Impact of Alternative Treatment Strategies and Delivery Systems for Soil-transmitted Helminths in Kenya (TUMIKIA)

Impact of Alternative Treatment Strategies and Delivery Systems for Soil-transmitted Helminths in Kenya

The Impact of Different Treatment Strategies on the Transmission Dynamics of Soil-transmitted Helminths: a Cluster Randomised Trial in Kenya

Kenya Medical Research Institute, Kenya Ministry of Health, Imperial College London, Emory University

The mainstay of control of soil-transmitted helminths (STH) is school-based deworming but recent modelling has highlights that in all but low very transmission settings, the treatment of school-aged children is unlikely to interrupt transmission, and that new treatment strategies are required. This study seeks to answer the question: is it possible to interrupt the transmission of STH and if so, what is the most cost-effective treatment strategy and delivery system to achieve this goal? In this study, two paired community cluster randomised trials in different settings in Kenya will evaluate the impact and cost-effectiveness of annual school-based deworming, annual community-based deworming, and biannual community-based deworming. The interventions are (i) annual mass anthelmintic treatment delivered either to pre-school and school-aged children, as part of a national school-based deworming programme, or to the entire community delivered by community health workers. The primary outcome measure is the prevalence of hookworm infection (the most common STH species), assessed by periodic cross-sectional, age-stratified parasitological surveys. Secondary outcomes include intensity of hookworm, prevalence and intensity of Ascaris lumbricoides, treatment coverage, and among a randomly selected sub-sample of participants who will be followed longitudinally, worm burden and proportion of eggs unfertilised. A nested process evaluation, using semi-structured interviews, focus group discussions and a stakeholder analysis will investigate the community acceptability, feasibility given the local and regional health system structures and processes, and scale-up of the interventions.

The study will be conducted in two settings of Kenya that have contrasting epidemiological and programmatic characteristics, Kwale County on the south Kenyan coast and Bungoma County in western Kenya. Allocation to study group will be by cluster, using predefined units used in public health provision - termed Community Units (CUs), which comprise approximately 1,000 households or 5,000 people. CUs will be randomized to one of three groups, receiving either (i) annual school-based deworming; (ii) annual community-based deworming; (iii) biannual community-based deworming. In nine CUs, a longitudinal study will be conducted in order to better understand the transmission dynamics of STH.

Pre-school and school children (typically 2-14 years) will receive albendazole treatment from trained school teachers, as part of the ongoing national school-based deworming programme.

Standard school-based deworming supplemented by annual community-based deworming (2-99 years). All household members who are not enrolled in school will receive albendazole treatment from trained community health workers.

Biannual school- and community-based deworming (2-99 years). All household members who are not enrolled in school will receive albendazole treatment from trained community health workers

The prevalence of hookworm will be measured in a final age-stratified, community cross-sectional survey, which will be conducted approximately 24 months after the start of the intervention. Selected individuals will be asked to provide a stool sample which will be examined in duplicate and within one hour of preparation using the Kato-Katz method. Parasite prevalence will be defined as the proportion of slides that are positive for hookworm eggs. A baseline survey will be conducted prior to implementing the intervention and an interim survey conducted at 12 months. In a random subset of individuals, additional confirmatory diagnosis of infection will be based on real-time polymerase chain reaction (PCR).

The prevalence of Ascaris will be measured in a final age-stratified, community cross-sectional survey, which will be conducted approximately 24 months after the start of the intervention. Selected individuals will be asked to provide a stool sample which will be examined in duplicate and within one hour of preparation using the Kato-Katz method. Parasite prevalence will be defined as the proportion of slides that are positive for hookworm eggs. A baseline survey will be conducted prior to implementing the intervention and an interim survey conducted at 12 months. In a random subset of individuals, additional confirmatory diagnosis of infection will be based on real-time PCR.

The intensity of STH species will be measured in a final age-stratified, community cross-sectional survey, which will be conducted approximately 24 months after the start of the intervention. Selected individuals will be asked to provide a stool sample which will be examined in duplicate and within one hour of preparation using the Kato-Katz method. Intensity of infection will be quantified as eggs per gram of faeces. A baseline survey will be conducted prior to implementing the intervention and an interim survey conducted at 12 months.

• Treatment coverage will be measured using both routine data, and data collected during scheduled STH stool surveys. Teachers and community health workers (CHWs) will be provided with treatment registers and asked to provide a full record of all individuals who have received treatment. To augment these data, population-based coverage surveys using multistage clustering sampling will be carried out among a random subsample of communities.

Inclusion Criteria: Usual resident of study community or student enrolled in study school; Willingness of adult aged 18 years and above or parent/guardian to provide written informed consent; Provision of written assent to participate from children aged 8 years and above. Exclusion Criteria: Visitor to household at time of household visits; Refusal of informed consent; Refusal to assent by children aged 8 years and above.

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