Mississippi Board of Animal Health issues alert for New World screwworm

The Mississippi Board of Animal Health urges animal owners to be aware of New World screwworm (NWS), an invasive pest that poses a serious threat to livestock and other warm-blooded animals, including pets, and in rare cases, humans.

Adult screwworm flies have orange eyes, a metallic blue or green body, and three dark stripes along their backs. The unique ability of screwworm larvae to feed on fresh flesh is what makes this insect so dangerous to livestock and other animals.

NWS was eradicated from the United States decades ago; however, recent detections of the pest in Mexico highlights the potential for reintroduction and spread, particularly in southern states. In addition, the northward spread of NWS is possible through natural wildlife movements.

USDA has suspended live cattle, horse, and bison imports through U.S. ports of entry along the southern border. Animal owners should be vigilant in checking animals regularly, especially if animals have traveled internationally. Owners should inspect wounds and treat them promptly.

Things to look for include wounds that won’t heal or worsen over time, foul-smelling discharge or visible larvae (maggots) in a wound, signs of discomfort or unusual behavior, such as animals avoiding feed or isolating themselves.

Infestation may be found in wounds resulting from routine procedures such as castration, dehorning, or branding, and may also occur from minor injuries like insect bites or around the navel of newborn livestock.

If you suspect NWS, contact the board at 601-359-1170 or 888-722-3106 (after hours). Suspicious cases will be evaluated, and samples may be submitted for laboratory confirmation. Contact your local veterinarian for assistance with treating your animal for suspicious wounds.