Covid-19: What you need to know today
There are four animals that have become relevant in the context of the coronavirus disease (Covid-19). This column is about them.
It was only in 2013, after a decade of looking for the source of the Sars-CoV (or Sars-CoV-1) virus that causes the Severe Acute Respiratory Syndrome, that scientists found the natural host of the virus, horseshoe bats — specifically, horseshoe bats in a cave outside a large city in China’s Yunnan province. Somehow, the virus had made the jump from the bats, to civets in Guangdong, and from them to humans (the Chinese eat civet meat and the first people to be infected were wildlife traders from Guangdong). A fascinating article in Scientific American in March narrated this quest as part of its profile of Shi Zhengli, a virologist in Wuhan. Scientists say the bats may well be the natural host of the virus that causes the coronavirus disease too.
Horseshoe bats, then, are the first animals of relevance in the context of Covid-19. That shouldn’t surprise anyone. Research has established that bats are hosts to more zoonoses (pathogens that can cross over to humans, causing an infection) than any other species.
Sometimes, the transmission happens directly. Sometimes, it happens through another animal. In the case of Sars, it was the masked palm civet that was the intermediary. In the case of the Middle East Respiratory Syndrome, or Mers, it was a species of camel. In the case of Covid-19, scientists believe the intermediary was the pangolin — specifically, the Malayan Pangolin. India has a species of pangolin too, the Indian Pangolin. Pangolins are widely used in Chinese medicine, so it’s easy to see how SarsCoV-2 could have jumped from bats to pangolins to humans.
The pangolin, then is the second animal of relevance in the context of Covid-19, which, as of Thursday, has infected 3.8 million people, and killed 265,000 (of the 3.8 million, 1.3 million have recovered).
The global scale of the pandemic, which has no cure right now, has meant everyone knows the significance of ChAdOx1 nCoV-19. This is the vaccine being developed at the University of Oxford. The vaccine hopes to tackle Covid-19 by injecting a weakened adenovirus into which genetic material from Sars-CoV-2 has been inserted — something that should generate an immune response. The adenovirus the scientists at Oxford are using is one that causes cold in chimpanzees, which explains the name of the vaccine (Ch for chimpanzee and Ad for adenovirus). We humans share 99% of our DNA with chimpanzees and bonobos (another ape, and one that belongs to the same genus as chimpanzees).
Chimpanzees are the third animal of relevance in the context of Covid-19, especially given that ChAdOx1 nCoV-19 remains our best bet yet. There are expectations that it will be available this year itself, and India’s Serum Institute has already started making it — taking a bet that an ongoing clinical trial will work.
But chimpanzees aren’t the only potential saviours of the human race. Over the past two days, there has been a lot of focus on llamas, the ungulates with pretty eyelashes. It turns out that they have antibodies that can tackle Covid-19 (the findings of a study on this were published earlier this week on the respected journal, Cell). It also turns out that the antibodies produced by llamas can be merged with antibodies produced by other species, including humans. Indeed, research has shown that all other members of the family llamas belong to, camelidae, produce antibodies with the same property — they are stable at higher temperatures, and lend themselves to genetic engineering because of their small size.
The llama, then, is the fourth animal of relevance in the context of the pandemic. And if llamas hold the answer to the virus, they will become as famous as the horses that helped humankind in the fight against diphtheria -- but that’s another story.