About 85% of the population of two Somali communities harboured soil-transmitted intestinal nematodes and/or protozoa. The commonest parasite (75% in the Lafoole institution and 59% in the Afgoye institution) was Trichuris trichiura. Mixed infections were common. The source of infection is contaminated fields around dwelling quarters, because of indiscriminate defaecation. One of the factors responsible for the higher incidence of hookworm in Lafoole (45%) compared with Afgoye (1.5%) may be the different soil character of the surrounding fields.

In Somali nomads the incidence of intestinal helminths is very low compared with that observed in Somalian closed institutions and practically no Entamoeba infection occurs. Schistosoma haematobium eggs are observed in urine of 50% of adults nomads. Immunological tests reveal that the relative prevalences of leishmaniasis (the lowest), malaria, and toxoplasmosis (the highest) in nomads are similar to those shown by the same techniques in settled communities.

No abstract

The intestinal helminth status of an age-stratified sample (6 to 20 years old) from a Somalian community has been assessed and the typical pattern of highly aggregated parasite distribution found. A reinfection study on a sample of 40 children (treated and untreated with a pentapeptide identical to the active site of the thymic hormone thymopoietin) seemed to indicate that immunological factors play a significant role in modulating the population dynamics of infection in endemic communities.