A 28-year-old man from a forested district of Odisha is admitted with fever, altered sensorium and seizures. His thin smear shows many red cells with two or more delicate ring forms, some applique forms and a few crescent-shaped gametocytes. Which feature of this parasite explains his cerebral involvement?

Sequestration through PfEMP1 binding

Dormant hypnozoites in the liver

Invasion of only young red cells

A 9-year-old boy from Bihar has fever for 3 months, a spleen 8 cm below the costal margin and pancytopenia. His rK39 test is positive. Total protein is 9.2 g/dL with albumin 2.4 g/dL. Which mechanism explains the protein values?

Polyclonal B-cell activation raising IgG

Monoclonal plasma cell proliferation

Loss of albumin through the kidneys

Increased albumin breakdown by the spleen

A 34-year-old woman from a tribal area of Madhya Pradesh has a massive spleen reaching the right iliac fossa, mild anaemia and repeated fevers over several years. Smears are negative for malaria parasites, but serum IgM is very high and antimalarial antibody titres are raised. Bone marrow shows no malignancy. What is the most likely diagnosis?

Hyperreactive malarial splenomegaly

Malaria and blood parasites

26 NEET-PG practice questions on Malaria and blood parasites, part of Microbiology. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Medium
A 28-year-old man from a forested district of Odisha is admitted with fever, altered sensorium and seizures. His thin smear shows many red cells with two or more delicate ring forms, some applique forms and a few crescent-shaped gametocytes. Which feature of this parasite explains his cerebral involvement?
1. ADormant hypnozoites in the liver
2. BSequestration through PfEMP1 binding
3. CBinding to the Duffy antigen
4. DInvasion of only young red cells
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Answer: B · Sequestration through PfEMP1 binding
Multiple rings, applique forms and crescent gametocytes identify Plasmodium falciparum. Infected red cells express PfEMP1 on surface knobs, which bind receptors such as ICAM-1 on brain capillary endothelium, so the mature parasites are sequestered out of the peripheral blood. This blocks microcirculation and drives local inflammation, causing cerebral malaria. Severe malaria is treated with parenteral artesunate.
- A: Hypnozoites cause relapses in P. vivax and P. ovale, not cerebral malaria.
- C: Duffy antigen binding is how P. vivax enters red cells.
- D: Preference for young red cells limits parasitaemia in P. vivax; falciparum invades red cells of all ages.
Question 2 · Hard
A 12-year-old boy with falciparum malaria is admitted in Ranchi. On the thick smear, the technician counts 240 asexual parasites against 200 white cells. His total leucocyte count is 7,500/µL. What is his parasite density?
1. A6,250 parasites/µL
2. B900 parasites/µL
3. C18,000 parasites/µL
4. D9,000 parasites/µL
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Answer: D · 9,000 parasites/µL
On a thick smear, parasites are counted against white cells and the count is converted using the patient's own leucocyte count. Parasites/µL = (parasites counted / leucocytes counted) x leucocyte count = (240 / 200) x 7,500 = 1.2 x 7,500 = 9,000/µL. The result helps to monitor the response to treatment, and high parasitaemia is one of the criteria for severe malaria. If the leucocyte count is not known, an assumed value of 8,000/µL is used.
- A: Inverts the ratio (200/240 x 7,500).
- B: Misplaces the decimal (1.2 x 750).
- C: Divides by 100 instead of 200 white cells.
Question 3 · Medium
A 9-year-old boy from Bihar has fever for 3 months, a spleen 8 cm below the costal margin and pancytopenia. His rK39 test is positive. Total protein is 9.2 g/dL with albumin 2.4 g/dL. Which mechanism explains the protein values?
1. AMonoclonal plasma cell proliferation
2. BLoss of albumin through the kidneys
3. CIncreased albumin breakdown by the spleen
4. DPolyclonal B-cell activation raising IgG
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Answer: D · Polyclonal B-cell activation raising IgG
