Environmental contamination and risk factors for geohelminth transmission in three informal settlements in Durban metropole, South Africa

Abstract

Informal settlements/slums are characterised by a lack of adequate sanitation and safe drinking water. Contaminated soil and water sources combined with poor hygiene and environmental conditions results in the transmission of soil transmitted helminths to humans. The aim of the present study was to assess environmental contamination and risk factors for geohelminth transmission in three informal settlements in Durban, South Africa. Each settlement had different types of sanitation facilities namely; flush toilets, pit latrines and chemical toilets. Thirty adult members from 30 households from each settlement were interviewed to determine their knowledge, attitudes and behaviour on geohelminth transmission. Furthermore, two hundred soil samples were collected from areas considered potential sources of infection and processed for the detection and identification of geohelminth eggs. Prevalence and intensities of geohelminth infections from school-age children were also assessed. From the total collection in the three settlements, 31.6% (95/190) were positive for geohelminth eggs with Ascaris lumbricoides, Trichuris trichiura and Taenia spp. eggs being recovered. Quarry Road West (57%; 114/200) showed the highest levels of soil contamination followed by Briardene (27%; 54/200) and Smithfield (11%; 22/200). Stool samples collected from 135 children were found to contain parasite eggs of A. lumbricoides and T. trichiura. Prevalences and intensities of infection were highest in Quarry Road West for both A. lumbricoides (42%, 57/135; 6.0eggs/g) and T. trichiura (10%, 14/135; 1.9eggs/g) and 9.6% (13/135) harboured dual infections. Open defaecation by community members was observed as the main contributing factor for the presence of geohelminth eggs in soil.

Keywords: Geohelminth eggs; Infection rates; Informal settlements; Sanitation; Soil contamination.

Fig. 1

Map of South Africa showing the locations of the three study settlements

Fig. 2

Mean geohelminth prevalences of Ascaris lumbricoides, Trichuris trichiura and dual infection recorded in the three study settlements (N = 47 in Briardene, N = 50 in Quarry Road West and N = 38 in Smithfield)

Fig. 3

Intensities of Ascaris lumbricoides and Trichuris trichiura infection (geometric mean eggs/g faeces ± SE) in 135 children aged 1–16 years in the three study settlements (N = 47 in Briardene, N = 50 in Quarry Road West and N = 38 in Smithfield)