AGENTS AFFECTING HEALTH OF MOTHER AND CHILD IN A RURAL AREA OF KENYA .3. EPIDEMIOLOGY OF MEASLES

  • 1 January 1977
    • journal article
    • research article
    • Vol. 29  (4) , 428-440
Abstract
Between April 1974 and March 1976 surveillance of measles was conducted by 12 fieldworkers making fortnightly home visits among a total population of 24,000 living in nearly 4000 households scattered in variable density throughout an area of 87 km2 in the northern division of the Machakos district, Kenya. The diagnosis of measles was verified by one of the project''s physicians according to standardized procedures and was, whenever possible, supported by virus isolation and serum antibody level determination. Because not all reported patients were actually seen during the period of clinical manifestations, the diagnosis remained doubtful in a number of cases. Incidence and mortality figures were estimated with 95% confidence limits based on the assumption that doubtful cases represent a P of measles of .33 and probable cases a P of .67. The estimated attack rate for the susceptible population 0-15 yr of age was 13.5%. When related to all children, susceptible or not, the attack rate was highest in the 1-2 yr age group (11%). Almost 15% of cases occurred below the age of 1 yr, 1% below 6 mo. of age and 6% between 6 and 8 mo. The estimated case fatality rate was 6.5%, fatality being highest between 1 and 2 yr of age. For the age group 0-15 yr measles accounted for 16.7% of all deaths. The estimated death rate per 100,000 total population was 113. The epidemiological pattern of measles suggests continuous re-introduction of the measles virus in a dispersed population causing micro-outbreaks of the disease in geographically widely separated spots throughout the year, which tends to keep the proportion of susceptibles down and the attack rate during a protracted epidemic relatively low.