Parasitology MCQS
1. A parasite is best defined as an organism that:
A. Lives independently B. Benefits both organisms C. Lives on or in a host and derives nourishment at its expense D. Lives freely in the environment
Correct Answer: C. Lives on or in a host and derives nourishment at its expense
Explanation: Parasitism is a non-mutual relationship. While the parasite gains nutrients and shelter, the host is typically harmed or weakened. This distinguishes it from commensalism (one benefits, one neutral) and mutualism (both benefit).
2. Parasitism is a form of:
A. Mutualism B. Commensalism C. Symbiosis with benefit to parasite only D. Neutral association
Correct Answer: C. Symbiosis with benefit to parasite only
Explanation: Symbiosis is a broad term for organisms living together. Parasitism is a specific symbiotic relationship where the metabolic dependency is one-sided, favoring the parasite.
3. Which of the following is NOT a main type of parasite?
A. Helminths B. Protozoa C. Ectoparasites D. Bacteria
Correct Answer: D. Bacteria
Explanation: In medical and veterinary context, “parasites” usually refer to eukaryotic organisms: Protozoa (single-celled), Helminths (worms), and Arthropods (ectoparasites). Bacteria are classified as prokaryotic microorganisms (microbiology).
4. Protozoology is the study of:
A. Helminths B. Arthropods C. Protozoa D. Bacteria
Correct Answer: C. Protozoa
Explanation: Protozoology is a branch of zoology dealing with protozoans, which are diverse, single-celled eukaryotic organisms.
5. The term “Protozoa” is derived from Greek words meaning:
A. Small animals B. First animals C. Single cell D. Microscopic life
Correct Answer: B. First animals
Explanation: The name comes from the Greek “protos” (first) and “zoa” (animals), reflecting the historical view of these organisms as the most primitive animal-like life forms.
6. Father of Protozoology is:
A. Robert Koch B. Louis Pasteur C. Antoni van Leeuwenhoek D. Edward Jenner
Correct Answer: C. Antoni van Leeuwenhoek
Explanation: Antoni van Leeuwenhoek was the first to observe and describe single-celled organisms (which he called “animalcules”) using his handcrafted microscopes.
7. Protozoa are:
A. Multicellular prokaryotes B. Unicellular eukaryotes C. Multicellular eukaryotes D. Asexual bacteria
Correct Answer: B. Unicellular eukaryotes
Explanation: Protozoa are complex single cells that contain a true nucleus and membrane-bound organelles, making them eukaryotes.
8. Babesia parasites are found inside:
A. Leukocytes B. Platelets C. Red blood cells D. Hepatocytes
Correct Answer: C. Red blood cells
Explanation: Babesia species are intraerythrocytic parasites. They multiply within Red Blood Cells (RBCs), eventually causing them to rupture (haemolysis), which leads to hemoglobinuria.
9. Babesia was first observed by Babes in:
A. 1878 B. 1888 C. 1893 D. 1901
Correct Answer: B. 1888
Explanation: Victor Babeș, a Romanian pathologist, first identified the microorganism in the blood of cattle suffering from “Texas Fever” in 1888.
10. Babesia is transmitted by:
A. Mosquito B. Sand fly C. Hard ticks D. Fleas
Correct Answer: C. Hard ticks
Explanation: Babesia is primarily transmitted by Ixodid (hard) ticks. The parasite undergoes part of its life cycle (gametogony and sporogony) within the tick vector.
11. Babesia bigemina transmission was first discovered by:
A. Koch and Jenner B. Babes and Leeuwenhoek C. Smith and Kilborne D. Theiler and Ross
Correct Answer: C. Smith and Kilborne
Explanation: The discovery by Theobald Smith and F.L. Kilborne in 1893 was monumental, as it was the first time an arthropod was proven to be a vector for a protozoan disease.
12. All are names of Babesiosis EXCEPT:
A. Texas fever B. Red water disease C. East Coast fever D. Tick fever
Correct Answer: C. East Coast fever
Explanation: East Coast fever is specifically caused by Theileria parva. Babesiosis is commonly known as Red water (due to bloody urine) and Texas fever.
