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Latin American Countries Combat Screwworm Pest through IAEA Project


Methods to combat the New World Screwworm, including the sterile insect technique (SIT), are discussed at a research centre operated by the Uruguayan Wool Secretariat. (Photo: IAEA)

Latin American countries have started work with the IAEA and its partners to prevent the re-introduction of the New World screwworm into Central and North America from where it has been eradicated and build capacity for the suppression and eventual eradication of this insect pest in some regions of South America and the Caribbean.

The screwworm affects both livestock production and human health. With the help of nuclear techniques, a new project to address the screwworm problem, organized by the IAEA in cooperation with the Food and Agriculture Organization of the United Nations (FAO), the United States Department of Agriculture (USDA) and the USA-Panama Commission for the Eradication and Prevention of the New World Screwworm (COPEG), is underway.

The new project will focus on strengthening surveillance systems for early detection of the pest, emergency response to pest outbreaks in screwworm-free areas and the development of capacity for progressive pest suppression and eradication through a comprehensive approach known as area-wide insect pest management. This approach targets the entire population of an insect throughout a large area, and incorporates the sterile insect technique (SIT). SIT involves the sterilization of large numbers of male flies with radiation in a mass-rearing facility before releasing them into the wild, where their mating produces no offspring. Over time, the pest population is reduced and can ultimately be eliminated.

Although the screwworm has been eliminated from the United States, Mexico and Central America using SIT in conjunction with other methods as part of an area-wide insect pest management approach, it persists in several areas throughout South America and the Caribbean.

During the project’s first coordination meeting, held from 19-23 March in Montevideo, Uruguay, representatives from several countries in the region presented the status of the screwworm and discussed how to continue improving efforts to prevent and combat the insect. “The workplan and activities were planned in accordance with the varying needs of each country involved in the project, though effective control of the pest requires a regional approach considering its transboundary nature,” said Walther Enkerlin, an entomologist in the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture.  

The screwworm fly lays eggs in wounds and soft tissues in warm-blooded animals, including humans and livestock such as cows, causing a disease known as myiasis. When the larvae hatch from the eggs, they feed on the surrounding tissue, resulting in sores and lesions that are highly susceptible to bacterial infection. These infections can be deadly if left untreated. Since it was eliminated in the USA, Mexico and Central America, the economic benefit due to the eradication of the New World screwworm has amounted to approximately US $1.3 billion per year according to the New York Academy of Sciences.

“SIT has proven to be a highly effective technique, and it is important that we expand its implementation as part of an overall approach in Latin America,” said Moises Vargas, an international animal health expert, formerly at the FAO’s Regional Office for Latin America. “We are establishing a sound plan for the prevention and progressive control of the New World screwworm throughout the region.”

The next steps of the project, delivered through the IAEA’s technical cooperation programme, will include reviewing and updating a road map for the progressive control of the screwworm in the region, preparing a strategic plan and an economic feasibility assessment and continuing to build capacity in surveillance, diagnosis and emergency response to pest invasions in previously cleared areas.

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