- Horseshoe crabs' blue blood is so valuable that a quart of it can be sold for $15,000.
- This is because it contains a molecule that is crucial to the medical research community.
- Today, however, new innovations have resulted in a synthetic substitute that may end the practice of farming horseshoe crabs for their blood.
One of humanity's strangest and most macabre activities is slowly coming to an end, a trend that every horseshoe crab should celebrate. For the time being, however, hundreds of thousands of horseshoe crabs are being harvested from the ocean off the US's east coast and drained of their valuable blue blood.
It's a surreal practice, but there's good reason for it. Limulus Polyphemus—the Atlantic horseshoe crab—has extremely valuable blood. Unlike the blood of vertebrates, horseshoe crabs do not use hemoglobin to transport oxygen throughout their body. Instead, they use hemocyanin, a chemical that gives their blood that distinctive blue color – but this isn't what makes their blood so valuable. Instead, it's the kind of immune cells they carry.
Life-saving blue blood
Vertebrates carry white blood cells in their blood streams; invertebrates like the horseshoe crab carry amebocytes instead. When an amebocyte comes into contact with a pathogen, it releases a chemical that causes the local blood to clot, which researchers believe is a mechanism for isolating dangerous pathogens. Specifically, the amebocytes in horseshoe crab blood solidifies when it comes into contact with endotoxins, a pervasive and sometimes deadly product of bacteria that kicks immune systems into gear, sometimes resulting in fever, organ failure, or septic shock.
The presence of endotoxins in drugs, needles, or anything that comes into contact with human blood is a serious problem. Researchers used to give rabbits a sample of whatever material or substance they were interested in and observe them for hours to see if their immune system reacted, implying the presence of endotoxins. But the amebocytes in horseshoe blood were a game changer—instead of conducting time-consuming tests on rabbits, horseshoe crab amebocytes could be added to a sample of a substance. If the sample started to clot, then endotoxins were there.
The substance derived from horseshoe blood is called Limulus Amebocyte Lysate, or LAL, and it quickly became nearly as valuable as gold. Thanks to the ubiquity of endotoxins and the dire need to test for their presence, a quart of horseshoe crab blood could fetch $15,000. To cash in, companies harvest as many as 600,000 crabs a year. Up to 30% of their blood is drained before they are returned to the ocean, although a procedure this traumatic obviously entails some mortality. Estimates vary wildly. Some official sources put the mortality estimate at around 3 or 4%, but these figures typically represent mortality directly resulting from transportation and handling. Other organizations put the mortality rate as high as 30%.
A new substitute
A horseshoe crab heading for the ocean.
Photo: Shutterstock.
Fortunately for horseshoe crabs, this practice may be dying out. Researchers discovered that a molecule in LAL called factor C was responsible for its clotting action. Researchers genetically modified the guts of insects—who belong to the same phylum as horseshoe crabs, Arthropoda—to produce factor C. As a result, the insects began pumping out factor C, which could then be sold as recombinant factor C (rFC) on the market as a viable substitute to horseshoe crab blood.
Though rFC has been on the market since 2003, it's been slow to gain traction. Initially, it was only being produced by one manufacturer, the Lonza Group. Pharmaceutical companies are wary to rely on a single manufacturer in case an emergency occurs, and their supply is cut off. The Food and Drug Administration's (FDA's) regulatory process was quite slow as well. But these obstacles are gradually being overcome. Hyglos GmbH, another pharmaceutical manufacturer, began producing rFC in 2013. European regulatory bodies have approved its use, which lays the groundwork for future approval by the FDA. Major pharmaceutical companies who have used rFC have confirmed that it works just as well as LAL. Today, experts believe that rFC will become the dominant method of detecting endotoxins, letting horseshoe crabs off the hook.
A close up of Bathynomus raksasa
Humanity knows surprisingly little about the ocean depths. An often-repeated bit of evidence for this is the fact that humanity has done a better job mapping the surface of Mars than the bottom of the sea. The creatures we find lurking in the watery abyss often surprise even the most dedicated researchers with their unique features and bizarre behavior.
A recent expedition off the coast of Java discovered a new isopod species remarkable for its size and resemblance to Darth Vader.
The ocean depths are home to many creatures that some consider to be unnatural.
Bathynomus raksasa specimen (left) next to a closely related supergiant isopod, B. giganteus (right)
Sidabalok CM, Wong HP-S, Ng PKL (ZooKeys 2020)
According to LiveScience, the Bathynomus genus is sometimes referred to as "Darth Vader of the Seas" because the crustaceans are shaped like the character's menacing helmet. Deemed Bathynomus raksasa ("raksasa" meaning "giant" in Indonesian), this cockroach-like creature can grow to over 30 cm (12 inches). It is one of several known species of giant ocean-going isopod. Like the other members of its order, it has compound eyes, seven body segments, two pairs of antennae, and four sets of jaws.
The incredible size of this species is likely a result of deep-sea gigantism. This is the tendency for creatures that inhabit deeper parts of the ocean to be much larger than closely related species that live in shallower waters. B. raksasa appears to make its home between 950 and 1,260 meters (3,117 and 4,134 ft) below sea level.
Perhaps fittingly for a creature so creepy looking, that is the lower sections of what is commonly called The Twilight Zone, named for the lack of light available at such depths.
It isn't the only giant isopod, far from it. Other species of ocean-going isopod can get up to 50 cm long (20 inches) and also look like they came out of a nightmare. These are the unusual ones, though. Most of the time, isopods stay at much more reasonable sizes.
