First Screwworm Case Confirmed in Ciudad Juárez, Chihuahua
Ciudad Juárez, Chihuahua, August 18 – The National Service of Health, Safety, and Agri-Food Quality (Senasica) has confirmed the first active case of screwworm in cattle in Ciudad Juárez, Chihuahua. This development, based on an update from August 17, 2026, places Juárez among the municipalities in Chihuahua with an active presence of this pest.
The detection in Ciudad Juárez is particularly significant due to its strategic border location and its proximity to essential infrastructure for livestock transport to the United States. Specifically, it is near the Santa Teresa port in New Mexico, one of the crossings considered for the gradual reopening of Mexican livestock trade.
State-wide Situation: Reduction in Active Cases
Despite the new case in Juárez, the state of Chihuahua has observed a decrease in the total number of active screwworm cases. The state has accumulated 148 cases, with 82 currently active across 29 municipalities. This figure represents a reduction from the 107 active cases reported just days prior.
Within Chihuahua, Matamoros currently leads with the highest number of active cases, totaling 13. It is followed by Coronado with nine, Balleza with five, and both Jiménez and Rosales reporting four cases each. Other affected municipalities include Aldama, Allende, Camargo, Chihuahua, Delicias, Hidalgo del Parral, Huejotitán, López, and Nonoava. Ciudad Juárez now accounts for one active case.
Screwworm Threat and Border Vigilance
The screwworm primarily poses a threat to livestock, as its larvae develop in wounds, leading to severe injuries. The pest can also affect other animals and, in rare instances, humans.
This detection occurs at a critical juncture for cross-border livestock trade between Mexico and the United States. On July 24, the U.S. Department of Agriculture (USDA) announced a plan for the gradual reopening of southern ports to livestock trade. This reopening is contingent on Mexico’s adherence to the Joint Action Plan against the screwworm.
The first port slated for reopening is Douglas, Arizona, scheduled for August 24. Following this, U.S. authorities will assess the possibility of opening the Santa Teresa and Columbus crossings in New Mexico for the entry of live cattle, bison, and horses.
The USDA retains the option to modify this timeline if an increased risk is identified in Sonora or Chihuahua. While the emergence of a case in Juárez serves as a new warning for the border region, the overall state balance indicates a decline in active cases.
Senasica categorizes a case as active upon diagnosis. After 15 days, it can be reclassified as inactive if no new wounds or larvae are detected.
Related Information
- The screwworm is a parasitic insect whose larvae infest the wounds of warm-blooded animals.
- Symptoms in livestock include visible wounds with larvae, foul odor, and behavioral changes.
- Prevention measures include regular inspection of livestock, prompt treatment of wounds, and adherence to biosecurity protocols.
