Sustaining Progress towards NTD Elimination: An Opportunity to Leverage Lymphatic Filariasis Elimination Programs to Interrupt Transmission of Soil-Transmitted Helminths (original) (raw)
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Background & objectives: One third of the world’s population is infected with one or more of the most common soil-transmitted helminths (STH). Albendazole (ALB) is being administered with diethyl carbamazine (DEC) in filariasis endemic areas to eliminate lymphatic filariasis (LF) and helminth infections. In this study, the cumulative impact of seven annual rounds of mass drug administrations (MDA) of DEC and ALB on STH infection in school children in selected villages in southern India was determined. Methods: During 2001-2010, seven MDAs were implemented by the Tamil Nadu state health department, India. LF and STH infections were monitored in school children from 18 villages of the two treatment arms (viz, DEC alone and DEC+ALB). Kato-Katz cellophane quantitative thick smear technique was employed to estimate STH infections at three weeks, six months and one year post MDA. Results: Prior to treatment, an overall STH prevalence was 60 per cent. After each MDA, infection markedly reduced at three weeks post-treatment in both the arms. The prevalence increased at six months period, which was maintained up to one year. After seven rounds of MDA, the infection reduced from 60.44 to 12.48 per cent in DEC+ALB arm; while the reduction was negligible in DEC alone arm (58.77 to 52.70%). Interpretation & conclusions: Seven rounds of MDA with DEC+ALB reduced the infection load significantly, and further sustained low level of infection for 10 years. However, complete parasite elimination could not be achieved. To curtail STH infection in the community, MDA should be regularized and environmental sanitation measures need to be improved by effective community-based campaigns.
PLOS Neglected Tropical Diseases, 2020
Soil-transmitted helminth (STH) infections are the most widespread of the neglected tropical diseases, primarily affecting marginalized populations in low-and middle-income countries. More than one billion people are currently infected with STHs. For the control of these infections, the World Health Organization (WHO) recommends an integrated approach, which includes access to appropriate sanitation, hygiene education, and preventive chemotherapy (i.e., large-scale, periodic distribution of anthelmintic drugs). Since 2010, WHO has coordinated two large donations of benzimidazoles to endemic countries. Thus far, more than 3.3 billion benzimidazole tablets have been distributed in schools for the control of STH infections, resulting in an important reduction in STH-attributable morbidity in children, while additional tablets have been distributed for the control of lymphatic filariasis. This paper (i) summarizes the progress of global STH control between 2008 to 2018 (based on over 690 reports submitted by endemic countries to WHO); (ii) provides regional and country details on preventive chemotherapy coverage; and (iii) indicates the targets identified by WHO for the next decade and the tools that should be developed to attain these targets. The main message is that STH-attributable morbidity can be averted with evidence-informed program planning, implementation, and monitoring. Caution will still need to be exercised in stopping PLOS NEGLECTED TROPICAL DISEASES
Current WHO protocols for mass drug administration in helminth control
Microbiology Australia, 2016
Soil transmitted helminths (STH), comprising Ascaris, Trichuris, Strongyloides and the hookworms remain a significant cause of morbidity amongst people in many parts of the world, including Australia. Other important helminth infections include lymphatic filariasis (LF), schistosomiasis and onchocerciasis. Preventive chemotherapy (mass drug administration [MDA]) campaigns are frequently conducted for these helminth infections in endemic areas, but the target population groups, duration of campaigns, cointerventions (e.g. vector control) criteria for inclusion, drugs used and doses of drugs differ.
