Parasitology Quiz 26 Quiz InstructionsThis quiz consists of 20 multiple-choice questions.You will be awarded 5 marks for each correct answer. Question 1: Which of the following temperature and duration combinations is required to reliably destroy the cysticerci of Taenia solium in pork?Continuous chilling at 0°C for 70 daysContinuous freezing at -10 to -8°C for 4 daysContinuous freezing at -4°C for 24 hoursQuick freezing at -18°C for 12 hours Question 2: The 'Asian Taenia' is a closely related variant of Taenia saginata. In which primary anatomical organ of its intermediate host (the pig or wild boar) are its cysticerci localized?Striated skeletal muscleBrain ventriclesLiverLungs Question 3: In heavy infections of Toxoplasma gondii in pigs, focal leucomalacia in the cerebral white matter of fetuses is often observed. What is the primary underlying cause of this specific neuropathological change?Direct mechanical destruction of myelin by invading tachyzoitesAnoxia arising from placental pathologyMineralization of the cerebral ventriclesToxin release during the rupture of tissue cysts containing bradyzoites Question 4: Consider the lifecycle and stages of Toxoplasma gondii. Arrange the following developmental events in the correct chronological order starting from the ingestion of oocysts/sporocysts by a pig:I. Endodyogeny leading to host cell ruptureII. Spread via the hematogenous routeIII. Sporozoite penetration of the intestinal wallIV. Waning host immunity and cyst rupture releasing bradyzoitesV. Antibody-mediated suppression and tissue cyst formationIII -> II -> I -> V -> IVII -> III -> I -> V -> IVIII -> I -> II -> IV -> VI -> III -> II -> V -> IV Question 5: Match the following Sarcocystis species with their correct combination of definitive host and pathogenicity in pigs:1. Sarcocystis suicanis2. Sarcocystis porcifelis3. Sarcocystis suihominisA. Definitive host: Cat; Pathogenicity in pigs: Non-pathogenicB. Definitive host: Dog; Pathogenicity in pigs: Severely pathogenicC. Definitive host: Human; Pathogenicity in pigs: Severely pathogenic1-B, 2-A, 3-C1-A, 2-B, 3-C1-C, 2-A, 3-B1-B, 2-C, 3-A Question 6: Assess the following statements regarding the diagnosis of Toxoplasma gondii:Assertion (A): The Sabin-Feldman dye test (DT) is the longest established serological method for toxoplasmosis and is considered the gold standard.Reason (R): The dye test has high validated reliability and sensitivity specifically when used for diagnosing Toxoplasma gondii infections in swine.Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.Both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.Assertion is correct, but Reason is incorrect.Assertion is incorrect, but Reason is correct. Question 7: Evaluate the following statements regarding the biology of Sarcoptes scabiei on pigs:I. Male mites are typically smaller than females and die shortly after copulation.II. Both sexes feed and burrow at the skin surface before mating occurs on the skin.III. The entire egg-to-adult life cycle is highly efficient, with over 90% of hatched larvae completing development.IV. Host hypersensitivity and clinical lesions typically manifest progressively 3 weeks into the initial infection.Which of the statements are correct?I, II, and IV onlyI, III, and IV onlyII and III onlyI, II, III, and IV Question 8: Acute sarcocystosis in pigs caused by Sarcocystis suihominis is characterized by a biphasic fever. During which post-infection days do these two febrile phases typically occur?1-3 days and 7-9 days5-9 days and 11-15 days10-12 days and 18-20 days2-4 days and 14-18 days Question 9: Under microscopic evaluation of the adult nematode Suifilaria suis, which set of morphological features is key for identification?Male hind end has equal spicules and female tail has a single long spike.Male hind end is straight, and female lays thin-shelled unembryonated eggs.Male hind end is spirally coiled with unequal spicules (left shorter than right), and female tail tip bears small tubercles.Male hind end is spirally coiled with a single spicule, and female tail is smooth and rounded. Question 10: Haematopinus suis is the largest blood-sucking louse of domestic animals. It is a suspected vector for which group of swine pathogens?African swine fever virus, Eperythrozoon suis, and swine pox virusClassical swine fever virus, Toxoplasma gondii, and porcine circovirusFoot-and-mouth disease virus, Sarcocystis suicanis, and swine influenza virusPorcine reproductive and respiratory syndrome (PRRS) virus, Suifilaria suis, and erysipelas Question 11: Match the porcine ectoparasites Sarcoptes scabiei (1) and Demodex phylloides (2) to their distinct morphological or biological traits:W. No eyes or stigmata, dorsal surface has transverse ridges and a