New World screwworm (NWS) is a dangerous parasitic fly whose larvae feed on the living tissue of warm‑blooded animals. Infestations can develop rapidly, causing severe tissue damage and, without prompt treatment, can be fatal. All warm‑blooded animals are at risk, including livestock, pets, wildlife, and, in rare cases, people and birds.
Current Status
Current Arkansas Status: No confirmed cases
Current U.S. Status: Visit screwworm.gov or view the confirmed case dashboard for the latest information.
If You Suspect NWS
Animal owners and veterinarians can submit information, including location and photographs, to the Arkansas Department of Agriculture through an online reporting tool. Department staff will respond to submissions with instructions for next steps, including sample submission and additional precautions.
If NWS is suspected, isolate the affected animal immediately and avoid moving any animals off the premises, as movement can rapidly spread the pest. Animal owners can also contact their regular veterinarian or call the Arkansas Department of Agriculture (501) 823-1746 to report suspicious cases.
Animal Entry Requirements
All warm-blooded animals traveling from an infested state, but not an Infested Zone, must be accompanied by an Interstate Certificate of Veterinary Inspection (iCVI) dated within 7 days of entry into Arkansas and must include the following statement: “All animals in shipment were inspected and found free of evidence of NWS infestation.”
Group-housed food producing animals may be visually inspected in their group settings according to federal NWS response guidance. Individual inspection is required for all other animals.
Table eggs, hatching eggs, and chicks under 5 days of age are exempt from this interstate movement requirement, as are National Poultry Improvement Plan (NPIP) Types B, C, D, and J moving on a USDA VS Form 9-3.
Movement of animals into Arkansas from identified NWS Infested Zones will be restricted according to established federal NWS response guidance and a state entry permit will also be required for those animals. Obtain a state entry permit.
Signs and Symptoms
Infested animals may develop wounds that fail to heal, accompanied by a foul odor or visible maggots in or around the affected area. Tissue damage can progress quickly, and animals may become lethargic, lose appetite, or show signs of significant discomfort or pain. Because symptoms can worsen in a short period of time, timely recognition and action are essential.
High-Risk Situations
Any situation that exposes an animal to open wounds or stressed conditions can increase vulnerability to NWS. Branding, castration, dehorning, and birthing events—particularly when navels remain open—are known risk factors. Injuries caused by predators, surgical sites, or stress caused by transport or sale events may also create opportunities for NWS to establish an infestation.
Prevention
Preventive management remains the most effective defense against NWS. Regularly monitor animals, especially during fly season, and treat any wounds as soon as they appear. Maintaining clean facilities, reducing fly breeding sites such as accumulated manure, and using consistent fly‑control practices all help reduce the likelihood of infestation. Keeping animals healthy and minimizing the creation of wounds significantly lowers risk.
The U.S. Food and Drug Administration (FDA) maintains a list of animal drugs available for treatment and prevention NWS. There are pesticides to potentially use against NWS. View list of pesticides for control of NWS in Arkansas.
Livestock owners are encouraged to obtain a valid Premises Identification Number (PIN) to increase their readiness for NWS response. A valid PIN is required for interstate and intrastate animal movement from an NWS Infested Zone.
Regulatory Response
If NWS is confirmed in Arkansas, state and federal officials will implement a coordinated response to contain and eliminate the pest. This may include quarantines, movement restrictions, and establishing surveillance zones. These measures are put in place to protect the state’s livestock industries, wildlife, and companion animals.
Resources
- NWS Fact Sheet for Veterinarians (Arkansas Department of Agriculture)
- NWS Fact Sheet for Producers (Arkansas Department of Agriculture)
- Screwworm.gov (U.S. Department of Agriculture)
- NWS Response Playbook (U.S. Department of Agriculture)
- NWS Information for Veterinarians (U.S. Food and Drug Administration)
- NWS Information (American Veterinary Medical Association)