Cutaneous myiasis B. Somatic myiasis C. Nasal myiasis D. Intestinal myiasis
Correct Answer: C. Nasal myiasis
Explanation: The sheep nasal bot fly, Oestrus ovis, deposits larvae directly into the nostrils of sheep. The larvae then migrate into the nasal sinuses.
39. Cochliomyia macellaris (hominivorax) causes:
A. Nasal myiasis B. Screw worm myiasis C. Somatic myiasis D. Furuncular myiasis
Correct Answer: B. Screw worm myiasis
Explanation: Cochliomyia hominivorax is the primary Screwworm fly. It is highly dangerous because it lays eggs in fresh wounds, and the larvae feed on living healthy tissue.
40. Babesia is classified as a:
A. Intestinal protozoa B. Haemoprotozoan parasite C. Tissue protozoa D. Flagellate protozoa
Correct Answer: B. Haemoprotozoan parasite
Explanation: Because Babesia lives and multiplies within the blood (haemo) cells, it is categorized as a haemoprotozoan.
41. Babesia parasites multiply mainly inside:
A. Hepatocytes B. Endothelial cells C. Erythrocytes D. Lymphocytes
Correct Answer: C. Erythrocytes
Explanation: Babesia undergoes asexual reproduction (merogony) specifically inside erythrocytes (red blood cells).
42. Which tick was first reported to transmit Babesia bigemina?
A. Rhipicephalus sanguineus B. Ixodes ricinus C. Boophilus (Rhipicephalus) annulatus D. Dermacentor reticularis
Correct Answer: C. Boophilus annulatus
Explanation: This was the landmark discovery by Smith and Kilborne, proving for the first time that an arthropod could transmit a protozoan disease.
43. Theileria was named in honor of:
A. Babes B. Koch C. Arnold Theiler D. Smith
Correct Answer: C. Arnold Theiler
Explanation: The genus was named after Sir Arnold Theiler, a Swiss-South African veterinary bacteriologist who contributed extensively to the study of African livestock diseases.
44. Which Theileria species causes East Coast fever?
A. T. annulata B. T. equi C. T. parva D. T. bovis
Correct Answer: C. T. parva
Explanation: Theileria parva is the agent of East Coast Fever, a devastating disease of cattle in East and Central Africa.
45. The vector of Theileria parva is:
A. Ixodes ricinus B. Rhipicephalus appendiculatus C. Boophilus microplus D. Argas persicus
Correct Answer: B. Rhipicephalus appendiculatus
Explanation: The “Brown Ear Tick,” Rhipicephalus appendiculatus, is the primary biological vector of T. parva.
46. Coccidiosis in cattle is commonly caused by:
A. Eimeria tenella B. Eimeria bovis C. Isospora canis D. Toxoplasma gondii
Correct Answer: B. Eimeria bovis
Explanation: Eimeria bovis and Eimeria zuernii are the most pathogenic species causing intestinal coccidiosis in cattle.
47. Eimeria species have how many sporocysts?
A. 2 B. 4 C. 6 D. 8
Correct Answer: B. 4
Explanation: A sporulated oocyst of the genus Eimeria contains 4 sporocysts. This is a key diagnostic feature used to distinguish it from the genus Isospora.
48. Each sporocyst of Eimeria contains:
A. 1 sporozoite B. 2 sporozoites C. 4 sporozoites D. 8 sporozoites
Correct Answer: B. 2 sporozoites
Explanation: Following the “4×2” rule, each of the 4 sporocysts contains 2 sporozoites, totaling 8 sporozoites per oocyst.
49. Toxoplasma gondii primarily affects which organs?
A. Kidney and pancreas B. Brain, heart, liver, lung, spleen C. Skin and intestine D. Blood only
Correct Answer: B. Brain, heart, liver, lung, spleen
Explanation: Toxoplasma gondii is a multi-systemic parasite. In the intermediate host (including humans), it forms tissue cysts in high-metabolic organs like the brain, heart, and liver.
50. Definitive host of Toxoplasma gondii is:
A. Dog B. Human C. Cat D. Sheep
Correct Answer: C. Cat
Explanation: Members of the Felidae (cat) family are the only definitive hosts. They are the only animals in which the parasite undergoes sexual reproduction and sheds oocysts in the feces.