Foundation A Block MCQs

Foundation A (Y2)

1) Which of the following describes the basic reproductive number (R₀) of an infectious disease?

a) The average number of new infections generated by a single infected individual in a completely susceptible population.

b) The average number of new infections generated by a single infected individual in a population with some immunity.

c) The proportion of the population that is immune to a disease.

d) The number of new infections caused by an infected individual in a partially susceptible population.

e) The measure of how many new cases of a disease are generated through contaminated food or water.

2) Which of the following terms best describes a disease that is regularly found and consistently present in a specific geographic area or population?

a) Epidemic

b) Pandemic

c) Endemic

d) Outbreak

e) Sporadic

3) The net reproductive number (Rₙ) differs from the basic reproductive number (R₀) because it:

a) Represents the potential for disease spread in a population with some immunity and interventions.

b) Measures the number of new infections in a completely susceptible population.

c) Reflects the proportion of susceptible individuals in a population.

d) Is used to calculate the severity of a disease outbreak.

e) Indicates the effectiveness of a vaccine.

4) Which of the following is NOT a method of vehicle transmission of infectious diseases?

a) Contaminated water

b) Airborne particles

c) Direct contact with infected individuals

d) Contaminated food

e) Contaminated surfaces (fomites)

5) Which type of transmission involves the transfer of pathogens from mother to offspring during pregnancy, childbirth, or breastfeeding?

a) Horizontal transmission

b) Fomite transmission

c) Vertical transmission

d) Vector transmission

e) Airborne transmission

6) In the context of sepsis, what does disseminated intravascular coagulation (DIC) involve?

a) Reduced clotting due to a deficiency in coagulation factors.

b) Increased clotting and bleeding due to excessive coagulation factors and fibrin formation.

c) Inhibition of the immune response leading to increased susceptibility to infections.

d) Increased production of white blood cells leading to systemic inflammation.

e) Decreased blood flow to vital organs due to vascular collapse.

7) What does the term “endosymbionts” refer to?

a) Organisms living in close association with other organisms but outside their cells.

b) Microorganisms that live on the surface of other organisms without causing harm.

c) Pathogens that spread through contaminated food and water.

d) Organisms that live inside the cells or tissues of another organism in a mutually beneficial relationship.

e) Inanimate objects that carry infectious agents.

8)What is the primary causative agent of throat infections?

A) Staphylococcus aureus
B) Streptococcus pneumoniae
C) Streptococcus pyogenes
D) Escherichia coli
E) Haemophilus influenzae

9)Which of the following is used to identify tuberculosis in clinical specimens? 

A) Gram stain
B) Ziehl-Neelsen stain
C) Acid-fast bacillus culture
D) Both B and C
E) PCR testing

Question 10: In Gram-positive bacteria, what role do teichoic acids play?

A) They form a protective capsule around the bacterial cell.
B) They help maintain the structural integrity of the cell wall.
C) They allow bacteria to swim using flagella.
D) They bind oxygen molecules for cellular respiration.
E) They are involved in the breakdown of peptidoglycan.

Question 11: Staphylococcus aureus is primarily characterized by which of the following features?
A) Gram-negative, cocci, anaerobic
B) Gram-positive, cocci, and facultative anaerobic
C) Gram-positive, bacilli, and obligate anaerobic
D) Gram-negative, bacilli, and aerobic
E) Gram-positive, cocci, and strict aerobic

Question 12: Streptococcus pneumoniae can be differentiated from other streptococci by its ability to:
A) Ferment lactose
B) Hydrolyse urea
C) Cause alpha-haemolysis on blood agar
D) Grow in high salt concentrations
E) Form a capsule visible under light microscopy

Question 13: Clostridium difficile is primarily responsible for which of the following clinical conditions?
A) Antibiotic-associated diarrhoea
B) Infective endocarditis
C) Necrotising fasciitis
D) Viral gastroenteritis
E) Chronic sinusitis

Question 14: Which of the following characteristics best describes Candida albicans?
A) Gram-negative yeast, aerobic
B) Dimorphic fungus that can exist as yeast and filamentous form
C) Obligate anaerobic yeast
D) Non-dimorphic fungus that only grows as a mould
E) Gram-positive, non-motile bacilli

Question 15: Histoplasma capsulatum is primarily transmitted through which of the following routes?
A) Foodborne transmission
B) Inhalation of aerosolised spores
C) Direct contact with skin lesions
D) Blood transfusion
E) Sexual contact

Question 16: A patient with HIV presents with severe headache, fever, and photophobia. A lumbar puncture reveals increased opening pressure. What is the most likely causative organism?
A) Histoplasma capsulatum
B) Candida albicans
C) Coccidioides immitis
D) Cryptococcus neoformans 

E) Aspergillus fumigatus

Question 17: What type of organism is Plasmodium falciparum, the causative agent of malaria?

