COVID-19 shows “Eat @#$% & die!” is a warning, not a metaphor
KUNMING, China; LONDON, U.K.; SEATTLE––One might imagine that the midst of a global pandemic of COVID-19, a disease apparently originating in bats, would not be the best time for selling bat-processed coffee.
At this writing, COVID-19 has infected nearly 175,000 people, worldwide, killing more than 6,700.
But even without the COVID-19 threat, from a public health perspective there never was a good time to sell bat-processed coffees, and never will be, any more than there ever was a good time to sell coffee made from coffee cherries culled from civet poop, elephant poop, or the droppings of any other animal.
Boiling coffee water doesn’t mean beans
Roasting the coffee cherries, and then saturating them with scalding hot water as the final step of the coffee-making process, might kill any pathogens before ingestion by novelty-seekers, including the coronaviruses that cause SARS and COVID-19.
Meanwhile, however, anyone involved in collecting and handling a bat-processed coffee, or a civet-processed coffee, or any other animal-processed coffee, might potentially be exposed to any pathogen associated with the animal. Should that pathogen prove to be as infectious as COVID-19, the sterilizing properties of coffee-roasting and boiling water might be academic.
To be sure, the “Wild Bat Geisha” coffee sold by the Sea Island company of London, England, originates with the help of tiny Jamaican fruit bats “in the forests surrounding the Coffea Diversa Estate in Biolley, southern Costa Rica, on the border of Panama,” says the Sea Island web site.
Bats nibble coffee cherries, not excrete them
This is half a world and many millions of years of evolution away from the insectivorous bats of Hebei province, China, believed to be the incubators of both SARS and COVID-19.
“The wild bats feed on the exotic coffee cherries,” continues the Sea Island web site, “but, unlike most wild animal coffees, like the famous Kopi Luwak civet cats, the cherries are not ingested whole. Instead, the bat breaks the skin of the ripe cherry with its teeth, feeds on the pulp and licks the sugar-rich mucilage.
“The coffee cherries are left on the tree and exposed to the sun as nature’s own way of drying the coffee in its parchment,” Sea Island says.
Readers may judge for themselves whether they wish to try bat-processed coffee, currently priced at upward of $200 a pound. But the mere existence of such a commodity raises further questions about bats, coffee, and COVID-19.
Can humans pass COVID-19 back to bats?
Perhaps the first such question should be whether the 27 known cases of COVID-19 found among humans in Costa Rica between March 5 and March 15, 2020 could potentially infect the previously unexposed Costa Rican bat population.
Epidemiological science currently does not know whether COVID-19 can be transmitted from humans back to bats, or to any other animal. Pangolins are the only other species identified as yet as a potential COVID-19 carrier, though one dog was found to have briefly been infected, without becoming ill.
But if COVID-19 could pass from humans back to bats, Costa Rica might be the worst of all places for that to occur. Costa Rica, located where North and South America first joined, hosts at least 110 bat species, descended from species native to both the northern and southern hemispheres, each with close relatives ranging throughout the Americas, all living in close proximity to many other species.
Among the bats native to Costa Rica are all three species of vampire, who feed by sucking the blood of animal and sometimes human hosts: the common vampire bat (Desmodus rotundus), the hairy-legged vampire bat (Diphylla ecaudata), and the white-winged vampire bat.
Vampire bats would be the most likely candidates to contract COVID-19 or any other virus from humans. Lest that prospect seem unlikely, consider that rabies outbreaks transmitted to humans by vampire bats have been reported by the international Program for Monitoring Emerging Diseases (ProMED) in 19 of the 26 years it has existed.
If a virus can move from bat to human in one direction, it very likely can move from human to bat in the other, especially since it is the bat sucking human blood, not the other way around.
Consider white-nose syndrome
The densely clustering social habits of bats, and tendency of most bat species to favor the same caves, hollow trees, and attics as many more, would then practically guarantee that any disease occurring among some bats could soon afflict many bats of multiple species.
