Question

A child presented with bluish white spots in the mouth followed by a rash. What is the genome of probable diagnosis?

• A. Enveloped virus with single stranded RNA
• B. Naked virus with single stranded RNA
• C. Double stranded Naked RNA
• D. Double stranded Enveloped RNA

Hint:

Think about the classic childhood illness with oral white spots and rash, and recall the family of viruses it belongs to.

Answer 1

The Correct Option is A

Step 1: Identify the diagnosis. The child has bluish-white spots in the mouth (Koplik's spots) followed by a skin rash. This clinical picture is characteristic of Measles (Rubeola).

Step 2: Identify the causative agent. Measles is caused by Measles morbillivirus (MeV), belonging to the family Paramyxoviridae, genus Morbillivirus.

Step 3: Identify the genome type. Measles morbillivirus is a single-stranded, negative-sense, enveloped, non-segmented RNA virus. The nucleocapsid has a helical symmetry and associates with the matrix protein (M) at the base of a double-layered lipid envelope. Therefore, the genome of the measles virus is that of an enveloped virus with single-stranded RNA.

Step 4: Eliminate distractors. Option B is incorrect because Paramyxoviruses are enveloped, not naked. Option C describes Reoviruses, which have double-stranded RNA. Option D is incorrect because the measles genome is single-stranded, not double-stranded.

Conclusion: The correct answer is Option A -- Enveloped virus with single-stranded RNA.