New World screwworm (NWS) is a serious pest of livestock and wildlife. USDA is leading a coordinated One Health response to combat NWS. This is not a food safety issue—the U.S. food supply remains safe. The current risk to animals and people in the United States is very low.
Stopping the Spread
U.S. Readiness
Planning and preparing for an outbreak of NWS is essential to protect public health, animal health, agriculture, the environment, our food supply, and the economy.
With the support of industry, State, and Tribal partners, the United States remains vigilant against and fully prepared for possible screwworm incursions. As part of our five-pronged plan to defeat screwworm, we are supporting robust response activities in Mexico and Central America to push the pest back, and we have teams in place to bolster our defenses and respond quickly to prevent further spread.
Mass production and targeted dispersal of sterile flies remain critical components of our effective response.
Sterile flies are one of the most important tools we have for eradicating screwworm. USDA is investing heavily in new and existing sterile fly infrastructure to ramp up production and expand our domestic response capacity.
With these investments, production will approach approximately 500 million sterile flies per week—the same amount we used to eradicate NWS from the United States decades ago.
Learn More About Sterile Insect Technique
Track Status of Sterile Fly Production and Dispersal Facilities
USDA has intensive surveillance and monitoring systems in place along the U.S.-Mexico border to detect screwworm.
We also have strict trapping, surveillance, and movement protocols established in Mexico, and we work closely with our counterparts there to ensure the protocols are followed.
Across the Federal Government, we're driving innovation to win the fight against screwworm.
Science and collaboration are critical to our success. USDA has announced the NWS Grand Challenge. This funding opportunity makes up to $100 million available to support innovative projects that enhance sterile NWS fly production, strengthen preparedness and response strategies, and safeguard U.S. agriculture, animal health, and trade.
We're also pursuing extensive research to bolster our response strategies and ensure we have all the tools we need to detect, control, and eliminate this pest.
The U.S. Government is using all resources at our disposal to stop screwworm.
USDA has established a dedicated New World Screwworm Directorate within APHIS focused on coordinating and implementing the Secretary’s plans. We are collaborating closely with the U.S. Centers for Disease Control and Prevention, U.S. Department of the Interior, and numerous other agencies to ensure a unified Federal response.
What You Need To Know
Producers
- The Facts About New World Screwworm (451.98 KB) | USDA
- Using Sterile Insect Technique To Fight Screwworm | USDA
- New World Screwworm | USDA
- NWS Photo Gallery | USDA
- New World Screwworm Story Map | USDA
- How To Reduce Risk of New World Screwworm on Livestock Operations | USDA NRCS)
- NRCS Resources for New World Screwworm Preparedness and Response | USDA NRCS)
Recorded Webinars
- Webinar for Animal Industry | USDA
Veterinarians
- Dear Veterinarian Letter: Use of FDA-Authorized Animal Drugs Against New World Screwworm Myiasis | FDA
- Animal Drugs for New World Screwworm | FDA
- New World Screwworm: Information for Veterinarians | FDA
- New World Screwworm: Be Aware and Prepare (Information for Veterinarians) | USDA
- New World Screwworm: Veterinary Considerations for Dogs and Cats Traveling Internationally (383.55 KB) | USDA, CDC, FDA, U.S. CBP
- Standard Operating Procedure for Possible Detections of New World Screwworm in Animals | USDA
Recorded Webinars
- New World Screwworm Webinar for Veterinarians and Animal Health Regulatory Officials | USDA
- Zoonoses & One Health Update | CDC (The New World screwworm update starts at 32:55.)
