MCQs on Malaria Parasites (Plasmodium spp) - Medical Microbiology

                               MCQ on Malaria Parasites, Plasmodium spp

                                    Figure: Plasmodium spp (in peripheral blood)

1. Malaria is widespread in numerous countries and is known to be a major cause of death due to parasitic infections, claiming millions of lives worldwide, with the highest mortality rates observed in Africa. 
Which age group of people are more vulnerable to malaria? 
a) 10 - 15 years of age
b) > 5 years of age   
c) < 40 years of age
d) 10- 25 years of age

2. Which of the following Plasmodium spp is the most virulent and also a leading cause of human fatalities from malaria  worldwide each year?
a) Plasmodium knowlesi
b) Plasmodium malariae
c) Plasmodium falciparum  
d) Plasmodium vivax 

3. Which of the following human disease is transmitted from the vector Anopheles mosquito?
a) Dengue
b) Encephalitis
c) Filaria
d) Malaria     

4. A 27 year old male with no known pre-existing health conditions visits a clinic with high fever, he reports a sudden onset of high fever, with temperatures spiking up to 104°F. He experiences frequent chills and profuse sweating and feels extremely tired and weak. He complains of a severe, throbbing headache. He has muscle aches and joint pain. He feels nauseous and has vomited a few times and reports experiencing diarrhea.
Upon examination, the healthcare provider observes high fever of 104°F (40°C), jaundice (yellowing of the skin and eyes) is noted. The healthcare provider can palpate an enlarged spleen upon physical examination.
Based on the clinical presentation and examination, malaria is suspected as the primary diagnosis. The symptoms, including fever, chills, sweats, headache, muscle pain, and gastrointestinal symptoms, are indicative of a potential malarial infection.
Which of the following diagnostic tests is essential for confirming malaria in this case?
a) Blood glucose test
b) Blood smear for malaria parasites
c) Chest X-ray
d) Electrocardiogram (ECG)

5. Which of the following statements is Not true regarding the thick and thin blood smear in the microscopic examination method?
a)All asexual stages of the Plasmodium spp can be seen
b) If the result is negative, no further repeat blood smears are needed 
c) If the result is negative, repeat blood smears should be taken every 12 hours for 48 hours
d) The ring stage, schizonts, and merozoites can be observed 

6. Which of the following phase/cycle involves Plasmodium parasites primarily residing and multiplying within hepatocytes (liver cells) of the infected host?
a) Asexual cycle (Erythrocytes)
b) Erythrocytic cycle
c) Exoerythrocytic cycle
d) Sexual phase (gametocytes)

7. Which of the following Plasmodia has general features related to P. vivax and infections similar to that caused by P. falciparum?
a) P. knowlesi   
b) P. ovale
c) P. malariae
d) None of the above

8. Which of the following distinctive feature in RBCs distinguishs P. vivax and P. ovale from other Plasmodium spp?
a) Maurer's dots
b) Schuffner's dots
c) Ring stages
d) Banana shaped gametocytes

9. When an individual contracts P. falciparum infection, the parasite primarily focuses on invading red blood cells and liver cells, potentially causing severe infections. In the most extreme cases, the parasites may expand their influence and infiltrate the central nervous system. These complications can result in conditions like hemolytic anemia, which manifest as symptoms such as jaundice and alterations in the color of urine.
Which term is commonly used to describe the complications resulting from P. falciparum infection? 
a) Rift valley fever
b) Yellow fever
c) Blackwater fever   
d) Kala-azar    

10. All forms of malaria exhibit symptoms resembling those of influenza. After a few days following infection, individuals may undergo recurring episodes of fever, which are medically referred to as malarial paroxysms.
What is the characteristic periodicity of paroxysms (symptomatic periods) in P. vivax infections?
a) Irregular and unpredictable
b) No periodicity
c) Regular 24-hour cycle
d) Regular 48-hour cycle

11. All of the following statements regarding recurrent malaria (relapse, recrudescence, and reinfection) are correct, Except?
a) Some patients develop malaria again after a period of time
b) Recrudescence is due to insufficient treatment, relapse is due to the reappearance of merozoites from hypnozoites
c) It can be seen in all Plasmodium spp causing malaria     
d) The highest rate of relapses occurs with malaria caused by P. vivax

12. A thin blood smear is a laboratory technique used as a microscopic examination for the diagnosis of various blood-related conditions, including malaria.
Which of the following dyes/stain is used for the identification?
a) Lactophenol cotton blue
b) Giemsa stain  
c) Safranin
d) Crystal violet

13. Schuffner's dots in RBCs are the characteristic feature of  P. vivax and P. ovale in the blood sample, and the Maurer dots are seen in which of the following malarial parasite?
a) P. knowlesi
b) P. malariae and P. falciparum
c) P. falciparum      
d) P malariae

14. Which stage of Plasmodium is responsible for the cyclical fever and clinical symptoms in malaria?
a) Gametocytes
b) Merozoites
c) Oocysts
d) Sporozoites

15. Which stage of Plasmodium is responsible for transmission from the mosquito to the human host?
a) Gametocytes
b) Merozoites
c) Oocysts
d) Sporozoites

