Horseshoe Crabs, 'Living Fossils' Vital to Vaccine Safety


Horseshoe crabs, “living” fossils” vital for vaccine safety

The blood of horseshoe crabs is currently essential for pharmaceutical research to detect the presence of bacterial contaminants.

On a full moon night, scientists and volunteers stroll on a protected beach in Delaware Bay to observe horseshoe crabs, or “horseshoe crabs”, which spawn in their millions along the eastern seaboard of the United States between late spring and early summer.


The group walks to shore setting a measuring frame on the sand to count the horseshoe crabs, straightening those tipped over by the tide.

With their helmet-like shells, spike-like tails, and five pairs of legs connected to their mouths, these horseshoe crabs aren't immediately endearing.

But these strange marine animals are vital to vaccine safety: their bright blue blood, which clots in the presence of harmful bacterial compounds called endotoxins, has been essential for testing the safety of biomedical products since the 1970s, when tests on rabbits were introduced. been abandoned.

Besides being harmless to humans, they are really easy to love, once you understand them, explain to the man. AFP Laurel Sullivan, who works for the State of Delaware to educate the public about these invertebrates.

For 450 million years, these creatures from another age have roamed the planet's oceans, seeing dinosaurs appear and then die out and the first fish transform into land animals and then humans. /p>

In the spring, horseshoe crabs come to the beaches to mate and lay their eggs in the sand.

Today, however, these living fossils are listed as a vulnerable species in America and endangered in Asia, due to habitat reduction, overharvesting for food or bait, and use by the pharmaceutical industry, a major growth sector, especially since the COVID-19 pandemic.

The term crab is not entirely appropriate for these animals, which are more like spiders and scorpions, and are made up of four subspecies: one lives on the Atlantic coast of the x27;North America and the Gulf of Mexico, and the other three in Southeast Asia.

The horseshoe crab, also called the Moluccan crab, has 10 eyes and feeds by crushing their food, worms and clams, between their legs, before bringing it to their mouths.

The males are significantly smaller than the females, which they gather in group of up to 15 individuals when breeding.

To breed, the males spray their sperm on the golf ball-sized clusters of 5,000 eggs, which they lay on the sand.

These eggs, tiny green balls, are also a vital food source for migrating birds, including the Near Threatened Red Knot.

Shorse crabs have ancestors that appeared 450 million years ago.

Nivette Perez-Perez, a scientist with the Delaware Inland Bays Center, shows a large egg strip that stretches across most of the beach at the James Farm Ecological Reserve, upon which black-headed gulls swoop down at the bright orange beaks rush to feast.

Like others in the area, Ms. Perez-Perez has succumbed to the charm of horseshoe crabs. You're so cute, she tells a female she picks up to show off her anatomical features.

Mating is a dangerous activity for horseshoe crabs because it is on the beach that they are most vulnerable: with the tide, some end up on their backs, and although their long tails are hard helps them straighten up, not all are so lucky. About 10% of the population dies each year, their bellies baked by the sun.

In 1998, Glenn Gauvry, founder of the Group on Ecological Research and Development, participated in a campaign called Just Flip Them, encouraging the public to help crabs that are still alive.

Winning hearts is what matters most, he told AFP on Pickering Beach in Delaware Bay, a cap bearing his slogan and adorned of horseshoe crab badges on the head.

The horseshoe crab uses its tail to turn around when stranded on the beach.

If we can't get people to care about these animals and feel close to them, they're less likely to want legislation to protect them, he explains.

Each year, approximately 500,000 horseshoe crabs are harvested for the pharmaceutical industry. Their blood is used in a chemical called Limulus Amebocyte Lysate, which identifies a type of bacteria that can contaminate drugs, needles and devices like hip replacements.

This process causes the About 15% of horseshoe crabs died, with survivors released back into the sea.

A new synthetic process, called recombinant factor C, shows promise but has yet to be proven. regulated.

Horseshoe crabs are a finite source with potentially infinite demand, and those two things are mutually exclusive, says Allen Burgenson of the company. Swiss biotechnology company Lonza, which manufactures the new test.


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