A new international study has shown that rates of the parasitic disease schistosomiasis have rebounded to pre-intervention levels in the north-western African republic of Mali.
The study was led by The University of Queensland’s Dr Archie Clements and published today in the Public Library of Sciences Journal (PLoS) Neglected Tropical Diseases.
It found that 10 years after the apparently successful conclusion of a donor-funded schistosomiasis control program from 1982–1992, national prevalence of the disease had returned.
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.
The study found that clusters of schistosomiasis infections occurred in generally the same areas in Mali across time periods, although the precise locations varied.
Mali had been one of the first countries in sub-Saharan Africa to initiate a national schistosomiasis control program which began as a partnership between the Malian Ministry of Health, the World Health Organization and the German Technical Cooperation (Deutsche Gesellschaft für Technische Zusammenarbeit, GTZ).
Lack of government funding curtailed the program’s activities after 1998, until a new control initiative, backed by the Schistosomiasis Control Initiative, began in 2004.
Dr Clements undertook the study with co-authors Elisa Bosqué-Oliva, of the Schistosomiasis Control Initiative; Moussa Sacko, Aly Landouré and Robert Dembélé,of the Ministère de la Santé; Mamadou Traoré and Godefroy Coulibaly, of the Institut National de Recherche en Santé Publique; Albis F Gabrielli, of the World Health Organisation; Alan Fenwick of Imperial College London; and Simon Brooker of the London School of Hygiene & Tropical Medicine.
The comparative study looked at the spatial distribution of schistosomiasis in Mali in 1984-1989 and 2004-2006.
The researchers found that the spatial distribution of schistosomiasis is extremely stable, even in the face of large-scale drug distribution-based control programmes.
Dr Clements, who is a senior lecturer in UQ’s School of Population Health, said that the long-term stability of schistosomiasis clusters meant that reviewing historic data should be the first step when planning targeted contemporary control programs.
“If these control programs are to have a sustainable impact on the burden of schistosomiasis they must be delivered over a very long time period,” Dr Clements said.
The study authors also found that measures to reduce exposure to the disease, such as improvements in sanitation and hygiene, are key factors in the successful long-term control of schistosomiasis.
The full paper, “A Comparative Study of the Spatial Distribution of Schistosomiasis in Mali in 1984-1989 and 2004-2006”, can be read in the May 5 edition of the journal.
The Schistosomiasis Control Initiative was funded by the Bill and Melinda Gates foundation. Simon Brooker was supported by a Career Development Fellowship from the Wellcome Trust.
Media: Vanessa Mannix Coppard, UQ School of Population Health, phone 042 420 7771, email: v.mannixcoppard@sph.uq.edu.au
