Leading epidemiologists are finally acknowledging that the recently huge expenditures for virus hunting (mostly focused on bats) have little practical value in disease prevention. The June 7 issue of Nature contains a key paper titled, “Pandemics: spend on surveillance, not prediction.” In it Edward Holmes, Andrew Rambaut, and Kristian Anderson combine their expertise to advocate a much-needed change of course in prevention of viral transmission from animals to humans, one that may also considerably brighten the future of bats.
They emphasize that broad surveys of animal viruses have little practical value when it comes to disease prevention and warn that “Trust is undermined when scientists make overblown promises about disease prevention.” They “urge those working on infectious disease to focus funds and efforts on a much simpler and cost-effective way to mitigate outbreaks—proactive, real-time surveillance of human populations.”
Bats have an exceptional record of living safely with humans. But, they have been disproportionately searched, and victimized by virus hunter speculation, apparently because they are unpopular and easy to sample. This is an Angolan free-tailed bat (Mops condylurus), a species targeted for eradication following premature speculation linking it to the 2014 Ebola outbreak.
These experts explain that predicting when and where a virus will emerge in people is misguided and unlikely to be achievable. Determining which of an estimated 1.6 million animal viruses, deemed to be potentially capable of transmission to humans, would also prove prohibitively costly. They conclude that “given the rarity of outbreaks and the complexity of host-pathogen interactions, it is arrogant to imagine that we could use such surveys to predict and mitigate the emergence of disease.”
Currently, the most effective way to fight outbreaks is to monitor human populations in the countries and locations that are most vulnerable. Recommended actions include detailed screening and isolation of people exhibiting difficult-to-diagnose symptoms and monitoring of animal die-offs.
This is not the first warning against recent investment of billions of dollars on viral witch hunts that unfortunately have focused primarily on bats. Nevertheless, it appears to be the first to be taken seriously by a major journal of science.
On June 17, 2017, Nature published a paper, “Bats are global reservoir for deadly coronaviruses,” which claimed that finding these viruses could help predict where they are likely to make the next jump from animals to humans. After supporting virus hunting in bats, at the very end, it briefly admitted that Michael Osterholm, a prominent epidemiologist, believes that researchers and politicians should, instead direct their limited resources to halting outbreaks of already known-to-be deadly viruses.
A similar article titled, “Can Virus Hunters Stop the Next Pandemic Before It Happens?” was published on January 25, 2018 by the Smithsonian. Though this article asks the right question, it too mostly promotes the virus hunting approach. Only at the very end, does it acknowledge Robert Tesh, also a leading expert on zoonotic viruses, as having an opposing view.
Referring to the so-called virus hunters, he expressed his opinion that “A lot of the stuff they produce is hype. It’s more PR than science.” Tesh refers to Zika and West Nile viruses, noting that neither is new. They were transported to new areas, then spilled over, events that he doubts could have been predicted. He also notes that many reassortment viruses mutate quickly and that no amount of discovery could prepare for that. Tesh concludes that “Given these variables and how little we really understand them, people who claim they can predict what will happen are fooling themselves and the funding agency.”
Though Osterland, Tesh and others have previously expressed doubts about virus hunter claims, the current paper in Nature is the first to treat such concerns with appropriate respect. I’m delighted to see such progress in countering a now almost universal misperception that, has not only led to huge misallocation of public health funding, but also threatens the future of inappropriately maligned bats.
References
Holmes, E.C., A. Rambout, and K.G. Andersen. 2018. Pandemics: spend on surveillance, not prediction. Nature, 558:180-182.
Maxmen, A. 2017. Bats are global reservoir for deadly coronaviruses. Nature, 546:340.
While conducting her Ph.D. thesis research, Bea Maas and her team (Maas et al. 2013) collected data that would surprise even her. When insect-eating bats and birds were excluded from cacao trees in Sulawesi, Indonesia, the crop yield fell by 31 percent. And when she compared losses due to night versus daytime exclusion, bats versus birds, she discovered that bats accounted for 22 percent of the prevented losses.
A control site in the same study (poles without netting).
To obtain such data, Bea selected 15 plantations where she enclosed 120 cacao trees in 60 exclosures (like huge, mesh cages) constructed of nylon mesh. There were four exclosure treatments per plantation, one daytime, one nighttime, one day and night, and one always left open as a control.
A bat/bird exclosure in Sarawak, Indonesia, built with bamboo poles and commercial nylon monofilament netting with a mesh size of 2 x 2 cm. These were opened and closed like curtains daily.
