101. Which substance released during rupture of infected red blood cells is linked with fever in malaria?
ⓐ. Haemozoin
ⓑ. Histamine
ⓒ. Serotonin
ⓓ. Melanin
Correct Answer: Haemozoin
Explanation: Haemozoin is a malarial pigment associated with the blood stage of infection. It is released when infected red blood cells burst. Its release is linked with the characteristic bouts of chills and fever. This makes haemozoin a key clue in understanding the symptom pattern of malaria.
102. Fill in the blank in the most accurate way:
In malaria, the sequence in the human host is sporozoite entry → liver phase → invasion of ______.
ⓐ. platelets
ⓑ. red blood cells
ⓒ. salivary glands
ⓓ. skin glands
Correct Answer: red blood cells
Explanation: After the initial liver stage, the parasite does not remain confined there. It enters the bloodstream and infects red blood cells, where it multiplies again. This stage is closely connected with fever recurrence and other clinical features. Red blood cell invasion is therefore the next major step after the liver phase.
103. A patient with malaria shows fever at repeated intervals rather than a continuous fever. This pattern is best explained by
ⓐ. periodic release of pollen from air sacs
ⓑ. repeated blockage of intestinal villi
ⓒ. daily multiplication only in liver tissue
ⓓ. synchronized rupture of infected red blood cells
Correct Answer: synchronized rupture of infected red blood cells
Explanation: Malaria often produces fever in repeated bouts because many infected red blood cells rupture around the same time. Each rupture releases parasite-related products into the blood and triggers a fresh febrile episode. This cyclical destruction gives the disease its periodic pattern. Continuous fever without such cycles is less typical of malaria.
104. Which stage of malaria is most directly associated with the typical symptoms seen during infection in humans?
ⓐ. The stage restricted only to mosquito gut
ⓑ. The stage involving infected red blood cells
ⓒ. The stage before the parasite enters the body
ⓓ. The stage limited only to external skin surface
Correct Answer: The stage involving infected red blood cells
Explanation: The blood stage is closely linked with the usual clinical manifestations of malaria. Infection and rupture of red blood cells produce chills, fever, and weakness. Although the liver stage is important for early development, the symptomatic phase is more directly related to the erythrocytic stage. Red blood cell involvement therefore explains the classic symptoms of malaria.
105. Which comparison between typhoid and malaria is correct?
ⓐ. Typhoid is food- and water-borne, whereas malaria is vector-borne.
ⓑ. Typhoid is caused by protozoans, whereas malaria is caused by bacteria.
ⓒ. Typhoid spreads through female Anopheles, whereas malaria spreads through contaminated food.
ⓓ. Typhoid and malaria are both mainly spread by shared utensils.
Correct Answer: Typhoid is food- and water-borne, whereas malaria is vector-borne.
Explanation: The two diseases differ sharply in their route of transmission. Typhoid is commonly acquired through contaminated food and water, while malaria requires an infected female Anopheles mosquito. This difference helps separate intestinal bacterial infection from mosquito-borne protozoan disease. Transmission route is therefore a reliable basis for comparison.
106. Which sequence best represents the broad life-cycle logic of malaria?
ⓐ. Infected food → intestine → liver → skin lesions
ⓑ. Housefly bite → blood → lungs → stool cysts
ⓒ. Infected female Anopheles bite → sporozoites enter human → liver stage → red blood cell stage
ⓓ. Contaminated water → gut → lymph vessels → muscles
Correct Answer: Infected female Anopheles bite → sporozoites enter human → liver stage → red blood cell stage
Explanation: Malaria begins when an infected female Anopheles mosquito injects sporozoites into a human host. These first reach the liver and later move into red blood cells. The blood stage is then linked with repeated fever and chills. This sequence captures the broad logic of the human phase of infection.
107. Assertion (A): The female Anopheles mosquito is essential for continuation of malaria transmission.
Reason (R): Part of the parasite’s development occurs inside the mosquito.
ⓐ. Both A and R are true, but R is not the correct explanation of A.
ⓑ. A is true, but R is false.
ⓒ. A is false, but R is true.
ⓓ. Both A and R are true, and R is the correct explanation of A.
Correct Answer: Both A and R are true, and R is the correct explanation of A.
