en.wikipedia.org/wiki/Cochliomyia_hominivorax
4 corrections found
The United States officially eliminated the screwworm in 1982 using the sterile insect technique
The U.S. did not eradicate New World screwworm in 1982. USDA sources state it was eradicated from the United States in 1966, with a later Florida Keys outbreak eliminated in 2017.
Full reasoning
This date is incorrect. USDA APHIS says, "Using sterile insect technique, we eradicated NWS from the United States in 1966 and successfully eliminated a small outbreak from the Florida Keys in 2017." The USDA National Agricultural Library likewise states that "The United States was declared officially free of indigenous screwworms in 1966."
So while 1982 is a real year in the broader regional eradication history, it is not the year the United States officially eliminated screwworm. The correct U.S. eradication date is 1966.
2 sources
- New World Screwworm Prevention for Animals
Using sterile insect technique, we eradicated NWS from the United States in 1966 and successfully eliminated a small outbreak from the Florida Keys in 2017.
- 1958-1969 · STOP Screwworms: Selections from the Screwworm Eradication Collection
The United States was declared officially free of indigenous screwworms in 1966.
Currently, due to eradication programs, the species is distributed exclusively in South and Central America to the Panama Canal and some Caribbean islands.
This distribution statement is outdated. Official U.S. sources say the outbreak has moved north through Central America and Mexico, and USDA confirmed U.S. detections in Texas in June 2026.
Full reasoning
The claim says the species is exclusively distributed only as far north as the Panama Canal, but current official sources contradict that.
USDA APHIS states that New World screwworm "has moved northward through Central America and Mexico" in recent years. CDC likewise says that since 2023 the outbreak has moved northward through Central America and Mexico. USDA then confirmed U.S. detections on June 3, 2026, beginning with a calf in Zavala County, Texas.
Because the species had already spread through Mexico and into the United States by June 2026, it was no longer accurate to describe its distribution as exclusive to South/Central America up to the Panama Canal plus some Caribbean islands.
3 sources
- New World Screwworm Prevention for Animals
In recent years, NWS has moved northward through Central America and Mexico.
- New World Screwworm Outbreak | CDC
Since 2023, an outbreak of NWS has moved northward through Central America and Mexico, primarily infesting livestock, pets, and wildlife, but also people.
- USDA Confirms New World Screwworm in Texas
WASHINGTON, D.C., June 3, 2026—The U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed the detection of a New World screwworm (NWS) in a bovine in Zavala County, Texas.
From 1966 to 2025, the species was considered extirpated from the US
This skips the documented 2016–2017 Florida outbreak. U.S. agencies say the most recent U.S. outbreak before 2026 occurred in Florida in 2016–2017.
Full reasoning
The statement implies there were no U.S. occurrences between 1966 and 2025, but official sources say that is not true. CDC states that "The most recent outbreak of NWS in the United States occurred during 2016–2017 in Florida," and USDA APHIS says it "successfully eliminated a small outbreak from the Florida Keys in 2017."
So even if the species was eradicated nationally in 1966, the claim that it was considered extirpated continuously from 1966 to 2025 is inaccurate because a U.S. outbreak occurred in 2016–2017.
2 sources
- Preparing for New World Screwworm Infestations in Humans | CDC
The most recent outbreak of NWS in the United States occurred during 2016–2017 in Florida; a collaborative response ... successfully re-eradicated the flies from the state.
- New World Screwworm Prevention for Animals
Using sterile insect technique, we eradicated NWS from the United States in 1966 and successfully eliminated a small outbreak from the Florida Keys in 2017.
Campaigns against the flies continue in Mexico, Nicaragua, Costa Rica, Panama, and Jamaica with financial assistance from the United States Department of Agriculture (USDA), which is trying to push the parasite south of the narrow Isthmus of Panama.
This is outdated. By 2026, USDA said screwworm had already moved north through Central America and Mexico, and U.S. response had shifted to defending the U.S.-Mexico border and responding to U.S. cases.
Full reasoning
The claim describes USDA as if it were still trying to keep New World screwworm south of Panama, but official 2026 sources show the situation had already changed.
USDA APHIS states that New World screwworm "has moved northward through Central America and Mexico" in recent years. In January 2026, APHIS announced it was shifting sterile-fly dispersal efforts to defend the U.S. border, with operations along the border with Tamaulipas, Mexico and about 50 miles into Texas. USDA then confirmed a Texas detection on June 3, 2026.
So by 2026, the parasite was no longer being contained south of the Isthmus of Panama; it had spread far north of Panama, through Mexico, and into the United States.
3 sources
- New World Screwworm Prevention for Animals
In recent years, NWS has moved northward through Central America and Mexico.
- Sterile Fly Dispersal Efforts to U.S. Border New World Screwworm
The new dispersal area, or polygon, will include operations about 50 miles into Texas, along the U.S. border with the state of Tamaulipas, Mexico.
- USDA Confirms New World Screwworm in Texas
WASHINGTON, D.C., June 3, 2026—The U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed the detection of a New World screwworm (NWS) in a bovine in Zavala County, Texas.