A flesh-eating parasite known as the New World screwworm has spread to Arizona, marking the third US state affected after New Mexico and Texas. The fly has been linked to dozens of animal cases in the United States and can infest livestock, wildlife, pets, and, in rare cases, humans.
This week, the New World screwworm infestation reached Arizona. According to the latest confirmed case data, there have been 74 animal cases since the fly re-entered the United States in June.
Female screwworm flies lay hundreds of eggs in an animal’s wound or other moist opening. The eggs hatch into voracious maggots that feed on living tissue. Their screw-like shape allows them to burrow deeper into flesh, causing severe and sometimes fatal wounds before the mature larvae drop to the ground and emerge as adult flies.
Because the species can devastate livestock, the United States eliminated it in the 1960s by releasing sterile male flies, which reduced the insects’ reproductive success. For years, biological barriers along the Darién region at the Panama-Colombia border helped keep the pest from spreading north. In 2022, however, that barrier was breached, and the flies eventually returned to the United States through Central America.
No one is entirely safe
The New World screwworm is primarily viewed as a threat to the livestock industry, but it can also cause serious harm to wild animals and domestic pets. Human infections are rare but can be devastating.
According to the latest data from the Mexican Ministry of Health, Mexico has confirmed 806 screwworm infestations since the fly’s re-emergence. Nine people have died from the infections.
Source: arstechnica.com