2020
In Liberia, the most common neglected tropical diseases (NTDs) are: lymphatic filariasis (LF); schistosomiasis (SCH); soil-transmitted helminthiasis (STH); and onchocerciasis (Oncho). My research sought to explore an integrated approach for the control of these NTDs to assist the Ministry of Health (MoH) in establishing a better coordinated , economical and cost-effective intervention. As a result of my research, the MoH, in collaboration with the Centre for Neglected Tropical Diseases (CNTD) at the Liverpool School of Tropical Medicine, progressively unified the disease-specific vertical programmes into a single umbrella, entitled: 'The Integrated NTDs Programme'. Previously, Oncho control was the only tropical disease programme established within the MoH and acted as a stand-alone. Steps towards integration were first tailored upon the existing vertical delivery mechanisms for Oncho i.e., Community-Directed Treatment with Ivermectin (CDTI) through existing drug distribution networks and school-based programmes. The aim of my study was to develop and implement an integrated strategy for LF, SCH and STH first using the CDTI Oncho networks to obtain data on the prevalence and risk factors for these diseases simultaneously. During my study period, certain activities within the MoH were suspended due to the emergency response to the Ebola epidemic. This eventually led my thesis to be structured into two parts, pre-and postepidemic. Pre-epidemic-LF: The first national baseline disease mapping by immunochromatographic test (ICT) cards and baseline microfilaria pre-Mass Drug Administration (MDA) in Liberia. This provided epidemiological data for the entire country, which was used by the MoH to identify implementation units for MDA. The overall ICT prevalence was 24.0% with the highest percentage prevalence observed in the coastal region. The study also revealed that LF was endemic in 13 out of the 15 counties in Liberia. The baseline microfilaria result reported, in the study, a 6.0% prevalence rate. A total of 1,498 men were examined for the clinical manifestation of the disease, of which, 12.0% hydrocele and 6.0% lymphoedema cases were observed. A population-based knowledge and compliance study on LF was carried out in Bong County. Analysis of the results showed that more than 60.0% of the participants were aware of the disease, but only 43.0% of the participants admitted to taking both Albendazole and Ivermectin, demonstrating low treatment coverage, even though 50.0% of the participants knew the mode of LF transmission. Post-epidemic-STH iv and SCH: Parastiological surveillance studies were undertaken in Bong County as a representative epidemiological indicator for the national control programme to provide up-to-date information on SCH and STH. An epidemiological update on urogenital and intestinal SCH was undertaken amongst schoolchildren in Bong County, northern Liberia alongside observations on STH. A cross-sectional study examined 1,003 school-aged children from 10 schools representing eight health districts in the country where MDA campaigns were ongoing. In total, 12.0% of the children were infected with Schistosoma mansoni and 11.0% infected with Schistosoma haematobium, while general prevalence of STH was much lower with hookworm having the highest prevalence of 3.0%. For the first time, a knowledge attitude and practices survey for SCH, LF and STH was assessed amongst school-aged children in Bong County, northern Liberia, which highlighted the need for better health education and improved sanitation. For example, analysis of data demonstrated that from the 1,003 participants 92.0% had not heard of LF, 86.0% had not heard of STH, and 90.0% had not heard of SCH. Only 9.0% of participants had access to pipe water. To investigate the morbidity associated with SCH, a cross-sectional assessment using portable ultrasound was undertaken, which was the first ever field-based investigation in Liberia. Of the 272 school-aged children examined, morbidity was low (<1.0%) demonstrating little clinical moribidity in this school-based setting.My research was activated and first guided by recommendations from the World Health Organization (Global Plan to Combat NTDs, 2008-2015) to examine ways in which interventions against NTDs could be better coordinated and streamlined. The concept of integrated NTD control is attractive in resource poor settings such as Liberia as it can rationalize costs associated with logistics, staffing, and also better delivery of medicines. My research suggests that, the integrated approach to controlling NTDs is possible, cost-effective, and less time consuming. The recommendations made are that, the integrated NTDs programme at the MoH should collaborate with other health service programmes at the MoH, the Ministry of Education, the Liberia water and sewer company, the National Drug Service, and other relevant stakeholders in order to achieve its goal and produce more maintainable impact. The conclusions are that, an integrated disease programme should strengthen and not threaten or compromise the current efforts to efficiently coordinate , reduce, eliminate, and ultimately eradicate specific diseases within the NTDs. v ACKNOWLEDGEMENTS I feel privileged to have had the opportunity to carry out this study as a demonstration of knowledge gained during the period studying for my PhD. It would be impossible not to remember those who in one way or another, directly