Children's airborne infections. Measles. Prevention
Childhood infections are the most common infectious diseases that occur more often or almost exclusively in childhood and even mainly in early or preschool age. Infectious diseases used to occupy the first place in the structure of childhood mortality. But over the years, various studies by immunologists, microbiologists, and virologists have been carried out: a stable system for combating childhood infections has been developed, as a result of which significant successes have been achieved.
In our country, morbidity has decreased sharply - up to the elimination of individual nosological forms, mortality has decreased for all infections; childhood infections have almost lost their significance in the mortality of the population.
Transmission routes, the mechanism of infection, primarily depends on the localization of the infection in the body, which determines the method of excretion of the pathogen into the environment. In infections with damage to the nose and respiratory tract, transmission occurs by airborne droplets (measles, whooping cough, influenza, and others).
In airborne infections, pathogens during coughing, sneezing, talking with mucus from the throat, respiratory tract enter the environment: the mucus is sprayed into small particles that surround the patient. The infection persists in the air, from here it enters the throat and respiratory tract of a healthy child.
Measles is an acute infectious disease of a viral nature, which occurs with a characteristic fever, generalized damage to the mucous membranes of the respiratory tract, mouth, throat and eyes, is accompanied by rashes and frequent complications from the respiratory system.
The causative agent of measles belongs to micro viruses, which is secreted from the mucus of the nasopharynx and from the patient's blood during the catarrhal period and at the beginning of the rash. The virus is pathogenic for humans and some species of monkeys. It is not stable in the external environment, in the air in daylight, in droplets of saliva it dies within half an hour; when dried, it dies immediately, when heated to 500C - within 15 minutes, at 600C and above - immediately. At low temperatures and in the dark, it can be stored for a long time, at +40C - up to several weeks, and at -150C or lower - up to several months.
The source of infection is a patient with any form of measles, including a weakened form that occurs as a result of passive immunization, as well as patients who fell ill despite active immunization. A patient with measles is contagious in the last 1-2 days of incubation, in the catarrhal period, in the first 3 days of rashes.
The route of transmission of infection is airborne.
Susceptibility to measles is very high, the contagion coefficient approaches 100%. Children of the first 3 months have innate immunity, transmitted from the mother. After 3 months. immunity decreases and by 6-8 months. disappears. After measles of any form, the body becomes immune for life: the corresponding antibodies are stored in the blood.
The incidence of measles is highest at the age of 2 to 7 years, then it decreases, and after 14 years only a few isolated cases are recorded.
As for all airborne infections, measles is characterized by seasonal fluctuations, the maximum of which falls on the winter-spring months - from December to May.
The incubation period is 9-10 days; in children who were administered gamma globulin during the incubation period, it can be delayed up to 21 days.
In the course of the disease, 3 periods are distinguished:
1) initial, or catarrhal;
2) rash period4
3) pigmentation period.
Catarrhal period – begins with a runny nose, cough, conjunctivitis, symptoms of general intoxication. Cough is rough, barking. Body temperature rises to 380-390C, general malaise, lethargy, headache, loss of appetite are noted. On the 2-3rd day, red spots of irregular shape appear on the mucous membrane of the hard and soft elevation. On the mucous membrane of the cheeks, and sometimes the lips, small (poppy-seed-sized) spots appear that do not merge with each other and are tightly welded to the tissue (they are not removed with a spatula). They persist for 2-4 days, and after their disappearance, the mucous membrane remains hyperemic and loose for several more days. The catarrhal period lasts 2-3 days, less often it fluctuates from 1-2 to 5-6 days. The temperature is high all this time, and before the appearance of rashes it decreases, sometimes to normal figures.
The rash period begins with a new increase in temperature and increased symptoms of general intoxication. The rash is characterized by a gradual progression. The first elements of the rash appear behind the ears, on the bridge of the nose, then the rash spreads to the face, neck and upper chest. The following 2 days - the trunk, upper limbs, on the 3rd day - the lower limbs. The rashes are severe, in places merge. When they appear, they look like pink roseola or small plaques, later they become brighter, increase, and after a day they lose their plaque-like appearance, change color - to brown, do not disappear when pressed and do not turn into pigment spots in the same order in which the rash appeared - first on the face, gradually on the trunk and legs.
The period of pigmentation lasts 5-6 days and, in the absence of complications, proceeds with a normal temperature. Most children have asthenic symptoms and increased irritability, fatigue, weakness, headache, insomnia for several more days, memory impairment is often observed, sometimes endocrine disorders occur.
Most children who have measles are treated at home. Children with severe forms of the disease, with complications, are subject to hospitalization.
The patient is provided with bed rest, isolated so that he does not contact healthy children.
Drug treatment is not used, or is very limited (symptomatic).
Prevention of measles consists of active immunization, which is carried out with a live attenuated vaccine. After the vaccine is administered, stable long-term immunity develops in 98-99% of cases. Children are vaccinated from 12-15 months. Vaccination is carried out once, by subcutaneous administration of a live vaccine. Clinical reactions to vaccination can occur from the 6th to the 20th day, most often on the 13th-17th day after vaccination. They are mainly weak, expressed by an increase in body temperature to 37.2-37.50C, sometimes minor catarrhal phenomena (runny nose, cough), and last 1-2 days.
Passive immunization consists in the administration of gamma globulin to children who have been in contact with measles patients (who have not had measles before). Gamma globulin contains antibodies, due to which measles does not develop, or occurs in a milder form, depending on the dose of the drug and the time of its administration. Gamma globulin is administered intramuscularly on the 4th-6th day after contact with the patient, at a dose of 3 ml of the drug. Passive immunity is short-lived, no more than 2 weeks, therefore, with repeated contacts, gamma globulin is administered again.