A) Bacterium
B) Fungus
C) Helminth
D) Protozoan
E) Virus

Question 18: What is the primary risk factor for developing mucormycosis (zygomycetes)?

A) Advanced age
B) Diabetes mellitus
C) Recent surgery
D) Pregnancy
E) Asthma

Question 19: Which organism is responsible for causing the disease known as myiasis?

A) Taenia solium
B) Strongyloides stercoralis
C) Dermatophytes
D) Fly larvae
E) Plasmodium falciparum

Question 20: Which of the following is a characteristic feature of Schistosoma spp.?

A) Cestode that causes intestinal issues
B) Trematode associated with bilharzia
C) Nematode causing skin infections
D) Protozoan with a complex lifecycle in water
E) Arthropod vector for malaria

Question 21: What is the primary risk factor associated with Aspergillus infections?

A) Diabetes
B) HIV/AIDS
C) Immunosuppression
D) Recent surgery
E) Pregnancy

Question 22: Which of the following best describes the mechanism of action of aminoglycosides?

A) Inhibit DNA synthesis by targeting DNA gyrase
B) Bind to the 50S ribosomal subunit, blocking peptide bond formation
C) Bind to the 30S ribosomal subunit, causing mRNA misreading
D) Inhibit cell wall synthesis by blocking peptidoglycan cross-linking
E) Bind to RNA polymerase, inhibiting mRNA transcription

Question 23: A patient diagnosed with invasive aspergillosis is started on amphotericin B. What is the primary mechanism of action of amphotericin B?

A) Inhibition of ergosterol synthesis
B) Binding to ergosterol, creating pores in the fungal membrane
C) Inhibition of DNA synthesis by blocking thymidine kinase
D) Binding to the 30S subunit, disrupting protein synthesis
E) Blocking the production of fungal cell wall components

Question 24: What allows herpes simplex virus (HSV) to evade the immune system and cause recurrent infections?

A) It rapidly mutates, changing its surface antigens.
B) It forms resistant spores that escape immune detection.

C) It integrates into the host genome, preventing immune detection.
D) It blocks T cell activation through surface proteins.
E) It hides in immune-privileged sites like neurons and becomes latent.

Question 25: How do nucleoside reverse transcriptase inhibitors (NRTIs) work in the treatment of HIV?

A) They block the enzyme integrase, preventing viral DNA from integrating into the host genome.
B) They directly inhibit viral protease, preventing protein cleavage.
C) They prevent the initial binding of HIV to CD4+ cells.
D) They mimic natural nucleosides, getting incorporated into viral DNA, but prevent further elongation.
E) They bind to the RNA of the virus, preventing reverse transcription.

Question 26: What is the role of HBsAg in chronic Hepatitis B infection?
A) It serves as a decoy to distract the immune system from recognizing infectious virions.
B) It integrates into the host genome and suppresses immune recognition.
C) It is a viral protein that downregulates CD8+ T cell activity.
D) It blocks interferon production in infected hepatocytes.
E) It facilitates the binding of HBV to hepatocytes by acting as a receptor.

Question 27: What is the most common bacteria found in the GI tract?

  1. Bifidobacteria
  2. Bacteroides
  3. Enterobacteriaceae
  4. Lactobacilli
  5. Clostridium difficile

 Question 28: Which type of plasmodium causes the most severe malaria symptoms?

  1. Plasmodium malariae
  2. Plasmodium Knowlesi
  3. Plasmodium Vivax
  4. Plasmodium ovale
  5. Plasmodium Falciparum

Question 29: What is the most common bacterial cause of meningitis?

  1. Streptococcus pneumoniae
  2. Haemophilus influenzae
  3. Neisseria Meningitidis
  4. Strep aureus
  5. Pseudomonas aeruginosa

Question 30: Which of the following does not currently have a vaccine available?

