() The Department of Health and Human Services has cleared the way for an emergency use authorization from the Food and Drug Administration allowing the use of animal drugs to help treat or prevent screwworm infestations.

The New World screwworm infests warm-blooded animals including wildlife, livestock and pets causing severe tissue damage and sometimes death.

HHS said the move is aimed at eradicating threats to animal populations and protecting food supply chains.

“Our priority is to safeguard both animal health and the nation’s food supply,” said FDA commissioner Marty Makary. “FDA is acting swiftly and responsibly to help ensure we have the necessary tools to prevent and control New World Screwworm, minimizing risks to agriculture and public health.”

Screwworms were eradicated from North America and Central America decades ago but have progressed north and are approaching the U.S. border with Mexico.

There are currently no FDA-approved drugs for fighting screwworms in the United States. The emergency use authorization allows the use of certain animal drugs approved for other purposes or that are available in other countries but not formally approved in the U.S.

The cattle trade between Mexico and the U.S. could bring screwworms in, with Texas being at particular risk.

Texas Gov. Greg Abbott warned the screwworm has the potential to “crush” the state’s cattle industry.

“This is an enormous challenge, and you need to understand the magnitude,” said Abbott. “Just in Texas, this can result in billions of dollars of losses a year.”

What are screwworms?

Screwworms are fly larvae that burrow into an animal’s flesh, feeding on the living flesh.

As more maggots hatch, the wound on the animal can grow, causing serious harm or death to the host animal.

What do screwworms attack?

Screwworm infestation begins when a fly lays eggs on the open wound of an animal.

The most common infestations are in wildlife, livestock and outdoor pets.

Human infections are possible but rare, and officials said the risk to human health remains low.

Where are screwworms coming from?

Screwworms were eradicated in the U.S. by the early 1980s after scientists discovered how to use gamma radiation to sterilize male flies and reduce the population. Eventually, they were eradicated in Central America as well.

Today, screwworms are mostly a concern in South America and the Caribbean. However, they have been moving north, closer to the U.S., and can also be brought into the country through the cattle trade.

Have there been screwworm outbreaks before?

Since the eradication of screwworm in the U.S., Mexico and Central America and the establishment of a biological barrier in Panama, there have been few screwworm outbreaks in the U.S.

Florida reported a screwworm outbreak in 2016, but it was limited to the Florida Keys.