Field studies in seven villages in representative parts of Guatemala produced evidence of a high community dosage of Shigella and a relative infrequency of Salmonella. Rectal swabs, taken every 2 months from approximately 1,000 children over a period of 2 years and cultured bacteriologically, gave an average infection rate of 6.0% for Shigella, with a range from 0 to 17.2%. The rate for Salmonella was 0.2%.
By periodic prevalence determinations, a seasonal increase in Shigella infection was identified during March through May, although a secondary autumnal increase sometimes occurred. The major frequency of infection was among children aged 2 to 4 years. Infection rates were higher in the lowlands than in the highlands. Less infection occurred among Indians than among non-Indians.