Yesterday the Centers for Disease Control and Prevention (CDC) issued a Health Alert Network (HAN) advisory on recent animal cases of New World screwworm (NWS) in the Mexican state of Tamaulipas, which shares a border with Texas.
“No NWS infestations related to this outbreak have been identified in people or animals in the United States as of January 20, 2026. However, given the potential for geographic spread, CDC is issuing this Health Advisory to increase awareness of the outbreak,” the CDC said.
NWS myiasis (maggot infestation) is transmitted when parasitic flies lay eggs in wounds or in other body cavities, such as the nose, ears, eyes, or mouth. Cattle and horses are typically infected, but flies can also lay eggs on people and other warm-blooded animals. If untreated, infections can be deadly in humans.
Clinicians should consider travel history
As of yesterday, Central America and Mexico have tracked 1,190 cases and seven deaths in people in an ongoing outbreak. Tamaulipas currently has eight active animal cases.
The United States has previously eradicated NWS through releasing sterile male flies to mate with the female NWS fly, which is a type of blowfly. The United States will use that tactic again if NWS is reintroduced in Texas or elsewhere, the CDC said. Last year, the United States did see a travel-related case in Maryland, the country's first human case in 50 years.
For clinicians, the CDC recommends considering a diagnosis of NWS in people who present with visible egg masses in wounds or orifices, and other symptoms in anyone who has recently traveled to an area where NWS is present.
There have not been any studies to prove that any specific medication is useful in treatment in humans.
“The treatment of NWS in humans is removal of all eggs and larvae, which might require surgical extraction if the larvae are embedded deeply into tissues,” the CDC said. “There have not been any studies to prove that any specific medication is useful in treatment in humans.”