16. What is the relation between the disease sickle cell anemia and malaria? 
Select the correct answer:
a) Sickle cell anemia patients with HbS homozygous allele are resistant to malaria
b) Sickle cell anemia patients  HbS homozygous allele are more susceptible to malaria caused by P. vivax
c) Sickle cell trait individuals with  HbA & HbS heterozygote alleles are resistant to malaria
d) Individuals with sickle cell anemia genes HbA & HbS heterozygote genes are at low risk from malaria

17. Which of the following statements is most correct about the "exoerythrocytic phase" of the development of the Plasmodia?
a) The sporozoites of plasmodia do not divide and remain outside the red blood cells
b) This phase occurs only in P. vivax and P. ovale
c)The sporozoites are called hypnozoites during the exoerythrocytic phase 
d) There is a long duration of time between initial infection and the appearance of the symptoms 
e)All of the above  

18. When the sporozoites enter the human blood, they are carried to the liver where they replicate and develop into merozoites. The merozoites are released into the blood and the parasites invade RBCs. Which of the following statements is Not true regarding the developmental phase of  Plasmodia inside the RBCs?
a) The phase is known as the erythrocytic phase of malaria
b)The merozoites go through asexual reproduction   
c) The phase lasts for two to three days    
d)The merozoites go through sexual reproduction and develop into a zygote 

19. What is the primary target for Plasmodium vivax infection within the red blood cells?
a) Erythrocytes
b) Leukocytes
c) Platelets
d) Reticulocytes

20. The malaria drug hydroxychloroquine was falsely reported to be effective in which type of viral infection in 2020?
a) Dengue
b) Influenza
c) COVID-19  
d) Swine flu
e) Hepatitis 

21. In 2021 World Health Organization (WHO) has recommended the first-ever vaccine against malaria.
Which of the following age group of people can get the dose of the vaccine who are living in the malaria epidemic regions?
a) children 5 months to 10 years 
b) 15 years and older
c) 60 years and older
d) Infants only

22. Name the organ in which the malarial parasite could reside and stay dormant for up to one year during the transmission of the disease in humans
a) Kidney
b) Liver
c) Intestines
d) Gall's bladder

23. Which of the following is the most common type of symptom that occur in people infected with malaria?
a) Muscle aches and low-grade fever
b) Skin rashes and swollen legs and hands 
c) Mouth rashes and itchy skin 
d) High-grade fever and chills

24. Malaria cannot be spread from person to person and is not a sexually transmitted disease

25. Which of the following parasitic infections can be treated if drugs are available and administered during the initial stages of the infection? 
Select all the correct options
a) Measles
b) Chagas disease
c) Malaria
d) Toxoplasmosis

WHO recommended second vaccine for malaria: Please click

1- b) > 5 year of age
2- c) Plasmodium falciparum. P. falciparum is one of several species of the Plasmodium genus responsible for causing malaria. It is the most virulent and dangerous species, leading to the most severe cases of the disease. 

3- d) Malaria    
4- b) Blood smear for malaria parasites. To confirm the diagnosis and determine the specific strain of malaria, a blood smear is examined under a microscope to detect the presence of malarial parasites and identify the species.

5- b) If the result is negative, no further repeat blood smears are needed.
6- c) Exoerythrocytic cycle. Mosquito carrying infectious sporozoites bites a human host, during the mosquito's blood meal, sporozoites are injected into the host's bloodstream. The sporozoites travel from the bloodstream to the liver and multiply within hepatocytes (liver cells) of the infected host. 
7-a) P. knowlesi   
8-b) Schuffner's dots. Schüffner's dots or Schüffner's granules, are small, round, reddish to orange granulations found within red blood cells infected with certain species of malaria parasites, such as Plasmodium vivax and Plasmodium ovale. Schüffner's dots are characteristic of these specific malaria species and aid in their identification in stained blood smears when examining infected blood samples under a microscope. 

9-c) Blackwater fever  
10- d) Regular 48-hour cycle
11-c) It can be seen in all Plasmodium spp causing malaria 
12-b) Giemsa stain 
13-c) P. falciparum. Maurer's dots represent a series of small, vesicle-like structures that form within the erythrocyte's cytoplasm as part of the complex interactions between the P. falciparum and the host cell. They are not visible in the blood smear itself but are observed using electron microscopy and other advanced techniques.

14- b) Merozoites. Infected hepatocytes (in liver) rupture, releasing merozoites into the bloodstream. Merozoites invade red blood cells (erythrocytes) and develop into ring-stage trophozoites.

15- d) Sporozoites. Mature sporozoites are released from the oocysts and migrate to the mosquito's salivary glands.
16-d) Individuals with sickle cell anemia genes HbA & HbS heterozygote genes are at low risk from malaria
17- e) All of the above
18- d) The merozoites go through sexual reproduction and develop into a zygote
19- d) Reticulocytes. P. vivax infects only the reticulocytes; thus the parasitemia is limited to approximately 2% to 5% of the available RBCs.

20-c) COVID-19
21. a) children 5 months to 10 years
22. b) Liver
23. d) High-grade fever and chills
24. a) TRUE
25. b), c), and d)   (Measles is not a parasitic disease, it is a very common viral infection)


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