Key facts
- Screwworm has been confirmed in U.S. livestock.
- This is the first case detected since 1976.
- Screwworms are larvae of flies that feed on living flesh.
- The parasite poses a significant threat to livestock and wildlife.
- The potential case was detected in South Texas.
The United States has confirmed its first case of screwworm affecting livestock since 1976. Officials announced the confirmation of this dangerous parasite. Screwworms are the larvae of a specific type of fly that feed on living flesh, posing a significant threat to livestock and wildlife populations. The potential case was detected in South Texas. Screwworm's maggots typically enter an animal through an open wound and feed on its living flesh, eventually killing the host if left untreated. In rare cases, they will infect humans. The parasitic fly has resurged throughout the Americas since 2023.