A research update on schistosomiasis for COUNTDOWN

By Russell Stothard

It is important to ensure that COUNTDOWN’s implementation research is best guided by the latest information from other research groups and Neglected Tropical Disease (NTD) programmes.  Being invited to present my work, I found the 14th International Symposium on Schistosomiasis an exciting place to learn about research outputs from groups such as SCORE, the Brazilian National Control Programme and from individuals presenting their own state-of-the-art research. Much of this was captured by video interviews and posted on Facebook, a very valuable learning resource.

Amongst others, Phil LoVerde’s work on redeveloping oxaminquine to have activity against all schistosome species was the best example of how meticulous molecular studies breathe new life into older drugs. Having an alternative treatment that can synergise with praziquantel (PZQ), our only antischistosomal drug, is important to safeguard future options in chemotherapy.  That said and in terms of public health, several of us highlighted why better access and scale-up of PZQ treatment was needed now, especially if WHO 2020 targets are to be realised.

As part of a round table discussion addressing the needs of treatment of infants and preschool children, I presented our recent work in Uganda alongside colleagues from the paediatric praziquantel consortium  who are developing an orally dispersible tablet.  The need for better PZQ access now is very clear and next month WHO-Geneva will convene a two day meeting to review and revise their treatment guidelines as the magnitude of this problem in young children is exposed. This has important repercussions for progress towards the WHO 2020 targets.

The Question and Answer Panel on paediatric schistosomiasis

It is now widely accepted that young children develop overt disease in later childhood and also contribute to disease transmission. For these two reasons alone there is now sufficient international interest and momentum to provide treatment to them which our COUNTDOWN work will move towards changing national control policies in each of our supported countries.

Whilst we already know that schistosomiasis control goes beyond more traditional aspects of the health system, forging dialogue between the Ministries responsible for agriculture, water and sanitation and education is needed. The round table session sponsored by SCORE in the attempt to eliminate urogenital schistosomiasis from Zanzibar provided the latest information about these island-wide trials on Unguja and Pemba.

The challenges of bringing such high-level stakeholders together in a co-ordinated was discussed by David Rollinson. He also showed that provision of biannual PZQ treatment could depress infection prevalence but only so far, and not evenly across the studied communities (i.e. shehias). Furthermore, health education and sanitation initiatives did not yield the expected declines in transmission with infection prevalence even increasing in some shehias despite intensified control. These results show we are still a long way from breaking transmission on the island, and better strategies for elimination of hotspots are needed. The importance of snail control and the difficulties associated with it were discussed at length. Simply put, if we cannot prevent and contain infections in snails we will never eliminate schistosomiasis in people.

About access to PZQ treatment, other studies from SCORE in East and West Africa showed that ‘treatment holidays’ were not a good idea and should be abandoned. A ‘treatment holiday’ is defined as the intervening period between biennial rather than annual tablet administration. The original rationale was that in communities where prevalence was between 10-50% it was thought that biennial treatment alone was sufficient and cost-effective to bring the disease under control when PZQ was under much shorter supply. This is clearly not the case and PZQ treatment regimes, as per Zanzibar, are now favouring biannual as the only way forward as more PZQ is available globally. Future COUNTDOWN workplans will investigate more formally biannual treatment regimes in terms of its operational feasibility and health impact significance.

Lester Chitsulo receiving his award from Rosa SoaresDuring the conference, a major honour was bestowed on Lester Chitsulo in thanks of his long standing work on schistosomiasis control based from the WHO-Geneva office. For just over 15 years, Lester was the NTD (schistosomiasis) desk-officer and had recently retired, being succeeded by Amadou Garba. Other distinguished retired researchers included Zilton Andrade and Ronaldo Amaral.

One of the important aspects within this meeting was witnessing the close association of the National Control Programme of Brazil with the many researcher and research arms of academia. In Africa, it was noted that this research capacity was much lower and needed a significant boost.

Owing to recent financial fragility within Brazilian economy and associated health budget cuts, this meeting was nearly cancelled. I therefore very warmly congratulate Mitermayer Reis and the symposium organisers for their continued perseverance, welcoming this opportunity for up-to-date discussions which help frame our future COUNTDOWN research with best available information.


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