Parasitology MCQs Set 4
76. Rickettsia is best described as:
A. Free-living protozoa B. Intracellular haemoparasite C. Helminth D. Arthropod
Correct Answer: B. Intracellular haemoparasite
Explanation: Rickettsia are specialized bacteria that are obligate intracellular pathogens. In veterinary medicine, they are often grouped with haemoparasites because they infect blood cells or vascular endothelial cells and are transmitted by arthropod vectors.
77. Plasmodium infects which cells in mammals?
A. Platelets B. Erythrocytes and endothelial cells C. Neurons D. Lymphocytes
Correct Answer: B. Erythrocytes and endothelial cells
Explanation: The malaria parasite (Plasmodium) undergoes an initial phase in the liver (exo-erythrocytic) and a subsequent phase in the erythrocytes (red blood cells). Certain species also affect the vascular endothelial cells, leading to cerebral malaria.
78. Vector of Plasmodium in mammals is:
A. Culex B. Aedes C. Anopheles D. Mansonia
Correct Answer: C. Anopheles
Explanation: Mammalian malaria is transmitted exclusively by the female Anopheles mosquito. The sexual phase of the parasite’s life cycle occurs within the mosquito’s gut.
79. Plasmodium in birds is transmitted by:
A. Anopheles B. Culex C. Sand fly D. Tick
Correct Answer: B. Culex
Explanation: Unlike mammalian malaria, avian malaria is primarily transmitted by mosquitoes of the genus Culex. This is a key distinction in veterinary entomology.
80. Isospora contains how many sporocysts?
A. 1 B. 2 C. 4 D. 8
Correct Answer: B. 2
Explanation: The genus Isospora is characterized by a sporulated oocyst containing 2 sporocysts. This is used to distinguish it from Eimeria, which contains four.
81. Each sporocyst of Isospora contains:
A. 2 sporozoites B. 4 sporozoites C. 8 sporozoites D. 16 sporozoites
Correct Answer: B. 4 sporozoites
Explanation: Following the “2×4” rule, an Isospora oocyst has 2 sporocysts, each containing 4 sporozoites, for a total of 8 sporozoites per oocyst.
82. Tuzzeria differs from Eimeria by having:
A. Sporocysts B. Free sporozoites C. Cysts D. Schizonts
Correct Answer: B. Free sporozoites
Explanation: In the genus Tuzzeria, the oocyst contains 8 free sporozoites that are not enclosed within sporocysts, unlike Eimeria where they are paired inside four sporocysts.
83. Eimeria tenella primarily affects:
A. Duodenum B. Ileum C. Caecum D. Colon
Correct Answer: C. Caecum
Explanation: Eimeria tenella is the most pathogenic coccidium of chickens, causing severe “caecal coccidiosis” characterized by bloody droppings and high mortality.
84. Eimeria acervulina affects the:
A. Caecum B. Duodenum C. Ileum D. Colon
Correct Answer: B. Duodenum
Explanation: E. acervulina typically infects the upper small intestine (duodenum), producing characteristic white transverse patches or “ladder-like” lesions on the mucosa.
85. Eimeria brunetti infects:
A. Upper small intestine B. Medium small intestine C. Ileum D. Caecum
Correct Answer: C. Ileum
Explanation: E. brunetti is known for causing lesions in the lower small intestine, specifically the ileum, and the neck of the caeca.
86. Eimeria necatrix mainly affects:
A. Duodenum B. Medium portion of small intestine C. Ileum D. Caecum
Correct Answer: B. Medium portion of small intestine
Explanation: E. necatrix is highly pathogenic and primarily targets the mid-portion of the small intestine. Interestingly, its final stage of development (oocyst production) occurs in the caeca.
87. Larval stage of cestodes is collectively called:
A. Miracidium B. Metacestodes C. Cercaria D. Sporocyst
Correct Answer: B. Metacestodes
Explanation: The various larval forms of tapeworms (such as cysticercus, coenurus, and hydatid) are collectively referred to as metacestodes.
88. First larval stage of cestode in arthropods is:
A. Plerocercoid B. Cysticercoid C. Procercoid D. Hydatid
Correct Answer: C. Procercoid
Explanation: In tapeworms with indirect life cycles involving aquatic hosts (like Diphyllobothrium), the procercoid is the first larval stage that develops within the first intermediate host, usually a crustacean (copepod).
89. Coenurus is the larval form of:
A. Echinococcus B. Taenia multiceps C. Dipylidium D. Hymenolepis
Correct Answer: B. Taenia multiceps
Explanation: Taenia multiceps produces a Coenurus cyst (specifically Coenurus cerebralis in the brain of sheep), which contains multiple protoscolices attached to the internal wall of a single fluid-filled bladder.
