Steven Kenyon Ault

The Neglected Tropical Diseases of Latin America and the Caribbean: A Review of Disease Burden and Distribution and a Roadmap for Control and Elimination

The neglected tropical diseases (NTDs) represent some of the most common infections of the poorest people living in the Latin American and Caribbean region (LAC). Because they primarily afflict the disenfranchised poor as well as selected indigenous populations and people of African descent, the NTDs in LAC are largely forgotten diseases even though their collective disease burden may exceed better known conditions such as of HIV/AIDS, tuberculosis, or malaria. Based on their prevalence and healthy life years lost from disability, hookworm infection, other soil-transmitted helminth infections, and Chagas disease are the most important NTDs in LAC, followed by dengue, schistosomiasis, leishmaniasis, trachoma, leprosy, and lymphatic filariasis. On the other hand, for some important NTDs, such as leptospirosis and cysticercosis, complete disease burden estimates are not available. The NTDs in LAC geographically concentrate in 11 different sub-regions, each with a distinctive human and environmental ecology. In the coming years, schistosomiasis could be eliminated in the Caribbean and transmission of lymphatic filariasis and onchocerciasis could be eliminated in Latin America. However, the highest disease burden NTDs, such as Chagas disease, soil-transmitted helminth infections, and hookworm and schistosomiasis co-infections, may first require scale-up of existing resources or the development of new control tools in order to achieve control or elimination. Ultimately, the roadmap for the control and elimination of the more widespread NTDs will require an inter-sectoral approach that bridges public health, social services, and environmental interventions.

Neglected diseases of neglected populations: Thinking to reshape the determinants of health in Latin America and the Caribbean

BackgroundPeople living in poverty throughout the developing world are heavily burdened with neglected communicable diseases and often marginalized by the health sector. These diseases are currently referred to as Neglected Diseases of Neglected Populations. The neglected diseases create social and financial burdens to the individual, the family, the community, and the nation.DiscussionNumerous studies of successful individual interventions to manage communicable disease determinants in various types of communities have been published, but few have applied multiple interventions in an integrated, coordinated manner. We have identified a series of successful interventions and developed three hypothetical scenarios where such interventions could be applied in an integrated, multi-disease, inter-programmatic, and/or inter-sectoral approach for prevention and control of neglected diseases in three different populations: a slum, an indigenous community, and a city with a mix of populations.SummaryThe objective of this paper is to identify new opportunities to address neglected diseases, improve community health and promote sustainable development in neglected populations by highlighting examples of key risk and protective factors for neglected diseases which can be managed and implemented through multi-disease-based, integrated, inter-programmatic, and/or inter-sectoral approaches. Based on a literature review, analysis and development of scenarios we visualize how multiple interventions could manage multiple disease problems and propose these as possible strategies to be tested. We seek to stimulate intra- and inter-sectoral dialogue which will help in the construction of new strategies for neglected diseases (particularly for the parasitic diseases) which could benefit the poor and marginalized based on the principle of sustainability and understanding of key determinants of health, and lead to the establishment of pilot projects and activities which can contribute to the achievement of the Millennium Development Goals.

Elimination of Neglected Diseases in Latin America and the Caribbean: A Mapping of Selected Diseases

In Latin America and the Caribbean, around 195 million people live in poverty, a situation that increases the burden of some infectious diseases. Neglected diseases, in particular, are often restricted to poor, marginalized sections of the population. Tools exist to combat these diseases, making it imperative to work towards their elimination. In 2009, the Pan American Health Organization (PAHO) received a mandate to support the countries in the Region in eliminating neglected diseases and other poverty-related infections. The objective of this study is to analyze the presence of selected diseases using geo-processing techniques. Five diseases with information available at the first sub-national level (states) were mapped, showing the presence of the disease (“hotspots”) and overlap of diseases (“major hotspots”). In the 45 countries/territories (approximately 570 states) of the Region, there is: lymphatic filariasis in four countries (29 states), onchocerciasis in six countries (25 states), schistosomiasis in four countries (39 states), trachoma in three countries (29 states), and human rabies transmitted by dogs in ten countries (20 states). Of the 108 states with one or more of the selected diseases, 36 states present the diseases in overlapping areas (“major hotspots”). Additional information about soil-transmitted helminths was included. The analysis suggests a majority of the selected diseases are not widespread and can be considered part of an unfinished agenda with elimination as a goal. Integrated plans and a comprehensive approach, ensuring access to existing diagnostic and treatment methods, and establishing a multi-sectoral agenda that addresses social determinants, including access to adequate water and sanitation, are required. Future studies can include additional diseases, socio-economic and environmental variables.

