Maryland Resident Diagnosed With Flesh-Eating Screwworm After Central America Travel

Maryland Resident Diagnosed With Flesh-Eating Screwworm After Central America Travel

The New World Screwworm (NWS, Cochliomyia hominivorax) is a flesh-eating parasitic fly whose larvae infest open wounds of warm-blooded animals, including livestock, wildlife, pets, and occasionally humans, causing severe tissue damage and often death if left untreated.

The larvae burrow into living flesh using sharp mouth hooks, distinguishing them from other blowflies that feed only on dead tissue.

The last time we reported on the post, the U.S.-Mexico border had been reopened for cattle imports, which were previously halted due to concerns about the spread.

In my initial article, I noted that humans were rarely infested with the screwworm. It is now being reported that such a case was identified in Maryland in a person who had recently traveled from El Salvador.

The US Centers for Disease Control and Prevention and the Maryland Department of Health are investigating the case of the flesh-eating parasite, which was confirmed on August 4, HHS spokesperson Andrew Nixon said.

“This is the first human case of travel-associated New World screwworm myiasis (parasitic infestation of fly larvae) from an outbreak-affected country identified in the United States,” Nixon said in an email. “Currently, the risk to public health in the United States from this introduction is very low.”

A spokesperson for the Maryland Department of Health said in a statement that the Maryland resident has recovered from the infection and that “there is no indication of transmission to any other individuals or animals.”

The infection likely occurred when eggs were dropped next to a wound by a female fly; however, mosquitoes or ticks with attached screwworm eggs can also cause human infection when eggs are deposited during a bite.

A person can contract myiasis when females drop their eggs on or near a person’s wound, nose or ears.

It can also be transferred through ticks and mosquitoes after the fly attaches its eggs to the insects, per the above source.

In the case of an infection, a lump will develop in the person’s tissues as the larvae grow and eat flesh. It can be fatal if not treated at an early stage, health experts warn.

In previous posts, we covered the sterile screwworm farms that the U.S. Department of Agriculture (USDA) was setting up to combat the infestation. In an announcement earlier this month, the USDA indicated that it would also utilize “Tick Riders” and trained dogs as additional mitigation actions.

Animals don’t know borders, and that leaves the U.S potentially vulnerable to NWS from wildlife migrating across the border. USDA is working aggressively to ramp up the hiring of USDA-employed mounted patrol officers, known as “Tick Riders,” and other staff who will focus on border surveillance.

The Tick Riders, who are mounted on horseback, will be complemented by other animal health experts who will patrol the border in vehicles and will provide the first line of defense against an NWS outbreak along the United States-Mexico border.

USDA will also begin training detector dogs to detect screwworm infestations in livestock and other animals along our border and at various ports of entry. These dogs will be essential to help control the spread of the NWS.

USDA is working closely with the U.S. Department of the Interior and the U.S Customs and Border Protection to monitor the border for NWS-infected wildlife that could pose a threat to the United States.

I wish the “Tick Riders” a ton of success!

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