The tropical fly, commonly called a
New World Screwworm, lays hundreds of larvae (pictured) in the wounds of animals
and humans, which hatch within hours and consume their host's tissue
A terrifying flesh-eating parasite is pouring into the US from across the border in Mexico.
The tropical fly, commonly called a New World Screwworm (NWS), lays hundreds of
larvae in the wounds of animals and humans, which hatch within hours
and consume their host's tissue.
These infestations can lead to deep, painful wounds that become infected and often result in death if left untreated.
Texas Governor Greg Abbot issued a declaration of disaster on Tuesday, as the screwworms endanger the state's booming beef industry.
The
declaration gives Abbot's task force greater authority, resources and
speed needed to confront the growing threat posed by the parasite. When
screwworms became a major problem in the US, it cost the US $200 million
- roughly $1.8 billion today - in livestock
As the screwworms move closer to Texas, Florida officials reported their first case last week.
The
Florida Department of Agriculture and Consumer Services found larvae in
an open wound on a horse imported from Argentina. The horse has since
been quarantined.
'The New World
Screwworm was eradicated from the US more than four decades ago,'
Florida officials announced. 'Its return would pose a serious threat to
livestock, wildlife, and domestic animals, particularly in states like
Florida with warm climates and abundant animal populations.'
Texas Agriculture Commissioner Sid Miller cautioned Florida residents not to panic.
'I want to set the record straight on the recent New World Screwworm detection in Florida,' Miller said in a statement.
'This detection did not constitute evidence of a US outbreak or domestic New World Screwworm infestation.
'It was thankfully caught during a routine inspection of an imported horse arriving from a country south of the Darién Gap.'
However,
he urged Texas ranchers and families to remain vigilant along the
southern border and continue to routinely inspect all warm-blooded
animals, including livestock, wildlife and pets, and report any
suspicion of larvae infestation immediately.
'This
is a serious risk to our livestock industry and one that the Texas
Department of Agriculture has been preparing for through our own
heightened surveillance, coordination, and response planning,'
said Miller.
'The New World screwworm is inching closer to Texas each and every day, and we must be proactive in responding to this threat.'
The screwworm begins its attack when a female fly lays her eggs in an open wound or body orifice.
The above map shows areas that the screwworm could inhabit in blue. These include parts of Florida and Texas
These
flies are attracted to the scent of exposed tissue and openings, which
can be as small as a tick bite, a nasal or eye passage, a newborn’s
navel, or genital areas, according to the Texas Parks and Wildlife
Department (TPWD).
Once laid, the eggs hatch into larvae that burrow into the flesh like tiny screws, the agency said.
A
single female can lay 200 to 300 eggs at a time and as many as 3,000
over her lifetime, KHOU 11 reported. Infestations may also become
visible on the skin.
In 2024, an unnamed patient in Maryland recently returned to the US from El Salvador and had been infested with the parasite.
Department of Health and Human Services officials revealed the case but stressed that the risk to the public was 'very low'.
The infection was first reported by Maryland officials and at the CDC on August 4.
The
worms were eliminated in the US in 1966, but sporadic cases have been
detected since amid outbreaks in Central America. The latest case is not
the first case ever in the US, but the first case in an individual who
had traveled to the US from a country battling an outbreak.
The infection was first reported by officials in Maryland and at the CDC on August 4.
ADDENDUM: From Texas A&M
What is the New World screwworm?
The New World screwworm (Cochliomyia hominivorax), also known as the
primary screwworm, is a tropical fly capable of surviving in the
southern U.S. The New World screwworm is incapable of overwintering in
regions that experience low temperatures or extended dry periods — they
don’t do well below 45 degrees and certainly die if frozen; however, the
larvae can burrow about six inches into the soil, changing the
temperatures that they experience.
This fly poses a serious threat to livestock and wildlife because it
deposits eggs into the wounds of living animals, thereby leading to
larval infestations. Because they can host on any living mammal, they
can also affect pets and humans.
This metallic green-blue fly with large orange eyes is about twice
the size of a common house fly. New World screwworms do not bite
animals; their damage comes from laying eggs in the open wounds of
living, warm-blooded animals — though rarely birds. The immature fly
larvae, or maggots, feed on the living tissues of hosts, burrowing into
the animal’s tissue, causing tremendous damage and often resulting in
the host’s death.
Why is it called a screwworm?
Screwworms get their name from how they feed — they burrow or “screw”
into wounds. This can cause quite a bit of damage as they tear at the
tissue with their sharp mouth hooks. The wound gets bigger and deeper as
more eggs hatch and larvae feed. If wounds go untreated, infestations
can lead to serious harm or be fatal.
