Ravaging New World Screwworm parasites have spread to Arizona, joining Texas and New Mexico as the third US state plagued by the flesh-eating maggots. Since flies re-invaded the country in June, 74 animal cases have been identified, threatening livestock, wildlife, and domestic pets as the infestation moves northward.
Arizona Joins Texas and New Mexico in the Infestation
The New World Screwworm infestation crossed into a third state this week, with Arizona confirming its first cases alongside ongoing outbreaks in New Mexico and Texas. arstechnica.com reported that 74 animal cases have now been identified across the US since the flies re-invaded the country in June.
The female flies lay hundreds of eggs directly into open wounds and moist orifices of living animals. The resulting voracious maggots resemble screws, tortuously boring and twisting into living flesh. This causes severe and sometimes fatal wounds before the parasites drop to the ground to develop into adults.
Eradication History and the Breached Biological Barrier
The parasite was previously eliminated from the United States in the 1960s. Federal authorities achieved eradication at that time through the massive aerial release of sterile male flies to disrupt successful breeding cycles.
For decades, the United States maintained freedom from the pest by upholding a biological barrier along the Darién Gap at the border of Panama and Colombia. However, that critical barrier was breached in 2022. The flies have since made their steady way back through Central America and across the US border.
Human Toll and Regional Spread
While the infestation presents an immediate economic threat to the livestock industry, domestic pets and wildlife face severe risks. In rarer cases, humans are also targeted by the savage insects.
Data released by arstechnica.com via Mexico’s Ministry of Health shows that Mexico has confirmed 806 human screwworm infestations since the flies reemerged. Out of those human cases, nine people have died.
