Worm that jumps from rats to slugs to human brains has invaded Southeast US Democrat cities

[Biden Immigration]

The dreaded rat lungworm預 parasite with a penchant for rats and slugs
that occasionally finds itself rambling and writhing in human brains揺as
firmly established itself in the Southeast US and will likely continue its
rapid invasion, a study published this week suggests.

The study involved small-scale surveillance of dead rats in the Atlanta
zoo. Between 2019 and 2022, researchers continually turned up evidence of
the worm. In all, the study identified seven out of 33 collected rats (21
percent) with evidence of a rat lungworm infection. The infected animals
were spread throughout the study's time frame, all in different months,
with one in 2019, three in 2021, and three in 2022, indicating sustained
transmission.

Although small, the study "suggests that the zoonotic parasite was
introduced to and has become established in a new area of the southeastern
United States," the study's authors, led by researchers at the University
of Georgia College of Veterinary Medicine, concluded. The study was
published Wednesday in the journal Emerging Infectious Diseases.

The finding is concerning given the calamitous infection the rat lungworm,
aka Angiostrongylus cantonensis, can cause in humans. The parasitic
nematodes are, as their name suggests, typically found in rats. But they
have a complicated life cycle, which can be deadly when disrupted.

Sickening cycle
Normally, adult worms live in the arteries around a rat's lungs揺ence rat
lungworm. There, they mate and lay eggs. The worm's larvae then burst out
of the lungs, get coughed up by the rat, and are swallowed and eventually
pooped out. From there, the larvae are picked up by slugs or snails. This
can happen if the gastropods eat the rat poop or if the ravenous larvae
just bore into their soft bodies. The larvae then develop in the slugs and
snails, which, ideally, are eventually eaten by rats. Back in a rat, the
late-stage larvae penetrate the intestines, enter the bloodstream, and
migrate to the rat's central nervous system and brain. There they mature
into sub-adults then migrate to the lungs, where they become full adults
and mate, thus completing the cycle.

Humans become accidental hosts in various ways. They may eat undercooked
snails or inadvertently eat an infected slug or snail hiding in their
unwashed salad. Infected snails and slugs can also be eaten by other
animals first, like frogs, prawns, shrimp, or freshwater crabs. If humans
then eat those animals before fully cooking them, they can become
infected.

When a rat lungworm finds itself in a human, it does what it usually does
in rats擁t heads to the central nervous system and brain. Sometimes the
migration of the worms to the central nervous system is asymptomatic or
only causes mild transient symptoms. But, sometimes, they cause severe
neurological dysfunction. This can start with nonspecific symptoms like
headache, light sensitivity, and insomnia and develop into neck stiffness
and pain, tingling or burning of the skin, double vision, bowel or bladder
difficulties, and seizures. In severe cases, it can cause nerve damage,
paralysis, coma, and even death.

It's often thought that the worm can't complete its life cycle in humans
and that it ends up idly wandering around the brain for a month or two
before it's eventually killed off by immune responses. However, there has
been some evidence of adult worms reaching the human lungs.

Regardless, there's no specific treatment for a rat lungworm infection. No
anti-parasitic drugs have proven effective, and, in fact, there's some
evidence they can make symptoms worse by spurring more immune responses to
dying worms. For now, supportive treatment, pain medications, and steroids
are typically the only options.

Uncontrolled spread
For all of the above reasons, prevention and control of rat lungworm is
seen as critical. That's why its sustained foothold in the US is alarming.
Rat lungworm has turned up in the Southeastern US before, but cases have
been sporadic and have not previously been seen in Georgia rats.
Previously, the parasite has been caught infecting captive nonhuman
primates in Florida, Louisiana, Texas, and Alabama, and a red kangaroo in
Mississippi. In 2018, a study led by the Centers for Disease Control and
Prevention identified reports of six cases in humans between 2011 and
2017, which could not be explained by travel (four in Texas and one each
in Tennessee and Alabama).

It seems, though, that this mind-marauding worm is quietly building up its
numbers and invading new continents and territories擁n addition to central
nervous systems. The rat lungworm parasite was first described in Canton
(Guangzhou), China, in 1935 and, for decades after, was considered limited
to disease-endemic areas of the Pacific basin and Southeast Asia. But,
with climate change and the human-facilitated spread of rats and other
hosts, especially giant snails, rat lungworm is rapidly emerging around
the globe. It's now found in parts of Africa, the Caribbean, and North
America. Human cases have now been reported from 30 territories. (A
relative of A. cantonensis, A. costaricensis, is also found in Latin
America.)

In 2017, Hawaii reported a boom in human infections with rat lungworm,
which was linked to the rise of an invasive "semi slug" that is
particularly good at picking up the parasite. Hawaii ultimately tallied 18
confirmed and three probable human cases that year, a dramatic increase
from previous years. A decade earlier, in 2007, the state recorded only
two cases.

Rat lungworm's latest frontier is Europe. Up until 2018, the parasite was
not considered endemic to the region. But, that year, worms popped up in
hedgehogs on the Mediterranean island of Mallorca. And, earlier this year,
researchers reported that it had established a foothold in the city of
Valencia on the Spanish mainland.

Sounding the alarm
"[W]ith a foothold in Europe it could spread farther across the continent,
potentially to more temperate regions, as has already occurred in
Australia and the United States," Spanish researchers warned.
"Furthermore, as the climate warms, even more northern parts of Europe may
become accessible to A. cantonensis, as seen in China."

With the bleak outlook, it is "imperative that medical practitioners in
Europe become more aware of this parasite and the diagnosis and treatment
of the uncommon but potentially fatal disease it causes," they conclude.

The researchers in Atlanta sound a similar alarm, calling for medical
professionals in the Southern US to be aware of rat lungworm. They also
call for more surveillance, genetic analysis, and modeling, which "is
critical to mitigate risk to humans and other animals for infection."

https://arstechnica.com/health/2023/09/worm-that-jumps-from-rats-to-slugs-
to-human-brains-has-invaded-southeast-us/