Update on the Mapping of Prevalence and Intensity of Infection for Soil-Transmitted Helminth Infections in Latin America and the Caribbean: A Call for Action

It is estimated that in Latin America and the Caribbean (LAC) at least 13.9 million preschool age and 35.4 million school age children are at risk of infections by soil-transmitted helminths (STH): Ascaris lumbricoides, Trichuris trichiura and hookworms (Necator americanus and Ancylostoma duodenale). Although infections caused by this group of parasites are associated with chronic deleterious effects on nutrition and growth, iron and vitamin A status and cognitive development in children, few countries in the LAC Region have implemented nationwide surveys on prevalence and intensity of infection. The aim of this study was to identify gaps on the mapping of prevalence and intensity of STH infections based on data published between 2000 and 2010 in LAC, and to call for including mapping as part of action plans against these infections. A total of 335 published data points for STH prevalence were found for 18 countries (11.9% data points for preschool age children, 56.7% for school age children and 31.3% for children from 1 to 14 years of age). We found that 62.7% of data points showed prevalence levels above 20%. Data on the intensity of infection were found for seven countries. The analysis also highlights that there is still an important lack of data on prevalence and intensity of infection to determine the burden of disease based on epidemiological surveys, particularly among preschool age children. This situation is a challenge for LAC given that adequate planning of interventions such as deworming requires information on prevalence to determine the frequency of needed anthelmintic drug administration and to conduct monitoring and evaluation of progress in drug coverage.

Administration of triclabendazole is safe and effective in controlling fascioliasis in an endemic community of the Bolivian Altiplano.

Background The Bolivian northern Altiplano is characterized by a high prevalence of Fasciola hepatica infection. In order to assess the feasibility, safety and efficacy of large-scale administration of triclabendazole as an appropriate public health measure to control morbidity associated with fascioliasis, a pilot intervention was implemented in 2008. Materials and Methods Schoolchildren from an endemic community were screened for fascioliasis and treated with a single administration of triclabendazole (10 mg/kg). Interviews to assess the occurrence of adverse events were conducted on treatment day, one week later, and one month after treatment. Further parasitological screenings were performed three months after treatment and again two months later (following a further treatment) in order to evaluate the efficacy of the intervention. Results Ninety infected children were administered triclabendazole. Adverse events were infrequent and mild. No serious adverse events were reported. Observed cure rates were 77.8% after one treatment and 97.8% after two treatments, while egg reduction rates ranged between 74% and 90.3% after one treatment, and between 84.2% and 99.9% after two treatments. The proportion of high-intensity infections (≥400 epg) decreased from 7.8% to 1.1% after one treatment and to 0% after two treatments. Conclusion Administration of triclabendazole is a feasible, safe and efficacious public health intervention in an endemic community in the Bolivian Altiplano, suggesting that preventive chemotherapy can be applied to control of fascioliasis. Further investigations are needed to define the most appropriate frequency of treatment.

Methodological Bias Can Lead the Cochrane Collaboration to Irrelevance in Public Health Decision-Making.

1 Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland, 2 Children Without Worms, Task Force for Global Health, Decatur, Georgia, United States of America, 3 WHO Collaborating Centre for Neglected Tropical Diseases, Public Health Laboratory Ivo de Carneri, Zanzibar, United Republic of Tanzania, 4 Neglected Infectious Diseases, Pan American Health Organization, World Health Regional Office for the Americas, Washington, DC, United States of America, 5 Neglected Tropical Diseases, World Health Organization Regional Office for the Eastern Mediterranean, Cairo, Egypt, 6 Malaria, Other Vectorborne and Parasitic Diseases, World Health Organization Regional Office for Europe, Copenhagen, Denmark, 7 WHOCollaborating Centre for Research and Training in Parasite Epidemiology and Control, Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada, 8 Vector-Borne and Neglected Tropical Diseases Control, World Health Organization Regional Office for South-East Asia, New Delhi, India, 9 WHOCollaborating Centre for the Monitoring of Anthelminthic Drug Efficacy for Soil-Transmitted Helminthiasis, Department of Virology, Parasitology and Immunology, University of Ghent, Ghent, Belgium, 10 Global Schistosomiasis Alliance and Public Health Laboratory Ivo de Carneri, Zanzibar, United Republic of Tanzania, 11 Malaria, Other Vectorborne and Parasitic Diseases, World Health Organization, Regional Office for Western Pacific, Manila, Philippines