  1. Norovirus
  2. Measles
  3. COVID-19
  4. Pertussis
  5. Tuberculosis

Question 31: Which of the following is ribavirin used to treat?

  1. Measles
  2. HIV
  3. COVID-19
  4. Hepatitis B
  5. Herpes Simplex Virus Type 1

Question 32: Which of the following works on the P site of the 50s subunit of the ribosome of a bacteria to prevent the exit/release of the polypeptide chain?

  1. Tetracycline
  2. Aminoglycosides
  3. Macrolides
  4. B-lactam
  5. Glycopeptides

 Question 33: Which of the following is a metamonad subtype of a protozoa?

  1. Cryptosporidium
  2. Toxoplasma Gondii
  3. Giardia lamblia *
  4. Taenia solium
  5. Entamoeba histolytica

Question 34: How do echinocandins work?

  1. They target the glucan synthase enzyme (Fks1p) that is unique to fungal cell walls. This interrupts the ß1,3 linkage between glucan molecules.
  2. They target lanosterol 14-alpha demethylase enzyme used to synthesise ergosterol. This causes other toxic molecules to be produced instead causing pores to form in the cell membrane.
  3. Binds to active site of protease enzyme preventing the polypeptide chain from being cleaved.
  4. Binds to transpeptidase enzyme preventing the linkage of D-alanine & L-Lysine amino acids.
  5. Acts as a competitive inhibitor of PABA preventing the synthesis of dihydropteroate synthase.

Question 35: What class of parasites are stronglyoides stercoralis?

  1. Helminth – trematode
  2. Helminth – nematode 
  3. Helminth – Cestode
  4. Protozoa – apicomplexan
  5. Protozoa – metamonad

Question 36: Which one of the following parasites classically presents with ‘Katayama fever’?

  1. Stronglyoides stercoralis
  2. Giardia lamblia 
  3. Schistosoma
  4. Toxoplasma gondii
  5. Cryptosporidium

Question 37: Which of the following fungi require keratin to grow?

  1. Dermatophytes
  2. Tinea corporis
  3. Mycetoma
  4. Candida
  5. Cryptococcus neoformans

Question 38: Which of the following pathogens utilise a whole killed vaccine?

  1. Pneumococcal meningococcal
  2. Pertussis
  3. Tetanus
  4. Hepatitis B
  5. Diphtheria

 Question 39: How is the diagnosis of cryptosporidiosis unique to other parasites?

  1. Diagnosed via trichrome staining
  2. Diagnosed via serology
  3. Diagnosed via acid-fast staining 
  4. Diagnosed via immunoassays
  5. Diagnosed via PCR

Question 40: Which of the following is an example of a subcutaneous fungal infection?

  1. Mucormycosis
  2. Histoplasma
  3. Candida
  4. Aspergillus
  5. Mycetoma

Question 41: Which of the following an apicomplexan transmitted via contaminated water & food mainly whilst travelling?

  1. Cryptosporidiosis
  2. Giardia lamblia
  3. Toxoplasma gondii
  4. Taenia solium
  5. Strongyloides stercoralis

 Question 42: Which of the following is not used in the treatment of bacterial pathogens?

  1. Aminoglycosides
  2. B-lactams
  3. Tetracycline
  4. Macrolides
  5. Amphotericin B

 Question 43: Which of the following helminths can spread to the brain & cause seizures, strokes, radiculopathy, strokes or even fatality?

  1. Taenia solium
  2. Toxoplasma
  3. Schistosoma
  4. Giardia lamblia
  5. Cryptosporidium

Question 44: Which class of the Herpes family is said to have a “dew drops on a rose” appearance in a dermatomal distribution?

  1. Herpes Simplex virus type 1
  2. Herpes Simplex virus type 2
  3. Varicella Zoster Virus 
  4. Epstein Barr Virus
  5. Cytomegalovirus

Question 45: What fungal infection is a feared complication in a diabetic ketoacidosis patient?

  1. Aspergillus
  2. Mycetoma
  3. Mucromycosis
  4. Candida
  5. Cryptococcus

Question 46: Which of the following is a helminth tapeworm infection caused by undercooked pork?

  1. Taenia Solium
  2. Tinea capitis
  3. Tinea giardia
  4. Toxoplasmosis
  5. Taenia coli


Question 47: Which of the following medications converts dihydrofolate to tetrahydrofolate in folate metabolism?

