Over the past two years, researchers from London School of Hygiene & Tropical Medicine and the Kenya Medical Research Institute have been conducting one of the largest research project of its type to answer the question of how best to treat the world’s most common neglected tropical disease - soil transmitted helminths (STH).
As the TUMIKIA project nears completion, the trial coordinator Dr Kate Halliday outlines the opportunities and challenges of surveying 24,000 households in Kwale County, Kenya.
Strengthening the evidence base
More than 1.5 billion people globally are infected with at least one species of STH (intestinal worms, which include roundworm, whipworm and hookworm). As diagnosis of STH is relatively expensive, mass treatment for STH in ‘high-risk’ groups – such as school-age children - in the form of a deworming tablet once a year is a safe, efficient and cost-effective method of reducing levels of STH infection. This strategy has been recommended by the World Health Organisation for almost two decades.
Despite the successful scale-up of school-based deworming programmes, in many communities the highest levels of STH continue to be found in adults, who are not routinely treated. As a result, re-infection with STH occurs rapidly, requiring indefinite annual re-treatment of all school-children in endemic areas.
Recent mathematical modelling has predicted that broadening mass treatment for STH to all individuals – not simply those at highest risk - may potentially be a more effective way to reduce STH infection across the entire community. To address this knowledge gap and advise policy makers both nationally and globally, the TUMIKIA research project has set out to evaluate whether community-based deworming is more effective at controlling – and ultimately eliminating – STH.
What's the optimal approach?
The two-year TUMIKIA project brings together research expertise from the LSHTM, the Kenya Medical Research Institute, the Kenyan Ministry of Health and Ministry of Education, Science & Technology, Deworm the World at Evidence Action and Imperial College London to evaluate the effectiveness of three different approaches to tackling STH;
- Annual school-based deworming: where only pre-school and school-age children receive deworming once a year
- Increased coverage: where all community members (including adults) receiving deworming once a year
- Increased coverage & frequency: where all community members receive deworming twice a year
In early 2015, an initial baseline survey of 24,000 households drawn from villages and communities across Kwale was conducted to measure the levels of STH infections and collect data on factors which could influence STH infection. Participant communities were then split up into 120 clusters of about 1000 households, and randomly assigned to one of the three treatment approaches under investigation.
Following two years of school-based and/or community-based deworming the survey teams have now returned to conduct a final endline survey to evaluate the effect of these different strategies on STH infections in each participant community. The endline survey began in mid-March, running until mid-May.
The design of the endline survey mirrors that of the baseline survey. From each cluster, 225 households are selected at random to take part in a survey which records the size and composition of the household, their socio-economic status, and hygiene and sanitation practices. One family member is then selected at random to provide a stool sample for STH analysis.
Logistical challenges of research
To embark on a survey of this size is a considerable logistical undertaking. More than 110 field officers, 40 laboratory technicians and 30 data officers have been hired to collect, analyse and record the 24,000 surveys and stool samples collected.
At each household, field officers use a specially programmed smartphone to conduct a detailed questionnaire. As well as conducting a census, the questionnaire aims to builds a picture of each household by collecting data on a range of factors - from the number of livestock the household owns, to the sanitation practices of household members. At the end of each questionnaire the smartphone randomly selects one household member to provide a stool sample for analysis.
The 110 field officers engaged in surveying and collecting samples from the 24,000 participant households
One of the key challenges facing the research project is the distance and terrain that each team has to cover. Some of the clusters are a 260 kilometre roundtrip from the study office, while others require the teams to use a combination of cars, motorbikes and boats to reach remote communities. Once teams arrive at their study cluster, field officers are often faced with dispersed communities requiring a long day of walking between households.
Teams of technicians set up the laboratory at local health facilities near each of the clusters being surveyed to analyse the day’s samples. Microscope slides created from these samples are read using the kato-katz technique to estimate the number of STH eggs present. Using this approach, researchers are able to estimate the number and intensity of STH infections in each community.
A proportion of samples are preserved and stored for subsequent molecular analysis.
A system of checks and measures
Smartphone data collection has not only improved the speed and efficiency of conducting a survey on this scale with the use of barcodes for samples scanned in the field and then again in the lab, but has also enabled the study team to develop thorough data monitoring processes that can be used in real time to ensure that data being collected is both accurate and representative.
For example, while each questionnaire is being conducted the smartphones collect and transmit a series of GPS coordinates, as well as measuring the time taken to complete each questionnaire. Once each completed questionnaire has been uploaded at the end of the day, the entire dataset can be reviewed immediately. This allows the TUMIKIA supervisors to closely monitor the work of all team members, ensuring the integrity of the final dataset.
The results of each stool examination - along with household and individual data collected by questionnaire - will be compared with results from the baseline survey to determine whether community-based deworming is a more effective approach than school-based deworming alone to control and eliminate STH infections.
The findings from this research will be announced by the end of 2017.