In the midst of the COVID-19 pandemic, another source of deadly and increasingly common disease outbreaks goes largely unnoticed to much of the world. Stanford researchers working in rural Kenya have identified the most productive breeding habitats for certain mosquitoes – spreaders of untreatable viruses that infect millions every year – and identified related community perspectives that could provide a solution. Their findings, recently published in PLOS Neglected Tropical Diseases, point to more effective and efficient health interventions being led by women and children.
“Until everyone in the world has reliable access to clean tap water, interventions by the low-tech community targeting unused water containers can significantly reduce the risk to human health from vector-borne diseases,” the said Study lead author, Desiree LaBeaud, Professor of Pediatrics at Stanford Medical School.
The Aedes aegypti mosquito, while tiny, poses an overwhelming threat to global public health. It carries a variety of viruses such as dengue, chikungunya, zika and yellow fever for which there are no vaccines or therapies. Human victims suffer from a range of symptoms, including life-threatening encephalitis and bleeding or debilitating arthritis that lasts for years. Over the past two decades, disease outbreaks caused by mosquitoes have become increasingly common and unpredictable.
Countries on every continent except Antarctica have suffered a number of Aedes aegypti-spread virus outbreaks in recent years. These outbreaks were poorly reported and infections were often misdiagnosed in some African countries, where public health efforts have long focused on night mosquitoes that transmit malaria. For example, the researchers found that residents of the study area had limited awareness of daytime Aedes aegypti mosquitoes, and prioritized sleeping under bed nets as the primary protection against mosquito-borne diseases.
A new approach to source reduction
Due to the lack of tap water, most of the people in the region get water from rainfall, wells or boreholes. Many people also leave stored water uncovered in various containers. The researchers surveyed hundreds of residents and measured mosquito incidence in buckets, canisters and other water-containing containers – the most common breeding area for Aedes aegypti mosquitoes.
More than half of the mosquitoes found by the researchers were in tires, buckets, and small containers with no immediate purpose, and nearly 40 percent of the mosquitos found were in buckets that were used for laundry. Although tires made up less than 1 percent of all containers, they contained almost a third of the mosquitoes found by the researchers.
The results suggest that reducing the number of unused containers lying around could be an efficient and effective means of mosquito control. Rather than trying to cover or reduce the number of all water-containing containers or all containers of a certain type – a complex and difficult approach for members of the community – national and local health interventions should target the most likely habitats for mosquito breeding, such as laundry buckets and bins without a purpose, like tires and trash, the researchers said.
According to the researchers, who emphasize that women and children are the most likely actors of change, education and empowerment, as well as community events like garbage cleanup, are to deal with the accumulation of useless containers. Women, who are most likely to collect and store water for households, can use simple nets such as torn bed nets to cover laundry bins. Children, who are generally more willing to come up with new ideas and adopt new behaviors, may want to collect unused containers or turn unused tires into toys so they don’t collect water for mosquito farming.
“It sounds simple, but targeting specific containers can have a huge impact,” said study director Jenna Forsyth, a postdoctoral fellow at Stanford Woods Institute for the Environment. “It’s inexpensive, requires relatively little behavioral changes, and scales easily.”
The research was funded by the Stanford Maternal & Child Health Research Institute, the Center for African Studies, and the Emmett Interdisciplinary Program on Environment and Resources.
Source of the story:
Materials provided by Stanford University. Originally written by Rob Jordan. Note: The content can be edited by style and length.