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Title: Research on Screwworms: male-only strains, Cryopreservation and reducing ammonia in mass rearing

Author
item Skoda, Steven
item Chaudhury, Muhammad
item Phillips, Pamela
item SAGEL, AGUSTIN - Us Embassy, Panama

Submitted to: United States Animal Health Association Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/9/2015
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Screwworm myiasis is devastating to warm blooded animals. The eradication of screwworms from mainland North America using the sterile insect technique (SIT) is an unprecedented achievement; re-invasion is prevented by maintenance of a barrier at the Panama – Colombia border. Several potential advantages of male only strains of the screwworm for the eradication and prevention programs have been identified. These include: 1) more efficient population suppression, 2) increased potential plant capacity, 3) reduced diet costs and 4) improved bio-security of the Program. Transgenic lines have been obtained carrying a single-component tetracycline-repressible female-lethal system. In single-component strains female mortality is late in larval development. Therefore, two component systems have been developed and are being tested for female mortality that is early in development. Cryopreservation of screwworm embryos has been implemented at the screwworm mass rearing facility in Panama. Cryopreservation allows agencies involved in eradication efforts against screwworms to eliminate the practice of rearing a backup strain and will allow for the storage of screwworms embryos from different genetic backgrounds for use in future eradication efforts as well as research projects. Embryos from the current mass rearing strain and the backup strain have been cryopreserved; research strains, including the male only lines, are currently being cryopreserved. Potassium permanganate in the screwworm larval diet reduces ammonia production and is a viable replacement for formaldehyde as an antimicrobial. Soy powder, used as a substitute for milk replacer in the larval diet, reduces the chance of calcium binding with tetracycline used with male only strains. These research accomplishments are being transferred to, or will be implemented by, the Panama – U.S. Commission for Eradication of Screwworms.