New World Screwworm

The New World Screwworm (NWS) is a parasitic worm that is not an foreigner to the United States. Until the 1960's, this invading parasitic worm was in the United States.  Efforts of the US government combated the vector and pushed it down to South America.  In recent years, the NWSW has been battling it's was North.  Sporadic occurrences have been detected, mainly due to immigration and migration of people and animals. 

Below are some links for reference to the NWS

https://www.cdc.gov/new-world-screwworm/about/

https://www.cdc.gov/dpdx/newworldscrewwormmyiasis/index.html

https://www.cdc.gov/dpdx/resources/pdf/benchaids/nws-teledx-bench-aid-508.pdf