No
Key Points
- Myiasis is a parasitic infestation of fly larvae (maggots) in human tissue.
- New World screwworm (NWS) is a species of parasitic fly that can cause myiasis and feeds on live tissue.
- NWS primarily affects livestock, but can infest any species of warm-blooded animals and people.
- NWS is typically found in South America, Cuba, Haiti, and the Dominican Republic.
- You are at higher risk for NWS if you travel in these areas, are around livestock in rural areas where the flies are, and if you have an open wound.
Overview
New World screwworm (NWS) infestation occurs when NWS fly larvae (Cochliomyia hominivorax) infest the tissue or flesh of warm-blooded animals and people. Screwworm flies are attracted to and lay eggs on and in open wounds. NWS does not regularly occur or spread in the United States. The parasite is typically found in South America and the Caribbean, although Mexico and countries in Central America are reporting cases in animals and people. If you travel to areas where the flies are present, have an open wound, spend time among livestock animals, or sleep outdoors, you may be at greater risk of becoming infested with NWS.
Current Situation (02/05/2026)
Visit the CDC website for updates
- There has been one confirmed case of NWS in a person who returned to the United States after traveling to El Salvador. Currently, the NWS fly has not been detected in the United States and there is no immediate risk of infestation to people.
- Recently, Mexico and countries in Central America have been experiencing an outbreak of NWS.
- In the outbreak region, NWS is primarily infesting livestock, wildlife, and pets. However, there are also cases of NWS in people.
- Infestations by NWS maggots can cause painful and foul-smelling wounds. If not caught early and treated, it can lead to extensive tissue damage, and potentially death.
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.
Resources
CDC
USDA/APHIS
WEBINARS
COUNTRY-SPECIFIC INFORMATION ON NWS