Explanation: Malaria transmission depends on the mosquito not just as a carrier, but as a necessary host for parasite development. Certain stages of Plasmodium occur in the mosquito before it can infect another human. This directly explains why the female Anopheles is essential in the transmission cycle. Without that stage, the cycle would be interrupted.
108. Which statement about malaria is correct?
ⓐ. Houseflies act as the main vector and contaminate food.
ⓑ. The common cold virus produces the recurrent fever pattern.
ⓒ. The parasite remains only in liver cells throughout the disease.
ⓓ. Human infection involves liver and red blood cell stages.
Correct Answer: Human infection involves liver and red blood cell stages.
Explanation: The human phase of malaria includes an early liver stage followed by infection of red blood cells. Both stages are important, but the blood stage is more closely associated with the classic symptoms. Houseflies and respiratory viruses are unrelated to malaria transmission. Recognizing the two main host stages helps in understanding the disease clearly.
109. Which organism is not a vector in the transmission of malaria?
ⓐ. Infected female Anopheles
ⓑ. Female mosquito carrying Plasmodium
ⓒ. Housefly carrying faecal contamination
ⓓ. Blood-feeding Anopheles involved in parasite transfer
Correct Answer: Housefly carrying faecal contamination
Explanation: Malaria is a vector-borne disease transmitted by an infected female Anopheles mosquito. Houseflies may mechanically spread some intestinal infections, but they do not transmit malaria. This distinction helps separate malaria from diseases linked with contaminated food and water. Knowing the correct vector is essential for prevention and diagnosis.
110. Which statement correctly describes the role of the mosquito in malaria?
ⓐ. It serves only as a passive carrier without any parasite development.
ⓑ. It acts as the vector and supports part of the parasite’s life cycle.
ⓒ. It contaminates food with cysts that later infect humans.
ⓓ. It transmits only bacterial forms of the pathogen.
Correct Answer: It acts as the vector and supports part of the parasite’s life cycle.
Explanation: The female Anopheles mosquito is a biological vector, not merely a passive carrier. Important stages of Plasmodium development occur in the mosquito before the parasite can be passed to another human. This makes the mosquito an essential host in the life cycle. The disease therefore depends on both human and mosquito phases.
111. Which comparison is correct?
ⓐ. Malaria is spread by contaminated water, whereas typhoid is spread by mosquito bite.
ⓑ. Malaria is caused by fungi, whereas amoebiasis is caused by viruses.
ⓒ. Malaria involves a biological vector, whereas typhoid does not.
ⓓ. Malaria and common cold are both mainly transmitted by shared utensils.
Correct Answer: Malaria involves a biological vector, whereas typhoid does not.
Explanation: Malaria requires an infected female Anopheles mosquito for transmission, making it a vector-borne disease. Typhoid, in contrast, spreads mainly through contaminated food and water and does not require a biological vector. This difference is one of the clearest contrasts between the two diseases. Route of spread often gives a strong clue to diagnosis.
112. Assertion (A): Mosquito control is an important preventive measure against malaria.
Reason (R): The parasite must pass through the female Anopheles mosquito to continue transmission.
ⓐ. Both A and R are true, and R is the correct explanation of A.
ⓑ. Both A and R are true, but R is not the correct explanation of A.
ⓒ. A is true, but R is false.
ⓓ. A is false, but R is true.
Correct Answer: Both A and R are true, and R is the correct explanation of A.
Explanation: Malaria control depends heavily on interrupting mosquito-based transmission. Because the parasite requires the female Anopheles mosquito to move between human hosts, reducing mosquito numbers lowers the spread of disease. The reason directly explains the value of mosquito control. Public health measures such as preventing mosquito breeding are therefore highly effective.
113. Amoebiasis in humans is caused by
ⓐ. Ascaris lumbricoides
ⓑ. Entamoeba histolytica
ⓒ. Wuchereria bancrofti
ⓓ. Plasmodium falciparum
Correct Answer: Entamoeba histolytica
Explanation: Amoebiasis is a protozoan disease caused by Entamoeba histolytica. This organism infects the intestinal region and produces characteristic digestive symptoms. It is different from helminths such as Ascaris or filarial worms, and also different from malarial parasites. Correct pathogen identification helps in distinguishing intestinal infections from vector-borne diseases.
