All of the statement regarding measles are true except-
**Core Concept**
Measles is a highly contagious viral disease caused by the measles virus, primarily affecting the respiratory system and resulting in a characteristic rash. The measles virus is a member of the paramyxovirus family, with a high viral load and rapid replication rate contributing to its contagious nature.
**Why the Correct Answer is Right**
Measles virus infection leads to the formation of IgM antibodies, which appear in the blood 7-10 days after the onset of symptoms. The measles virus also causes the destruction of the respiratory epithelium, leading to the characteristic symptoms of cough, coryza, and conjunctivitis. Additionally, measles virus infection can lead to complications such as otitis media, pneumonia, and encephalitis, particularly in malnourished or immunocompromised individuals.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because measles is not caused by a bacterium, but rather by a virus.
**Option B:** This option is incorrect because while measles is highly contagious, it is not spread through the air by coughing or sneezing; rather, it is spread through respiratory droplets and close contact with an infected individual.
**Option C:** This option is incorrect because measles can lead to complications, but it is not typically associated with the development of autoimmune disorders such as multiple sclerosis.
**Clinical Pearl / High-Yield Fact**
The measles vaccine is a live attenuated vaccine, which provides immunity against measles virus infection for up to 10 years after vaccination. It is essential to note that the measles vaccine is not effective in individuals with immunodeficiency disorders and should not be administered to such individuals.
**Correct Answer:** D