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Crushed seashells and vinegar could be the key ingredients in an inexpensive and readily available way to lure and trap disease-carrying insects in developing nations, according to a new UF/IFAS study. By using these simple ingredients, insect experts can find easier ways to trap and monitor disease-carrying insects, says Nathan Burkett-Cadena, a UF/IFAS assistant professor of entomology, who led the recent study.
Mosquitoes transmit malaria, West Nile virus and chikungunya virus. Monitoring these insects is critical to understanding when and where to control them and lessen the risk of human disease. Insect experts the world over use carbon dioxide, the same gas that humans exhale, to attract blood-feeding bugs to traps, so they can measure their abundance, test them for diseases and make decisions about whether or not to control them.
Commercial forms of carbon dioxide are readily available in the U.S., as bottled gas or dry ice.
But carbon dioxide is much tougher to come by in developing countries, particularly those in Africa, making it tougher to monitor the insects. Even when the gas is available, a single tank can costs hundreds of dollars. In the U.S., the same tank would only cost about $15.
For the latest study, researchers used ingredients as simple as crushed seashells and vinegar to create carbon dioxide gas to trap disease-carrying bugs like mosquitoes and black flies. They tested the compounds at the UF/IFAS Florida Medical Entomology Lab in Vero Beach and at a site in Burkina Faso, a nation in western Africa, where diseases like malaria and river blindness prevail.
When they used their new method of producing carbon dioxide to bait mosquito traps in Florida and black fly traps in Africa, the traps attracted up to 25 times more disease-carrying bugs than did traps that did not have the bait. Up to 6,000 mosquitoes were caught in a single trap baited with baking soda and citric acid -- the same acid found in citrus fruits.
“We developed and tested inexpensive and easily reproducible methods of carbon dioxide production from the combination of acids and carbonates,” says Burkett-Cadena, a faculty member at the Vero Beach lab. “Our works shows that a variety of readily available natural carbonate materials, such as limestone, chalk, seashells and baking soda, can be combined with weak acids, like vinegar, to produce carbon dioxide.”
This increases the efficacy of traps targeting blood-feeding insects and arachnids that carry human diseases. Limestone and chalk are carbonate-based and are readily available worldwide.
“The methods used here are inexpensive, easy to implement and effective for attracting blood-feeding insects and arachnids to traps in a wide range of locations,” Burkett-Cadena says.
“Trapping insects that transmit diseases is the first and perhaps most important step in protecting humans from the diseases they transmit,” he says. “After the insects are trapped, they are identified, then tested for the diseases they transmit. When infected bugs are found, mosquito control agencies spring into action to suppress the pest population before humans get infected. Scientists and public health workers around the world rely on carbon dioxide to attract these disease-carrying bugs to their traps.”
In the study published online in the journal Acta Tropica, Burkett-Cadena said he hopes scientists further explore this simple bug-bait method. In addition to UF/IFAS, scientists from the University of South Florida and the World Health Organization helped with the study.
Source: University of Florida Institute of Food and Agricultural Sciences