The New World screwworm (NWS) fly was once endemic in Mexico—as well as the US. The flies lay hundreds of eggs in the wounds, inflamed tissue, mucous membranes, and orifices of warm-blooded creatures. The resulting maggots hatch within a day and begin ravenously feasting on the living flesh of their victims. While the fly’s maggots generate ghastly, life-threatening wounds in a variety of warm-blooded species, including humans, they’re particularly devastating to livestock.

Amid a decades-long eradication effort, the fly’s populations were wiped out from the US, Mexico, and Central America. This was largely done with massive aerial releases of sterilized male flies, a technique that works because female NWS flies only mate once in their lifespans. Mexico declared NWS eradicated in 2003. Panama declared eradication in 2006 and kept an active, biological barrier along the Darién Gap at the border with Colombia. But in 2022, the barrier was breached, and Mexico began seeing cases in animals in 2024.

Since the breach, there have been more than 36,000 animal cases of NWS in Mexico, with nearly 2,000 active as of August 5, according to the US Department of Agriculture. While human NWS infections—called myiasis—are a small fraction of the overall cases, the infestations can be severe and horrifying. The maggots can cause painful, rapidly enlarging deep wounds, which can destroy muscle, cartilage, and bone—even the skull—if not caught quickly. The wounds pose the risk of irreparable damage, secondary infection, sepsis, and, in extreme cases, death.

Collective problems require collective solutions, America cannot solve this problem with each nation working alone, indeed if even one large "united" nation in the northern part decides to violently flaunt logic everyone will be irreperably harmed.