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*Rates were calculated by multiplying the percentage of cases with known age group by total reported cases and dividing by the population in that age group.
The 1984 reported age-specific incidences of rubella declined or remained constant for all age groups. Children 0-4 years of age continued to have the highest overall incidence (1.4 cases/100,000 population) and accounted for one-third of all cases with age reported. Incidence declined by 25% in persons under 15 years old. The incidence for persons 15 years of age or older, who accounted for 48% of the cases, declined by 13% between 1983 and 1984 as a result of continued efforts to identify and vaccinate susceptible persons of childbearing age, particularly postpubertal females.
RUBELLA (German measles) Age distribution and incidence of reported rubella cases, United States, 1982-1984
Grand Total 2,325 100.0 1.0 970 100.0 0.4 752 100.0 0.3
-70 *Reported number of cases per 100,000 population, extrapolated from the age distribution of cases with known age.
RUBELLA Incidence of reported rubella and of congenital rubella syndrome (CRS), United States, 1966-1984
1966 '67 68 69 70 71 72 73 74 75 76 '77 '78 79 80 81 82 83 84
*Includes proration of cases of unknown age in > 15-year-olds. tRate per 100,000 births of confirmed and compatible cases of CRS by year of birth. Reporting for recent years is provisional, as cases may not be diagnosed until later in childhood. Average annual United States estimate based on data from Illinois, Massachusetts, and New York City for the 3-year periods 1966-1968, 1969-1971, and 1972-1974. Age-specific data were not available for U.S. totals until 1975.
Recent declines in rates of congenital rubella syndrome (CRS), recorded by the National Congenital Rubella Syndrome Register (NCRSR), parallel the decline in overall rubella incidence and, more specifically, in the incidence for persons 15 years of age or older. In the period 1979-1984, the reported rate of rubella among persons in this group declined 96%, from 4.8 to 0.2 cases/100,000 population. Similarly, reported data showed that 57 confirmed and compatible cases of CRS occurred in 1979 and that only two such cases occurred in 1984 (a 96% decline). The number of cases of CRS declined by 72% between 1983 (seven cases) and 1984.' It is important to note, however, that although there have been decreases in the number of reported cases of CRS, the reported figure is believed to underestimate the actual total.
*Cases reported to the MMWR have been reclassified by date of birth rather than date of report and stratified into confirmed and compatible cases. Annual totals may change as a result of delayed diagnosis and reporting. (CDC. Rubella and congenital rubella - United States, 1983; MMWR 1984;33: 237-42,247).
SALMONELLOSIS (excluding typhoid fever) – Rates, by year, United States, 1955-1984
A slight decrease in reported cases of human salmonellosis was noted in 1984. This decrease most likely represents annual variation rather than a reversal of the secular trend toward increasing rates of salmonellosis in the United States. This steady increase in reported rates is thought to reflect increasing incidence of the disease rather than more efficient reporting. Thirty-six percent of all salmonellosis cases reported with known age in 1984 occurred in children less than 5 years old, although the rate of increase in reported cases of salmonellosis was greater once again in 1984 among older age groups.
SHIGELLOSIS - Rates, by year, United States, 1956-1984
For 1984, 17,371 cases of shigellosis were reported in the United States. Approximately 70% of the Shigella isolates reported to CDC each year are Shigella sonnei, with Shigella flex, neri accounting for a large percentage of the rest. Contrasting Salmonella and Shigella infections shows that Salmonella is most frequently isolated from children less than 1 year of age. whereas Shigella is most commonly isolated from 2-year-olds. The two highest peaks in incidence of Shigella infections during the past decade are unexplained.