Trends in Parasitology
Volume 19, Issue 12, December 2003, Pages 547-551
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Research Focus
Soil-transmitted helminth infections: updating the global picture

https://doi.org/10.1016/j.pt.2003.10.002Get rights and content

Abstract

Public health workers and parasitologists have long been interested in estimating numbers infected with particular parasite species. Recent changes in social and economic conditions, in addition to implementation of control in some regions of the world, have changed the global picture of soil-transmitted helminth infections. This article brings global estimates up to date, reveals some interesting new trends and discusses the future for control.

Section snippets

Updated distributions and estimates

The work forms part of WHO's revision of disease burden estimates and uses the methodology developed by Chan et al. [5], building upon recent applications of geographical information systems to derive updated atlases of helminth infection 7, 8. To reflect recent changes in the epidemiology of infection, data were taken from only 1990 onwards wherever adequate data were available, although there are some exceptions (see footnote of Table 1). An extensive search of the literature, which included

Changes in the global situation

To explore changes in the global situation, comparisons are made between the current estimates and those of 1994 (Figure 2). In both the Americas and Asia, there appears to have been a marked decline in prevalence and in absolute numbers of all three infections since 1994. This decline reflects a change that has occurred over a period of more than a decade because some of the prevalence data used for the 1994 estimates dated back to the 1960s. In several Asian and Latin American countries,

Burden of the poor

That the poorest people in the world suffer the greatest burden of infectious disease is beyond doubt 12, 13. Outside the developing world, the 20th century saw dramatic reductions in the prevalence of infection as a result of improvements in living standards and specific control programmes – Japan and Korea being the commonly cited examples 14, 15. In the developing world, inadequate water and sanitation and crowded living conditions, combined with lack of access to health care and low levels

The future of control

Although it is not possible to claim that the figures presented here are definitive, they do provide an assessment of the current global situation. Such a perspective needs to be complemented by each country analyzing its own infection patterns based on detailed and continually updated epidemiological evidence, essential for planning control. Where information is currently lacking, there is a need to identify further in-country data sources of information or conduct new surveys. Nonetheless,

Acknowledgements

Financial support for this work was provided by WHO, the Wellcome Trust, and the Disease Control Priorities Project of the Bill and Melinda Gates Foundation. We thank E.A. Padmasiri (WHO Southeast Asia regional office) and Dimbeswar Bora (National Institute of Communicable Diseases, Delhi) for their assistance in gathering prevalence data with regard to India.

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