By Darren Turley
TAD Executive Director
Last year, Texas dairy farmers were caught off guard by an outbreak of Highly Pathogenic Avian Influenza (HPAI) in their herds. At the same time, Panama experienced a dramatic surge in cases of New World Screwworm, with reported incidents skyrocketing from 25 to over 6,500 within a single year.
The New World screwworm outbreak, initially confined to Panama, has since spread northward through Central America, including Costa Rica, Nicaragua, Honduras, Guatemala, Belize, El Salvador and now Mexico. Authorities had hoped to contain the disease within Mexico’s southern peninsula, but containment efforts have so far failed.
On May 11, the U.S. Department of Agriculture announced that the United States would suspend imports of live cattle, horses and bison through ports along the southern border with Mexico on a “month-by-month basis” until “a significant window of containment is achieved.”
The screwworm was last eradicated from the U.S. in 1966. USDA now says the parasite was recently detected in remote farms in Mexico about 700 miles away from the U.S. border.
In 1976, an outbreak in Texas affected more than 1.4 million cattle and hundreds of thousands of sheep and goats. If such an outbreak occurred now, the USDA estimates it would cost the Texas economy $1.8 billion.
The Texas Association of Dairymen is actively engaging with policymakers and stakeholders to advocate for protective measures for dairy producers.
What exactly is the New World screwworm? It’s a parasitic fly whose larvae infest livestock and other warm-blooded animals. The adult fly, similar in size to a housefly, has distinctive orange eyes, a metallic blue-green body and three dark stripes along its back. The name “screwworm” refers to the spiral shape of the larvae, which burrow into living tissue to feed.
Infestation begins when a female fly lays eggs on a superficial wound or natural opening on a host animal. One female can lay up to 400 eggs at a time and as many as 2,800 eggs over her 10-to-30-day lifespan. After hatching, larvae feed on the host for five to seven days before dropping to the ground to pupate. New adults emerge, mate within a few days, and continue the cycle.
To combat this pest, the USDA has used a proven method eradication method that advantage of the fly’s own biology. Female screwworm flies typically mate only once during their lifetime, so releasing large numbers of sterile males gradually reduces the population.
Currently, Mexico has reported more than 1,200 cases, with new infections increasing by 20% to 25% each week. Discussions are underway about reactivating or retooling a facility in Texas to produce sterile flies, but the process requires time and significant funding. Meanwhile, the disease continues to spread rapidly.
The Texas Association of Dairymen, in coordination with other agricultural organizations, supports a swift response by state and federal lawmakers and agriculture officials. We want to protect our dairy farmers, who have made Texas the #3 milk producing state in the nation. Without prompt and coordinated action, the risk to U.S. livestock remains high.
