Koplik spot true is ?

Ans. is 'a' i.e., Pathognomic of measls Measle Caused by RNA virus. Highly contagious droplet spread from secretion of nose and throat 4 day before and 5 days after rash. Secondary attack rate >90% in contact. Prodromal phase - characterized by fever, rhinorrhea, conjuctival congestion and dry hackig cough. Koplik spots-bluish-gray specks or "grains of sand" on a red base-develop on the buccal mucosa opposite the second molars Generally appear 1-2 days before the rash and last 3-5 days Pathognomonic for measles, but not always present Rash appears on D4 first behind pinna on neck the spread of face, thrunk and abdomen. SSPE is long term complication seen in measls.