The New World screwworm ( Cochliomyia hominivorax ) is spreading further across the United States and finding new kinds of hosts to burrow itself into.

Several new cases of infestations caused by the parasitic fly have been reported this past week, including the first ever documented in Arizona since the screwworm reemerged in the country earlier this year. New Mexico officials also recently reported the first U.S. case found in a pet cat. October has seen a sizeable increase in reports of the screwworm affecting both domestic and wild animals.

“We have been preparing for this possibility for a long while and are acting swiftly,” said Ryan Wolker, a state veterinarian with the Arizona Department of Agriculture, in a statement released Wednesday.

Infesting cats and dogs

Despite being a fly, the screwworm is named after its horrific larval form. Unlike many species, screwworm maggots prefer to feed on living flesh.…