MICROBIOLOGY

Question 1

Koplik spots are tiny white spots surrounded by bluish-red areola in the buccal mucosa. These spots are associated in which of the following viruses?

A. Rubella
B. Rubeola
C. Chicken pox
D. Small pox

Answer 1

B. Rubeola ✅ (Measles virus)

Explanation:
Koplik spots are pathognomonic (highly characteristic) for Measles (Rubeola virus). They appear as tiny white spots with a bluish-red halo on the buccal mucosa, usually near the second molars.

Clinical Course of Measles (Rubeola):
1. Incubation Period (7-14 days) – No symptoms.

2. Prodromal Phase (2-4 days):
   High fever (up to 104°F or 40°C) 🌡️
   Cough, Coryza (runny nose), and Conjunctivitis (“3 C’s”) 👀👃💨
   Koplik Spots appear 1-2 days before rash onset
3. Exanthem (Rash) Phase (Days 3-5):
   Maculopapular rash starts on face and behind ears → spreads downward to trunk and limbs
   Rash darkens and may desquamate (peel)
4. Recovery Phase (1-2 weeks) – Rash fades in the same order it appeared.

Why the other options are incorrect?
A. Rubella (German Measles) ❌
Causes a milder rash (does not darken)
No Koplik spots
Associated with Congenital Rubella Syndrome if contracted during pregnancy.

C. Chickenpox (Varicella-Zoster Virus) ❌
Characterized by vesicular “dew drop on a rose petal” rash, not Koplik spots.

D. Smallpox (Variola Virus) ❌
No Koplik spots
Rash is centrifugal (starts on face and extremities, then spreads).

Key Takeaway:
Koplik spots are an early sign of Measles (Rubeola) and help distinguish it from other viral exanthems. ✅

Question 2

Baby measles or roseola infantum is caused by what virus?

A. HHV-3
B. HHV-4
C. HHV-5
D. HHV-6

Answer 2

D. HHV-6 ✅ (Human Herpesvirus 6)

Explanation:
Baby measles (Roseola infantum), also known as Exanthem Subitum, is a viral infants and young children (6 months to 2 years old).

Key Clinical Features of Roseola Infantum:
1. High fever (≥ 39-40°C or 102-104°F) 🌡️
Lasts 3-5 days
Child appears well despite fever (“happy fever”)

2. Sudden fever resolution → Maculopapular rash appears
   Pink, non-itchy rash starts on trunk → spreads to face and limbs
   Rash disappears in 1-2 days
3. Other Symptoms:
   Mild upper respiratory symptoms (cough, congestion)
   Occasional febrile seizures (due to rapid temperature rise)

Why the other options are incorrect?
A. HHV-3 (Varicella-Zoster Virus - VZV) ❌
Causes Chickenpox (Varicella) and Shingles (Herpes Zoster)
Vesicular rash, not maculopapular.

B. HHV-4 (Epstein-Barr Virus - EBV) ❌
Causes Infectious Mononucleosis (“kissing disease”)
Symptoms: fever, pharyngitis, lymphadenopathy, splenomegaly.

C. HHV-5 (Cytomegalovirus - CMV) ❌
Causes CMV infection, often in immunocompromised patients or congenital CMV in newborns.

Key Takeaway:
Roseola Infantum (Baby Measles) is caused by HHV-6 and presents with high fever followed by a sudden rash after fever subsides. ✅

Question 3

The primary colonizer of plaque

A. Actinomyces
B. Rods and cocci
C. Fusobacterium
D. Prevotella and Porphyromonas

Question 4

PPE stands for

A. Personal Protective Eyewear
B. Personal Protecting Eyewear
C. Personal Protecting Equipment
D. Personal Protective Equipment

Question 5

Which of the following diseases is not caused by a spirochetes?

A. Syphilis
B. Tuberculosis
C. Leptospirosis
D. NUG/ Vincent’s Disease / Trench mouth

Question 6

A child diagnosed with acute herpetic gingivostomatitis should be treated with which of the following drugs?

A. Oral antivirals
B. Antibiotics
C. Observe
D. Prescribe mouth wash or oral rinse

Question 7

This is a type of candidiasis commonly present in denture-wearing geriatric patients with an incidence of 65%. The disease is seen as localized erythema of the oral mucosa under the patient’s denture.

A. Acute atrophic candidiasis
B. Chronic atrophic candidiasis
C. Hyperplastic candidiasis
D. Acute pseudomembranous candidiasis