South Dakota Health Officials Issue Warning: New World Screwworm Poses Threat to Livestock and People

Warning Issued in South Dakota: Identify New World Screwworm Threatening Livestock and People with Detailed Visual Guide.

Northeast Radio SD News - Watertown, SD - The South Dakota Department of Health is calling on agricultural producers, farm owners, and field employees to stay vigilant against the New World screwworm (NWS), a dangerous parasite that can cause severe injury or death in livestock, pets, wildlife, and even humans.

Unlike common maggots that feed on dead tissue, NWS maggots are unique because they eat living flesh. This aggressive feeding behavior causes wounds to expand rapidly, leading to extreme pain, potential infection, and fatalities if left untreated.

A Growing Risk in Small Spaces

The threat begins when NWS flies seek out open wounds or body openings—including the eyes, ears, nose, and mouth—to lay their eggs. Alarmingly, a wound as small as a bug bite is enough to trigger an infestation. Once the eggs hatch, the maggots burrow deep into the living tissue to feed.

Recognizing the Signs

Health officials urge everyone working outdoors to monitor themselves and their animals for the following symptoms:

·         Visible Movement: Seeing or feeling maggots moving within a wound or sore.

·         Unusual Sensations: An itchy feeling or the sensation of movement inside a wound.

·         Poor Healing: Painful sores that get worse or fail to heal after a few days.

·         Physical Indicators: A foul smell or unexpected bleeding from a wound site.

Prevention and Protection

To keep the workforce and community safe, the Department of Health recommends several immediate preventative measures:

·         Cover Up: Wear loose, long-sleeved shirts, long pants, socks, and hats to limit skin exposure to bug bites.

·         Wound Care: Clean all cuts or breaks in the skin immediately and keep them covered with adhesive bandages or gauze.

·         Use Repellent: Apply EPA-registered insect repellent frequently. Note: Never apply insecticides intended for animals to human skin.

What to Do If an Infestation is Suspected

If you suspect NWS, do not attempt to remove the maggots yourself. Producers are encouraged to create a safe reporting environment where employees can flag concerns without fear of punishment.

If maggots or eggs fall out of a wound, they should be collected in a leak-proof container—ideally preserved with rubbing alcohol—to be examined by a doctor or veterinarian. Immediate medical or veterinary care is the only way to stop the spread of NWS and ensure a full recovery.

For more information on NWS in animals and further safety guidelines, visit www.screwworm.gov.