Parasitology Review Quiz Questions and Correct Solutions 2023

Parasitism - A symbiotic relationship in which one animal, the host, is injured through the activities of the other animal, the parasite. Parasites of medical significance belong to four phyla - Protozoa, Platyhelminthes, Aschelminthes, and Arthropoda. Phylum protozoa - Eukaryotic (unicellular) and have organelles that function in nutrition or locomotion. Trophozoites stage - The growing stage of parasites; feed by engulfing particles and move by flagella, cilia, or pseudopodia. Cyst stage - More resistant and typically is the form shed in stools and transmitted by the fecal-oral route. Sarcodina - This subphylum of Protozoa includes Amoeba, which is a group of organisms that move by means of cytoplasmic protrusions called pseudopodia. E. histolytica is the most medically significant species of this group. Entamoeba histolytica - The agent of amebic dysentery, amebic liver abscess, and amebiasis. Non-pathogenic Entamoeba - Entamoeba coli, Entamoeba hartmanni, Entamoeba gingivalis, Iodamoeba butschlii, and Endolimax nana. Sporozoa - This class is primarily tissue parasites with an involved life cycle that alternates between sexual and asexual generations. Plasmodium species - Found as blood parasites and cause the disease malaria. Toxoplasma, Pneumocystis, and Sarcocystis species - Species that spread throughout various organs and tissues. Isospora species - These species colonize the intestinal mucosa. Anopheline mosquitoes - Definitive hosts of the malarial parasites. Life cycle of Malaria - The female mosquito first must bite a human who is infected with malaria. Sexual reproduction occurs within the mosquito with the development of sporozoites. Sporozoites enter the salivary glands of the mosquito and are inoculated into the next person bitten. The sporozoites enter the liver and begin an asexual maturation stage. After several generations have developed, they invade the red blood cells (RBCs).