  1. Sulphonamides
  2. ß-lactam
  3. Penicillin
  4. Trimethoprim
  5. Acyclovir

Question 48: Which of the following is the most common adjuvant used in vaccines?

  1. Magnesium
  2. Argon
  3. Phosphate
  4. Alum
  5. Potassium

Question 49: Which of the following molecules are NOT released when mast cells undergo degranulation?

  1. Heparin
  2. Histamine
  3. Chymase
  4. Tryptase
  5. Thrombin

Question 50: Which interleukin do T helper cells secrete that triggers B cell to undergo class switch & form IgE antibodies during a type 1 hypersensitivity response?

  1. IL-2
  2. IL-4
  3. IL-6
  4. IL-8
  5. IL-10

Question 51: Which of the following gram-positive bacterial chains, release superantigens?

  1. Staphylococcus aureus
  2. Coagulase negative staphylococcus
  3. Streptococcus pneumoniae
  4. Streptococcus viridians
  5. Streptococcus pyogenes

Question 52: Which of the following is classified as immune-mediated cytotoxic hypersensitivity?

  1. Type I
  2. Type II
  3. Type III
  4. Type IV
  5. Type V

Question 53: Grave’s disease (hyperthyroidism) is classified as which of the following hypersensitivity reactions?

  1. Type II
  2. Type III
  3. Type IV
  4. Type V
  5. Type VI

Question 54: Which of the following is a characterised by blue-green pigment secreting gram-negative bacteria.

  1. Neisseria Gonorrhoea
  2. Streptococcus pyogenes
  3. Coagulase positive staphylococcus
  4. Pseudomonas aeruginosa
  5. Enterobacteriaceae

Question 55: Which of the following is a class of herpes that causes infections in pneumoniae in patients with HIV?

  1. Cytomegalovirus
  2. Streptococcus pneumoniae
  3. Pneumocystis jirovecii
  4. Invasive aspergillosis
  5. Invasive candidiasis

Question 56: Which of the following drugs causes immunodeficiency by blocking IL-2 production preventing T cell proliferation?

  1. Steroids
  2. Specific pharmacologic immune modulators
  3. Cytotoxic agents
  4. Bone marrow transplants
  5. Biologics

Question 57: Which of the following is classified as a dimorphic organism?

  1. Mucormycosis
  2. Cryptococcus neoformans
  3. Dermatophyte
  4. Candida
  5. Histoplasma

Question 58: A 58-year-old man is admitted to the intensive care unit with septic shock secondary to bacterial pneumonia. He develops diffuse bleeding from intravenous sites, and laboratory results reveal prolonged prothrombin time (PT), partial thromboplastin time (PTT), low fibrinogen, and thrombocytopenia. Which of the following best explains why sepsis can lead to impaired blood clotting in this patient?

A) Activation of tissue factor causes localized clotting, leading to reduced clotting factors concentration in blood and secondary bleeding (disseminated intravascular coagulation)
B) Excessive inflammatory cytokines inhibit thrombin generation, preventing clot formation and leading to primary bleeding tendency
C) Sepsis results in a decrease in endothelial production of von Willebrand factor (vWF), preventing adequate platelet adhesion and aggregation
D) Pro-inflammatory cytokines suppress the synthesis of clotting factors in the liver, leading to systemic bleeding without clot formation
E) Sepsis leads to an overproduction of plasminogen activator inhibitor-1 (PAI-1), causing hyperfibrinolysis and a direct reduction in fibrin clot stability

Question 59: A 65-year-old woman is admitted to the emergency department with a fever, rapid heart rate, and confusion after a urinary tract infection. Her blood pressure is 80/50 mmHg despite intravenous fluids, and she is diagnosed with septic shock. Which of the following mechanisms best explains why septic shock results in hypotension?

A)Increased capillary permeability leading to massive fluid loss from the intravascular space into tissues, causing relative hypovolemia

B) Direct bacterial invasion of the myocardium, causing acute heart failure and a drop in cardiac output
C) Dehydration due to fever-induced sweating and vomiting, causing hypovolemia and secondary hypotension
D)Loss of vascular smooth muscle tone due to excessive production of nitric oxide, leading to systemic vasodilation
E) Suppression of the adrenal glands by bacterial endotoxins, leading to insufficient cortisol production and vascular collapse

Question 60: A 52-year-old man presents to the emergency department with fever, chills, confusion, and a heart rate of 120 beats per minute. His blood pressure is 85/50 mmHg, and his respiratory rate is 28 breaths per minute. Sepsis is suspected, and the Sepsis 6 bundle is initiated. Which of the following is a component of the Sepsis 6 bundle that directly helps stabilize the patient’s circulation?

