New World Screwworm

New World screwworm (NWS) is a fly that lays its eggs in wounds or body openings such as the eyes, ears, nose, and mouth. The eggs hatch into maggots (parasitic larvae). The maggots burrow into and feed on living tissue or flesh. NWS primarily affects livestock, but it can also occur in companion animals, wildlife, and people. NWS is not contagious. It does not spread directly from animal to animal, animal to person, or person to person.

Situation Summary

  • NWS is typically found in South America and parts of the Caribbean. NWS was previously found in the United States, but it was eliminated in 1966.
  • Since 2023, NWS flies have moved northward from Panama through every country in Central America and Mexico.  
  • On June 3, the U.S. Department of Agriculture (USDA) announced the detection of NWS in a cow in Zavala County, Texas. Since then, NWS has been confirmed in other animals in Texas and New Mexico.
  • No cases of NWS have been detected in animals or people in Virginia. 
  • VDH is closely monitoring this situation. The risk to Virginia is currently very low except for animals or people who have traveled to areas where the NWS fly is circulating.  
  • VDH works closely with the Virginia Department of Agricultural and Consumer Services (VDACS) and the Virginia Department of Wildlife Resources (DWR) on issues affecting animal and human health. If an NWS response in Virginia is needed, VDH will coordinate with these partners.  

A list of resources for the public and special groups can be found below.

Resources