Visceral leishmaniasis drives massive polyclonal B-cell activation, so serum IgG rises greatly while albumin falls, reversing the albumin to globulin ratio. This hypergammaglobulinaemia was the basis of the old aldehyde (formol-gel) test. The antibodies are not protective, because immunity to Leishmania depends on a Th1 cell response that the disease suppresses. Protein electrophoresis shows a broad polyclonal gamma band, unlike the narrow M band of myeloma.
- A: Monoclonal proliferation gives a narrow M band and is not caused by kala-azar.
- B: Kala-azar does not usually cause nephrotic-range albumin loss.
- C: The spleen does not break down albumin; low albumin reflects liver and nutritional effects.
Question 4 · Medium
A 34-year-old woman from a tribal area of Madhya Pradesh has a massive spleen reaching the right iliac fossa, mild anaemia and repeated fevers over several years. Smears are negative for malaria parasites, but serum IgM is very high and antimalarial antibody titres are raised. Bone marrow shows no malignancy. What is the most likely diagnosis?
1. AChronic myeloid leukaemia
2. BNon-cirrhotic portal fibrosis
3. CHyperreactive malarial splenomegaly
4. DVisceral leishmaniasis
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Answer: C · Hyperreactive malarial splenomegaly
Hyperreactive malarial splenomegaly (tropical splenomegaly syndrome) is an abnormal immune response to repeated malaria in endemic areas. It gives massive splenomegaly, very high polyclonal IgM and high malarial antibody titres, while smears are usually negative. Hepatic sinusoidal lymphocytosis is seen on liver biopsy. The spleen shrinks slowly with long-term antimalarial prophylaxis, which also confirms the diagnosis.
- A: CML would show a high leucocyte count with a myelocyte peak and the BCR::ABL1 fusion.
- B: Portal fibrosis causes splenomegaly with varices but not high IgM or malarial antibodies.
- D: Kala-azar raises IgG and shows amastigotes in marrow or spleen.
Question 5 · Medium
A 40-year-old fisherman from Cherthala in Alappuzha has recurrent lymphangitis and swelling of the right leg. A night blood smear shows sheathed microfilariae with a kinky body and two separate nuclei at the tip of the tail. Which parasite is this?
1. AMansonella ozzardi
2. BWuchereria bancrofti
3. CLoa loa
4. DBrugia malayi
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Answer: D · Brugia malayi
Brugia malayi microfilariae are sheathed and lie in kinky curves, and the tail carries two distinct terminal nuclei. Wuchereria bancrofti microfilariae are also sheathed but lie in smooth curves with a tail tip free of nuclei. In India, brugian filariasis is found mainly in parts of Kerala, especially around Cherthala, where Mansonia mosquitoes breed among aquatic plants such as Pistia. It causes lymphoedema mostly below the knee and rarely affects the genitals.
- A: Mansonella ozzardi microfilariae are unsheathed and occur in the Americas.
- B: W. bancrofti has a tail tip free of nuclei and smooth curves.
- C: Loa loa occurs in Africa and has nuclei running continuously to the tail tip.
Question 6 · Easy
A district malaria laboratory receives blood from a febrile labourer. The technician prepares both a thick and a thin smear from the same finger prick. What is the main advantage of the thick smear?
1. AEasier identification of the species
2. BShows changes in the infected red cell
3. CHigher sensitivity for detecting parasites
4. DBetter preservation of parasite morphology
Answer and explanation in LearnFree account
Question 7 · Medium
A 7-year-old boy who lived in Jharkhand until a year ago has generalised oedema and heavy proteinuria. His father says he had fever every fourth day for months in the past. A blood smear shows band forms across normal-sized red cells and rosette schizonts. Which parasite best explains both problems?
1. APlasmodium knowlesi
2. BPlasmodium falciparum
3. CPlasmodium vivax
4. DPlasmodium malariae
Answer and explanation in LearnFree account
Question 8 · Medium
A 32-year-old man from Chennai has had nocturnal cough and wheeze for 3 months that has not improved with inhalers. Chest X-ray shows diffuse fine mottling. Absolute eosinophil count is 6,200/µL (reference below 500/µL), serum IgE is very high, antifilarial antibodies are strongly positive and night smears show no microfilariae. Which drug is the treatment of choice?
