Horseshoe crabs and horseshoe crab products are in use for medical purpose in many countries across the Indian ocean. Stories about this animal were gathered and written by students. They are all part of a pedagogical project, funded by the National University of Singapore and the Université de Paris. The Bestiary site is a work-in-progress and a participatory educational tool, representing animals whose products or body parts are used to promote health and healing.

Blue Blood

A Story by Teo Jun Jie

Horseshoe crabs are highly sought after in the medical industry due to their blood, blue in color due to the copper elements. (…) Horseshoe-crab blood is exquisitely sensitive to toxins from bacteria so it is used to test for contamination during the manufacture of anything that might go inside the human body.

Symbolism of Horseshoe crabs in Buddhism

In Chinese Buddhism, the tradition of Fang Sheng 放生 traces its origins back to at least the sixth century, when monks organized for worshipers to release fish and tortoises into temple ponds. Chinese Buddhists believe that the compassionate act of releasing captive animals will cleanse one’s sins and bring good karma. Modern day enthusiasm for this centuries-old enthusiasm has raised concerns among the Buddhist community in Hong Kong. Horseshoe crabs are seen as an object used by Buddhists to repent and for good health. In Hong Kong, the trend of purchasing horseshoe crabs from fishermen and releasing them back to the waters has seen a resurgence in recent years. Before being freed, the animals are blessed by Buddhist monastics or devotees and the accumulated merit is dedicated to someone who is ill or has died in the belief that the person will benefit. However, research has shown that this practice threatens the population of horseshoe crabs. Indeed, it is a practice aimed to save lives. However, as they are unlikely to adapt to new environments or survive exposure to polluted waters where they are normally released, it puts them at a higher risk.


Benefits in the medical industry

Horseshoe crabs are highly sought after in the medical industry due to their blood. Their blood is blue in color due to the copper elements in their blood. The blood contains a special clotting agent which is used to make a concoction called “Limulus Amebocyte Lysate” or “LAL”. Horseshoe-crab blood is exquisitely sensitive to toxins from bacteria so it is used to test for contamination during the manufacture of anything that might go inside the human body: every shot, every IV drip, and every implanted medical device. Therefore horseshoe crabs play a very important role as a litmus test before the medicine is allowed to enter the human body and anyone who has had an injection, vaccination, or surgery has benefitted from horseshoe crabs. Before LAL, scientists had no easy way of knowing whether a vaccine or medical tool was contaminated with bacteria. 

It is clear that there have been no reports about Horseshoe crabs being a zoonose carrier. From its existence some 445 million years ago, there have been no cases of horseshoe crabs creating or spreading any diseases to humans. Conversely, as mentioned above, horseshoe crabs have been beneficial to humans since scientists found a way to use their blood. Due to this characteristic, the population of horseshoe crabs has decreased drastically. In 2016, the International Union for the Conservation of Nature bumped the American horseshoe crab up to ‘Vulnerable’ on its red list, one step below ‘Endangered’. And the US population could keep falling, by as much as 30% over the next 40 years. Blood from horseshoe crab is also being used in the production of the coronavirus vaccine. As the coronavirus has no definite timeline, we might have to depend on horseshoe crabs in the long run at least until another solution is found.

Speaking to my brother, who is a TCM certified doctor, he mentioned that up to this date, there is still very little use of Horseshoe crabs in Chinese medicine. However, he highlighted the importance of horseshoe crabs to western medicine, as mentioned above. All in all, horseshoe crabs remain a very important part of human life. The recent Covid-19 has also increased the need for vaccine testing in the world, in turn increasing the importance of such compounds to test the vaccine created by countries.

Horseshoe crab (Gopalpur, Orissa, India, 2012) © Annu Jalais
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