Protozoology - Sporozoa MCQs

Ans. is 'c' i.e., Laveran . The specific causative agent of malaria was discovered in the red blood cells of a patient in 1880 by Alophonse Laveran, a French army surgeon in Algeria. Remember . Romanowsky developed a method of staining malaria parasites in blood films.

Answer- D. PNH Red cell surface antigen that offer protection against malaria Duffy blood group system ABO (H) blood group system Glycophorins Gerbich antigen Complement receptor type I Knops blood group Abnormalities of the red cell cytoskeleton which may offer protection include South-east asia ovalocytosis Hereditary elliptocytosis Hereditary spherocytosis Sickle cell HbA/S

The above question describes the staining method of modified ZN staining , wherein 5% sulphuric acid is used instead of 20%. The former concentration shows positive with M. Leprae, whereas the latter shows acid fastness for M.TB and Atypical mycobacteria. Oocysts of Cyclospora, Isospora and Cryptosporidium are also acid fast with 5% H2SO4 Nocardia, Legionella and Tenia oocysts are acid fast with 0.5%-1% H2SO4. Actinomyces is not acid fast. Reference: Essentials of Medical Microbiology, by Apurba Sastry and Sandhya Bhat, 3rd edition, page 29

Ans. is 'c' i.e., Malaria 792. Following are examples of human "dead end" disease except - a) Bubonic plague b) Japanies ecephalitis c) Hydatid disease d) Leishmaniasis Correct Answer - D Ans. is 'd' i.e., Leishmaniasis Dead and host o A dead end host is an infected person from which infectious agents are not transmitted to other susceptible host or from which a parasite cannot escape to continue its life cycle. o The diseases in which human acts as dead end host, i.e., dead and disease : ?

Option D - These are inherent, natural, non-immune mechanisms of host resistance against malarial parasites which have evolved as survival advantage under environmental stress induced by Plasmodia. Duffy negative RBC lacks glycoprotein receptors required by merozoite to attach and penetrate. Thus duffy negative blood group people are naturally protected from P.vivax. Reference: Paniker's textbook of Parasitology - 8th Edition, Pg. No. -80

Option C - Merozoites released from liver cells infects RBS’s. Inside RBC, they convert into early trophozoite- late trophozoite and Schizont. Late trophozoite, early and mature schizonts are not found in peripheral blood as this stage occurs inside capillaries of internal organs like spleen, liver and kidney. Thus, only trophozoite (ring forms ) and gametocytes are diagnostic forms present in peripheral blood smear. Reference: Paniker's textbook of Parasitology - 8th Edition, Page no : 73

Option B - P.vivax merozoites after entering into RBC convert into early trophozoite(ring form) about 2.5 -3 in diameter which remains in middle of RBC. This early ring form further convert to late trophozoite form having size of 6-7 . In order to accommodate such a large ring, RBC has to enlarge. RBCs infected with P.vivax became pale, enlarged, irregular and became mottled having Schuffner's dots. Reference: Paniker's textbook of Parasitology - 8th Edition, Pg. No. -72

Option B - Sporozoite is an infective form developed in the female anopheles mosquitoes after external incubation period. It is formed when introduced inside the human body through mosquito bite. It undergoes asexual development inside liver cells (pre-erythrocytic schizogony). Merozoites released from pre-erythrocytic schizogony infects RBCs and undergoes a developmental cycle of trophozoite-schizont-merozoite. Reference : Paniker's Textbook of Parasitology, 8th Edition, Page Number-67.