The GSA Blog

The elimination of schistosomiasis is within reach

Every single year schistosomiasis kills over 200,000 people. This devastating disease is far-reaching, causing suffering and debilitation to more than 249 million and posing a threat to over 700 million people primarily in the world’s most impoverished communities[1].

Yet the goal of controlling and ultimately eliminating this largely neglected ‘silent killer’ is very much within reach. Indeed, we have never been in a better position to make such a great impact in the battle against schistosomiasis.

To do this, however, we must minimise the discrepancy between the quantities of donated Praziquantel, the highly effective recommended treatment for schistosomiasis, and the numbers of people being treated in endemic countries as an urgent priority.

Treatment coverage is not keeping up with the dramatically increasing drug availability; between 2012 and 2013 there was only a relatively small rise in the number of people being treated with Praziquantel, from 42 million to 47.3 million, whereas Merck’s donations of the drug radically increased from 75 million tablets in 2014 to 100 million in 2015, and from 2016 they have pledged to contribute up to 250 million tablets annually[2]. There is, however, little point having Praziquantel available if it cannot get to the people who need it the most.

The answer lies largely with Preventive Chemotherapy (PC) programmes, also called Mass Drug Administration (MDA) programmes. MDA, where drugs are administered to populations irrespective of disease status, immediately improves health, prevents the irreversible long-term effects of schistosomiasis in children when they take a Praziquantel tablet every year, and reduces the rate of infection. MDA therefore helps control and reduce morbidity, the detectable signs and symptoms of the disease[3]. When large scale MDA programmes are implemented  in combination with adequate hygiene and sanitation, access to safe water, vector control, and education programmes to inform communities about the disease and how to prevent it, will make it possible to eliminate – this vicious disease[4],[5]. This comprehensive approach is critical for reducing transmission of schistosomiasis and ultimately reaching the elimination goal.

We can see the success of MDA in Zanzibar, where the Zanzibar Elimination of Schistosomiasis Transmission (ZEST) project has been making strides towards eliminating schistosomiasis as a public health problem on the islands of Unguja and Pemba since July 2011. Along with MDA, which has entailed six rounds of treatment since 2012, the project also undertakes interventions in snail control, which involves spraying infected water bodies with Niclosamide, a safe, biodegradable molluscicide, at least once a year to reduce the host snail population, and behavioural change, which includes setting up schistosomiasis awareness days in schools and designing and installing safe urinals and washing areas in communities[6],[7]. Outside of sub-Saharan Africa, there has been much progress in controlling and eliminating schistosomiasis in Eastern Mediterranean Countries in the past 20 years. For example, schistosomiasis has been eliminated in Iran, Lebanon, Morocco and Tunisia, while seven other countries in the region have reached low schistosomiasis endemicity[8]. This example of successful implementation of national control and elimination programmes in the Eastern Mediterranean Region, following WHO recommended strategies, provides the impetus for other regions to follow suit and replicate this accomplishment.

The vehicle to achieve the elimination of schistosomiasis is available, effective, and free to those who need it; what is urgently needed is collaborative action between stakeholders at all levels, from the GSA and the WHO to the local health ministries on the ground, to mobilise the hundreds of millions of Praziquantel tablets from warehouses to the impoverished and often remote communities where they are so desperately needed. Although very much achievable, improved tools and better resources, along with robust programme implementation – including training and monitoring and evaluation – are required to facilitate the effective delivery of Praziquantel and reach the target of elimination.

The burden of schistosomiasis must be considered a priority by national governments down to local health ministries and further research must be undertaken to find solutions to logistical obstacles, particularly in Africa. If all key actors play the role that they have set out to play, the WHO targets of regularly providing preventive treatment to 75% of school-aged children in all endemic countries and eliminating schistosomiasis regionally, in the Americas and Western Pacific, and nationally, in selected African countries, by 2020 can certainly be achieved[9].