A) Administering broad-spectrum antibiotics immediately
B) Delivering high-flow oxygen to maintain oxygen saturation
C) Obtaining blood cultures prior to antibiotic administration
D) Initiating intravenous fluid resuscitation with crystalloids
E) Measuring serum lactate and repeating the measurement if elevated

Question 61: The urinary bladder is typically a sterile environment, even though urine may sometimes contain potential pathogens. Which of the following best explains why the bladder remains sterile under normal conditions?

A)The presence of a thick mucosal layer lining the bladder prevents adherence of bacteria to the bladder wall
B) The acidic pH of urine inhibits bacterial growth within the bladder
C)  Regular contraction of the detrusor muscle leads to frequent flushing of pathogens from the bladder
D) A protective layer of immunoglobulin A (IgA) coats the bladder surface, neutralising potential pathogens in the urine
E) The unidirectional flow of urine from the kidneys to the urethra prevents retrograde migration of pathogens

Question 62: A 72-year-old woman is admitted to the hospital for pneumonia and receives a 10-day course of broad-spectrum antibiotics. Shortly after completing the treatment, she develops severe diarrhoea, abdominal pain, and fever. Stool testing confirms a diagnosis of Clostridium difficile (C. diff) infection. Which of the following best explains why C. diff infections commonly occur after antibiotic use?

A) Antibiotics lead to increased production of C. diff spores, causing overgrowth in the intestinal tract
B) Broad-spectrum antibiotics kill normal gut microbiota, allowing overgrowth of C. diff bacteria and toxin production
C) Antibiotics directly induce mutations in C. diff bacteria, making them pathogenic
D) C. diff colonises the gut during antibiotic therapy by adhering to damaged mucosa caused by the antibiotics
E) Antibiotic use leads to hypersecretion of gastric acid, creating a favourable environment for C. diff proliferation

Question 63: Which of the following Toll-like receptors (TLRs) is primarily responsible for recognizing Staphylococcus aureus and initiating the innate immune response?

A) TLR2
B) TLR3
C) TLR4
D) TLR5
E) TLR7

Question 64: A Gram-stained throat swab sample from a patient with a sore throat revealed a purple  cocci arranged in chains. The bacteria produce a clear disc on blood agar. Based on the bacterial morphology and hemolytic pattern, which of the following is the most likely pathogen?

A) Staphylococcus aureus
B) Streptococcus pneumoniae
C) Escherichia coli
D) streptococcus Pyogenes
E) Klebsiella pneumoniae

Question 65: A 24-year-old woman presents with abdominal pain, diarrhea (sometimes bloody), and fever after consuming undercooked chicken. A stool culture reveals curved, Gram-negative rods with a “gull-wing” appearance. Which of the following is the most likely pathogen responsible for her symptoms?

A) Escherichia coli (E. coli)
B) norovirus
C) Campylobacter jejuni
D) Shigella dysenteriae
E) Clostridium difficile

Question 66: A 30-year-old man presents with itchy, red, scaly patches on his feet and between his toes. A skin scraping from the lesion reveals branching, septate hyphae under microscopic examination, and fungal culture identifies colonies with a characteristic red color. Which of the following is the most likely causative organism?

A) Candida albicans
B) Trichophyton rubrum
C) Aspergillus fumigatus
D) Malassezia furfur
E) Cryptococcus neoformans

Question 67: A 45-year-old diabetic woman presents with complaints of vaginal itching, white cottage cheese-like discharge, and burning sensation during urination. On examination, her vaginal mucosa appears erythematous with a thick white discharge. A potassium hydroxide (KOH) test of the discharge reveals budding yeast and pseudohyphae. What is the most likely causative organism?

A) Aspergillus fumigatus
B) Candida albicans
C) Trichomonas vaginalis
D) Gardnerella vaginalis
E) Human papillomavirus

Question 68: A 60-year-old diabetic man presents with fever, facial swelling, black necrotic tissue in his nasal cavity, and headache. His medical history includes poorly controlled diabetes mellitus. A CT scan reveals sinus involvement with orbital extension. A biopsy of the nasal tissue reveals broad, non-septate hyphae with right-angle branching under microscopic examination. Which of the following is the most likely causative organism?

