Final answer:
Koplik spots are pathognomonic for measles, a virus that can cause severe complications and is characterized by distinct symptoms and rash, differentiating it from other conditions like HSV-1.
Step-by-step explanation:
Koplik spots are distinct white lesions on the buccal mucosa and are pathognomonic for measles. Measles, an illness characterized by symptoms such as high fever, conjunctivitis, sore throat, and a macular rash that becomes confluent, can lead to severe complications like pneumonia or encephalitis, particularly dangerous for children. The presence of Koplik's spots is a diagnostic feature that helps distinguish measles from other viral infections like Herpes Simplex Virus Type 1 (HSV-1), which typically presents as cold sores or fever blisters around the mouth but does not cause Koplik spots.