or indirectly, played a role in the realisation of this research project. Let me therefore thank them all equally. First, I am indebted to the all-powerful GOD for all the blessings He showered me and for being with me throughout my studies. Second, to my supervisors Professor Russell Stothard and Dr Benjamin Koudoumany thanks for your exemplary monitoring and supportthis project would not have been a success without your help. My very special thanks and appreciation also goes to the entire Liverpool School of Tropical Medicine, Centre for Neglected Tropical Diseases team. Third, I take this opportunity to express my deep gratitude to my family, and friends who are a constant source of motivation and for their never-ending support and encouragement. Fourth, to the Neglected Tropical Diseases unit of the Ministry of Health headed by Mr Karsor Kollie-I am forever grateful. Finally, to my hard-working research assistants Mrs Lasee Kolee, Mr
PLoS neglected tropical diseases, 2014
Robust reference values for fecal egg count reduction (FECR) rates of the most widely used anthelmintic drugs in preventive chemotherapy (PC) programs for controlling soil-transmitted helminths (STHs; Ascaris lumbricoides, Trichuris trichiura, and hookworm) are still lacking. However, they are urgently needed to ensure detection of reduced efficacies that are predicted to occur due to growing drug pressure. Here, using a standardized methodology, we assessed the FECR rate of a single oral dose of mebendazole (MEB; 500 mg) against STHs in six trials in school children in different locations around the world. Our results are compared with those previously obtained for similarly conducted trials of a single oral dose of albendazole (ALB; 400 mg). The efficacy of MEB, as assessed by FECR, was determined in six trials involving 5,830 school children in Brazil, Cambodia, Cameroon, Ethiopia, United Republic of Tanzania, and Vietnam. The efficacy of MEB was compared to that of ALB as previo...
Parasites & Vectors, 2016
Background: Soil-transmitted helminth (STH) infections are amongst the most prevalent infections in the world. Mass drug administration (MDA) programmes have become the most commonly used national interventions for endemic countries to achieve elimination. This paper aims to describe the effect of an 8-year MDA programme on the prevalence, intensity of infection and co-infection of STH in Burundi from 2007 to 2014 and critically appraise the trajectory towards STH elimination in the country. Results: Annual STH parasitological surveys (specifically, a "pilot study" from 2007 to 2011, an "extension study" from 2008 to 2011, and a "national reassessment" in 2014; n = 27,658 children), showed a significant drop in prevalence of infection with any STH ("pooled STH") between baseline and 2011 in both studies, falling from 32 to 16 % in the pilot study, and from 35 to 16 % in the extension study. Most STH infections were of low intensity according to WHO classification. The national reassessment in 2014 showed that prevalence of pooled STH remained significantly below the prevalence in 2007 in both studies but there was no further decrease in STH prevalence from 2011 levels during this time. Spatial dependence analysis showed that prevalence of Trichuris trichiura and Ascaris lumbricoides had a tendency to cluster over the years, whilst only trends in spatial dependence were evident for hookworm infections. Spatial dependence fluctuated over the course of the programme for Ascaris lumbricoides and Trichuris trichiura. However, spatial trends in spatial dependence were evident in 2010 for Ascaris lumbricoides. Analysis of spatial clustering of intensity of infection and heavy infections revealed that the intensity changed over time for all parasites. Heavy intensity was only evident in Ascaris lumbricoides for 2008 and did not appear in proceeding years and other parasites. Conclusions: These results demonstrate that sustained annual MDA significantly reduced the prevalence of STH infection in school-age children but was unable to achieve elimination. Additionally, significant decline in prevalence was accompanied by a drop in spatial clustering of infection indicators across all sites from 2008. The lack of consistency in the results of the spatial dependence analysis highlights that MDA programmes can interrupt the normal transmission dynamics of STH parasites.
The American journal of tropical medicine and hygiene, 2004
Annual mass treatment with antifilarial drugs is the cornerstone of the global program to eliminate lymphatic filariasis (LF). Although the primary goal of the program is to interrupt transmission of LF, additional public health benefits also are expected because of the known anthelminthic properties of these drugs. Since rapid re-infection with intestinal helminths occurs following treatment, annual de-worming may not be sufficient to produce a lasting reduction in the prevalence and intensity of these infections. We conducted stool examinations in four sentinel communities before and approximately nine months after each of two rounds of mass drug administration (MDA) with diethylcarbamazine and albendazole in the context of an LF elimination program in Leogane, Haiti. At baseline, overall Ascaris, Trichuris, and hookworm infection prevalences were 20.9%, 34.0%, and 11.2%, respectively (n = 2,716 stools). Nine months after the second MDA, Ascaris, Trichuris and hookworm prevalences...