Cultural, social and economic influences on ongoing Schistosoma mansoni transmission, despite a decade of mass treatment, and the potential for change

点击翻译按钮获取中文摘要

Schistosomiasis, commonly known as Bilharzia, is a parasitic disease which infects over 240 million people worldwide. Over 90% of these people live in poor rural communities in sub-Saharan Africa. The disease causes anaemia, abdominal pain, stunted growth and reduced cognitive development in children, and up to 200,000 deaths per year. Over 600 million people live in areas where they are at risk of infection. The eggs of the parasite Schistosoma mansoni, are excreted in human stool, hatch in fresh water and infect snails, where they reproduce asexually to produce 1000s of larvae (called cercariae) per day. These cercariae infect humans by directly burrowing through the skin, and developing into adult worms. The life-cycle is maintained by open defecation, or inadequate containment of human faeces, enabling eggs to reach fresh water sources, followed by contact with infected water through activities such as bathing, swimming, washing clothes or fishing.Current control focuses on drug treatments given annually on a national scale to school children. However, despite over a decade of national control programmes in countries such as Uganda, high infection levels persist in hotspot areas. Drug treatment alone will not reduce the disease in these areas and additional interventions are needed. It is known that improved sanitation and access to clean safe water supplies can stop people from getting infected. However, many areas with the disease lack money and resources to improve sanitation and furthermore, when sanitation is improved, it is not always used. We do not fully understand what makes people alter water and sanitation focused behaviours even in the presence of good facilities.Therefore, the project aims to understand better how people living in endemic communities manage their risk of schistosomiasis and how they might change their behaviour if additional resources were provided.This project has two overlapping parts. In part one, we will work directly with communities who experience a lot of schistosomiasis to establish how people currently try to reduce the risk of infection for themselves and their families as well as the risk of passing those infections on through open defecation. We will work in three villages in Uganda using social science methods to observe people going about their everyday life. We will interview them in groups and individually about their understanding of the disease, its effects, how they get infected and their current and desired strategies for reducing infections in the whole community. These data will be used to build up a picture of high and low risk practices and perceptions of disease risk, and how practices and perceptions vary by gender, age, occupation and other factors.In the second part, this information will be incorporated into household surveys to measure what is needed to change an individual's behaviour. Our methodologies allow us to quantify the ways in which people currently respond to the risks posed by schistosomiasis, and how they might respond if investments in washing, sanitation and hygiene resources in their communities were made. We will also use these models to show how human behaviour is influenced by an understanding of the lifecycle of the parasite, and by knowledge of other people's behaviour.Our findings will help us identify "best bets" for investments likely to reduce transmission and re-infection which are likely to work in the long-term. Results will inform future research studies, where these interventions are tried out at village and regional levels. Together the programme of work we plan will inform us on how best to control and potentially eliminate bilharzia in given areas, helping to improve the health of children in infected communities.