What to know
- On June 3, 2026, USDA confirmed, in Texas, the first US animal case in the current outbreak of New World screwworm.
- No locally acquired human infestations have been reported in the United States.
- Since 2023, an outbreak of NWS has moved northward through Central America and Mexico, primarily infesting livestock, pets, and wildlife, but also people.
- Infestations by NWS maggots can cause painful, foul-smelling wounds in animals and people. If not treated early, they can lead to extensive tissue damage and potentially death.
Current situation
On June 3, 2026, the US Department of Agriculture Animal and Plant Health Inspection Service (USDA-APHIS) reported the first animal case in the United States. For more on NWS in animals go to screwworm.gov.
There have been no reports of locally acquired human infestations with NWS. The risk of infestation in people remains low. Risk is localized to areas where NWS flies are circulating.
In 2023, Panama and Costa Rica identified an outbreak of NWS. Since that time, all countries in Central America and Mexico, where NWS was previously controlled, have identified cases in animals, including livestock, pets, and wildlife, and in people.
Cases of NWS
As of June 8, 2026
- In the United States, USDA-APHIS is reporting initial animal cases at screwworm.gov
- In Mexico and Central America, more than 185,000 NWS cumulative cases reported in animals and more than 2,100 cases in people
Since NWS's re-emergence in Central America and Mexico, one case was confirmed in August 2025, in a person who returned to the United States after traveling to El Salvador.
CDC is closely following this outbreak and is working with the USDA, the Department of the Interior (DOI), and other federal and state, local, and tribal partners to prevent further spread of NWS among people and animals.
The strategy to respond to and control the NWS outbreak, led by USDA and in coordination with other federal agencies, includes the release of sterile flies, animal movement controls and surveillance, and outreach and education in affected areas.
What you should do
In areas where the NWS flies are present, the best way to protect yourself from infestation is to
- Keep open wounds clean and covered, no matter how small or location on the body.
- Wear loose-fitting, long-sleeved shirts and pants, hats, and socks to limit exposed skin.
- Treat clothing and gear with products containing 0.5% permethrin.
- Sleep indoors or in rooms with screens.
Watch for symptoms
If you see or feel maggots (larvae) in or on a wound or other area of your body, contact your healthcare provider immediately. They will need to remove all of the maggots, sometimes through surgery. Do not try to remove or dispose of the maggots yourself.
Symptoms can include
- Unexplained, painful wounds or sores that do not heal.
- A foul-smelling odor or bleeding from the site of the infestation.
- Seeing maggots or feeling movement in open wounds or sores or in the areas of the body such as the nose, mouth, eyes, ears, or genitals.
Report suspected cases
If you are a healthcare provider and you suspect a patient has an NWS infestation, report it immediately to your local or state health department. Veterinarians should report any suspicious animal cases immediately to their state animal health official and APHIS office.