Arizona joins the infestation
Arizona joined New Mexico and Texas this week as the third US state plagued by the New World Screwworm infestation. I find the 74 animal cases identified in the US since the flies re-invaded the country in June to be a horrifying development. The flies lay hundreds of eggs in wounds and moist orifices of animals, and the resulting ravenous, flesh-eating maggots feast on their victims; they bore into the flesh before they drop to the ground to develop into adults. These maggots resemble screws and tortuously bore and twist into living flesh, causing severe, sometimes fatal wounds. I find it gruesome that these horrifying parasites can devastate wildlife, domestic pets, and in rare instances, humans. The ravenous maggots fester in wounds and have taken to eating people’s pets.
A breach in the biological barrier
The US eliminated these flies in the 1960s through aerial releases of sterile male flies to thwart successful breeding. A biological barrier along the Darien Gap at the border of Panama and Colombia held the flies at bay for years until the barrier was breached in 2022. I think it is appalling that the flies made their way back to the US through Central America after such successful elimination. While these flies primarily threaten the livestock industry, they also devastate wildlife, domestic pets, and in rarer cases, humans. According to Mexico’s Ministry of Health, the country has confirmed 806 human cases of screwworm infestations since the flies reemerged, and nine people died from the savage maggots.
| Region | Case Type | Count |
|---|---|---|
| United States (since June) | Animal cases | 74 |
| Mexico (since reemergence) | Human infestations | 806 |
| Mexico (since reemergence) | Human deaths | 9 |
The flies move through Central America to reach the southern border, where they can attack livestock, wildlife, and pets. This return to the US follows the breach of the biological barrier in the Darien Gap between Panama and Colombia.
