Sustainability of ongoing interventions key to successful schistosomiasis control

A decade after the conclusion of a schistosomiasis control program in Mali, prevalence of the disease had regressed to pre-intervention levels, according to a study published May 5 in the open-access journal PLoS Neglected Tropical Diseases.

The researchers, led by Dr Archie Clements at the University of Queensland, found that clusters of schistosomiasis infections occurred generally in the same, original areas ten years after the end of a donor-funded control program, conducted between 1982 and 1992.

Schistosomiasis is a parasitic disease caused by several species of fluke of the genus Schistosoma. Although it has a low mortality rate, schistosomiasis often is a chronic illness that can damage internal organs and, in children, impair growth and cognitive development.

Mali is one of the first countries in sub-Saharan Africa to have initiated a national schistosomiasis control program, which began as a partnership between the Malian Ministry of Health, the WHO, and the German Technical Cooperation (GTZ). Lack of government funding curtailed the program's activities after 1998, until a new program, backed by the Schistosomiasis Control Initiative, began in 2004.

Clements and his co-authors undertook a comparative study of the spatial distribution of schistosomiasis in Mali between 1984-1989 and 2004-2006. They show that the spatial distribution of schistosomiasis was similar in both time periods, even in the face of large-scale control program based on mass distribution of anti-parasitic drugs.

According to Clements, long-term stability in the spatial distribution of schistosomiasis means that reviewing historic data can provide a useful, initial source of evidence for planning targeted contemporary control program.

"However, if these control program are to have a sustainable impact on the burden of schistosomiasis they must be delivered over a very long time period, or supplementary methods need to be implemented, such as improvement in water sanitation and hygiene," he said.