How sewer robots helped a Taiwan city kill off disease-carrying mosquitoes

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How sewer robots helped a city in Taiwan kill disease-carrying mosquitoes: machine scanned sewers for larvae to eliminate

Dengue fever, malaria, Zika, West Nile virus and other mosquito-borne diseases may have finally met their match in crowded cities in the tropics.

An unmanned underground robotic probe sent into the sewage system of the city of Kaohsiung, Taiwan has proved deadly effective in locating the hidden pools of stagnant water where mosquitoes breed.

The sewer robot is searching so that the exterminators of Taiwan can destroy it.

Researchers at Taiwan’s National Mosquito-Borne Diseases Control Research Center found that their robot hunter has drastically reduced the city’s mosquito population, reducing the number of blood-sucking insects by nearly 70 percent.

Researchers at Taiwan’s National Mosquito-Borne Diseases Control Research Center found that their robot hunter helped drastically curb the city’s mosquito population, reducing the number of blood-sucking insects by nearly 70 percent, based on their “gravitrap index.”

Researchers designed an unmanned ground vehicle (above) to search cracks and crevices deep in Kaohsiung's sewers.  Their system also included a real-time monitoring station (bottom left) for receiving high-resolution images of mosquito breeding grounds back from the sewer

Researchers designed an unmanned ground vehicle (above) to search cracks and crevices deep in Kaohsiung’s sewers. Their system also included a real-time monitoring station (bottom left) for receiving high-resolution images of mosquito breeding grounds back from the sewer

The measurement comes from “gravitraps” laid over Kaohsiung, cylindrical traps with a sticky inside designed to attract females Aedesor “yellow fever,” mosquitoes.

The scientists and pest control experts recorded a drop in their “gravitrap index (GI),” which measures the density of nearby mosquito populations, from 0.62 to 0.19.

Several mosquito species in the genus Aedes are notorious for spreading diseases, such as dengue fever, chikungunya, and zika

Several mosquito species in the genus Aedes are notorious for spreading diseases, such as dengue fever, chikungunya, and zika

Increasing urbanization worldwide has led to sprawling sewage systems, in which mosquitoes have found fertile breeding grounds, far from the prying eyes of public health officials who have struggled to keep the bugs from spreading disease.

A map of sewage ditches in the Sanmin District of Kaohsiung City, Taiwan, where the team's mosquito-hunting robot was nesting, marked with red lines

A map of sewage ditches in the Sanmin District of Kaohsiung City, Taiwan, where the team’s mosquito-hunting robot was nesting, marked with red lines

Different mosquito species in the genus Aedes are particularly notorious for spreading disease in humans, including dengue fever, chikungunya, yellow fever, and the Zika virus.

Led by Wei-Liang Liu, a researcher at Taiwan’s National Mosquito-Borne Diseases Control Research Center, the researchers designed an unmanned ground vehicle (UGV) to search cracks and crevices deep in the sewers of the city of Kaohsiung.

Their system also included a wire-controlled zipline and real-time surveillance station, which received high-resolution images of these hard-to-reach mosquito breeding grounds from their UGV hunter in the sewer depths.

Liu and his team put this mosquito ‘search and destroy robot’ to work May to August 2018, focusing their test on five administrative districts of Kaohsiung.

The researchers specifically deployed the bot in those areas to explore previously challenging “covered roadside sewer ditches,” measuring the success of the UGV with “gravitraps” from nearby mosquitoes.

The system detected telltale signs of mosquito activity in 20.7 percent of sewers inspected, according to their study, published this week in PLOS neglected tropical diseases. Those signs ranged from tiny larval eggs to full-fledged adults.

Liu and his team then bombarded those mosquito-infested sewers with insecticides or high-temperature water jets.

“The widespread use of UGVs could potentially eliminate some of the breeding sources of vector mosquitoes,” report Liu and his co-authors, “thus reducing the annual prevalence of dengue fever in the city of Kaohsiung.”