When closed, all bat and bird species were excluded, but arthropods were allowed entry, including large spiders, butterflies, and moths. The exclosures were opened and closed like curtains, daily at 5:30 am and at 6:30 pm for 15 continuous months. Using standardized systems, all arthropods were counted and digitally photographed daily and nightly, and cacao damage was documented every two weeks. More than 70,000 fruits were examined, including over 4,000 ripe, harvested fruits.
When Bea extrapolated the economic impact of bats saving growers an estimated 520 U.S. dollars per hectare across 1.5 to 1.6 million hectares of cacao, this value translated into savings of 780 to 832 million U.S. dollars annually! It is important to note that studied plantations were in or near natural vegetation. Without this biodiversity balance, such impressive savings likely would not have been possible.
She calculated the separate value of bats when quizzed about it after appearance of the original paper in Ecology Letters. Bats accounted for 22 percent, birds 9 percent, of savings (Maas et al. 2018, p 62). The economic extrapolations from these numbers are from her personal communication.
Intermediate roundleaf bats (Hipposideros larvatus) are exceptionally widespread, found in Sarawak and most of Southeast Asia. They roost in caves, rock crevices and buildings, and feed on a wide variety of insects, from moths and beetles to stink bugs and mosquitoes.Trefoil Horseshoe Bats (Rhinolophus trifoliatus) range throughout most of Southeast Asia, living in understory forests. They roost alone in foliage, including beneath palm and rattan leaves. and hunt by listening and waiting for insects to fly by their feeding perches. Horseshoe bats feed on a wide variety of insects, especially moths, and were among the bats excluded in this study.The Philippine horseshoe bat (Rhinolophus philippinensis) ranges from Australia through the Philippines and into Southeast Asia. It feeds both in dense vegetation and in open areas, often in rainforests. It is one of several horseshoe bat species likely to have been excluded.Common Asian Ghost Bats (Megaderma spasma) are found throughout most of Southeast Asia, Indonesia and the Philippines. They form small groups, mostly consisting of a male and several females and their young, in caves, hollow trees, road culverts and buildings. Their large ears help detect prey sounds as they move through foliage. Prey consist mostly of large insects but also can include small vertebrates. This is one of many bat species most likely to have been excluded.
References
Maas, B. 2013. Bats and birds increase crop yield in tropical agroforestry landscapes. Ecology Letters 16:1480-1487.
We greatly appreciate Mongabay for its handling of the Nipah virus outbreak in Kerala, India. Its story, “Nipah infection in Kerala: Don’t blame the bats alone; improve public health,” appeared on May 30, authored by Haritha John and Gopikrishna Warrier. Needless alarm was avoided by balanced reporting. As so often is the case, the rarest threats make the biggest news. Fortunately, in this instance, the news was accurate, so did not cause needless panic.
Fruit-eating bats appear to be the natural reservoir for this virus. However, Nipah is easily avoidable, as noted in the Mongabay article. Human infections originate from drinking unpasteurized palm juice or from contact with pigs who have eaten contaminated fruit. The reported outbreak did kill 14 people, mostly from person-to-person transmission within a family and their immediate contacts. However, put in perspective, it was hardly grounds for the kind of panic too often created by needlessly scary speculation of potential pandemics killing millions. Thanks to level-headed health officials and media coverage, eradication of ecologically and economically essential bats was avoided.
A greater short-nosed fruit bat (Cynopterus sphinx) stealing a sip of sweet palm juice, often collected and consumed by people as a delicious drink. Humans who drink this juice only after pasteurization are safe from infection.
I share Benoit Nyemba and Fiston Mahamba’s concern regarding a potential resurgence of Ebola in the Democratic Republic of Congo, as Reuters News reported on May 8. Nevertheless, continuing to blame bats as the source is likely to reverse conservation progress essential to ecosystem health (Lopez-Baucells et al. 2018) and delay successful Ebola prevention. Understanding the true source is essential.
A male straw-colored fruit bat (Eidolon helvum). This is the species that was first erroneously blamed for infecting the two-year-old toddler identified as the index case that triggered the 2013-2014 Ebola outbreak. In the end no one could explain how a bat that never enters buildings and has a three-foot wingspan could have contacted a toddler without anyone knowing about it!
