The Impact of Lymphatic Filariasis Mass Drug Administration Scaling Down on Soil-Transmitted Helminth Control in School-Age Children. Present Situation and Expected Impact from 2016 to 2020

Abstract

Lymphatic filariasis (LF) and soil-transmitted-helminths (STH) are co-endemic in 58 countries which are mostly in Africa and Asia. Worldwide, 486 million school-age children are considered at risk of both diseases. In 2000, the World Health Organization (WHO) established the global programme to eliminate LF by 2020. Since then, the LF elimination programme has distributed ivermectin or diethylcarbamazine citrate (DEC) in combination with albendazole, thereby also treating STH. Consequently, many school-age children have been treated for STH through the LF programme. As treatment targets towards the 2020 LF elimination goal are achieved, many countries are implementing the transmission assessment survey (TAS) and, if the LF prevalence is estimated to be less than 1%, scaling down mass drug administration (MDA). We analysed the 2014 data on preventive chemotherapy (PC) reported from LF STH co-endemic countries and projected the year and location of TAS expected to be conducted between 2016 and 2020 to assess the impact of this scaling down on STH PC. Eighty percent of all co-endemic countries that have already stopped LF MDA nationally were able to establish STH PC through schools. It is estimated that 14% of the total number of children presently covered by the LF programme is at risk of not continuing to receive PC for STH. In order to achieve and maintain the WHO 2020 goal for STH control, there is an urgent need to establish and reinforce school-based deworming programmes in countries scaling-down national LF elimination programmes.

Efficacy and safety of co-administered ivermectin plus albendazole for treating soil-transmitted helminths: A systematic review, meta-analysis and individual patient data analysis

“…The safety review suggests that AEs of ivermectin-albendazole may be more common in populations with filariasis. Since filariasis and soil-transmitted helminthiases often co-exist [ 70 ], future studies must take into account filariasis either by excluding co-endemic areas or by diagnosing both diseases.…”

Soil-transmitted helminth infections

“…154 Unfortunately, the success of LF elimination and the scaling back of community-based drug distribution could increase their risk of STH unless other drug delivery platforms are put in place. 155 Trials are being conducted to determine the feasibility of breaking STH transmission in post-LF MDA settings, and the results may inform a new generation of improved public health control programmes . 52 Finally, some population groups are commonly left out of mass treatment programmes targeting STH, for example non-attending school-age children and women of reproductive age, and such at-risk populations require particular attention in both public health control programmes and individual case management.…”

Toward the 2020 goal of soil-transmitted helminthiasis control and elimination

“…Among others, these include (1) the need to maximize the impact of pharmaceutic donations of anthelmintic drugs, (2) the need to clarify targets to guide monitoring efforts moving forward, and (3) the need to take into account recent successes of the Global Program to Eliminate Lymphatic Filariasis (GPELF). The latter challenge results in the consequent scaling down of community-based control interventions, thus reducing the ancillary benefits of this strategy on soil-transmitted helminthiasis [ 14 ]. A complete transition from a lymphatic filariasis elimination program to a soil-transmitted helminthiasis control program will have important consequences so that efforts to ensure that all risk groups for soil-transmitted helminthiasis will be adequately covered need to be planned well in advance of the actual transition.…”