New World Screwworm (NWS) is re-emerging in some parts of the United States, though it remains rare in companion animals. Prevention and control in dogs and cats can be achieved through widespread use of long-acting, commonly used parasiticides, combined with consistent, evidence-based interstate NWS transport requirements aligned with those for other species.
Prevention and Treatment of NWS in Dogs and Cats
Expanding access to effective parasiticides in shelters and rescues is a simple, high-impact strategy. These products both prevent and treat NWS infestations. Because shelters concentrate animals, rapid treatment reduces the number of potential hosts.
We recommend immediate actions be taken to protect shelter animals from NWS. Priority measures include:
- Increase access to effective products through financial support or donations
- Expand remote veterinary supervision (required for prescription products), including expedited veterinarian of record
- Implement temporary emergency licensure for out-of-state veterinarians. Many shelters, especially in rural areas, lack access to a local veterinarian.
- Authorize trained shelter personnel to obtain and administer preventive treatments in emergency conditions
- Report suspected NWS infestations to the appropriate jurisdictional authority
Safeguarding shelter dog and cat transportation
Transport of dogs and cats from overpopulated regions to other areas of the United States is an essential, life-saving component of humane population management. Current NWS transport regulations of agricultural species are based on zones of infestation, administration of long-acting parasiticides, and a veterinary examination for Certificate of Veterinary Inspection (CVI) with attention to signs of NWS. With proper veterinary examination and treatment with effective parasiticides, shelter dogs and cats can also travel safely without spreading NWS.
We recommend aligning shelter dog and cat transport NWS requirements with evidence-based state, federal, and tribal regulations for other species. Priority measures for these requirements should include:
- Comply with evolving tiered, standardized interstate NWS transport requirements for other species based on infestation zones
- Require treatment with long-acting parasiticides prior to transport
- Require a CVI with attention to NWS signs and documentation of parasiticide treatment
A unified, cross-species regulatory framework would enable a coordinated, expert-led response to evolving NWS risks. This One Health approach is more likely to achieve compliance within the shelter and rescue community than regulations fragmented by species or blanket transport bans. Unified guidelines will better protect public health, agricultural systems, and animal welfare.
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