A) Aspergillus fumigatus
B) Candida albicans
C) Mucor species
D) Histoplasma capsulatum
E) Cryptococcus neoformans

Question 69: A 28-year-old woman returns from a two-week trip to West Africa. She presents with fever, chills, severe headache, myalgia, and nausea. On examination, she is febrile and mildly jaundiced with splenomegaly. Laboratory tests reveal thrombocytopenia and anemia. A thick and thin blood smear is ordered. Which of the following is the most likely causative organism?

A) Giardia lamblia
B) Toxoplasma gondii
C) Plasmodium falciparum
D) Cryptosporidium parvum
E) Schistosoma species

Question 70: The influenza virus is known for causing both seasonal epidemics and occasional pandemics. Which of the following best explains why influenza pandemics occur and how they differ from seasonal influenza outbreaks?

A) Gradual accumulation of point mutations in the hemagglutinin (HA) and neuraminidase (NA) genes (antigenic drift)
B) Rapid reassortment of gene segments between different influenza strains (antigenic shift)
C) Increased virulence due to the development of antiviral resistance
D) Widespread distribution of influenza A and B strains in unvaccinated populations
E) Direct person-to-person transmission through respiratory droplets

Question 71: A 42-year-old man presents with fatigue, intermittent low-grade fever, and mild jaundice. Laboratory tests show elevated liver enzymes and positive serology for a chronic viral infection. He reports no acute illness recently but recalls an asymptomatic phase after a potential exposure years ago. Which of the following is the most likely chronic viral infection in this patient?

A) Epstein-Barr virus (EBV)
B) Human immunodeficiency virus (HIV)
C)  Rotavirus
D) Influenza virus
E) Hepatitis B virus (HBV)

Question 72: A 60-year-old patient presents with a painful, vesicular rash localized to one dermatome on the left side of the chest. The patient reports a burning sensation preceding the rash and has no history of recent respiratory illness. Which of the following is the most likely diagnosis?

A) HSV-1 

B) HSV-5
C) HSV-4
D) HSV-3
E) HSV-2

Question 73: Which of the following vaccines is a live attenuated vaccine?

A) Pertussis vaccine
B) Human papillomavirus (HPV) vaccine
C) Hepatitis B vaccine
D) Pneumococcal vaccine
E) Oral polio vaccine (OPV)

Question 74: Which of the following antibiotics specifically targets DNA gyrase in bacteria?

A) Penicillin
B) Tetracycline
C) Fluoroquinolones
D) Erythromycin
E) Vancomycin

Question 75: Streptococcus pneumoniae has developed resistance to penicillin. Which of the following mechanisms best explains this resistance?

A) The bacterium produces beta-lactamase enzymes that break down penicillin.
B) The bacterium alters the penicillin-binding proteins (PBPs) to reduce the effectiveness of penicillin.
C) The bacterium alters its ribosomal binding site to prevent antibiotic binding.
D) The bacterium pumps out penicillin using efflux pumps.
E) The bacterium forms a biofilm that protects it from antibiotic penetration.

Question 76: A 45-year-old woman presents with complaints of muscle weakness that worsens as the day progresses. She reports difficulty in swallowing, speaking, and holding her eyelids open, with symptoms improving after rest. On examination, there is ptosis (drooping eyelids) and weakness in the facial and limb muscles. Which type of hypersensitivity reaction is most likely involved in the pathogenesis of her condition?

A) Type I hypersensitivity
B) Type II hypersensitivity
C) Type III hypersensitivity
D) Type IV hypersensitivity
E) Type V hypersensitivity 

Question 77: A 60-year-old male with a history of long-term steroid use for rheumatoid arthritis presents with frequent sinus infections and oral candidiasis. He reports increased fatigue and is more prone to developing infections that are hard to treat. His past medical history reveals no other significant immunodeficiencies. Which of the following is the most likely cause of his condition?

A) Primary immunodeficiency

B) Secondary immunodeficiency due to chemotherapy

C) Secondary immunodeficiency due to steroid use

D) HIV/AIDS-related immunodeficiency

E) Secondary immunodeficiency due to malnutrition