13. Pipe-stem diarrhoea in babesiosis is due to:
A. Liver failure B. Kidney damage C. Constriction of anal sphincter D. Intestinal ulceration
Correct Answer: C. Constriction of anal sphincter
Explanation: In severe cases of bovine babesiosis, the animal may pass thin, forceful streams of feces known as pipe-stem diarrhea, caused by spasms and the constriction of the anal sphincter.
14. Drug used for Babesia infection includes:
A. Albendazole B. Ivermectin C. Diminazene aceturate D. Praziquantel
Correct Answer: C. Diminazene aceturate
Explanation: Diminazene aceturate (Berenil) and Imidocarb dipropionate are the drugs of choice for treating piroplasmosis (Babesia and Theileria).
15. Theileria belongs to phylum:
A. Sarcomastigophora B. Ciliophora C. Apicomplexa D. Microsporidia
Correct Answer: C. Apicomplexa
Explanation: Like Plasmodium and Babesia, Theileria belongs to Apicomplexa, characterized by the presence of an apical complex used to penetrate host cells.
16. Tropical theileriosis is caused by:
A. T. parva B. T. annulata C. T. equi D. T. bovis
Correct Answer: B. T. annulata
Explanation: Theileria annulata causes Tropical theileriosis (Mediterranean Coast Fever), transmitted mainly by Hyalomma ticks.
17. East Coast fever is caused by:
A. Babesia bigemina B. Theileria parva C. Anaplasma marginale D. Trypanosoma evansi
Correct Answer: B. Theileria parva
Explanation: Theileria parva is the causative agent of East Coast Fever (ECF) in cattle, primarily in East and Central Africa.
18. Piroplasm stage of Theileria is found in:
A. Lymphocytes B. Macrophages C. RBCs D. Plasma
Correct Answer: C. RBCs
Explanation: The piroplasm is the stage found inside Red Blood Cells. It is the stage that is ingested by a tick during a blood meal.
19. Schizont stage of Theileria is found in:
A. RBCs B. Lymphocytes C. Neutrophils D. Hepatocytes
Correct Answer: B. Lymphocytes
Explanation: The schizont (Koch’s blue bodies) is the pathogenic stage that develops within lymphocytes (T and B cells), causing them to proliferate uncontrollably like cancer cells.
20. Helminthology is the study of:
A. Protozoa B. Arthropods C. Helminths D. Fungi
Correct Answer: C. Helminths
Explanation: Helminthology is the study of parasitic worms, including flukes, tapeworms, and roundworms.
21. Platyhelminthes include:
A. Nematodes only B. Trematodes and cestodes C. Arthropods D. Protozoa
Correct Answer: B. Trematodes and cestodes
Explanation: Phylum Platyhelminthes (Flatworms) is divided into Trematodes (Flukes) and Cestodes (Tapeworms). Nematodes are roundworms belonging to a different phylum.
22. Platyhelminthes are generally:
A. Dioecious B. Hermaphrodite C. Asexual D. Viviparous
Correct Answer: B. Hermaphrodite
Explanation: Most flatworms are monoecious (hermaphroditic), meaning a single individual possesses both male and female reproductive organs. A notable exception is Schistosoma.
23. Intermediate host of Fasciola hepatica is:
A. Fish B. Mosquito C. Snail D. Cow
Correct Answer: C. Snail
Explanation: The common liver fluke, Fasciola hepatica, requires a freshwater snail (typically of the genus Lymnaea) to complete its larval development.
24. Bottle jaw is associated with:
A. Dictyocaulus B. Fasciola hepatica C. Haemonchus D. Strongyloides
Correct Answer: B. Fasciola hepatica
Explanation: Bottle jaw (submandibular edema) is a classic clinical sign of chronic fascioliasis or haemonchosis, caused by severe hypoproteinemia (low blood protein).
25. Schistosoma japonicum lives in:
A. Liver B. Intestine C. Portal and mesenteric vessels D. Lungs
Correct Answer: C. Portal and mesenteric vessels
Explanation: Unlike other flukes, Schistosomes (blood flukes) live within the blood vessels—specifically the portal and mesenteric veins.