Which disease is characterized by a high degree of contagiousness when an infected person coughs or sneezes?

Measles is characterized by a high degree of contagiousness, particularly when an infected person coughs or sneezes. The virus that causes measles is highly infectious and can spread through respiratory droplets, which are released into the air when an infected individual breathes, coughs, or sneezes. These droplets can remain in the air or on surfaces for extended periods, allowing the virus to infect individuals who are in the vicinity, even after the infected person has left the area.

Furthermore, measles has a very high basic reproduction number (R0), typically ranging from 12 to 18, indicating that one infected person can potentially infect many others. This high level of contagiousness underscores the importance of vaccination to control and prevent outbreaks of the disease.

In contrast, while poliomyelitis, tetanus, and tuberculosis can also be serious, their modes of transmission and degree of contagiousness differ significantly. Poliomyelitis is primarily spread through fecal-oral transmission, tetanus is not contagious and requires a wound for infection, and tuberculosis spreads through airborne particles but is generally less contagious compared to measles.