The parasitic fly known as New World screwworm has New Mexico communities on high alert after a recent spike in confirmed cases across several counties.
As part of an ongoing campaign to educate the public about this pest, New Mexico State University’s Cooperative Extension Service has released a new publication that outlines and illustrates the general biology and characteristics of adult New World screwworm flies. The free guide, available at https://pubs.nmsu.edu/_b/B137/index.html, is a one-stop resource designed to help readers understand New World screwworm and its threats.
“Our goal was to create an updated, accessible overview of New World screwworm that brings together its history, biology and basic identification information in one place,” said Caleb Hubbard, assistant professor in NMSU’s Department of Entomology, Plant Pathology and Weed Science who co-wrote the new publication with Marcy Ward and Brandon Smythe. “We wanted to give readers a concise introduction to the pest and help them understand why it matters. The publication is intended to be useful to people who are unfamiliar with screwworm and want a clear starting point for learning more.”
New Mexico currently has 41 confirmed screwworm cases in Catron, Doña Ana, Grant, Hidalgo, Luna, Otero, Eddy and Sierra counties. Nationally, reported cases have climbed to 121 as of this week.
New World screwworm is a danger to livestock, wildlife and pets. It causes primary myiasis, the infestation of living tissue by fly larvae. Adult female screwworms can lay eggs in wounds and openings on vertebrate animals. After hatching, larvae feed on the host’s living tissue and can cause severe wounds, bacterial infections, animal stress and potentially death if untreated. The larvae produce a foul-smelling wound that attracts female screwworms to lay additional eggs.
The guide, which includes pictures of real infections, aims to illustrate the seriousness of New World screwworm.
“Seeing the damage screwworm can cause helps readers understand its significance in a way that a written description alone may not fully convey,” Hubbard said. “I see this publication as a resource that people can read and share with others who may know little about New World screwworm. I am still struck by how many people are unfamiliar with this pest and the damage it can cause. Our goal is to help close that awareness gap by making the information approachable and easy to understand.”
Hubbard said the screwworm outbreak in New Mexico is “rapidly evolving.” He added that weather may be contributing to the growing number of cases.
“The pace of the increase initially surprised me,” he said. “Looking back at conditions over the past two months, however, I suspect that milder temperatures may have created more favorable conditions for screwworm than the extreme heat we experienced during the summer. That could be one factor contributing to the recent increase.”
Still, Hubbard is hopeful that screwworm activity and infestations may decline as temperatures drop this fall and winter. He said continued surveillance and prompt reporting will remain important as state and federal officials monitor the situation.
Following confirmed screwworm cases in Doña Ana County, the New Mexico Livestock Board established animal inspection and travel requirements to help prevent its spread. To learn more about the requirements, visit https://nmsu.news/NWS-Travel-Requirements.
NMSU’s Cooperative Extension Service has also released two other screwworm publications, including a detailed identification guide and one tailored for livestock producers.
For more information on reporting screwworm cases in New Mexico, visit ScrewwormNM.org. For questions related to screwworm research and management, contact Hubbard at calebh@nmsu.edu.
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Cutline: Caleb Hubbard, assistant professor at New Mexico State University co-wrote a new publication that outlines and illustrates the general biology and characteristics of adult New World screwworm flies. (NMSU photo by Josh Bachman)