Measles
In 1954, a 13-year-old boy named David Edmonston sat in a hospital bed in the United States. His blood contained the measles virus that scientists would soon isolate and study. John Enders and Thomas C. Peebles took samples from this child to begin their work on the pathogen. They grew the virus in human kidney tissue and later in chick embryo cultures over three years of research. This process created an attenuated strain capable of replicating without causing disease. The resulting vaccine became widely available in the United States in 1963 after Maurice Hilleman further refined it at Merck. Before these breakthroughs, more than two million people died annually from the infection worldwide. The virus spreads through coughs and sneezes as airborne droplets that remain infectious for up to two hours. Nine out of ten non-immune people sharing living space with an infected person will contract the disease. Its reproductive number estimates vary beyond the frequently cited range of 12 to 18, with some reviews suggesting values between 3.7 and 203.3.
Symptoms typically develop 10 to 12 days after exposure to an infected person and last 7 to 10 days. Initial signs include fever often greater than 40 degrees Celsius, cough, runny nose, and inflamed eyes. Small white spots known as Koplik spots form inside the mouth two or three days after symptom onset. A red flat rash usually starts on the face before spreading to the rest of the body three to five days later. The rash begins on the back of the ears or on the face and thereafter covers the entire body. It is caused by the cellular and humoral immune system clearing infected skin cells. The characteristic measles rash changes color from red to dark brown before disappearing. Complications occur in approximately 30% of cases including diarrhea in 8% of patients and middle ear infection in 7%. Pneumonia affects 6% of cases while seizures, blindness, or inflammation of the brain may occur less commonly. One to three out of every 1,000 children who become infected will die from respiratory and neurological complications.
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Common questions
When was the measles vaccine first made available in the United States?
The resulting vaccine became widely available in the United States in 1963 after Maurice Hilleman further refined it at Merck. This followed three years of research where scientists grew the virus in human kidney tissue and chick embryo cultures to create an attenuated strain.
Who isolated the measles virus from a 13-year-old boy named David Edmonston?
John Enders and Thomas C. Peebles took samples from this child to begin their work on the pathogen. They successfully grew the virus in human kidney tissue and later in chick embryo cultures over three years of research.
How many people died annually from measles before breakthroughs occurred?
Before these breakthroughs, more than two million people died annually from the infection worldwide. The virus spreads through coughs and sneezes as airborne droplets that remain infectious for up to two hours.
What are the symptoms of measles Koplik spots and when do they appear?
Small white spots known as Koplik spots form inside the mouth two or three days after symptom onset. Initial signs include fever often greater than 40 degrees Celsius, cough, runny nose, and inflamed eyes.
Why does the characteristic measles rash change color from red to dark brown?
The rash changes color from red to dark brown before disappearing because it is caused by the cellular and humoral immune system clearing infected skin cells. A red flat rash usually starts on the face before spreading to the rest of the body three to five days later.