在世界各地，蝙蝠正承受這種錯誤資訊帶來的效應。我的馬來西亞同行，Sheema Abdul Aziz，花了數年時間，記錄狐蝠這不可或缺的授粉者，在東南亞每年數十億美元產值的榴蓮作物中扮演的關鍵角色。果農們原本打算加入她的一項大眾教育活動，闡述蝙蝠的價值，但現在卻因擔心受到公眾強烈反對而不願支持她的努力。
只要不碰觸蝙蝠 感染風險其實極低 然而事實通常不太會被報導
然而，這些事實通常不會被報導，而風險卻常被放大。3月11日的《科學人》(Scientific American） 提供了一個絕佳的例子。其談論武漢肺炎文章的副標題寫道：「武漢的病毒學家石正麗曾在蝙蝠洞中發現數十種致命的類SARS病毒，她警告那裡還有更多。」使用「致命」一詞，即是無端的臆測。
該文進一步聲稱，武漢爆發的疫情是過去26年中，第六次由蝙蝠所引發。事實上，文中所列的前四次（嚴重急性呼吸道症候群［SARS］、中東呼吸症候群 ［MERS］、亨德拉病毒感染症 ［Hendra］、伊波拉病毒感染 ［Ebola］） 看起來都是由蝙蝠以外的其他動物傳染給人類——然而蝙蝠仍承受了主要的責難。文中的第五次，立百病毒（Nipah virus），可能是由狐蝠傳播給人，只要蓋好採集容器或用巴斯德法對受污染的生椰棗汁進行消毒，即可輕易地預防。
某些病毒學家利用對大流行病的恐懼，去爭取用於普查自然界中病毒的研究經費，以作為預防或減輕這些可怕事件的可能方式。他們說服美國國家過敏與傳染病研究所（US National Institute of Allergy and Infectious Diseases），在2019年編列了48億美元的預算用於普查潛在的高風險病毒。
然而，也有許多權威專家強烈反對。他們認為，這項普查的成本極高，但卻幾無實用價值。病毒引起的疫病爆發極罕見，且其出現無法預測。演化病毒學家 Edward Holmes 及其夥伴指出，即使當下所有病毒都可分類及登錄，新的RNA病毒變異仍會不斷演化出來。他們直率地警告，承諾病毒普查可以預防甚至減輕大流行，不但會傷害信譽且是一種傲慢。
要了解為何病毒普查這策略終將失敗，可參考MERS、西尼羅熱（West Nile） 和茲卡病毒感染症（Zika） 的例子。MERS 是從一個看似不太可能的源頭—駱駝，跳到了人類身上，其發生地點—沙烏地阿拉伯，在過去也被認為是極不可能發生這類事件的地點。新興病毒專家 Robert Tesh 曾指出，西尼羅熱和茲卡病毒皆非新病毒。它們的溢出（spilled over） 僅是因為在輸送到新地區時發生了無法預期的事件。
It has been a bad decade for bats. Prior to the emergence of COVID-19, they were already in severe decline worldwide. Now, they are blamed as the culprits behind one of the costliest pandemics in modern history, even though the source and method of transmission haven’t been identified. Although scientists have an obligation to promptly disclose new threats, premature speculation about bats has been exaggerated in attention-grabbing media headlines. The result has been needless confusion, leading to the demonization, eviction, and slaughtering of bats even where they are most needed.
As of mid-March, “patient zero” for COVID-19 still had not been found, and who or what infected that person remains a mystery. There is even uncertainty about whether the viral jump from an unknown intermediate host to humans occurred in the location initially identified, an animal and seafood market in Wuhan, China. Despite these uncertainties, the media, with no small assistance from scientists, has sensationalized the risks, often without providing perspective, settling on bats as the likely culprit and thus making them targets in a viral witch hunt.
Around the world, bats are feeling the effects of this misinformation. My Malaysian colleague, Sheema Abdul Aziz, has spent years documenting the key role of flying fox bats as essential pollinators of Southeast Asia’s multibillion-dollar-a-year durian crop. Growers were planning to join her in a public education campaign explaining the value of bats, but now they fear a public backlash and are reluctant to support her efforts. A local resort has expressed fear of loss of sales due to a nearby flying fox colony. Fearing her research will trigger a new disease outbreak, private citizens have even asked the government to stop her from handling bats and to support eradication, something already reported in neighboring Indonesia. My colleagues in China are also deeply concerned about the demonization of bats and calls for their eradication.
Even in my home city of Austin, Texas, where we have safely enjoyed sharing a downtown bridge with 1.5 million bats for decades, growing numbers of people are asking about disease risks. Despite warnings from poorly informed health officials that our bats were rabid and dangerous, they’ve yet to transmit a single case of disease. They simply attract millions of tourist dollars each summer and control tons of crop pests each night. Texas bats are worth more than a billion dollars annually. Now bat-lovers are experiencing a backlash against putting up bat houses because neighbors say they fear that attracting bats will bring disease.
But simply telling people that bats are valuable and shouldn’t be killed can’t counter panic. I have personally investigated instances where fearful humans had burned, poisoned, or sealed caves, killing millions of bats at a time. Based on my experience, I have concluded that there is no greater threat than the intolerance and eradication that results from misguided fear.
