Scarlet Fever

What is Scarlet Fever?

Scarlet fever is an acute infectious disease, manifested by a small-dotted rash, fever, general intoxication, and sore throat. The causative agent of the disease is group A streptococcus. Infection occurs from patients with airborne droplets (when coughing, sneezing, talking), as well as through household items (dishes, toys, underwear). Patients are especially dangerous as sources of infection in the first days of the disease.

Brief historical information
The clinical description of the disease was first made by the Italian anatomist and doctor D. Ingrassia (1564). The Russian name of the disease comes from the English scarlet fever – “purple fever” – so called scarlet fever at the end of the XVII century. Streptococcal etiology of scarlet fever, suggested GN. Gabrichevsky and I.G. Savchenko (1905), proved by the works of V.I. Ioffe, I.I. Levin, the spouses Dick, F. Grifft, and R. Lansfield (30s-40s of the 20th century). A great contribution to the study of the disease made N.F. Filatov, I.G. Savchenko, A.A. Koltypin, V.I. Molchanov and other famous Russian doctors.

Causes of Scarlet Fever

The causative agent is streptococcus group A (S. pyogenes), which also causes other streptococcal infections – tonsillitis, chronic tonsillitis, rheumatism, acute glomerulonephritis, streptoderma, erysipelas, etc.

Beta-hemolytic toxigenic streptococcus group A colonizes the nasopharynx, less often the skin, causing local inflammatory changes (angina, regional lymphadenitis). Exotoxin produced by him causes symptoms of general intoxication and exanthema. Streptococcus under conditions conducive to microbial invasion, causes a septic component, manifested by lymphadenitis, otitis, septicemia. In the development of the pathological process, an important role is played by allergic mechanisms involved in the occurrence and pathogenesis of complications in the late period of the disease. The development of complications is often associated with streptococcal superinfection or reinfection.

The reservoir and source of infection is a person suffering from angina, scarlet fever and other clinical forms of respiratory streptococcal infection, as well as “healthy” carriers of group A streptococcus. The patient is most dangerous to others in the first days of illness; its contagiousness stops most often after 3 weeks from the onset of the disease. The carriage of group A streptococci is widespread among the population (on average, 15–20% of the healthy population); Many carriers emit a pathogen over a long period of time (months and years).

The transmission mechanism is aerosol, the transmission route is airborne. Typically, infection occurs with prolonged close contact with the patient or carrier. There are alimentary (food) and contact (through contaminated hands and household items) infection paths.

The natural susceptibility of people is high. Scarlet fever occurs in individuals who do not have antitoxic immunity when they are infected with toxigenic strains of bacteria that secrete erythrogenic toxins of types A, B and C. Post-infectious immunity is type-specific; in case of infection with streptococci of group A of another serovar, repeated disease is possible.

Major epidemiological signs. The disease is widespread; more often it is found in regions with a temperate and cold climate. The overall level and dynamics of the long-term and monthly incidence of scarlet fever mainly determine the incidence of preschool children attending organized groups. Every year, children attending child care facilities fall ill 3-4 times more often than children raised at home. This difference is most pronounced in the group of children of the first 2 years of life (6–15 times), while among children of 3–6 years it is less noticeable. Among these same groups, the highest rates of “healthy” bacterial carriers are noted.

Scarlet fever is associated with previous diseases of tonsillitis and other respiratory manifestations of streptococcal infections that occur in preschool institutions, especially soon after their formation. The incidence in the autumn-winter-spring period is the highest.