Measles is an infection caused by the measles virus. It spreads through coughing, sneezing, and contact with contaminated surfaces. It usually causes coldlike symptoms and a rash, but sometimes it can be fatal.

Anyone not given the measles vaccine or who has received only 1 dose can get measles. Children who are too young to be vaccinated have a high risk of infection. Unvaccinated people who travel internationally, attend college, or work in a hospital are also at increased risk. People with vitamin A deficiency may have a more severe case.

The first measles symptoms are high fever, runny nose, cough, loss of appetite, and conjunctivitis (red, watery eyes). After a few days, Koplik spots appear inside of the mouth and can look like grains of salt. Shortly thereafter, a rash of red, flat to slightly raised spots develops. It starts on the face and spreads downward to the rest of the body. The symptoms may last for a week after the rash appears. Some people may have a more severe case that can lead to ear infections, diarrhea, pneumonia, or encephalitis (an inflammation of the brain that can be deadly). Measles can cause miscarriage, stillbirth, or premature delivery in pregnant women. An infected mother may also deliver a newborn with measles.

麻疹是由麻疹病毒引起的感染。它通过咳嗽，打喷嚏和接触被污染的表面传播。它通常会引起类似感冒的症状和皮疹，但有时可能是致命的。

未接种麻疹疫苗或仅接种过1剂的任何人都可以接种麻疹。年龄太小而无法接种疫苗的儿童感染的风险很高。出国旅行，上大学或在医院工作的未接种疫苗的人群也面临更大的风险。维生素A缺乏症患者的情况可能更严重。

最初的麻疹症状是高烧，流鼻涕，咳嗽，食欲不振和结膜炎（红色，水汪汪的眼睛）。几天后，口腔内出现Koplik斑点，看起来像盐粒。此后不久，出现红色皮疹，平坦至微凸起的斑点。它从面部开始，并向下扩散到身体的其余部分。皮疹出现后，症状可能会持续一周。有些人的病情可能更严重，可能导致耳部感染，腹泻，肺炎或脑炎（可能致命的脑部炎症）。麻疹可导致孕妇流产，死产或早产。受感染的母亲也可能分娩带麻疹的新生儿。