1. AIvermectin
2. BDiethylcarbamazine
3. CAlbendazole
4. DPraziquantel
Answer and explanation in LearnFree account
Question 9 · Medium
A 42-year-old man was treated for falciparum malaria in a private clinic in Raipur with only 1 day of an ACT because he felt better. Three weeks later the fever returns, and the smear again shows P. falciparum rings. He has not left the city since. What best describes this episode?
1. ARelapse from dormant liver hypnozoites
2. BRecrudescence from surviving blood forms
3. CReinfection from a new mosquito bite
4. DDelayed release of liver schizonts
Answer and explanation in LearnFree account
Question 10 · Easy
A 19-year-old college student from Mangaluru has fever with chills for 4 days. The thin blood smear stained with Giemsa shows small ring forms, some red cells with two rings, and a few crescent-shaped gametocytes. Which species is most likely?
1. ABabesia microti
2. BPlasmodium falciparum
3. CPlasmodium vivax
4. DPlasmodium ovale
Answer and explanation in LearnFree account
Question 11 · Medium
In a medical college laboratory, a blood sample from a febrile patient is spun in a special capillary tube coated with acridine orange, and the buffy coat layer is examined under ultraviolet light. What does this quantitative buffy coat (QBC) test detect?
1. AParasite antigen by immunochromatography
2. BHost antibody by fluorescence
3. CHaemozoin pigment by polarisation
4. DParasite nucleic acid by fluorescence
Answer and explanation in LearnFree account
Question 12 · Medium
A 30-year-old soldier posted near Bikaner in Rajasthan for a year has a painless, crusted ulcer with raised edges on his cheek that has slowly enlarged over 4 months. There is no fever or splenomegaly. Smear from the ulcer margin shows amastigotes inside macrophages. Which organism is most likely?
1. ALeishmania tropica
2. BMycobacterium ulcerans
3. CSporothrix schenckii
4. DLeishmania donovani
Answer and explanation in LearnFree account
Question 13 · Easy
A 28-year-old man from a village in Uttar Pradesh has recurrent fever with painful swelling of the left leg and inguinal lymphadenitis. Lymphatic filariasis due to Wuchereria bancrofti is suspected. At what time should the peripheral blood sample be taken to look for microfilariae?
1. ABetween 6 am and 10 am
2. BAt the height of a fever spike
3. CBetween 10 pm and 2 am
4. DBetween 12 noon and 4 pm
Answer and explanation in LearnFree account
Question 14 · Medium
A 55-year-old man who had a splenectomy after a road accident develops high fever and haemolytic anaemia 3 weeks after a trekking holiday in the north-eastern United States, where he removed a tick. The smear shows small intra-erythrocytic rings, some arranged in tetrads, with no pigment and no gametocytes. Which parasite is most likely?
1. APlasmodium falciparum
2. BTrypanosoma cruzi
3. CBabesia microti
4. DPlasmodium malariae
Answer and explanation in LearnFree account
Question 15 · Medium
A 28-year-old woman develops fever with chills 2 weeks after receiving 3 units of whole blood for a postpartum haemorrhage in a district hospital in Assam. The smear shows Plasmodium vivax. After treating the blood stage with chloroquine, what is true about primaquine for her?
1. AIt is needed to prevent recrudescence
2. BIt is needed to clear the mature gametocytes
3. CIt is not needed because no liver stage forms
4. DIt is needed to clear the liver hypnozoites
Answer and explanation in LearnFree account
Question 16 · Hard
A 45-year-old businessman returns to Kolkata after a forest trip in Malaysian Borneo and has daily fever spikes for 5 days. Parasitaemia is high; the smear shows delicate rings resembling P. falciparum and band forms resembling P. malariae, with no crescents. The falciparum-specific RDT is negative. Which species is most likely?
1. APlasmodium malariae
2. BBabesia microti
3. CPlasmodium knowlesi
4. DPlasmodium falciparum
Answer and explanation in LearnFree account
Question 17 · Hard
A 48-year-old trader from Mizoram has fever for 6 days. The thin smear shows enlarged red cells with Schuffner's dots containing amoeboid trophozoites, and in other fields many small rings with some crescent-shaped gametocytes. G6PD activity is normal. Which treatment does this smear call for?
