	The Pan American Health Organization Promoting Health in the Americas

Health Surveillance and Disease Management / Communicable Diseases / Parasitic and Neglected Diseases

Framework for a Regional Program for Control of Soil-Transmitted Helminth Infections and Schistosomiasis in the Americas (Santo Domingo, Dominican Republic, 2–6 June 2003)

Full Text (25 pp, PDF, 2.3 MB) Introduction 1. Background: Geohelminths and Schistosomiasis, an Extensive Problem 1.1 The Global Problem 1.2 The Problem in the Americas (text to right) *2. Biomedical Aspects of the Problem* 2.1 Species Implicated 2.2 Transmission 2.3 Impact on Human Health 2.4 Drug Therapy *3. Epidemiological Foundations for the Control Program Soil-transmitted Helminth and Schistosome Infection* *4. Control Programs of Soil-transmitted Helminth and Schistosome Infections in the Americas* 4.1 Components of a Control Program 4.2 Objective of the Soil-transmitted Helminth and Schistosome Infection Control Program 4.3 Strategy of the Soil-transmitted Helminth and Schistosome Infection Control Program 4.4 Priority Countries, Areas, Populations, and Age Groups 4.5 Studies on the Prevalence and Intensity of Infection in the Selected Areas and Groups 4.6 Treatment Regimens based on Epidemiological Profiles of the Region 4.7 Health Education 4.8 Impact Monitoring and Assessment *5. Sustainability of the Program* 5.1 Social Mobilization 5.2 Involvement of the Ministries of Health 5.3 Multidisease Approach 5.4 Intersectoral Approach 5.5 Mobilization of Resources *6. Goals* *7. Development and Integration* 7.1 Actions 7.2 Communication, Social Mobilization, and Health Education 7.3 Community Participation 7.4 Drug Therapy 7.5 Monitoring and Impact Assessment 7.6 Design of a Manual for Working with the Community that Facilitates Program Implementation 7.7 Information Systems 7.8 Communications 7.9 Financing and Mobilization of Resources 7.10 Partnerships and Expansion of Networks 7.11 Annual Meetings 7.12 Development of Instruments 7.13 Research Priorities *8. Bibliographic References* PAHO Links - Parasitic Diseases - Neglected Diseases - Regional Program WHO Links - Control of Neglected Tropical Diseases - Partners in Parasite Control (PPC) - Schistomiasis and Soil-Transmitted Parasite Infections: Preliminary Estimates of the Number of Children Treated with Albendazole or Mebendazole (WER, No. 16, 2006, 81, 145–164) - Schistosomiasis - Intestinal Diseases, Parasitic - Tropical Disease Research		The Problem in the Americas An estimated 30% of the Latin American population suffers from soil-transmitted helminth infections (PAHO, 1998). However, this endemicity is not uniform. The relatively few studies conducted reveal prevalence rates that differ widely from country to country and even from area to area within a single country. This is due to climatic factors (lower prevalence in countries and areas farther from the tropics) and, more importantly, social and economic factors (higher prevalence in countries and areas with greater poverty). A 1995 survey among 2,015 children enrolled in public elementary schools in the National District of the Dominican Republic revealed a helminth infection prevalence of 44.7%. Interestingly, almost two years later, after two rounds of treatment with albendazole, the prevalence fell to 19.1%. In 1996, health authorities in Guatemala, Nicaragua, and El Salvador conducted studies on the prevalence of soil-transmitted helminth infections in their respective countries. In Guatemala a prevalence of over 90% was reported in six departments (provinces). In Nicaragua, where the study was conducted in five SILAI (Integrated Local Health Systems), the rates ranged from 40.7% in Managua's SILAI to 59.4% in Granada's. In El Salvador, a prevalence of 43% was found. One year later, in 1997, evaluations were conducted in six health regions of Honduras, yielding rates ranging from 27.3% to 88.6%. Studies in Brazil and Mexico, two of Latin America's largest nations geographically, showed the greatest differences in the prevalence rates of soil-transmitted helminth infections between areas of different socioeconomic levels within a country. For example, Tabasco, in Mexico's impoverished southeast, reported a rate of 94.7%, while in Jalisco, in the country's more well-off central zone, the prevalence rate was 2.5%. Analysis of the studies conducted in the Region reveals differences and deficiencies in the methodologies used to evaluate the prevalence and severity of soil-transmitted helminth infections. Careful rectification of these discrepancies, one of the purposes of the new program now being developed, should lead to the definition of standardized protocols that meet the needs of the regional initiative to control these parasitic infections. Different strategies for the control of soil-transmitted helminth infections have been applied in several countries in the Hemisphere, and more often than not have been discontinued. These strategies have managed to achieve a slight reduction in the prevalence and severity of these parasitic infections in the Region. In addition to the methodological differences employed in prevalence and severity studies to establish a baseline and monitor possible interventions, two additional obstacles have impeded local attempts to control soil-transmitted helminth infections in the Americas: Poor integration of the strategies utilized: This lack of integration has been seen in at least two areas: the failure to develop an adequate intersectoral approach, which hinders the proper use of a available infrastructure resources in other ministries and sectors, and absence of a necessary multidisease approach that achieves rational linkage between these programs and others already under way for the control of other diseases. The nature of the majority of the Region's health services, which were designed to cure diseases already present and not to offer comprehensive care to individuals. In the case of schistosomiasis, one of the main problems in the Region is the lack of reliable information. According to the data available today, eight countries are endemic for schistosomiasis: Brazil, Venezuela, Suriname, and Guyana on the continent; and the Dominican Republic, Puerto Rico, Martinique, and Saint Lucía in the Caribbean. The prevalence and intensity rates for these parasitic infections have apparently fallen to such a degree in most of these countries that current techniques are not sensitive enough to detect all cases. Hence, there is a need to work toward the development of diagnostic tools that are more sensitive than the existing ones. The previously mentioned Santo Domingo meeting of experts and managers of soil-transmitted helminth and schistosome infections control programs in the Americas, concluded that until there is a change in the socioeconomic conditions that foster the endemicity of these parasitic infections in the Region (something that will not occur in the short term), a control program is an initiative that is not only necessary, but currently feasible. Some of the points in its favor were the following: Worldwide, there is greater support for initiatives of this type. Resolution WHA54.19 adopted by the 54^th World Health Assembly is an example of this (WHA, 2001). Today, more experts (scientists, economists, politicians) believe that even though (they) are associated with relatively low mortality figures, (soil-transmitted helminth and schistosome infections) constitute an impediment to the health and socioeconomic development of large span of populations across the globe. There is satisfactory knowledge about the control measures to institute at all links in the chain of transmission and a clear awareness of the successes and failures of other control programs undertaken in the past, some of which are still in progress. Today, the drugs available for treatment of soil-transmitted helminth and schistosome infections are highly effective and inexpensive, produce few minor side effects, and some of them can be administered in single-dose regimens. In the case of soil-transmitted helminth infections in particular, efficient, inexpensive, accessible, and easily attainable diagnostic techniques are available. In the case of schistosomiasis, capacity has been developed in the Region to employ sanitary engineering techniques to eliminate foci of intermediary hosts. Sustainability will be one of the key challenges facing the Program for Control of Soil-transmitted Helminth and Schistosome Infections in the Region. This issue, whose more relevant aspects will be explored further later in this document, was widely discussed at the meeting in Santo Domingo. From it emerged the conviction that, in addition to the tasks related to each of its components, the design and implementation of this program in each country should include tools for enlisting social participation and mobilizing resources to ensure that its goals are met.