Horseshoe crab blood is key to making a COVID-19 vaccine—but the ecosystem may suffer. - National Geographic

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Each spring, guided by the full moon, hundreds of thousands of horseshoe crabs clamber onto beaches across the U.S. mid-Atlantic to lay their eggs. For hungry birds, it’s a cornucopia. For drug companies, it’s a crucial resource for making human medicines safe.That’s because these crustaceans’ milky-blue blood provides the only known natural source of limulus amebocyte lysate, a substance that detects a contaminant called endotoxin. If even tiny amounts of endotoxin—a type of bacteria—make their way into vaccines, injectable drugs, or other sterile pharmaceuticals such as artificial knees and hips, the results can be deadly.“All pharmaceutical companies around the world rely on these crabs. When you think about it, your mind is boggled by the reliance that we have on this primitive creature,” says Barbara Brummer, state director for The Nature Conservancy in New Jersey.Every year, pharmaceutical companies round up half a million Atlantic horseshoe crabs, bleed them, and return them to the ocean— after which many will die. This practice, combined with overharvesting of the crabs for fishing bait, has caused a decline in the species in the region in the past few decades. In 1990, biologists estimated 1.24 million crabs spawned in Delaware Bay, a main egg-laying spot and prime collection point for the companies. By 2002, that number had dropped to 333,500. In recent years, numbers of Delaware Bay spawning crabs have hovered around the same amount, with the 2019 survey estimating about 335,211. (The pandemic canceled the 2020 crab count.)Catching crabs and harvesting their blood is time-consuming, and the resulting lysate costs $60,000 per gallon. In 2016, a synthetic alternative to crab lysate, recombinant factor C (rFC), was approved as an alternative in Europe, and a handful of U.S. drug companies also began using it. The Link Lonk


July 03, 2020 at 02:24AM
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Horseshoe crab blood is key to making a COVID-19 vaccine—but the ecosystem may suffer. - National Geographic

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