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PERTUSSIS (Whooping cough) – Rates, by year, United States, 1957-1984
A total of 2,276 cases of pertussis were reported in the United States in 1984, a decrease of 8% from 1983. Between 1974 and 1984, the annual number of reported cases ranged from 1,010 to 2,463. Because of problems in the clinical and laboratory diagnosis of pertussis and because of different case criteria used by the individual states, it is likely that many cases of pertussis in the United States go unreported.
PERTUSSIS (Whooping cough) – Rates, by state, United States, 1984
Only North Dakota and the District of Columbia did not report cases of pertussis in 1984. Seven states reported 100 or more cases - Washington (326), Indiana (259), Oklahoma (247), California (163), New York (129), Wisconsin (114), and Hawaii (102) - and accounted for 1,340 (59%) of the 2,276 cases.
PERTUSSIS (Whooping cough) — Rates,' by age group, United States, 1984
'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.
Because of the continued high level of vaccine coverage-95% or greater of all children entering school since 1981 - the overall risk of pertussis remains small. However, 62% of 2,276 reported cases in 1984 were in persons less than 5 years old, and 38% were in those less than 1 year old. Supplementary information on 1,968 pertussis cases with onset in 1984 indicates that among the 840 (43%) of these patients who were less than 1 year old, 613 (73%) were hospitalized, 209 (25%) had pneumonia, 28 (3%) had at least one seizure, and 11 (1%) died. Pertussis remains a disease with substantial health impact, particularly among infants. Further reduction in the incidence of the disease requires continued efforts to ensure ageappropriate administration of DTP vaccine, especially among infants, as recommended by the Immunization Practices Advisory Committee.
PLAGUE – Cases in humans, by year, United States, 1955-1984
Thirty-one cases of human plague were reported in the United States during 1984, more than twice the average annual incidence in the period 1973-1982 (13.9 cases/year), but fewer than the 40 cases reported during 1983. Six (19.4%) of the cases were fatal. Patients ranged in age from 14 months to 70 years, but unlike previous years, most cases occurred in persons older than 20 years. One case occurred in the O- to 9-year age group, and nine in the 10- to 19-year age group. Twenty-three of the patients (74.2%) were male. Four patients contracted secondary plague pneumonia and were potentially infective to others via the respiratory route. Two patients had plague meningitis and four presented with primary plague septicemia. The remaining patients had bubonic plague.
As in past years, most of the patients were exposed to infection in New Mexico (16 cases, 51.6%). California reported six cases, a record number since 1924; Colorado reported three cases; and Arizona and Utah, two cases each. Texas reported one case, its second indigenous case since 1920; and Washington reported one case, its first case since 1913 and the first outside the Seattle-King County area. One New Mexico patient was hospitalized and died in southern Colorado.
In contrast to recent years, only four (12.9%) of the 31 cases occurred in American Indians; all four were Navajo. American Indians accounted for 52.5% of the cases in 1983, 47.4% of the cases in 1982, and 46.2% of the cases in 1981. The attack rate for Navajos in 1984 was reduced to 2.6 cases/100,000 population from the rate of 12.1/100,000 in 1983.
Evidence of plague infection was detected among mammals and their fleas in 11 western states during 1984.
POLIOMYELITIS (Paralytic) – Rates, by year, United States, 1951-1984
The incidence of paralytic poliomyelitis declined rapidly following the introduction and widespread use of inactivated poliovirus vaccine in 1955 and of oral poliovirus vaccine (OPV) in 1961. In the period 1973-1984, an average of 12 cases of paralytic poliomyelitis were reported each year. Eight cases were reported in 1984.
Of the 138 paralytic poliomyelitis cases reported with onset of illness during the period 1973-1984, 85 (62%) were classified as vaccine-associated and occurred in individuals with no known deficiencies in immune status. Thirty-five (41%) of the 85 cases were in OPV recipients, and the remaining 50 cases were in persons who were known contacts of OPV recipients. Fourteen cases occurred in immune-deficient individuals; 13 were vaccine-associated (11 in OPV recipients and two in contacts). An additional 16 (11%) cases occurred in individuals without a known temporal exposure to either the vaccine or a vaccine recipient, six had poliovirus isolates characterized as vaccine-like, eight had isolates that were characterized as wild, and in two cases no virus was isolated. Only 10 (7%) epidemic cases occurred, all in 1979, and 13 (10%) were classified as imported. The last case of paralytic poliomyelitis caused by wild virus in the United States was in an immune-deficient individual in 1981.