The discovery of this new species was published in ZooKeys. The remainder of the specimens from the trip are still being analyzed. The full report will be published shortly.
What benefit does this find have for science? And is it as evil as it looks?
The discovery of a new species is always a cause for celebration in zoology. That this is the discovery of an animal that inhabits the deeps of the sea, one of the least explored areas humans can get to, is the icing on the cake.
Helen Wong of the National University of Singapore, who co-authored the species' description, explained the importance of the discovery:
"The identification of this new species is an indication of just how little we know about the oceans. There is certainly more for us to explore in terms of biodiversity in the deep sea of our region."
The animal's visual similarity to Darth Vader is a result of its compound eyes and the curious shape of its head. However, given the location of its discovery, the bottom of the remote seas, it may be associated with all manner of horrifically evil Elder Things and Great Old Ones.
On May 12, 2021, the Republican governor of Ohio, Mike DeWine, announced five US$1 million lottery prizes for those who are vaccinated. Meanwhile, in West Virginia, younger citizens are being enticed to get the shot with $100 savings bonds, and a state university in North Carolina is offering students who get vaccinated a chance to win the cost of housing. Many companies are paying vaccinated employees more money through bonuses or extra paid time off.
The push to get as many people vaccinated as possible is laudable and may well work. But leading behavioral scientists are worried that paying people to vaccinate could backfire if it makes people more skeptical of the shots. And ethicists have argued that it would be wrong, citing concerns over fairness and equity.
As a behavioral scientist and ethicist, I draw on an extensive body of research to help answer these questions. It suggests that incentives might work to save lives and, if properly structured, need not trample individual rights or be a huge expense for the government.
In the United States, incentives and disincentives are already used in health care. The U.S. system of privatized health insurance exposes patients to substantial deductibles and copays, not only to cover costs but to cut down on what could be deemed as wasteful health care – the thinking being that putting a cost to an emergency room visit, for example, might deter those who aren't really in need of that level of care.
In practice, this means patients are encouraged to decline both emergency and more routine care, since both are exposed to costs.
Paying for health behaviors
In the case of COVID-19, the vaccines are already free to consumers, which has undoubtedly encouraged people to be immunized. Studies have shown that reducing out-of-pocket costs can improve adherence to life-sustaining drugs, whether to prevent heart attacks or to manage diabetes.
A payment to take a drug goes one step further than simply reducing costs. And if properly designed, such incentives can change health behaviors.
Payments and cash prizes have been shown effective in encouraging blood donations, adherence to blood thinner drugs, blood glucose monitoring, physical activity and smoking cessation.
And for vaccination in particular, payments have been successful for human papillomavirus (HPV) in England; hepatitis B in the United States and the United Kingdom; and tetanus toxoid in Nigeria. The effects can be substantial: For example, for one group in the HPV study, the vaccination rate more than doubled with an incentive.
For COVID-19, there are no field studies to date, but several survey experiments, including one my group conducted with 1,000 Americans, find that incentives are likely to work. In our case, the incentive of a tax break was enough to encourage those hesitant about vaccinations to say they would take the shot.
Coercion concerns
Even if incentives will save lives by increasing vaccinations, there are still other ethical considerations. A key concern is protecting the autonomous choices of people to decide what they put into their own bodies. This may be especially important for the COVID-19 vaccines, which – although authorized as likely safe and effective – are not yet fully approved by the Food and Drug Administration.
But already people are often paid to participate in clinical trials for drugs that have not yet been approved by the FDA. Ethicists have worried that such payments may be “coercive" if the money is so attractive as to override a person's free choices or make them worse off overall.
One can quibble about whether the term “coercion" applies to offers of payment. But even if offers were coercive, payments may still be reasonable to save lives in a pandemic if they succeed in greater levels of immunization.
During the smallpox epidemic nearly 100 years ago, the U.S. Supreme Court upheld the power of states to mandate vaccines. Compared with mandating vaccination, the incentives to encourage vaccines seem innocuous.
Exploitation and paternalism
Yet some still worry. Bioethicists Emily Largent and Franklin Miller wrote in a recent paper that a payment might “unfairly" exploit “those U.S. residents who have lost jobs … or slipped into poverty during the pandemic," which could leave them feeling as if they have “no choice but to be vaccinated for cash." Others have noted that vaccine hesitancy is higher in nonwhite communities, where incomes tend to be lower, as is trust in the medical establishment.
Ethicists and policymakers should indeed focus on the poorest members of our community and seek to minimize racial disparities in both health outcomes and wealth. But there is no evidence that offering money is actually detrimental to such populations. Receiving money is a good thing. To suggest that we have to protect adults by denying them offers of money may come across as paternalism.
Some ethicists also argue that the money is better spent elsewhere to increase participation. States could spend the money making sure vaccines are convenient to everyone, for example, by bringing them to community events and churches. Money could also support various efforts to fight misinformation and communicate the importance of getting the shot.
The cost of incentives
Financial incentives could be expensive as a policy solution. As in Ohio, lottery drawings are one way to cap the overall cost of incentives while giving millions of people an additional reason to get their shot.
The tax code could also allow for a no-cost incentive for vaccination. Tax deductions and credits are often designed to encourage behaviors, such as savings or home ownership. Some states now have big budget surpluses and are considering tax relief measures. If a state announced now that such payments would be conditional on being vaccinated, then each person declining the shot would save the government money.
Ultimately, a well-designed vaccination incentive can help save lives and need not keep the ethicists up at night.
Christopher Robertson, Professor of Law, Boston University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