Some bat species may be much more vulnerable to a newly introduced disease than their neighbors, as demonstrated by the havoc wrought by the white-nose fungal disease among little brown bats, tri-colored bats, and at least 11 other bat species among the 47 species native to North America, killing upward of eight million bats since 2008.
Eight other North American bat species are known to have been exposed to white-nose syndrome without suffering any particular consequences, possibly because ancestors on other continents somehow evolved immunity and passed it along.
Potential reservoir for repeated outbreaks
“Coronaviruses in bats from Mexico,” a study published in the May 2013 edition of The Journal of General Virology, described the discovery of 13 previously unidentified coronaviruses among 42 New World bat species. The bats carrying those coronaviruses might be more resistant to infection by COVID-19––or not.
Either way, transmission of COVID-19 backward from humans to New World bats could potentially introduce a reservoir for outbreaks to the Americas, which has previously existed––so far as anyone knows––in China.
How much do we know about Chinese bats?
“At least 147 bat species are present in China, which places it among the most bat-rich countries in the world,” reported the multiple authors of “Research trends on bats in China: A twenty-first century review,” published in the September 2019 edition of the journal Mammalian Biology.
The Mammalian Biology literature review found that 594 scientific articles produced in either English or Mandarin summarized findings pertaining to 135 bat species native to China. The research about most Chinese bat species was fragmentary, however, and a dozen catalogued Chinese bat species had not been researched at all.
Further, the abundance of Chinese bat species suggests that perhaps many more species have yet to be formally identified.
Where there are bats, there are diseases to which humans have historically rarely been exposed, chiefly because––although bats, nonhuman primates, and humans are all branches of the same family tree––humans and bats are seldom intentionally close to each other.
Most obviously, humans are active chiefly by day, bats almost exclusively by night. And even where humans and bats dwell in the same places, for example in old buildings, bats tend to occupy cracks and crevices in eaves and attics, rarely if ever descending to the human-occupied floors.
“Subtropical areas of Guangdong, Guangxi and Yunnan have the greatest risk of coronaviruses jumping to humans from animals—particularly bats, a known reservoir for many viruses,” reported Jane Qiu for Scientific American on March 11, 2020.
Bats brought SARS to civets––and, indirectly, to us
Among those viruses were the SARS coronavirus, which emerged to attack humans in November 2002, killing 774 people in 2003-2004, amid intensive efforts to suppress it through increasingly strict quarantines, and then disappeared as abruptly and mysteriously as it had come.
SARS was relatively rapidly traced back to palm civets sold in Chinese live markets.
“But how the civets got the virus remained a mystery,” wrote Qiu. “Two previous incidents were telling: Australia’s 1994 Hendra virus infections, in which the contagion jumped from horses to humans, and Malaysia’s 1998 Nipah virus outbreak, in which it moved from pigs to people. Both diseases were found to be caused by pathogens that originated in fruit-eating bats. Horses and pigs were merely the intermediate hosts.”
Hundreds of bat-borne coronaviruses
Eventually a team led by Wuhan Institute of Virology scientist Shi Zhengli explored Shitou Cave “on the outskirts of Kunming, the capital of Yunnan—where they conducted intense sampling during different seasons throughout five consecutive years,” Qiu recounted.
In Shitou Cave, “The pathogen hunters discovered hundreds of bat-borne coronaviruses with incredible genetic diversity,” Qiu wrote.
“The majority of them are harmless,” Shi Zhengli told Qiu.
“But dozens belong to the same group as SARS,” Qiu continued. “They can infect human lung cells in a petri dish, cause SARS-like diseases in mice, and evade vaccines and drugs that work against SARS. The team discovered a coronavirus strain in 2013 that came from horseshoe bats and had a genomic sequence that was 97% identical to the one found in civets in Guangdong.”
Further, Shi Zhengli’s team collected blood samples from more than 200 residents in four villages near Shitou Cave. They found that six people, nearly 3%, “carried antibodies against SARS-like coronaviruses from bats, even though none of them had handled wildlife or reported SARS-like or other pneumonia-like symptoms,” Qiu wrote. “Only one had travelled outside of Yunnan prior to sampling, and all said they had seen bats flying in their village.”
