A complicated relationship – the effect of community sanitation usage on worm infections in Ethiopian children

A toilet in Amhara, Ethiopia
24 March 2017

Globally, in 2010, an estimated 1.5 billion people were infected with at least one species of soil-transmitted helminth (STH), Ascaris lumbricoides, Trichuris trichiura and hookworm.

To control these infections, the World Health Organization recommends periodic mass deworming programmes of at risk populations including pre-school and school aged children. To support the long-term success of these deworming programmes it is widely accepted that communities need adequate sanitation, meaning access to and use of toilet facilities.   

Newly published research led by Dr William Oswald from the London Applied & Spatial Epidemiology Research group (LASER), seeks to build the evidence-base around this relationship between higher community sanitation usage and lower STH infections.

The analysis draws on data collected from population-based surveys and stool samples collected over a three year period to look at the association between the proportion of households in a community with latrines in use and the prevalence of STH infection among school-aged children in Amhara, Ethiopia.

The dataset linked community, household and individual information from over 11,000 children with complete parasitological results.

The data showed that children in communities with lower sanitation usage were on average poorer, with less household education and access to health facilities, than those in communities with higher sanitation usage.

The analysis did not find evidence that increased community sanitation usage offered the children surveyed increased protection against STH infection. Indeed, in the case of Trichuris trichiura and Ascaris lumbricoides STH species, prevalence of infection was higher in communities where more latrines were in use.  

These findings contrast with current understanding of the relationship between community sanitation and STH infections. Potential explanations for these findings range from the parasite infections pre-dating sanitation improvements to the impact of families sharing toilet and washing facilities.

The research highlights the complexity of the relationship between community sanitation and improved health outcomes and the need for continued investigation of the multiple factors impacting on infection rates. 

Further information

Download: Oswald et al. Association of community sanitation usage with soil-transmitted helminth infections among school-aged children in Amhara Region, Ethiopia. Parasites & Vectors (2017) 10:91

This paper was published as part of Parasites & Vectors’ London Centre for NTD Research Article series