The global progress of soil-transmitted helminthiases control in 2020 and World Health Organization targets for 2030.

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 control programs to avoid any rebound of prevalence and loss of accrued morbidity gains. Over the next decade, with increased country leadership and multi-sector engagement, the goal of eliminating STH infections as a public health problem can be achieved.

Markov model to forecast the change in prevalence of soil-transmitted helminths during a control programme: a case study in Vietnam.

BACKGROUND: A mathematical model based on the Markov methodology to predict the change in prevalence of soil-transmitted helminth (STH) infections during public health control activities is not available, but would be an extremely efficient planning tool. METHOD: We used the parasitological data collected during a deworming and iron supplementation programme for women of child-bearing age conducted in Vietnam between 2006 and 2011 to develop a Markov transition probability model. The transition probabilities were calculated from the observed changes in prevalence in the different classes of intensity for each STH species during the first year of intervention. The model was then developed and used to estimate the prevalence in year 2, 3, 4 and 5 for each STH species and for 'any STH infection'. The prevalence predicted by the model was then compared with the prevalence observed at different times during programme implementation. RESULTS: The comparison between the model-predicted prevalence and the observed prevalence proved a good fit of the model. CONCLUSIONS: We consider the Markov transition probability model to be a promising method of predicting changes in STH prevalence during control efforts. Further research to validate the model with observed data in different geographical and epidemiological settings is suggested to refine the prediction model.

Integration of deworming into an existing immunisation and vitamin A supplementation campaign is a highly effective approach to maximise health benefits with minimal cost in Lao PDR.

Infection with soil-transmitted helminths (STH) is a major public health problem in many developing countries, with pregnant women and children particularly at risk. Preventive chemotherapy, which is the intervention currently recommended by the WHO against the main helminth infections including those caused by STHs, aims at reducing morbidity through periodical administration of anthelminthic drugs either alone or in combination. The Expanded Programme on Immunization is one of the most widely implemented health programmes in the world and has well established access to children and women. The present study investigated the cost of the provision of anthelminthic drugs during existing immunisation campaigns. In Lao PDR, use of this integrated approach compared with implementation of the vertical deworming campaign alone allowed a reduction of the individual cost of deworming by 10 times (from US$0.23 in the vertical deworming campaign to US$0.03 in the integrated campaign). When drug cost was excluded, the cost of deworming an individual was US$0.007, implying that deworming 100 children would cost less than US$1 if drug donation was in place. The burden posed on health workers by the integration process was perceived as minimal and manageable. Moreover, delivery of anthelminthic drugs during immunisation campaigns enabled campaign teams to observe drug intake directly, which assured safety. These findings prove that integration is an opportunity to maximise health benefits through the delivery of multiple health products and the attainment of high coverage.