Bats can indeed transmit deadly diseases like rabies and Nipah to humans, though transmission is exceedingly rare and easily avoided. In the case of Ebola, bats have been too easily assumed guilty. A wide variety have been tested at outbreak locations. But, “Ebolavirus has yet to be isolated from bats, and no direct evidence links bats to Ebolavirus infection in humans.” (Spengler et al. 2016). Virologists still know “nothing about where it comes from and how it causes outbreaks.” (Kupferschmidt 2017).
Early Ebola outbreaks were traced to human consumption of infected chimpanzees, gorillas and duikers (Rouquet et al. 2005), though these animals were believed to be too susceptible to serve as reservoirs (Wittmann et al. 2007).
Nevertheless, subsequent research revealed Ebola antibodies in 10 percent of gorillas (Reed et al. 2014) and in 18.7 percent of pygmies (Mulangu et al. 2016), demonstrating that exposure is not as uniformly lethal in either great apes or humans as previously believed. Nancy Sullivan, a viral immunologist with the Vaccine Research Center at the National Institutes of Health, notes that “there is little evidentiary data to document widespread death of apes from Ebola” (Pedris 2017). These discoveries provide potential breakthroughs in the hunt for reservoirs.
The preponderance of evidence now points to sources other than bats (Leendertz 2016). There are four African species of Ebola: Sudan, Zaire, Bundibugyo, and Tai Forest Ebola. The geographical distributions are along separate river basins, and this is inconsistent with a highly mobile source, such as bats. Bats easily cross river basins. Experimentally infected bats can survive infection, as often cited, but they also show no evidence of viral shedding and are unlikely transmitters (Paweska et al. 2016).
Current claims that bats are the most likely sources of Ebola appear to have gained momentum from careless reporting of the index case for the 2013-2014 outbreak. The first team to investigate speculated a fruit bat origin, despite a complete lack of supporting evidence, as noted by a second team who also found no evidence of Ebola in a large sample of both fruit and insect-eating bats, but still speculated an insect-eating bat origin, whereupon the roost was burned with the bats inside (Saez et al. 2015).
It now seems likely that the disproportionate epidemiological focus on bats may have delayed much needed progress (Tuttle 2017) while doing great harm to the conservation of bats (Lopez-Baucells et al. 2018). Bats are economically and ecologically invaluable, but they also rank among our planet’s most endangered wildlife (Voigt and Kingston 2015). It’s time to halt the bias. People don’t tolerate animals they fear, and we need to know where Ebola is coming from.
TAKE ACTION!
Our combined voices can make a difference. Choose any or all means of contact to reach out to the staff at Reuters News and politely share your opinion in your own words. Editors do take notice. Remember, your response can be very simple such as, “I don’t appreciate premature speculation that creates needless fear of bats.” Editors just need to know you like or dislike an article in order for you to have impact. It’s numbers that count. Bats need all of you!
Hundreds of thousands of Straw-colored fruit bats (Eidolon helvum) beginning their evening departure from a city park in Ivory Coast, Africa. Cities often provide the only homes safe from commercial hunters who sell the bats for people to eat. Despite such large numbers having lived in close association with humans throughout recorded history, they have not caused any known disease outbreaks. Their remarkable safety record casts grave doubt on recent speculation of their being dangerous spreaders of Ebola.
References
Kupferschmidt, K. 2017. Hunting for Ebola among the bats of the Congo. Science, June 1.
Lopez-Baucells, A., Rocha, R. and A. Fernandez-Llamazares. 2018. When bats go viral: negative framings in virological research imperil bat conservation. Mammal Review 48(1): 62-66.
Mulangu, S., M. Borchert, J. Paweska, A. Tshomba, A. Afounde, A Kulidri, R. Swanepoel, J.J. Muyembe-Tamfum, and P. Van der Stuyft. 2016. High prevalence of IgG antibodies to Ebola virus in the Efe pygmy population in the Watsa region, Democratic Republic of the Congo. BMC Infec. Dis. June 10;16;263
Paweska, J.T., N. Storm, A.A. Grobbelaar, W. Markotter, A. Kemp, and P.J. van Vuren. 2016. Experimental inoculation of Egyptian fruit bats (Rousettus aegyptiacus) with Ebola virus. Viruses 8(2):29.
Pedris, L. 2017. Going viral: How advancements in Ebola disease detection in wild apes can help to prevent dangerous outbreaks. Mongabay, May 4.
Reed, P.E., S Mulangu, K.N. Cameron, A.U. Ondzie, D. Joly, M. Bermejo, P. Rouquet, G. Fabozzi, M. Bailey, Z. Shen, B.F. Kele, B. Hahn, W.B. Karesh, and N.J. Sullivan. 2014. A new approach for monitoring Ebolavirus in wild great apes. PLOS, Sept. 18, https://doi.org/10.1371/journal.pntd.0003143.