1. AACT plus single-dose primaquine only
2. BChloroquine plus primaquine for 14 days
3. CChloroquine alone for 3 days
4. DACT plus primaquine for 14 days
Answer and explanation in LearnFree account
Question 18 · Medium
A 24-year-old man from a filaria-endemic district of Uttar Pradesh has a left-sided hydrocele and painless scrotal swelling. He works night shifts and cannot come for a night blood sample. Which test can be done on a sample taken in the daytime to detect Wuchereria bancrofti infection?
1. ATissue biopsy of an inguinal node
2. BCirculating filarial antigen card test
3. CMembrane filtration of venous blood
4. DThick smear with Giemsa stain
Answer and explanation in LearnFree account
Question 19 · Medium
A 35-year-old engineer returns to Kochi after two years in Nigeria and has fever on alternate days. The thin smear shows trophozoites in enlarged red cells that are oval with ragged, fimbriated edges and have prominent stippling. Which species is most likely?
1. APlasmodium ovale
2. BPlasmodium vivax
3. CPlasmodium knowlesi
4. DPlasmodium falciparum
Answer and explanation in LearnFree account
Question 20 · Hard
A 16-year-old girl from Darbhanga, Bihar, has fever for 4 months, weight loss and a large spleen. A resident lists four statements about her likely disease: 1. Serum albumin to globulin ratio is usually reversed. 2. The leishmanin (Montenegro) skin test is positive during active disease. 3. Splenic aspirate shows amastigotes in macrophages. 4. The vector is the sandfly Phlebotomus argentipes. Which statements are correct?
1. A1, 3 and 4 only
2. B1 and 2 only
3. C3 and 4 only
4. D1 and 3 only
Answer and explanation in LearnFree account
Question 21 · Medium
A 26-year-old man from Gadchiroli with falciparum malaria passes dark, cola-coloured urine on the third day of treatment. His haemoglobin has fallen from 11.2 to 6.4 g/dL and serum creatinine is rising. Urine dipstick is strongly positive for blood, but microscopy shows no red cells. Which process explains the urine colour?
1. AMassive intravascular haemolysis
2. BConjugated hyperbilirubinaemia
3. CMyoglobin from rhabdomyolysis
4. DGlomerular bleeding from nephritis
Answer and explanation in LearnFree account
Question 22 · Medium
A 19-year-old man in Muzaffarpur, Bihar, was treated for kala-azar 2 years ago. He now has painless hypopigmented macules and small nodules over his face, chin and upper arms with normal sensation. Slit-skin smear from a nodule shows amastigotes. Why is this condition important for the elimination programme?
1. ASkin lesions are a reservoir for sandflies
2. BIt means the original drug was resistant
3. CIt spreads by direct skin contact
4. DIt spreads to others by droplets
Answer and explanation in LearnFree account
Question 23 · Easy
A 12-year-old girl from a village in Bihar has had fever for 2 months, a massive spleen and pancytopenia. A splenic aspirate shows small oval bodies inside macrophages, each with a nucleus and a rod-shaped kinetoplast. Which stage of the parasite is this?
1. APromastigote
2. BEpimastigote
3. CTrypomastigote
4. DAmastigote
Answer and explanation in LearnFree account
Question 24 · Medium
A medical college lecture on host factors in malaria lists four statements: 1. Sickle cell trait protects against severe falciparum malaria. 2. Red cells lacking the Duffy blood group antigen resist invasion by P. vivax. 3. P. vivax preferentially invades old, senescent red cells. 4. P. falciparum can invade red cells of any age. Which statements are correct?
1. A2, 3 and 4 only
2. B1 and 3 only
3. C1, 2 and 3 only
4. D1, 2 and 4 only
Answer and explanation in LearnFree account
Question 25 · Hard
A 24-year-old woman with falciparum malaria in Bastar becomes deeply comatose despite only 3% parasitaemia on the peripheral smear. The smear shows only ring forms and gametocytes. At autopsy, cerebral capillaries are packed with parasitised red cells. Which parasite protein mainly causes this sequestration?
1. ACircumsporozoite protein
2. BMerozoite surface protein 1
3. CPfEMP1 on red cell knobs
4. DHistidine-rich protein 2
Answer and explanation in LearnFree account

