Which of the following diseases is highly contagious and primarily spreads through respiratory droplets?

Measles is highly contagious and primarily spreads through respiratory droplets, making it very transmissible among individuals, especially in close quarters. The virus can remain active and contagious on surfaces and in the air for a significant period, sometimes up to two hours after an infected person has left the area. This airborne transmission underscores the importance of vaccination for measles to maintain herd immunity and protect those who may be more vulnerable, such as infants and individuals with weakened immune systems.

In contrast, while diphtheria can spread through respiratory droplets, it is less contagious compared to measles. Tetanus does not spread from person to person; instead, it is caused by a toxin from bacteria entering the body through wounds. Polio is primarily transmitted through fecal-oral routes rather than respiratory droplets, further distinguishing it from measles. Understanding these differences is crucial for public health strategies aimed at controlling the spread of infectious diseases.