Screwworm infestations “can be deadly, especially when involving the scalp,” the doctors wrote in their case report. “Larvae may burrow through the skull, dura [outer membrane around the brain], and into the brain, leading to an associated 8 percent mortality.” They called for physicians to remain vigilant, especially with scalp wounds.
Any opening is an opportunity
If there is another case that could rival the horror of that scenario, it might be a case report from August 2025. Doctors in Honduras reported the case of a 55-year-old man who developed a screwworm infestation in his hemorrhoids. He was in such pain that doctors had to put him under general anesthesia to see what was going on, which required surgery. When the surgeons started removing the bulging, damaged tissue around his anus, they found 22 screwworm larvae.
The doctors attributed his infection to his occupational exposure as a septic tank worker. His “prolonged exposure to fecal sludge, poor hygiene, regular latrine use, and minor skin breaks,” as well as prolapsed hemorrhoids were risk factors in this case, they wrote. (We are not linking directly to an image of the surgical site, but an image of the 22 larvae extracted is here.)
The surgeons carefully dissected the area and extracted all larvae. They surgically removed his hemorrhoids and started him on antibiotics and the anti-parasitic drug ivermectin. Nearly two weeks later, his pain had resolved and his wound was healing well.
While these cases highlight the risks of wounds and vulnerabilities, many others show that the flies will happily infest in normal orifices, such as the ears and nose.
In March of this year, doctors in Ecuador reported the case of a 75-year-old man with epilepsy who developed a screwworm infestation in his mouth. The case was caught late, and he died eight hours after admission to a clinic, where more than 300 larvae were pulled from his gums, tongue, lower lip, and the roof of his mouth.
As the savage flies spread in the US, the Centers for Disease Control and Prevention urges people in areas where screwworms are spreading to prevent exposure by keeping wounds clean and covered, wearing insect repellent, covering up with loose clothing to block access, and avoiding sleeping outside, especially during the day.
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