That was not all, Qiu reported.
“Three years earlier, Shi’s team had been called in to investigate the virus profile of a mineshaft in Yunnan’s mountainous Mojiang County—famous for its fermented Pu’er tea—where six miners suffered from pneumonia-like diseases (two of them died),” Qiu wrote.
“After sampling the cave for a year the researchers discovered a diverse group of coronaviruses in six bat species. In many cases, multiple viral strains had infected a single animal, turning it into a flying factory of new viruses.”
Bats infect pigs
A fungus “turned out to be the pathogen that had sickened the miners,” Shi Zhengli told Qiu, but added that “it would only have been a matter of time before they caught the coronaviruses if the mine had not been promptly shut.”
Shi Zhengli and colleagues in 2019 published warnings in the journals Viruses and Nature Reviews Microbiology about the potential for other bat-borne coronaviruses to infect humans.
For example, Qiu explained, “In late 2016 pigs across four farms in Qingyuan county in Guangdong—60 miles from the site where the SARS outbreak originated—suffered from acute vomiting and diarrhea, and nearly 25,000 of the animals died. The cause of the illness, called swine acute diarrhea syndrome (SADS), turned out to be a virus whose genomic sequence was 98% percent identical to a coronavirus found in horseshoe bats in a nearby cave.
“Pigs and humans have very similar immune systems,,” Qiu continued, “making it easy for viruses to cross between the two species,” with swine flu––which killed 12,000 of 61,000 human victims in the U.S. as recently as 2009––as a ready example.
Bats carry filoviruses, too
“A team at Zhejiang University in the Chinese city of Hangzhou found the SADS virus could infect cells from many organisms in a petri dish, including rodents, chickens, nonhuman primates and humans,” Qiu noted.
Almost exactly a year before COVID-19 began to terrorize the world, Shi Zhengli and Lin-Fa Wang at the Duke–National University of Sciences Medical School in Singapore identified a previously unknown filovirus, an even scarier type of virus than any known coronavirus––even SARS––in a Rousettus fruit bat, better known as an Egyptian fruit bat, caught in Měnglà County of far southern Yunnan.
The find followed up on the discovery of multiple filoviruses among 29 Rousettus fruit bats who were captured and “humanely killed” for study in the same area in June 2013, as reported in the September 2015 edition of the journal Emerging Infectious Diseases.
What makes a filovirus scary
Explained the January 2019 edition of the journal Nature Microbiology, “Ebola virus, Marburg virus and other members of the ‘filovirus’ family cause severe bleeding and organ failure. In Africa, at least one species of bat is known to host Marburg virus, and a number of bat species are suspected of carrying Ebola virus.”
“Měnglà,” the filovirus found in Měnglà County, “is substantially different from both Ebola and Marburg virus,” Nature Microbiology continued, “highlighting the genetic diversity of filoviruses in bats. The team found that the virus can infect cells from monkeys, hamsters, dogs, and humans. Research is needed to determine what the risk is of Měnglà virus spreading beyond bats,” and of course to find out what the consequences might be if it did.
Coming back around to coffee
This brings us full circle back around to bat-processed coffee. Yunnan, where both Shitou Cave and Měnglà County are located, has had a near-monopoly on coffee production in China since the late 19th century, when a French missionary stationed in China introduced coffee to China. To this day Yunnan accounts for 98% of all the coffee grown in China.
The Chinese government, World Bank and the United Nations Development Program in 1988 began jointly encouraging the Yunnan coffee industry to compete internationally for coffee export market share, with the global Starbucks chain, headquartered in Seattle, accounting for about half of Yunnan sales.
While coffee-drinking was slow to catch on in China, consumption––again stimulated by Starbucks––has rapidly increased in recent years.
Should the “Wild Bat Geisha” coffee marketed by Sea Island of London prove profitable, the arrival of less costly competition from Yunnan would appear inevitable, but quite unwise.