90. Strobilocercus is associated with:
A. Taenia taeniaeformis B. Taenia saginata C. Dipylidium caninum D. Echinococcus
Correct Answer: A. Taenia taeniaeformis
Explanation: Taenia taeniaeformis (the cat tapeworm) produces a strobilocercus larva in the liver of rodents. It is unique because it begins to develop segments while still in the larval stage.
91. Capillaria annulata infects:
A. Small intestine of poultry B. Trachea of poultry C. Crop of poultry D. Liver of poultry
Correct Answer: C. Crop of poultry
Explanation: Capillaria annulata (and C. contorta) are “threadworms” that burrow into the mucosal lining of the crop and esophagus of birds, causing thickening and inflammation.
92. Syngamus trachea is commonly known as:
A. Hair worm B. Gapeworm C. Lungworm D. Threadworm
Correct Answer: B. Gapeworm
Explanation: Syngamus trachea lives in the trachea of birds. Because the males and females are permanently fused in copula, they form a “Y” shape. Infected birds “gape” for air, a condition known as Gapes.
93. Setaria cervi is found in:
A. Heart B. Blood C. Peritoneal cavity D. Intestine
Correct Answer: C. Peritoneal cavity
Explanation: Setaria cervi is a common filarial worm found free-moving within the peritoneal cavity of cattle and buffaloes. Its microfilariae are found in the blood.
94. Largest louse of domestic mammals is:
A. Linognathus B. Haematopinus C. Felicola D. Menacanthus
Correct Answer: B. Haematopinus
Explanation: Members of the genus Haematopinus (the short-nosed sucking lice) are the largest lice found on domestic mammals, specifically cattle, pigs, and horses.
95. Long-nosed louse of mammals is:
A. Haematopinus B. Linognathus C. Felicola D. Lipeurus
Correct Answer: B. Linognathus
Explanation: Linognathus vituli is known as the Long-nosed sucking louse of cattle, often found on the head, neck, and dewlap.
96. Wing louse of domestic fowl is:
A. Menopon B. Lipeurus C. Goniocotes D. Cuclotogaster
Correct Answer: B. Lipeurus
Explanation: Lipeurus caponis is the common wing louse of chickens, typically found on the underside of the large wing feathers.
97. Head louse of domestic fowl is:
A. Menacanthus B. Goniocotes C. Cuclotogaster D. Lipeurus
Correct Answer: C. Cuclotogaster
Explanation: Cuclotogaster heterographus is the primary head louse of poultry, often causing irritation and stunted growth in chicks.
98. Rhipicephalus annulatus is primarily associated with:
A. Canine babesiosis B. Cattle fever C. Sheep scab D. Poultry paralysis
Correct Answer: B. Cattle fever
Explanation: Formerly known as Boophilus annulatus, this one-host tick is the primary vector for Bovine Babesiosis (Texas Cattle Fever).
99. Dermacentor reticularis mainly transmits:
A. Theileria B. Babesia spp. C. Anaplasma D. Trypanosoma
Correct Answer: B. Babesia spp.
Explanation: Dermacentor reticularis (the Ornate Cow Tick) is a significant vector for various Babesia species, particularly those affecting dogs and horses in Europe.
100. Demodex mite is classified as:
A. Burrowing mite B. Non-burrowing mite C. Tick D. Flea
Correct Answer: A. Burrowing mite
Explanation: Demodex mites live within the hair follicles and sebaceous glands. While they don’t “tunnel” like Sarcoptes, they are functionally classified as burrowing/follicular mites.
101. “Strike” refers to:
A. Egg laying by flies B. Larval invasion and tissue damage C. Adult fly feeding D. Pupation
Correct Answer: B. Larval invasion and tissue damage
Explanation: In veterinary medicine, a strike (or fly strike) occurs when blowfly larvae hatch on an animal and begin to actively invade and digest the host’s tissue.
102. Green bottle fly belongs to genus:
A. Calliphora B. Lucilia C. Sarcophaga D. Cochliomyia
Correct Answer: B. Lucilia
Explanation: Lucilia sericata and Lucilia cuprina are the primary Green bottle flies responsible for cutaneous myiasis (strike) in sheep.
103. Warble fly of cattle is:
A. Oestrus B. Hypoderma bovis C. Gastrophilus D. Lucilia
Correct Answer: B. Hypoderma bovis
Explanation: Hypoderma bovis (Northern Cattle Grub) and H. lineatum are the common warble flies. Their larvae migrate through the body to the back, where they create a breathing hole (warble) in the skin.