central patch of triangular scalesX. Elongate tapering body with a striated opisthosoma forming at least half the body lengthY. Life cycle includes a unique second hexapod larval stageZ. Third and fourth pairs of legs in females end in long setae and lack stalked pulvilli1: W, Z; 2: X, Y1: X, Y; 2: W, Z1: W, Y; 2: X, Z1: Z, Y; 2: W, X Question 12: What is a unique developmental feature of the larval stages of Demodex phylloides that distinguishes its life cycle from many other mites?The first larval stage has eight legs, which reduces to six in the second stage.It undergoes two consecutive hexapod larval stages, with the second stage possessing pairs of three-pronged claws instead of single claws.The larvae develop inside the mother mite and are born as active octopod protonymphs.Larval stages migrate to the lungs via the bloodstream before returning to hair follicles. Question 13: What is the most common primary site of Sarcoptes scabiei infestation in pigs, which acts as the main reservoir from which the mite population spreads?Ventral abdomen and axillaeFolds of the neck and jowlExternal ears and ear waxInner thighs and hocks Question 14: Assess the following statements regarding the pathogenicity of Sarcocystis suihominis:Assertion (A): Ingestion of pork containing Sarcocystis suihominis is highly hazardous to human health.Reason (R): In humans, the asexual merogony stages of Sarcocystis suihominis cause severe destruction of the vascular endothelium of the liver within 6 to 42 hours.Both Assertion and Reason are correct, and Reason is the correct explanation of Assertion.Both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.Assertion is correct, but Reason is incorrect.Assertion is incorrect, but Reason is correct. Question 15: Evaluate the following statements regarding the epidemiology and control of porcine sarcoptic mange:I. Sows are the main reservoir of infection and should be treated before entering the farrowing crate to protect piglets.II. Transmission between host species (e.g., from dogs to pigs) typically results in permanent, severe cross-infestations.III. Boars play an important role in transmission during service and should be treated twice annually.IV. Sarcoptes scabiei can survive off the host for 2 to 3 weeks depending on environmental conditions, making contaminated bedding a potential source.Which of the statements are correct?I, III, and IV onlyI, II, and III onlyII and IV onlyI, II, III, and IV Question 16: Under microscopic examination of a fresh mouth swab from a dog, you observe a piriform protozoan measuring 7–12 µm with four anterior flagella, an undulating membrane ending in a free posterior flagellum, and a prominent axostyle. Which parasite matches this description?Tritrichomonas suisTetratrichomonas canistomaeGiardia intestinalisEntamoeba suis Question 17: What is the correct migratory pathway of Spirocerca lupi larvae in the canine definitive host after they are liberated in the stomach?Penetrate stomach wall -> coeliac artery -> thoracic aorta -> oesophagusPenetrate stomach wall -> portal vein -> liver -> vena cava -> lungs -> trachea -> oesophagusPenetrate duodenum -> mesenteric lymph nodes -> thoracic duct -> lungs -> oesophagusPenetrate stomach wall -> peritoneal cavity -> diaphragm -> pleural cavity -> oesophagus Question 18: Consider the pathogenesis and diagnosis of Spirocerca lupi in dogs. Which of the following statements is/are correct?I. Oesophageal granulomas can reach up to 4.0 cm in size and may undergo neoplastic transformation into osteosarcomas.II. Spondylosis of the thoracic vertebrae and hypertrophic osteoarthropathy of the long bones are recognized complications.III. High numbers of characteristic thick-shelled, larvated eggs are consistently found in the faeces of all dogs carrying adult infections.IV. Sudden death from aortic rupture is a potential outcome of larval migration.I, II, and IV onlyII and III onlyI and IV onlyI, II, III, and IV Question 19: Match the pig parasites with their correct host relationships described in the text:1. Taenia solium2. Toxoplasma gondii3. Sarcocystis suicanisX. Pig (as intermediate host); Cat (as final host)Y. Pig (as intermediate host); Dog (as final host)Z. Pig, wild boar, rarely man (as intermediate host); Man (as final host)1-Z, 2-X, 3-Y1-X, 2-Y, 3-Z1-Y, 2-Z, 3-X1-Z, 2-Y, 3-X Question 20: Which morphological feature is characteristic of the adult hog louse, Haematopinus suis?Presence of prominent eyes and short, broad headAbsence of eyes and presence of prominent angular processes (temporal angles) behind the antennaeSymmetrical claws of varying sizes with a reduced thoracic sternal plateBody covered with dense dorsal spines and a terminal anus
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