Controlling Soil-Transmitted Helminthiasis in Pre-School-Age Children through Preventive Chemotherapy

Abstract

Pre-school age children account for 10%–20% of the 2 billion people worldwide who are infected with soil-transmitted helminths (STHs): Ascaris lumbricoides (roundworm), Trichuris trichiura (whipworm), and Ancylostoma duodenale/Necator americanus (hookworms). Through a systematic review of the published literature and using information collated at World Health Organization headquarters, this paper summarizes the available evidence to support the recommendation that pre-school children should be included in regular deworming programmes. The first section describes the burden of STH disease in this age group, followed by a summary of how infection impacts iron status, growth, vitamin A status, and cognitive development and how STHs may exacerbate other high mortality infections. The second section explores the safety of the drugs themselves, given alone or co-administered, drug efficacy, and the importance of safe administration. The third section provides country-based evidence to demonstrate improved health outcomes after STH treatment. The final section provides country experiences in scaling up coverage of pre-school children by using other large scale public health interventions, including vitamin A programmes, immunization campaigns, and Child Health days. The paper concludes with a number of open research questions and a summary of some of the operational challenges that still need to be addressed.

Effects of Annual Mass Treatment with Ivermectin for Onchocerciasis on the Prevalence of Intestinal Helminths

“…Although school-aged children typically have a higher worm burden than preschool-aged children, PACs are still at risk for infection, as shown in our study and others. 3,[34][35][36] Very few studies have been done looking at the negative effects on growth and development in the PAC age group. However, given the rapid rate of development it is conceivable that infections in this age may be more deleterious to subsequent growth and cognitive development than infections suffered in later childhood.…”

“…The available data shows that deworming of STH-infected PAC improves their health and allows them to reach their cognitive potential. 34,37 Although treatment of SAC may decrease the prevalence in the rest of the community, including in PAC, treatment in this age still appears warranted if age appropriate antihelminthic preparations can be manufactured.…”

Predisposition to ascariasis: patterns, mechanisms and implications

“…Subsequently, the World Health Organization have placed the treatment of school-age children at the heart of its commitment to the control of soiltransmitted helminths, with a target of regular treatment of at least 75 % of school-age children by 2010 (Albonico et al 2006). Helminth control within schools has proved to be highly effective in developing countries, with trained teachers distributing the drugs in combination with the provision of health education (Montresor et al 2002).…”

Prevalence and risk factors associated with worm infestation in pre-school children (6-23 months) in selected blocks of Uttar Pradesh and Jharkhand, India

“…[5] Young children have a high infection rate and suffer with a heavy worm burden of A. lumbricoides, Trichuris trichiura and/or schistosomes. [6] These parasitic infections manifest themselves as reduced growth rates through impaired nutrient utilization. Consequently the children are not able to achieve their full potential in physical performance and education.…”