By: Express News Service | New Delhi | Updated: December 5, 2020 8:06:51 amRain, an Atlantic bottlenose dolphin. (University of California - Santa Cruz)

When infected by the novel coronavirus SARS-CoV-2, people experience a drop in oxygen levels in their blood. This makes them vulnerable to damage in a large range of tissues. Compare this with marine mammals such as dolphins and whales, which spend their lifetime switching between environments of high and low oxygen levels, but tolerate both because their bodies have adapted that way.

In a review article published in Comparative Biochemistry and Physiology on Thursday, ecologist and evolutionary biologist Terrie Williams of the University of CaliforniaSanta Cruz explores how the diving physiology of marine mammals can help us understand the effects of Covid-19. Williams has spent decades studying the physiology of marine mammals and their extraordinary ability to perform strenuous activities while holding their breath for long periods under water. Texas A&M University marine biologist Randall Davis has co-authored the paper with her.

Marine mammals have ways to protect themselves and allow their organs to keep functioning while holding their breath for hours at a time. But to be able do that, they have had to undergo a whole suite of biological adaptations.

The fact that humans lack these adaptations makes it important for people to protect themselves from infection with this virus. Damage to oxygen-deprived tissues happens fast and can be irreversible, which may account for the long-term effects we are beginning to see in people after coronavirus infections, Williams said in a statement on her research. Follow Express Explained on Telegram

The heart and brain are especially sensitive to oxygen deprivation, and marine mammals have multiple mechanisms to protect these and other critical organs

Marine mammals have a capacity for carrying much more oxygen than humans.

Some marine mammals contract their spleen during dives, which releases oxygen-rich blood cells into the circulation.

To avoid blood clots resulting from such high concentrations of red blood cells, many marine mammal species lack a clotting mechanism found in other mammals.

Marine mammals have greatly increased concentrations of oxygen-carrying proteins such as myoglobin in heart and skeletal muscles, and neuroglobin and cytoglobin in the brain.

Numerous safety factors enable tissues in marine mammals to withstand low oxygen and the subsequent reperfusion of tissues with oxygenated blood. In humans, reperfusion after a heart attack or stroke often leads to additional tissue damage.

According to Williams, the solutions that marine mammals have evolved provide a natural template for understanding the potential for damage to oxygen-deprived tissues in humans.

There are so many ramifications of shutting down the oxygen pathway, and I think thats what were seeing in these Covid patients, she said.

Our heart and brain cells are meant to last a lifetime, and we cannot replace them once they are damaged, she added. Dolphins and whales have natural protections that humans lack, so we are highly vulnerable to hypoxia.

The research was funded by the Office of Naval Research.

Source: University of CaliforniaSanta Cruz

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Explained: From dolphins and whales, new insights on Covid-19 - The Indian Express