Infectious Diseases MCQs

1. The most common cause of community-acquired pneumonia is:
(A) Klebsiella pneumoniae
(B) Mycoplasma pneumoniae
(C) Streptococcus pneumoniae
(D) Legionella pneumophila

2. Which virus causes chickenpox?
(A) Measles virus
(B) Varicella-zoster virus
(C) Rubella virus
(D) Coxsackie virus

3. The causative agent of tuberculosis is:
(A) Mycobacterium leprae
(B) Mycobacterium tuberculosis
(C) Mycobacterium avium
(D) Mycobacterium kansasii

4. The BCG vaccine is given for prevention of:
(A) Leprosy
(B) Tuberculosis
(C) Typhoid
(D) Diphtheria

5. Which hepatitis virus is DNA-based?
(A) Hepatitis A
(B) Hepatitis B
(C) Hepatitis C
(D) Hepatitis E

6. Which hepatitis virus is transmitted through contaminated water?
(A) Hepatitis A and E
(B) Hepatitis B and C
(C) Hepatitis D
(D) All of the above

7. Koplik spots are pathognomonic of:
(A) Rubella
(B) Measles
(C) Mumps
(D) Chickenpox

8. The causative organism of diphtheria is:
(A) Corynebacterium diphtheriae
(B) Clostridium tetani
(C) Bordetella pertussis
(D) Haemophilus influenzae

9. The “whooping cough” is caused by:
(A) Bordetella pertussis
(B) Haemophilus influenzae
(C) Mycoplasma pneumoniae
(D) Streptococcus pyogenes

10. Which parasite causes malaria?
(A) Plasmodium species
(B) Toxoplasma gondii
(C) Trypanosoma
(D) Leishmania

11. The vector for malaria is:
(A) Aedes mosquito
(B) Anopheles mosquito
(C) Culex mosquito
(D) Sandfly

12. Blackwater fever is associated with:
(A) Plasmodium malariae
(B) Plasmodium vivax
(C) Plasmodium falciparum
(D) Plasmodium ovale

13. The causative agent of kala-azar is:
(A) Plasmodium vivax
(B) Leishmania donovani
(C) Trypanosoma cruzi
(D) Giardia lamblia

14. The vector for kala-azar is:
(A) Sandfly
(B) Tsetse fly
(C) Aedes mosquito
(D) Tick

15. Which protozoa causes sleeping sickness?
(A) Giardia
(B) Leishmania
(C) Trypanosoma brucei
(D) Plasmodium

16. Chagas disease is caused by:
(A) Trypanosoma cruzi
(B) Leishmania donovani
(C) Plasmodium falciparum
(D) Toxoplasma gondii

17. The causative agent of giardiasis is:
(A) Entamoeba histolytica
(B) Giardia lamblia
(C) Cryptosporidium
(D) Balantidium coli

18. The most common cause of traveler’s diarrhea is:
(A) Vibrio cholerae
(B) E. coli (ETEC)
(C) Salmonella typhi
(D) Shigella

19. The Widal test is used for diagnosis of:
(A) Tuberculosis
(B) Typhoid fever
(C) Leptospirosis
(D) Cholera

20. Rose spots are seen in:
(A) Typhoid fever
(B) Measles
(C) Rubella
(D) Malaria

21. The causative agent of cholera is:
(A) Vibrio cholerae
(B) E. coli
(C) Shigella
(D) Salmonella

22. Rice-water stools are seen in:
(A) Cholera
(B) Typhoid
(C) Dysentery
(D) Amebiasis

23. The vector of plague is:
(A) Rat flea
(B) Sandfly
(C) Tsetse fly
(D) Mosquito

24. The causative agent of plague is:
(A) Yersinia pestis
(B) Bacillus anthracis
(C) Brucella
(D) Salmonella

25. Weil’s disease is caused by:
(A) Leptospira interrogans
(B) Brucella
(C) Treponema pallidum
(D) Borrelia burgdorferi

26. The causative agent of syphilis is:
(A) Neisseria gonorrhoeae
(B) Treponema pallidum
(C) Haemophilus ducreyi
(D) Chlamydia trachomatis

