Measles is an infection caused by a virus, which causes an illness displaying a characteristic skin rash known as an exanthem. Measles is also sometimes called rubeola, 5-day measles, or hard measles.
Measles infections appear all over the world. Prior to the current effective immunization program, large-scale measles outbreaks occurred on a two to three-year cycle, usually in the winter and spring. Smaller outbreaks occurred during the off-years. Babies up to about eight months of age are usually protected from contracting measles, due to immune cells they receive from their mothers in the uterus. Once someone has had measles infection, he or she can never get it again.
Causes and symptoms
Measles is caused by a type of virus called a paramyxovirus. It is an extremely contagious infection, spread through the tiny droplets that may spray into the air when an individual carrying the virus sneezes or coughs. About 85% of those people exposed to the virus will become infected with it. About 95% of those people infected with the virus will develop the illness called measles. Once someone is infected with the virus, it takes about 7–18 days before he or she actually becomes ill. The most contagious time period is the three to five days before symptoms begin through about four days after the characteristic measles rash has begun to appear.
The first signs of measles infection are fever, extremely runny nose, red, runny eyes, and a cough. A few days later, a rash appears in the mouth, particularly on the mucous membrane which lines the cheeks. This rash consists of tiny white dots (like grains of salt or sand) on a reddish bump. These are called Koplik’s spots, and are unique to measles infection. The throat becomes red, swollen, and sore.
A couple of days after the appearance of the Koplik’s spots, the measles rash begins. It appears in a characteristic progression, from the head, face, and neck, to the trunk, then abdomen, and next out along the arms and legs. The rash starts out as flat, red patches, but eventually develops some bumps. The rash may be somewhat itchy. When the rash begins to appear, the fever usually climbs higher, sometimes reaching as high as 105 F (40.5 C). There may be nausea, vomiting, diarrhoea, and multiple swollen lymph nodes. The cough is usually more problematic at this point, and the patient feels awful. The rash usually lasts about five days. As it fades, it turns a brownish color, and eventually the affected skin becomes dry and flaky.
Many patients (about 5–15%) develop other complications. Bacterial infections, such as ear infections, sinus infections, and pneumonia are common, especially in children. Other viral infections may also strike the patient, including croup, bronchitis, laryngitis, or viral pneumonia. Inflammation of the liver, appendix, intestine, or lymph nodes within the abdomen may cause other complications. Rarely, inflammations of the heart or kidneys, a drop inplatelet count (causing episodes of difficult-to-control bleeding), or reactivation of an old tuberculosis infection can occur.
An extremely serious complication of measles infection is swelling of the brain. Called encephalitis, this can occur up to several weeks after the basic measles symptoms have resolved. About one out of every thousand patients develops this complication, and about 10-15% of these patients die. Symptoms include fever, headache, sleepiness, seizures, and coma. Long-term problems following recovery from measles encephalitis may include seizures and mental retardation.
A very rare complication of measles can occur up to 10 years following the initial infection. Called subacute sclerosing panencephalitis, this is a slowly progressing, smoldering swelling and destruction of the entire brain. It is most common among people who had measles infection prior to the age of two years. Symptoms include changes in personality, decreased intelligence with accompanying school problems, decreased coordination, involuntary jerks and movements of the body. The disease progresses so that the individual becomes increasingly dependent, ultimately becoming bedridden and unaware of his or her surroundings. Blindness may develop, and the temperature may spike (rise rapidly) and fall unpredictably as the brain structures responsible for temperature regulation are affected. Death is inevitable.
Measles during pregnancy is a serious disease, leading to increased risk of a miscarriage or stillbirth. In addition, the mother’s illness may progress to pneumonia.
Measles infection is almost always diagnosed based on its characteristic symptoms, including Koplik’s spots, and a rash which spreads from central body structures out toward the arms and legs. If there is any doubt as to the diagnosis, then a specimen of body fluids (mucus, urine) can be collected and combined with fluorescent-tagged measles virus antibodies. Antibodies are produced by the body’s immune cells that can recognize and bind to markers (antigens) on the outside of specific organisms, in this case the measles virus. Once the fluorescent antibodies have attached themselves to the measles antigens in the specimen, the specimen can be viewed under a special microscope to verify the presence of measles virus.
There are no treatments available to stop measles infection. Treatment is primarily aimed at helping the patient to be as comfortable as possible, and watching carefully so that antibiotics can be started promptly if a bacterial infection develops. Fever and discomfort can be treated with paracetamol (acetaminophen). Children with measles should never be given aspirin, as this has caused the fatal disease Reye’s syndrome in the past. A cool-mist vaporizer may help decrease the cough. Patients should be given a lot of liquids to drink, in order to avoid dehydration from the fever.
Some studies have shown that children with measles encephalitis benefit from relatively large doses of vitamin A.
Botanical immune enhancement (with echinacea, for example) can assist the body in working through this viral infection. Homeopathic support also can be effective throughout the course of the illness. Some specific alternative treatments to soothe patients with measles include the Chinese herbs bupleurum (Bupleurum chinense) and peppermint (Mentha piperita), as well as a preparation made from empty cicada (Cryptotympana atrata) shells. The itchiness of the rash can be relieved with witch hazel (Hamamelis virginiana), chickweed (Stellaria media), or oatmeal baths. The eyes can be soothed with an eyewash made from the herb eyebright (Euphrasia officinalis). Practitioners of ayurvedic medicine recommend ginger or clove tea.
The prognosis for an otherwise healthy, well-nourished child who contracts measles is usually quite good. In developing countries, however, death rates may reach 15–25%. Adolescents and adults usually have a more difficult course. Women who contract the disease while pregnant may give birth to a baby with hearing impairment. Although only 1 in 1,000 patients with measles will develop encephalitis, 10– 15% of those who do will die, and about another 25% will be left with permanent brain damage.
Measles is a highly preventable infection. A very effective vaccine exists, made of live measles viruses which have been treated so that they cannot cause actual infection. The important markers on the viruses are intact, however, which causes an individual’s immune system to react. Immune cells called antibodies are produced, which in the event of a future infection with measles virus will quickly recognize the organism, and kill it off. Measles vaccines are usually given at about 15 months of age; because prior to that age, the baby’s immune system is not mature enough to initiate a reaction strong enough to insure long-term protection from the virus. A repeat injection should be given at about 10 or 11 years of age. Outbreaks on college campuses have occurred among unimmunized or incorrectly immunized students.
Measles vaccine should not be given to a pregnant woman, however, in spite of the seriousness of gestational measles. The reason for not giving this particular vaccine during pregnancy is the risk of transmitting measles to the unborn child.
Surprisingly, new cases of measles began being reported in some countries—including the UK — in 2001 because of parents’ fears about vaccine safety. The combined vaccine for measles, mumps,and rubella (MMR) was claimed to cause autism or bowel disorders in some children. However, the World Health Organization (WHO) says there is no scientific merit to these claims. The United Nations expressed concern that unwarranted fear of the vaccine would begin spreading the disease in developing countries, and ultimately in developed countries as well. Parents in Britain began demanding the measles vaccine as a separate dose and scientists were exploring that option as an alternative to the combined MMR vaccine. Unfortunately, several children died during an outbreak of measles in Dublin because they had not received the vaccine. Child mortality due to measles is considered largely preventable, and making the MMR vaccine widely available in developing countries is part of WHO’s strategy to reduce child mortality by two-thirds by the year 2015.