September 09, 2021


Crab Wars: A Tale of Horseshoe Crabs, Ecology, and Human Health—2nd Edition. By William Sargent. Brandeis University Press. $24.95.

     Superficially crablike but much more closely related to spiders and scorpions, horseshoe crabs are nature’s blue bloods – literally. Their copper-based blood is blue and extremely rare: there are other creatures with non-red blood, such as some green-blooded skinks, but red is by far the dominant blood color, and blue is precious. Extremely precious, as William Sargent explains in Crab Wars.

     This 2021 update of a book originally published in 2002 has lost none of its relevance and has actually gained some in light of the COVID-19 pandemic. In it, Sargent looks at the many strangenesses of the horseshoe crab, which has lived largely unchanged for some 300 million years, and of how one particular strangeness is of crucial importance to modern medicine, including attempts to protect the world against the virus that causes COVID-19 and against whatever viruses are yet to come. This is Limulus amoebocyte lysate (simply called “lysate” for ease of reference), with which horseshoe crabs shut down wound-invading bacteria in an elegant use of their clotting system to fight infection.

     What matters directly to humans who are not intrigued by horseshoe crabs per se is that lysate has been found to make possible the most-reliable test for so-called gram-negative bacteria – highly dangerous organisms that are responsible for everything from meningitis to typhoid to Legionnaire's Disease. It is hard to overestimate just how important this makes lysate and, by extension, the horseshoe crab: every drug certified by the Food and Drug Administration must be tested using a stabilized version of the crab’s lysate.

     This of course means big money, big pharma, and big government, with Sargent wryly noting that “what makes for good politics does not always make for good medicine.” Indeed, some portions of Crab Wars discuss situations that are good in neither context, such as the attempt in 1976 to develop a swine-flu vaccine – which resulted in 52 deaths, $1.7 billion in lawsuits, and “modern medicine’s most flagrant miscalculation.” That debacle is what led to widespread use of the lysate test, which “was faster, easier to use, and several times more sensitive than the rabbit test” that had previously been the standard.

     Enter the usual suspects of greed, ecology and human health (only “greed” does not appear in the book’s subtitle, but it might as well be there). Sargent spins out his story beyond science and medicine into areas both wider and narrower, the latter giving a personal spin to the whole horseshoe-crab saga (“I was facing the summer penniless, unemployed, and stuck in the city” – that sort of thing). The zipping back and forth between larger and smaller issues can be disconcerting, although the desire to personalize the science this way is admirable. It is not the main story, however. That one involves the use of horseshoe crabs as bait, the ways in which the crabs fit into the overall ecosystem of which they are a part (everything fits into the ecosystem of which it is a part), and arching above all, the increasing importance of lysate for preserving human health – that is, the use of horseshoe crabs as a weapon against humanity’s eternal microscopic enemies.

     The book is in four sections called “Early Lessons,” “Commercialization,” “Environmental Conflicts,” and “Crabs and COVID.” Much of the material in the third portion of the book is predictable, involving wildlife protection, multinational corporations, exploitation (or simply “use,” a less-loaded word) of a finite resource, and peculiar details of the U.S. political system, such as arguments about how many horseshoe crabs from which source could be transferred for what purpose to where else. The fourth section, though, becomes truly intriguing, and not just because it brings matters more or less up to date. This section starts with “the five major producers” of lysate “bleeding several hundred thousand crabs a year and making tens of millions of dollars.” It then moves into an area that, at least in retrospect, seems obvious: why not protect the crabs, the ecology that depends on them, and the human race, by creating a synthetic substitute for lysate? It turns out that there is one, thanks to the diligent research in Singapore of Dr. Ling Jaek Ding, who was able to produce the alternative by some clever and lengthy work involving insects: “Insects and horseshoe crabs share their lineage through arthropods, which is much closer than the lineage they share with yeasts and mammals.”

     Dr. Ling’s alternative, though, has yet to be widely accepted, for reasons relating to politics, government ineptness, corporations’ reluctance to change, and the exigencies of the COVID-19 pandemic. It is because of the pandemic that the FDA has been slow to move on approving an alternative to use of lysate – although Sargent predicts that “within a year or two when the immediate crisis of the COVID pandemic passes, the FDA will approve” the alternative to use of horseshoe-crab blood for crucial medical testing. He suggests that even as that occurs, new government regulations should protect horseshoe crabs against being used as bait, modeling human handling of the crabs on our current regulation of the lobster industry. And he concludes with a once-over-lightly about COVID-19 vaccines and the continuing need for lysate in testing.

     Crab Wars is a short book – 160 pages – and refreshingly non-academic despite its publication by an academic press. It is intermittently fascinating but somehow, despite its brevity, is rather diffuse. Sargent seems hesitant to get too deeply into any of the topics he broaches, from horseshoe-crab anatomy to his own scientific interests to the corporate and governmental issues raised by horseshoe-crab management and wildlife management in general. All the topics are there, but in his largely successful determination to present a science/medicine book with a breezy style, Sargent is less than wholly successful in arguing for the seriousness of his purpose. That seriousness is in the book, as when Sargent writes that “if we were to lose all the lobsters, striped bass, or shrimp on the East Coast, it would be an environmental tragedy. But if the East Coast were to lose all its horseshoe crabs, it would be a major medical disaster.” But even so dire a statement as this is basically made in passing, on the way from one part of the story to the next, and therefore does not make the reader really sit up and take notice. In his desire to avoid being overly academic or overly alarmist, Sargent has produced a book that is closer to being a meandering (if brief) memoir than one with an intimate focus on an amazing creature whose fate is intimately intertwined with our own.

No comments:

Post a Comment