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Title: Sequence Characterized Amplified Regions (SCAR) that differentiate New World screwworms from other potential wound inhabiting flies

Author
item CHRISTEN, JOAN - University Of Nebraska
item Skoda, Steven
item HENG-MOSS, TIFFANY - University Of Nebraska
item LEE, DONALD - University Of Nebraska
item FOSTER, JOHN - University Of Nebraska

Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2014
Publication Date: 1/2/2015
Citation: Christen, J.A., Skoda, S.R., Heng-Moss, T.M., Lee, D.J., Foster, J.E. 2015. Sequence Characterized Amplified Regions (SCAR) that differentiate New World screwworms from other potential wound inhabiting flies. Journal of Veterinary Diagnostic Investigation. 27:25-30.

Interpretive Summary: Eradication of the screwworm from the United States, Mexico, and Central America was a resounding success. Each year livestock producers reap significant benefits when they do not need to treat animal wounds for this hideous affliction. The savings to wildlife, pets, and reduced human suffering are immeasurable. Guarding against the reintroduction of screwworms to North America or introduction to any other screwworm free area relies on rapid, reliable identification of suspected cases. Early larval stages, maggots, of flies in wounds are very difficult to identify. Identification of first instars suspected to be screwworms can be rapidly verified by using molecular techniques. DNA was cut from gels showing markers unique to screwworms and used as the basis to generate two species-specific molecular markers called sequence characterized amplified sequences (SCARS). Resulting primers, named CR92A1 and J1A2, produced products that successfully discriminated between screwworms, the closely related and very similar secondary screwworm, eight other species of blowflies that often infest wounds, three non-blowfly species, and one outlier. These primers may become important tools for the screwworm eradication and exclusion program for rapid identification of suspicious larval samples in presumed outbreaks.

Technical Abstract: Guarding against the introduction of screwworms, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), to North America or any other screwworm free area relies on rapid, reliable identification of suspected cases. Identification of first instars suspected to be C. hominivorax can be rapidly verified by using molecular techniques. DNA from excised markers generated by Random Amplified Polymorphic DNA-Polymerase Chain Reaction was used as the basis to generate two species-specific Sequence Characterized Amplified Region (SCAR) molecular markers. Resulting primers, named CR92A1 and J1A2, produced amplicons at 852 bp and 848 bp, respectively. The two primers successfully discriminated between C. hominivorax, C. macellaria (Fabricius) (Diptera: Calliphoridae), eight other species of blowflies, three non-calliphorid dipterans, and one non-dipteran outlier. These primers may become important tools for the screwworm eradication and exclusion program for rapid identification of suspicious larval samples in presumed outbreaks.