27. The chancre of syphilis appears in:
(A) Primary stage
(B) Secondary stage
(C) Tertiary stage
(D) Latent stage

28. Hutchinson’s teeth are a feature of:
(A) Sickle cell anemia
(B) Congenital syphilis
(C) Rickets
(D) Lead poisoning

29. The causative agent of gonorrhea is:
(A) Neisseria meningitidis
(B) Neisseria gonorrhoeae
(C) Chlamydia trachomatis
(D) Haemophilus ducreyi

30. The causative agent of chancroid is:
(A) Treponema pallidum
(B) Chlamydia trachomatis
(C) Haemophilus ducreyi
(D) Klebsiella granulomatis

31. The causative agent of lymphogranuloma venereum (LGV) is:
(A) Haemophilus ducreyi
(B) Chlamydia trachomatis
(C) Neisseria gonorrhoeae
(D) Klebsiella granulomatis

32. Donovan bodies are seen in:
(A) LGV
(B) Granuloma inguinale
(C) Chancroid
(D) Syphilis

33. The vector of dengue is:
(A) Anopheles mosquito
(B) Aedes aegypti mosquito
(C) Culex mosquito
(D) Sandfly

34. Dengue fever is also known as:
(A) Breakbone fever
(B) Blackwater fever
(C) Relapsing fever
(D) Yellow fever

35. The causative agent of yellow fever is:
(A) Flavivirus
(B) Togavirus
(C) Paramyxovirus
(D) Reovirus

36. Which hemorrhagic fever is spread by Aedes mosquito?
(A) Yellow fever
(B) Dengue
(C) Zika virus
(D) All of the above

37. The causative agent of AIDS is:
(A) HTLV
(B) HIV (Retrovirus)
(C) EBV
(D) Hepatitis B virus

38. CD4 cells are primarily targeted in:
(A) Hepatitis B
(B) HIV infection
(C) Tuberculosis
(D) Measles

39. The most common opportunistic infection in HIV is:
(A) Pneumocystis jirovecii pneumonia
(B) Tuberculosis
(C) CMV infection
(D) Cryptococcus

40. Oral thrush in HIV is caused by:
(A) Candida albicans
(B) Cryptococcus
(C) Aspergillus
(D) Mucor

41. The causative agent of meningococcal meningitis is:
(A) Neisseria meningitidis
(B) Streptococcus pneumoniae
(C) Haemophilus influenzae
(D) Listeria monocytogenes

42. The causative agent of tetanus is:
(A) Clostridium perfringens
(B) Clostridium tetani
(C) Clostridium botulinum
(D) Clostridium difficile

43. The toxin of Clostridium botulinum causes:
(A) Spastic paralysis
(B) Flaccid paralysis
(C) Muscle rigidity
(D) Seizures

44. Gas gangrene is caused by:
(A) Clostridium tetani
(B) Clostridium perfringens
(C) Clostridium botulinum
(D) Clostridium difficile

45. Which organism causes pseudomembranous colitis?
(A) Salmonella
(B) Shigella
(C) Clostridium difficile
(D) Vibrio cholerae

46. The causative agent of Lyme disease is:
(A) Treponema pallidum
(B) Borrelia burgdorferi
(C) Leptospira
(D) Rickettsia

47. Erythema migrans is seen in:
(A) Syphilis
(B) Lyme disease
(C) Measles
(D) Dengue

48. Rocky Mountain spotted fever is caused by:
(A) Rickettsia rickettsii
(B) Rickettsia prowazekii
(C) Borrelia
(D) Coxiella burnetii

49. Q fever is caused by:
(A) Coxiella burnetii
(B) Rickettsia typhi
(C) Brucella
(D) Bartonella

50. Cat scratch disease is caused by:
(A) Bartonella henselae
(B) Pasteurella multocida
(C) Brucella
(D) Francisella tularensis