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Malaria and blood parasites

A 12-year-old boy with falciparum malaria is admitted in Ranchi. On the thick smear, the technician counts 240 asexual parasites against 200 white cells. His total leucocyte count is 7,500/µL. What is his parasite density?

A 9-year-old boy from Bihar has fever for 3 months, a spleen 8 cm below the costal margin and pancytopenia. His rK39 test is positive. Total protein is 9.2 g/dL with albumin 2.4 g/dL. Which mechanism explains the protein values?

A 40-year-old fisherman from Cherthala in Alappuzha has recurrent lymphangitis and swelling of the right leg. A night blood smear shows sheathed microfilariae with a kinky body and two separate nuclei at the tip of the tail. Which parasite is this?

A district malaria laboratory receives blood from a febrile labourer. The technician prepares both a thick and a thin smear from the same finger prick. What is the main advantage of the thick smear?

A 42-year-old man was treated for falciparum malaria in a private clinic in Raipur with only 1 day of an ACT because he felt better. Three weeks later the fever returns, and the smear again shows P. falciparum rings. He has not left the city since. What best describes this episode?

A 19-year-old college student from Mangaluru has fever with chills for 4 days. The thin blood smear stained with Giemsa shows small ring forms, some red cells with two rings, and a few crescent-shaped gametocytes. Which species is most likely?

In a medical college laboratory, a blood sample from a febrile patient is spun in a special capillary tube coated with acridine orange, and the buffy coat layer is examined under ultraviolet light. What does this quantitative buffy coat (QBC) test detect?

A 30-year-old soldier posted near Bikaner in Rajasthan for a year has a painless, crusted ulcer with raised edges on his cheek that has slowly enlarged over 4 months. There is no fever or splenomegaly. Smear from the ulcer margin shows amastigotes inside macrophages. Which organism is most likely?

A 28-year-old man from a village in Uttar Pradesh has recurrent fever with painful swelling of the left leg and inguinal lymphadenitis. Lymphatic filariasis due to Wuchereria bancrofti is suspected. At what time should the peripheral blood sample be taken to look for microfilariae?

A 28-year-old woman develops fever with chills 2 weeks after receiving 3 units of whole blood for a postpartum haemorrhage in a district hospital in Assam. The smear shows Plasmodium vivax. After treating the blood stage with chloroquine, what is true about primaquine for her?

A 48-year-old trader from Mizoram has fever for 6 days. The thin smear shows enlarged red cells with Schuffner's dots containing amoeboid trophozoites, and in other fields many small rings with some crescent-shaped gametocytes. G6PD activity is normal. Which treatment does this smear call for?

A 24-year-old man from a filaria-endemic district of Uttar Pradesh has a left-sided hydrocele and painless scrotal swelling. He works night shifts and cannot come for a night blood sample. Which test can be done on a sample taken in the daytime to detect Wuchereria bancrofti infection?

A 35-year-old engineer returns to Kochi after two years in Nigeria and has fever on alternate days. The thin smear shows trophozoites in enlarged red cells that are oval with ragged, fimbriated edges and have prominent stippling. Which species is most likely?

A 12-year-old girl from a village in Bihar has had fever for 2 months, a massive spleen and pancytopenia. A splenic aspirate shows small oval bodies inside macrophages, each with a nucleus and a rod-shaped kinetoplast. Which stage of the parasite is this?