If someone gets measles, the first symptoms are irritability, runny nose, red, sensitive, watery eyes, hacking cough and fever. Then they often get characteristic small, red, irregularly shaped spots with bluish-white centers appear in the mouth, and 1-2 days later a characteristic rash appears on the forehead and spreads downward, and the fever peaks. When the rash reaches the feet, the illness is nearing it's end, and usually lasts another 2 weeks. The rash fades in the same order it appeared.
There are many possible complications of measles, like croup, bronchitis(infection of large lung tubes), bronchiolitis(infection of small lung tubes), pneumonia, conjuctivitis(pink-eye), myocarditis(infection of the heart), hepatitis(infection of the liver), meningitis(infection of the mesh holding the brain in place) and/or encephalitis(infection of the brain). Complications are more common in adults and babies with measles than in children. They are also more common in children with immune dysfunction. Measles is highly infectious, and 90% of those living in the same house as someone with measles will get it if not vaccinated. If a pregnant woman gets measles, her baby has an increased chance of miscarriage, premature birth and low birth weight, but there is no characteristic "Congenital Measles Syndrome".
If someone gets mumps, the first symptoms are fever, headache and lack of appetite. Then their salivary glands swell, causing the characteristic neck lumps which look like a hamster carrying food in xyr cheeks. One or both salivary glands may be affected, and one will often swell before the other. Over a period of 1-3 days, the swollen glands get more painful and hurt especially when the person swallows, talks, chews or drinks acidic juice(such as pop drinks). In rare cases other salivary glands swell, under the tongue, under the jaw, or all the way down the front of the chest.
Complications of mumps usually involve swelling of other glands or organs, such as encephalitis, meningitis, orchiditis(swelling of testicles), pancreatitis(swelling of the pancreas), arthritis, kidney problems, deafness, thyroiditis(thyroid swelling) and/or ovarian swelling. Adults are more likely to have complications, especially orchiditis(which affects 50% of adult/adolescent males who get mumps). Some people get mumps without any symptoms. It is estimated that 1/3-1/5 of people with mumps have no symptoms. If someone gets mumps during pregnancy, the baby may be miscarried or stillborn, but there is no "Congenital Mumps Syndrome".
If someone gets rubella, the first symptoms are mild fever and swollen, tender lymph nodes. After 1-2 days a rash appears, starting on the face and spreading downward. The rash on the face clears as it spreads downward, rather than after it reaches the feet as in measles. Especially in adolescents or adults, symptoms may also include conjuctivitis, headache, loss of appetite, stuffy/runny nose, and joint swelling(especially in young women).
Rubella is a mild illness, and the reason there is a vaccination for it is that prenatal rubella infection causes Congenital Rubella Syndrome in 30% of exposed babies, which is a syndrome of slow growth, slow learning, heart defects, low vision or blindness, deafness and/or liver/spleen/bone marrow problems. The most common characteristics of congenital rubella syndrome are cataracts, heart problems, deafness and slow learning.
Measles, mumps and rubella have not been eliminated like smallpox. In fact, measles is a common illness in countries without widespread vaccination. And there have been some outbreaks of vaccine-preventable illnesses in unvaccinated people, mostly children, in countries with widespread vaccination. In fact, some scientists are worried that measles could become endemic in UK as it was before vaccination.
In terms of the autistic toddler skill loss, there is some evidence to suggest it is mainly due to developmental stage. In autistic down syndrome children, the skill loss usually occurs between the ages of 3-7 years, instead of 1 1/2-3 years in chromosomally normal autistic children. Since the average IQ of DS people is 50 instead of 100, they tend to reach developmental stages at twice the normal age, which would mean they'd be at the developmental stage of an 18-36 month-old at their usual age of skill loss.