Sound check: Acoustic tools can help track disease spread in rainforest areas, study finds

KOTA KINABALU: Low-cost microphones could be a cost-effective, non-invasive tool to help track infectious disease risks in the rainforest and other rapidly-changing landscapes, research indicates.

A study funded by the Wellcome Trust, the Royal Society and the US State Department, and published in Trends in Parasitology, discusses how listening to the sounds of an ecosystem can help in the understanding of factors that drive the spread of disease between animals and people.

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In Malaysia, scientists have set up an acoustic monitoring grid to track when monkeys are moving into areas with mosquitos within the rainforest and plantation areas.

Dr Milena Salgado Lynn from Danau Girang Field Centre (DGFC) in Sabah said passive acoustic monitoring is typically used in wildlife conservation to investigate population dynamics and behavioural trends of animals.

“This includes sounds we cannot hear, like echolocation.

“More specifically, our work demonstrates how acoustic monitoring can be used to monitor the spread of zoonotic malaria from monkeys to mosquitos to people,” she added.

Dr Lynn said for mosquito-borne diseases such as malaria, detection of human activity at times when mosquitos are most active could indicate heightened disease risk and be used to identify where people are exposed.

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The findings are the result of a partnership between researchers from the University of Glasgow, DGFC and Rainforest Connection, an NGO which uses sound recording to monitor endangered species and send real-time alerts to prevent poaching and illegal logging in rainforests.

To track illegal activity, Rainforest Connection uses microphones to detect human noise in the forest – not specifically speech, but sounds of activity like chainsaws, gunshots or movement through the forest.

The researchers describe how acoustic monitoring – a cost-effective, non-invasive tool – could also be effectively used to strengthen early warning systems and improve disease surveillance.

“By recording the sounds that animals make, we can detect changes in wildlife that could impact human disease risk; for example, tracking the changes in frequency of animal calls to identify mass mortality in wildlife due to a disease outbreak,” said Dr Kimberly Fornace from the University of Glasgow.

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“Acoustic data could be used to detect changes in the location or behaviours of animals in areas where zoonotic diseases (like malaria, yellow fever, rabies, trypanosomiasis and Rift Valley fever) exist and could pose a risk to humans and other animals,” he said.

While acoustic monitoring would not replace existing field-based methods used to track disease risk, the researchers believe it could be a novel and useful tool in combination with current methods.

Emilia Johnson from the University of Glasgow’s School of Biodiversity, One Health and Veterinary Medicine said emerging infectious diseases pose a significant burden on global public health.

She said there was a need to better understand diseases that crop up at the boundaries where human activity and wildlife habitats meet.

“Sound recording provides an opportunity to collect and analyse useful data in real-time and over very broad scales; in this way, acoustic surveys can complement existing surveillance methods and offer important new insight into the dynamic ecosystems that underpin infectious disease epidemiology,” she said.

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