Measles (morbilli) is a highly contagious acute viral infection, manifested by high (febrile) temperature, specific exanthema, symptoms of General intoxication, generalized inflammatory damage to the pharynx, conjunctiva and respiratory organs. The contagious index of measles is almost 100%, i.e. the risk of infection in an unvaccinated person who comes into contact with the patient is extremely high. The disease remains one of the leading causes of death among young children worldwide.
Causes of measles
The causative agent of the disease is an RNA virus belonging to the genus Morbillivinis (family Paramyxoviridae). It is characterized by poor resistance to environmental conditions: it is inactivated when exposed to ultraviolet radiation, sunlight, drying, and disinfection. Heating up to 50 C is also detrimental to the virus. At room temperature, it remains viable for a maximum of 1 or 2 days, but usually no longer than 4 hours. To maintain activity for several weeks, it needs a low temperature – the optimal temperature range is from -15 to -20 0C.Despite the low resistance in the external environment, there are cases of spread of strains over a long distance through the ventilation system in a detached building. The source and reservoir of viruses is a sick person. They are spread by airborne droplets. A large amount is released with mucus when coughing, sneezing or just talking, starting from the last 2 days of the latent period, throughout the prodromal period, and continuing until 4 days of rashes. The patient is not dangerous to others from the 5th day from the appearance of spot-papular rash. Sometimes the period of contamination lasts up to 10 days from the beginning of the formation of the exanthemum. Cases of asymptomatic infection were not detected. Children under 5 years of age are more likely to get measles. Adults who have not undergone mandatory vaccination are less likely to get sick, but their risk of infection is very high, and the disease is more severe than in children. In the spring-winter period, there is a peak in the incidence, and the decline occurs in August and September. After recovery, the immune system remains stable for life with the preservation of anti-measles antibodies in the blood. Newborns whose mothers have had measles have colostral (maternal) immunity that lasts up to 3 months of the baby’s life. Therefore, infection with measles in these months is unlikely. Known isolated cases of intrauterine infection of the fetus from a mother who contracted measles during gestation. Currently, there is a decrease in the incidence of measles due to total routine vaccination in many countries of the world. Only mini-epidemics or isolated cases of infection are detected.
Prevention of measles
The most reliable prevention of measles is routine vaccination with live measles vaccine, carried out in accordance with the developed vaccination calendar, to create active immunity against measles viruses. The first combination vaccine against three infectious diseases – mumps, measles and rubella – is one year old kids ceases to operate when passive (innate) immunity transferred to them through the placenta from the mother. It is allowed to introduce associated vaccines against these infections on the same day with vaccination against diphtheria, polio, tetanus, hepatitis B, chickenpox, etc.the question of simultaneous vaccination is decided by a pediatrician for each child individually, based on the state of his health. The next vaccination (revaccination) is given to children at the age of 6 before starting school. Adolescents up to and including 17 years of age and adults up to 35 years of age who have not been vaccinated and have not been ill before are also given the measles vaccine. According to the instructions, it is necessary to make two vaccinations, the interval between which should not be less than 3 months. People who are in the zone of an epidemic outbreak and have not previously been vaccinated are shown mandatory vaccination regardless of their age.
A national laboratory for measles diagnostics has been established in Belarus on the basis of the laboratory of immunoprophylaxis of the RSPC of epidemiology and Microbiology. It works in full compliance with international standards and in close collaboration with similar laboratories in other countries, and is part of the who laboratory network. Belarusian specialists not only isolate measles viruses from patients, but also study them using the most modern molecular genetic methods. The received information is provided to an international database. Comparison of viruses isolated in Belarus with those circulating in other countries and regions allows us to determine the origin of the virus and determine the source of importation.
By the way
In Belarus, children have been vaccinated against measles once since 1967, and since 1987 they have been vaccinated twice – at 12 months and 6 years. These two vaccinations are enough to create a lifetime of immunity to this disease. How effective this measure is is shown by this fact: before the introduction of vaccination in Belarus, 50 to 80 thousand people fell ill with measles every year. Since the beginning of its use, the incidence has decreased by tens of thousands of times. And in the last decade, only isolated cases were registered, imported from Germany, Italy, Russia, Armenia, Thailand, and India, not counting this year and 2006, during which 149 measles patients were detected in Belarus. This was due to multiple imports of the virus from Ukraine, where in the same year the number of cases of measles exceeded 44 thousand people. In some years (for example, in 2008 and 2009), measles was not registered in Belarus at all.