High-precision mapping tools can pinpoint where schistosomiasis persists down to the household level, potentially transforming efforts to eradicate the disease, which affects 250 million people, a 13-year study has found.
Schistosomiasis is a parasitic infection that affects more than 250 million people worldwide. SciDev.Net.
“This is evidence that will help us improve our efforts to eradicate infectious diseases,” Carleton said, explaining that the “last push” is often the most difficult because the parasites settle in small pockets.
The study was a collaboration between the Colorado School of Public Health and China’s Sichuan Center for Disease Control and Prevention, with support from the National Institutes of Health.
As the region moved closer to eradication, the disease retreated into highly localized “hotspots” where transmission was found to be driven by specific household habits rather than village-wide factors.
To understand how this happened, the study followed a village in southwestern China for 13 years to understand how infection risk changed over time. Researchers from China and the United States then combined field-based data collection and traditional “shoe leather” surveys with artificial intelligence (AI) algorithms to analyze the data.
Carleton said the findings were based on a body of knowledge from her team. Several years ago, they compared two methods: a search for snails that spread schistosomiasis, and a risk-mapping approach that analyzes road networks and land-use patterns, such as the distance of households from roads, water sources, and other environmental features.
“Both of these studies show that it is possible to pinpoint potential locations of infection with great precision,” she added.
“We believe this high-precision approach to identifying potential pockets of disease will help health officials pinpoint where the disease may be spreading. This could allow them to deploy strategies to stop transmission in these areas.”
Many countries already have good census and health survey data, so the findings can be used in low-resource settings, but the challenge is getting the right infectious disease data and complementary data that can be used to tailor risk maps to specific regions, Carleton said.
He added: “We studied Schistosoma japonicus, which is found in China, Indonesia and the Philippines. However, there are other similar species of Schistosoma in the Americas, the Middle East and Africa. These parasites are similar, and ideally we would like to test whether we would find similar results in other regions.”
Christopher Jiwa, schistosomiasis research officer at the Medical Research Council/Uganda Virus Research Institute and the Uganda Research Unit at the London School of Hygiene and Tropical Medicine, who was not involved in the study, agrees that it is important for countries looking to eliminate the disease, especially LMICs. However, he cautions that “results always need to be carefully adapted to local conditions.”
The discovery is important for countries that are close to eradication, but countries like Uganda are far from achieving this, Jiwa said. SciDev.Net.
“While detailed monitoring may seem difficult in low-resource settings, it can be realistically achieved using village health teams, targeted mapping, and simple digital tools rather than expensive systems and processes,” he said.
He said research showing that infections become highly localized at the household level as overall infection rates decline means that mass treatment alone will not be enough to achieve eradication. Hygiene, agricultural practices, and environmental exposures must also be addressed.
To prevent a resurgence, policymakers should prioritize continued surveillance even after prevalence declines, strengthen sanitation practices such as the use of pit toilets, and focus on high-risk groups such as people living near lake shores, Jiwa advised.
Overall, this study confirms that elimination requires precision, persistence, and long-term commitment, rather than simply administering large doses of drugs. ”
Christopher Jiwa, Medical Research Council/Uganda Virus Research Institute, Schistosomiasis Researcher
Carleton said her team is applying some of the methods developed in schistosomiasis research to infectious diseases in the United States, from seasonal and avian influenza to West Nile virus.
“Infectious diseases rarely respect geopolitical borders,” she added.
“Cross-border scientific collaboration can help improve infectious disease response tools.”
