News Release

Urgent action needed to tackle impact of bilharzia on early child development

Scientists have discovered that early childhood bilharzia, an infection caused by a parasitic worm that lives in fresh water in the tropics, impacts early child development and educational attainment

Peer-Reviewed Publication

University of Edinburgh

These detrimental effects can be reversed within 6 months after treatment with the drug praziquantel, a new study reveals.

The findings highlight an urgent need to invest in continued mass administration of the drug, which has suffered heavily from the pause in programs tackling the disease during the Covid-19 pandemic.

Bilharzia (schistosomiasis) is the second most parasitic disease (to malaria) in African children.

It affects over 100 million people on the continent, but the drug praziquantel, which is taken as a single dose, is an effective, cheap and safe treatment for the disease. 

Bilharzia damages the urogenital tract leading to the classical symptom of blood in urine. If untreated this can progress to liver, spleen and kidney damage, bladder cancer as well as poor sexual and reproductive health in adulthood.

Previous studies and bilharzia control efforts have focused on older children aged 6 years above and young adults where these classic symptoms are visible.

However, clinical disease seen in older children and young adults is the result of infections contracted in the preschool years.

Scientists at the University of Edinburgh and Zimbabwe working in the Tackling Infections to Benefit Africa (TIBA) Partnership focused on studying early childhood bilharzia in children aged five years and below, a neglected group in terms of research and treatment.  

In earlier studies early childhood bilharzia was found in as many as 3 out of every 10 children aged 3-5 years and this is likely to be an underestimation.

This study, published in the journal PLOS Neglected Tropical Diseases, found that the health impact of early childhood bilharzia extends beyond the physical clinical symptoms, revealing for the first time, that bilharzia impacts early child development (ECD).

ECD provides the building blocks for educational achievement, economic productivity, responsible citizenship, lifelong health, strong communities, and successful parenting of the next generation.

The study funded by the UK National Institutes of Health Research and the British Academy, assessed ECD in rural Zimbabwean children aged 6–72 months in terms of physical development (Eye and Hand Coordination and Gross motor), Personal-Social-Emotional development, Language and Communication development, and Foundations of Learning development (memory and cognition).

The study shows that children with bilharzia score poorly for foundations for learning which represents critical psychometric measures (motivation, aptitude and knowledge), cognitive skills for learning, executive function, ways of thinking, problem solving, organizing and information planning, and analytic thought and memory.

However, children without bilharzia are within or well above the expected scores for their age group for all the development measures.

This means that from an early age bilharzia-infected children are disadvantaged in terms of educational attainment. This will impact on their economic productivity perpetuating a cycle of poverty.

The most important finding from the study was that these detrimental effects of bilharzia can be reversed within 6 months after treatment with praziquantel.

Previous studies by the group revealed that early childhood bilharzia changes energy metabolism and gut flora  and is associated with stunting and malnutrition, all of which can be reversed with the early treatment of bilharzia with praziquantel.

Children become infected with bilharzia when they come into contact with infected fresh water in rivers. Infection is passed on when human urine or faeces containing the schistosome eggs comes into contact with freshwater and infects a snail where the parasites mature into the stage infectious to humans. The parasites are then released into the water to infect people, hence the old name of bilharzia, snail fever.

Improving access to clean and safe water and sanitation (WASH) is the key to stopping transmission of bilharzia parasites.

Praziquantel treatment works in terms of reducing infection, reversing the disease symptoms and improving health. Thus, treatment and WASH provision are cost effective in terms of current and future health gains. Furthermore, WASH is integral to the control of many other infections endemic in Africa.

There is now a pressing need to ensure bilharzia programs already affected by the COVID-19 pandemic do not suffer even more from changes in funding priorities in health budget allocations.

Francisca Mutapi, Professor of Global Health Infection and Immunity, University of Edinburgh, said:

“The burden of bilharzia in African children is huge and unnecessary. It is unnecessary because we already have the tools to both treat bilharzia and stop its transmission.

If global development partners, stakeholders, and governments in bilharzia endemic countries are serious about achieving the United Nation Sustainable Development Goals and the African Union’s Agenda 2063, then they need to urgently invest in bilharzia control, prioritising early childhood bilharzia. If this is not done, we will be stuck in a perpetual cycle of poor health, education and poverty in the African countries that desperately need to break this cycle.”


For further information, please contact: Rhona Crawford, University of Edinburgh, Press and PR Office:

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