Animal Health Officials
- Emergency Management: New World Screwworm | USDA
- Standard Operating Procedure for Possible Detections of NWS in Animals | USDA
- Foreign Animal Disease Investigation Guide: New World Screwworm | USDA
- New World Screwworm: Information for Veterinarians | FDA
- New World Screwworm: Be Aware and Prepare (factsheet) | USDA
Recorded Webinars and Training
Wildlife Professionals
Healthcare Providers
- Clinical Overview of New World Screwworm (en Español) | CDC
- New World Screwworm Myiasis, Recommendations for Healthcare Providers | CDC
Recorded Webinars
- Resurgence of New World Screwworm in the Americas: What Healthcare Providers Need To Know | COCA | CDC
- Webinarios sobre gusano barrenador | COMISCA
- Zoonoses & One Health Update | CDC (The New World screwworm update starts at 32:55.)
Public Health Officials
- New World Screwworm Case Reporting for Health Departments
- Preparing for New World Screwworm Infestations in Humans
- CDC - DPDx - New World Screwworm
- Laboratory Diagnosis of New World Screwworm (en Español)
- Telediagnosis of New World Screwworm
- Clinical Overview of New World Screwworm (en Español)
Recorded Webinars
- Zoonoses & One Health Update | CDC (The New World screwworm update starts at 32:55.)
Clinical or Diagnostic Assistance
- For clinical inquiries and patient management-related questions, contact parasites@cdc.gov or 404-718-4745. Direct after-hours inquiries to CDC’s Emergency Operations Center at 770-488-7100.
- For diagnostic assistance for suspected human cases, contact dpdx@cdc.gov.
Drug Manufacturers
Travelers
New World screwworm (NWS) myiasis is a serious parasitic disease that can affect all warmblooded animals, including people. Recently, cases of NWS myasis have been reported in countries where it had previously been eliminated, including Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, and Panama. Travel to or from NWS-affected countries—particularly areas with active animal or human cases—can significantly increase the risk of infestation.
Human Health
People traveling to NWS-affected countries should:
- Clean and cover wounds.
- Avoid bug bites by using insect repellent and wearing loose-fitting, long-sleeved shirts and pants, socks, and hats.
- Sleep in a room with screened windows, or under a bed net, or inside a screened tent.
- Avoid spending time where livestock or other infested animals are located.
For more information on specific locations, visit CDC's Travelers’ Health website.
Traveling With Pets or Service Animals
To prevent the spread of NWS into the United States, pets and service animals arriving from NWS-affected countries must meet specific USDA and CDC import requirements:
- Bring a Pet from Another Country into the United States | USDA
- Bringing an Animal into the United States | CDC
- New World Screwworm: What You Need to Know Before Traveling Internationally with a Pet (203.54 KB)| USDA, CDC, FDA, U.S. CBP
Pet Owners
- New World Screwworm | USDA
Traveling Internationally With Pets or Service Animals
To prevent the spread of NWS into the United States, pets and service animals arriving from NWS-affected countries must meet specific USDA and CDC import requirements:
Hunters
- The Facts About New World Screwworm (451.98 KB) | USDA
- Using Sterile Insect Technique To Fight Screwworm | USDA
- New World Screwworm | USDA
- New World Screwworm: A Threat to Wildlife (Information for Hunters) (en Español (1.09 MB)) | USDA
- New World Screwworm Story Map | USDA
- NWS Photo Gallery | USDA
General Public
- The Facts About New World Screwworm (451.98 KB) | USDA
- Using Sterile Insect Technique To Fight Screwworm | USDA
- About New World Screwworm (en Español) | CDC
- New World Screwworm Outbreak | CDC
- New World Screwworm Myiasis, What You Need To Know | CDC
- New World Screwworm Communications Resources | CDC
- Preventing Mosquito Bites While Traveling | CDC
- Repellents: Protection Against Mosquitoes, Ticks, and Other Arthropods | EPA
- New World Screwworm Story Map | USDA
Questions?
USDA is leading an aggressive unified response to detections of NWS in the United States.
- For general questions, email screwworm@usda.gov.
- To report suspected cases in Texas livestock, contact the Texas Animal Health Commission Region Office or the State veterinarian on call at 1-800-550-8242. Report suspected cases in Texas wildlife to Texas Parks & Wildlife.
- For all other reporting, visit Report Suspected Cases of Screwworm.
