Measles

[Sonia]

A contagious febrile disorder commencing with catarrhal
symptoms, and marked by the appearance on the third day of an eruption
of distinct red circular spots, which coalesce in a crescentic form,
are slightly raised above the surface, and after the fourth day of the
eruption gradually decline; rubeola.

[Monty]

An infectious viral disease causing fever and a red rash, typically occurring in childhood.

[Sonia]

The frequently deadly disease that anti-vaxxers are willing to expose their children to out of an unfounded fear of autism. Can cause [blindness], [sterility], heart damage and life long complications, but hey, its better dead than slightly non-neurotypical.
See also [whooping cough].

[Rihanna]

Measles is a highly contagious viral infection that causes various cold-like symptoms and a characteristic rash.

Measles is caused by a virus.
Symptoms include fever, runny nose, hacking cough, red eyes, and a red itchy rash.
The diagnosis is based on typical symptoms and the characteristic rash.
Although the majority of children recover, occasionally measles can be fatal or lead to brain damage.
Routine vaccination can prevent the infection.
Treatment is aimed at relieving symptoms.

Before measles vaccination became widely available, measles epidemics occurred every 2 or 3 years, particularly in preschool-aged and school-aged children. Small, localized outbreaks occurred during the other years. Measles is still common in other countries. Worldwide, each year, measles infects about 20 million people and causes about 110,000 deaths, primarily in children. In the United States, measles is uncommon because of routine childhood vaccination. From 2000 to 2007, an average of only 63 cases per year were reported to the Centers for Disease Control and Prevention (CDC). Now, however, measles cases are increasing in the United States. In the first 6 months of 2019, over 1,000 cases of measles were reported to the CDC. This increase is the result of fewer children receiving the measles vaccine and the result of infection that is spread by travelers or immigrants from areas where measles is more common. Infection that is spread by travelers or immigrants especially occurs in places where many people group together (such as college campuses) or communities that limit contact with outsiders (such as traditional-observant Jewish communities, Amish, and Mennonites).
A woman who has had measles or has been vaccinated passes immunity (in the form of antibodies) to her child. This immunity lasts for most of the first year of life. Thereafter, however, susceptibility to measles is high unless vaccination is given. A person who has had measles develops immunity and typically cannot contract it again.
Children become infected with measles by breathing in small airborne droplets of moisture coughed out by an infected person. About 90% of people who are not immune to measles develop the disease after they are exposed to a person with measles. Measles is contagious from several days before until several days after the rash appears.