AUSTIN, Texas — According to the U.S. Department of Agriculture, the number of New World Screwworm cases has risen to 15 as of Sunday evening.

The most recent cases were confirmed as one in Crockett County, Texas on Saturday and two in Edwards County, Texas on Sunday.

New World Screwworm is a parasitic fly whose larvae burrow into the living flesh of warm-blooded animals, causing severe tissue damage and potential death.

The USDA has released more than 130 million sterile male flies in Texas since January in an effort to break the pest’s reproductive cycle.

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Officials urge livestock and pet owners to watch animals for symptoms including draining wounds, maggots, signs of discomfort, and lesions near openings in the body.

Officials encourage suspected cases to be reported immediately to a veterinarian or the USDA. The U.S. food supply is not at risk.

More information is available at screwworm.gov.