Eliminating Lymphatic Filariasis, Onchocerciasis, and Schistosomiasis from the Americas: Breaking a Historical Legacy of Slavery

velopment in the United States and in the Caribbean led to the spontaneous disappearance of LF in some areas and substantial declines in the prevalence of infection in others [7]. Ongoing transmission in the Western Hemisphere, now limited to four countries (Brazil, the Dominican Republic, Haiti, and Guyana), is concentrated in impoverished settings and appears to be a growing problem in urban slums. LF elimination programs based on the mass distribution of antifilarial drugs have been developed in all four countries and have resulted in declines in the prevalence of filarial infection ([8] and unpublished data). However, all four programs are resource challenged and none have achieved full coverage of at-risk populations.

Intersectoral Approaches to Neglected Diseases

The neglected diseases are a diverse group of communicable diseases that affect principally the worlds poorest people. They are linked to poverty, as both a cause and a consequence of same, and affect community security and family productivity. The neglected diseases cause acute and chronic illness, disability, and sometimes death, and they may carry stigma for those infected. Current interventions for neglected diseases emphasize the health sector, but to achieve sustainability and simultaneously combat poverty, an intersectoral approach to their prevention and control is needed. This chapter outlines some concepts for an intersectoral approach, including interventions from the nutrition and food security, education, and environmental sectors.

High prevalence of soil-transmitted helminths in Southern Belize- highlighting opportunity for control interventions

OBJECTIVE To assess prevalence and intensity of soil-transmitted helminths (STH) in school age children of two southern districts as baseline information prior to implement a deworming program against intestinal parasites as part of an integrated country development plan. METHODS Children randomly selected from urban and rural schools in Southern Belize provided one stool sample each, analysed by the Kato-Katz method to assess prevalence and intensity of STH infections. Epi Info software was used for data analysis; Chi-square test and Fischer exact test were applied to compare group proportions; P<0.05 was considered of statistical significance; descriptive statistics were expressed as percentages. RESULTS A total of 500 children from 10 schools participated in the study from May to December 2005. Prevalence of STH ranged between 40% and 82% among schools, with a median of 59.2%; the majority of light intensity, and with 2.2% high intensity infection. Trichuris and Ascaris infections presented similar frequency in children aged from 6 to 9 years old; hookworm infections tended to be more frequent in the older group 10 to 12 years old. Statistical significances (P≤0.01) were found in children in rural schools infected with any species of STH, in moderate Trichuris infections, in hookworm infections in rural areas with strong Mayan presence and in Ascaris infections in children of Mayan origin. CONCLUSIONS High prevalence of STH in Southern Belize provided sound ground for implementing an integrated deworming control program.

Progress towards the control and elimination of neglected tropical diseases in Brazil

The study by Aguiar-Santos et al.1 indicates that, in spite of several years of interventions aimed at eliminating lymphatic filariasis (LF) from Pernambuco, its transmission is still occurring at sustained levels (13.8% mf prevalence); the study also shows that soil-transmitted helminthiasis (STH) is still significantly prevalent among surveyed children (46.5% or 74/159). High prevalence of lymphatic filariasis (LF) is probably a reflection of the fact that the Pan American Health Organization (PAHO)/World Health Organization (WHO) recommendations2 related to mass drug administration (MDA) have only been partially followed in the past: this intervention has not been implemented in all endemic areas (individual case-management has instead been applied in low-prevalence areas), and a mono-therapy regimen of diethyl carbamazine (DEC) alone3 has been used instead of the recommended combination of DEC + albendazole.2 High-prevalence of STH is also a reflection of the fact that albendazole was not distributed in the framework of LF