Demographic characteristics of the Lambwe Valley population

Abstract

Thirty-four per cent of the population (11 079) in the Lambwe Valley study site was under the age of 10, and 59% were under the age of 20. The population was equally divided among males and females (M/F 0·99). The crude birth rate averaged 45‰; the death rate was 8‰ and the natural increase averaged 37‰. Infant and child mortality was 66‰ and 108‰ respectively. The average household size was 8·4 individuals. The population migrated to the Lambwe Valley primarily from other areas in Kenya, although 13% were from Tanzania. The predominant tribal group was Luo (59%) followed by the Abasuba (38%). A few Luyha and Kisii were also encountered. Population increased by 3·5-fold in the 1960s, followed by a 2·5-fold increase in the 1970s. Due to an aerial spray tsetse control programme, sleeping sickness had a low prevalence in October 1981 (one of 5749). Of 339 individuals confirmed as sleeping sickness patients by hospital records from within the study site 320 (94·3%) were traced to their homes. Mortality in domestic cattle (40%), goats (47%), sheep (55%), and dogs (50%) had occurred over the previous two years during an outbreak of trypanosomiasis.