Exaggerated warnings of bat disease risks aren’t just misguided. They threaten the health of entire ecosystems and economies. Researchers in Indonesia conservatively estimate that bats save cacao growers more than $700 million annually in avoided insect damage. In Mexico, tequila and mescal production worth billions annually relies on bats that pollinate agaves. From Southeast Asia to the Mediterranean, bats provide key pest control for rice growers. In South Africa, macadamia growers benefit from bat control of stink bugs.
Despite a long tradition of being misunderstood and feared, perhaps because of their nocturnal habits and erratic flight, bats have an outstanding record of living safely with humans. Millions living in backyard bat houses, city parks, and bridges have proven to be safe neighbors. I have never been attacked and am still healthy after more than 60 years studying and handling hundreds of species worldwide, sometimes surrounded by millions in caves. Because, like veterinarians, I am occasionally bitten by unfamiliar animals I handle, I’m vaccinated against rabies.
For anyone who simply avoids handling bats, the odds of contracting any disease from one are incalculably small. All diseases attributed to bats are easily avoided, even when bats live in one’s yard.
However, these facts typically go unreported, while risks are often magnified. The March 11 issue of Scientific American provides an excellent example. Its COVID-19 article subhead reads, “Wuhan-based virologist Shi Zhengli has identified dozens of deadly SARS-like viruses in bat caves, and she warns there are more out there.” The use of “deadly” is unjustified speculation.
The article additionally claims that the Wuhan outbreak is the sixth outbreak caused by bats in the past 26 years. In fact, the first four listed (SARS, MERS, Hendra, Ebola) appear to have been transmitted to people by animals other than bats—yet bats still receive primary blame. The fifth, the Nipah virus, which likely is spread to people from flying fox bats, is easily prevented by simply covering collection containers or pasteurizing contaminated palm juice.
Two possible scenarios have been hypothesized for the COVID-19 outbreak. The first is that a new coronavirus entered an intermediate host animal, such as a pangolin, where it evolved over an undetermined period to gradually become a threat to people. Alternatively, the new coronavirus could have been harmless when it first entered humans, but over time evolved to become virulent. Such scenarios would be difficult to predict, and a publication currently under review even points to mice and domestic pigs as possible sources.
So why has the media almost universally blamed bats? In part because scientists have disproportionately focused on sampling them.
Since 2005, when coronaviruses in horseshoe bats were first hypothesized to be the ancestors of the coronavirus that caused SARS, bats have received far more scrutiny than any other group of animals. For example, in the study on which the scariest headlines were based, researchers sampled nearly twice as many bats as rodents, shrews, and nonhuman primates combined and didn’t even include carnivores or ungulates.
Easily blamed, due to their lack of popularity, bats are also the easiest mammals to quickly sample in large numbers. This led to rapid publication of the results, and sensational speculations were deemed more acceptable when focused on already-feared animals.
Not surprisingly, more viruses have been found in bats than in less-surveyed species, so biased speculation has become a self-fulfilling prophecy. We don’t yet know if bats have more viruses than other animals because we haven’t similarly sampled others. And even if bats do have more, the number of viruses isn’t necessarily indicative of transmission risk. Many viruses are innocuous or possibly even beneficial.
Some virologists have capitalized on the fear of pandemics to promote funding for viral surveys in nature as a possible means of preventing or mitigating these scary events. They convinced the US National Institute of Allergy and Infectious Diseases to budget $4.8 billion in 2019 for surveys searching for potentially high-risk viruses. Referring to the COVID-19 pandemic, longtime surveying proponents now argue that the best way forward is to prevent future outbreaks by beginning with surveys to find and catalog wildlife viruses globally, focusing on what they consider to be high-risk animals, including bats.
However, many leading experts strongly disagree. They argue that such surveys would be extremely costly and have little practical value. Viral-caused outbreaks are exceedingly rare, and their emergence is unpredictable. The evolutionary virologist Edward Holmes and associates note that even if all current viruses could be cataloged, new variants of RNA viruses are constantly evolving. They bluntly warn of arrogance and loss of credibility resulting from promises that viral surveys could prevent or even mitigate pandemics.
To understand why surveying will fail as a strategy, consider the examples of MERS, West Nile, and Zika viruses. MERS jumped to humans from a seemingly unlikely source, camels, in Saudi Arabia, previously believed to be an extremely improbable location for such an incident. Robert Tesh, an expert on emerging viruses, has pointed out that neither West Nile nor Zika viruses are new. They simply spilled over when transported to new areas in incidents that couldn’t have been predicted.
A growing number of leading epidemiologists agree that it isn’t possible to predict the animal origin of the next viral outbreak. Unfortunately, their warnings are seldom covered by public media. When they are, they tend to be de-emphasized.
Finding the true source and means of infection for patient zero in the current outbreak seems far more important than condemning bats or spending billions on searches for potential pathogens. Such public health funds would be much better directed toward improved early detection in humans.
But we humans must also address our own culpability. Caging and slaughtering a wide variety of animals in markets virtually guarantees the spread of viral infections. Blaming already unpopular bats only increases already severe threats to their survival, despite scientific certainty about the enormous benefits they provide to both the environment and societies. Care about bats or not, we should see COVID-19 as a grim reminder that human well-being requires responsible stewardship of nature, not just dominance.