114. The usual site of infection by Entamoeba histolytica is the
ⓐ. large intestine
ⓑ. liver cell
ⓒ. alveolus
ⓓ. lymph vessel
Correct Answer: large intestine
Explanation: Entamoeba histolytica mainly lives in the large intestine. Its activity there causes irritation and damage that lead to abdominal discomfort and abnormal stools. This location helps separate amoebiasis from diseases of the lungs, blood, or lymphatic system. Site of infection is therefore a useful basis for identification.
115. Which set of symptoms is most characteristic of amoebiasis?
ⓐ. Fever, cough, chills, and bluish nails
ⓑ. Recurrent fever with rupture of red blood cells
ⓒ. Constipation, abdominal cramps, and stools with mucus and blood clots
ⓓ. Nasal congestion, sore throat, and hoarseness
Correct Answer: Constipation, abdominal cramps, and stools with mucus and blood clots
Explanation: Amoebiasis commonly produces intestinal symptoms rather than respiratory or blood-stage fever patterns. Constipation, abdominal pain, cramps, and stools containing excess mucus and blood clots are important features. These signs reflect irritation and damage in the large intestine. The symptom combination is therefore strongly suggestive of amoebic infection.
116. Which route most commonly spreads amoebiasis?
ⓐ. Bite of infected female mosquito
ⓑ. Droplet infection from coughing
ⓒ. Direct spread through casual touch
ⓓ. Faecally contaminated food and water
Correct Answer: Faecally contaminated food and water
Explanation: Amoebiasis is mainly transmitted when food or water becomes contaminated with human faecal matter containing the infective stage of the parasite. This makes poor sanitation a major risk factor. It is not primarily a droplet-borne or mosquito-borne disease. Safe food handling and clean water are therefore central to prevention.
117. Houseflies contribute to the spread of amoebiasis mainly as
ⓐ. biological hosts where sexual reproduction occurs
ⓑ. definitive hosts with tissue multiplication
ⓒ. mechanical carriers of contamination
ⓓ. blood-feeding vectors injecting parasites
Correct Answer: mechanical carriers of contamination
Explanation: Houseflies do not act as true biological vectors in amoebiasis. Instead, they mechanically carry infective material from contaminated matter to food and other surfaces. This helps the parasite reach new hosts indirectly. The difference between a mechanical carrier and a biological vector is important in disease transmission.
118. Which comparison between malaria and amoebiasis is correct?
ⓐ. Both are usually transmitted by the same mosquito vector.
ⓑ. Malaria is mainly vector-borne, whereas amoebiasis is mainly food- and water-borne.
ⓒ. Malaria affects the large intestine, whereas amoebiasis affects red blood cells.
ⓓ. Both are commonly spread by droplets from coughing.
Correct Answer: Malaria is mainly vector-borne, whereas amoebiasis is mainly food- and water-borne.
Explanation: The two diseases differ clearly in their transmission routes. Malaria depends on an infected female Anopheles mosquito, while amoebiasis usually spreads through faecally contaminated food and water, often aided by houseflies as mechanical carriers. Their body sites and symptom patterns are also different. Route of transmission provides one of the strongest contrasts.
119. A person develops abdominal pain and stools containing mucus and blood clots after repeatedly consuming unhygienic food from an open stall where flies are abundant. Which disease is most likely?
ⓐ. Pneumonia
ⓑ. Typhoid
ⓒ. Ringworm
ⓓ. Amoebiasis
Correct Answer: Amoebiasis
Explanation: The symptom pattern and exposure history strongly point to amoebiasis. Intestinal cramps, mucus, and blood clots in stool suggest infection by Entamoeba histolytica, and abundant flies around unhygienic food support contamination. This is very different from respiratory infections or skin fungal disease. The setting and symptoms together make the diagnosis more likely.
120. Fill in the blank in the most accurate way:
In amoebiasis, houseflies are important because they can act as ______.
ⓐ. mosquito vectors
ⓑ. blood parasites
ⓒ. mechanical carriers
ⓓ. immune barriers
Correct Answer: mechanical carriers
Explanation: Houseflies help spread amoebiasis by carrying infective material from contaminated sites to food or utensils. They do not inject the parasite like mosquitoes and do not serve as immune components. Their role is mechanical rather than biological. This difference is important for understanding transmission.
