01 November 2016

Schistosomiasis in Côte d’Ivoire: An interview with Prof. Dr. Eliézer K. N’GORAN

The Pediatric Praziquantel Consortium has initiated the Phase II clinical trial in Côte d’Ivoire, in Schistosoma mansoni-infected preschool-age children. Prof. Dr. Eliézer K. N’GORAN from the University Félix Houphouët-Boigny (Abidjan, Côte d’Ivoire) is the Principal Investigator of...

Can you describe the current situation regarding the schistosomiasis disease in Côte d’Ivoire?

As a developing country located in a humid tropical zone, with an economy strongly based on agriculture, schistosomiasis is an important concern for Côte d’Ivoire. Côte d’Ivoire is the largest producer of cacao worldwide. The population producing cacao, as well as other agricultural products, essentially lives in rural areas with rudimentary hygiene conditions. 

Right: Picture of Prof. Dr. Eliézer K. N’GORAN

Although most cases have been reported in rural areas, schistosomiasis affects the whole country. Cases of infection with the urinary form, S. haematobium, and the intestinal form, S. mansoni have been recorded in almost all health districts. However, it is important to note that the human health significance of this disease varies significantly across the country according to the eco-epidemiological situation.

In the central and northern areas of the country, where there are two main seasons and water shortages, schistosomes are mainly localized, present in areas situated around established water bodies. In the more humid southern zone of the country, several affected areas exist, in particular in the west and south-east where many creeks and shallow water ponds are used for domestic and agricultural activities. In these regions, children are often infected at a young age. Finally, we have also recorded important disease outbreaks around the large human-made dams in Kossou and Taabo along the Bandama River, and in Buyo on the Sassandra River.

Before 2012, there were only few interventions to treat cases of schistosomiasis and Mass Drug Administration took place within the framework of research projects, with the support of the WHO. Thanks to the support of the British Government’s Department for International Development (DFID) through the Schistosomiasis Control Initiative (SCI), important progress has been made. The ‘Programme National de Lutte contre la Schistosomiase les Géohelminthiases et la Filariose lymphatique (PNLSGF)’ of Côte d’Ivoire has undertaken mass distribution of praziquantel (PZQ) since 2012, starting in the major known centers of infection in the south-east part of the country. In addition, mapping of schistosomiasis at the national level was completed in 2014 and national coverage of mass treatment for schistosomiasis was achieved in 2015.

What strategy do you employ to fight schistosomiasis? What will be the essential factors of success to eliminate schistosomiasis and which actions take priority?

The strategy to fight schistosomiasis is defined by the WHO. In particular, the course of action specified for Africa is the implementation of preventive chemotherapy using the drug PZQ. Implementation is informed by the results from mapping infected areas which establishes the prevalence and intensity of schistosomiasis. Implementation takes the form of periodic mass distribution of the drug PZQ to the target exposed populations. Follow-up treatments and evaluation of the impact of the intervention are assured by selected sentinel sites in the various epidemiological contexts.

The factors essential to the success of these intervention programs intended to achieve the elimination of schistosomiasis are the following, in order of priority:

  • Maintenance of global mobilization to ensure continuity in implementation of the defined actions in the medium and long term
  • Optimization of activities to fight schistosomiasis by developing methods and tools, creating targeted interventions adapted to the specific characteristics of endemic zones and population groups at risk as the intervention plan is rolled-out
  • Mass treatment accompanied with health hygiene information and health training, to enhance awareness at decision-maker and population levels, strengthening resolve and participation in the prevention and fight against schistosomiasis
  • Operational research in parallel to optimization of interventions and the combining of actions in the most efficient way to achieve elimination

How important is it to treat pre-school children? How helpful will the new drug formula for pre-school children be and what actions would be required in parallel?

Pre-school age children remain a marginalized population. To date, there is no appropriate drug formulation for their treatment and they are, therefore, excluded from mass drug distribution campaigns. This is not only explained by the fact that schistosomiasis remained a neglected disease for a long time, but also by the underestimation of infestation levels in this segment of the population. We now know that in certain circumstances of high transmission, the level of infection in preschool children is high, thereby having important clinical consequences on this fragile population. Thus, we need an adequate formulation of the drug to treat this target population.

Left: children exposed to fresh water

In order to increase the “efficacy” of the interventions towards elimination of schistosomiasis, it is important to note that preschool children, school children and adults need to be taken into consideration. Of course, to be successful in eliminating schistosomiasis, implementation of mass drug distribution is not sufficient.  One needs to include information and educational activities via various approaches (documentaries, cartoons for children, etc.), improvements in hygiene conditions and water supply - activities from WASH (Water, Sanitation and Hygiene program), as well as targeting the aquatic snails - the intermediary hosts of schistosomiasis. These actions must be conducted in parallel to the mass treatment approach to produce long-term results. 

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