Rouquet, P. J-M. Froment, M. Bermejo, A. Kilbourn, W. Karesh, P. Reed, B. Kumulunqui, P. Yaba, A. Delicat, P.E. Rollin, and E.M. Leroy. 2005. Wild animal mortality monitoring in human Ebola outbreaks, Gabon and Republic of Congo, 2001-2003. Emerg. Infect. Dis. 11(2):283-290.
Saez, A.M., S. Weiss, K. Nowak, V. Lapeyre, F. Zimmermann, A. Dux, H.S. Kuhl, M. Kaba, S. Regnaut, K. Merkel, A. Sachse, U. Theisen, L. Villanyi, C. Boesch, P.W. Dabrowski, A. Radonic, A. Nitsche, S.A. J. Leendertz, S. Petterson, S. Becker, V. Krahling, E.Couacy-Hymann, C. Akoua-Koffi, N. Weber, L. Schaade, J. Fahr, M. Borchert, J.F. Gogarten, S. Calvignac-Spencer, and F.A. Leendertz. 2015. Investigating the zoonotic origin of the West African Ebola epidemic.
Tuttle, M.D. 2017. Give bats a break. Issues in Science and Technology. Spring edition.
Voigt, C.C. and T. Kingston (eds). 2016. Bats in the Anthropocene: Conservation of bats in a changing world. DOI 10,1007/978-3-319-25220-9_1.
This powerful article in Southeast Asia Globe, by Claire Baker-Munton, on the value of artificial bat roosts in Southeast Asia deserves much praise. With the help of Merlin’s photos, this article clearly promotes a better understanding of bats and their values. At a time when so many media headlines are attempting to grab readership by speculating potential linkage of bats to scary diseases, positive stories like this are crucial. In reality, as Claire points out, Cambodians have found bats to be highly valued neighbors.
TAKE ACTION!
Choose any or all means of contact to reach out with your praise and encouragement on behalf of bats.
While the public continues to be pummeled with scary claims of dire threats of disease from bats, Merlin has been rallying crucial leadership collaboration from within the international research community. In September, he provided an hour lecture, followed by an enthusiastic hour-long discussion, for virologists and epidemiologists at Brazil’s Oswaldo Cruz Foundation in Rio de Janeiro. And several days later he provided the keynote address for a joint annual meeting of Brazil’s Bat and Mammal Societies, with special attention to helping conservation-minded students.
Merlin Tuttle presenting keynote address for joint meeting of Brazil’s Bat and Mammal Societies in Pirenopolis.
In November, Merlin presented the inaugural address for a joint meeting of the Biology and Ecology Societies of Chile. A key concern there involved how to prevent bat killing due to irresponsible warnings of disease. Amazingly, even in a country where only one person in all history had died of a bat disease (rabies), fear of bats due to exaggerated media stories reportedly is posing a serious threat to conservation progress. Concerned attendees at the conference were delighted to learn of our disease resources and other information and photos available for their use. They were also most appreciative for advice on expanding threats from wind energy and pesticides. Merlin additionally agreed to provide photos for the bat section of a new book on Chilean mammals.
Merlin Tuttle speaking to virologists and epidemiologists at the Oswaldo Cruz Foundation in Rio de Janeiro, Brazil. A very friendly and helpful discussion followed.
Merlin providing the inaugural address for the 2017 joint meeting of the Biology and Ecology Societies of Chile, held in Puerto Varas, Patagonia.
“Actually this article neglected to mention another huge problem caused by these negative representations of bats. It’s not just about deliberate human killings of bats – even where bats are not being killed by people, the repercussions of this negative reputation are still damaging in indirect ways because it affects efforts and funding for research and conservation. I am currently the only person working on the conservation ecology of Pteropus in Malaysia, where there has been such a disproportionate amount of attention, effort, and money put into researching ONLY the virology and public health aspects of these bats. Hardly anyone is interested in looking at the conservation ecology aspect; never mind that these bats are important pollinators and seed dispersers, and are severely threatened by hunting – all topics which desperately require more attention and work. I can’t tell you how frustrating it is to be constantly approached by other researchers who are only interested in collaborating on virology, or to be told that I can only get funding if I include a disease and public health aspect in my project. Ultimately these bats will go extinct if people – including researchers and funders – are simply too focused on worrying about whether we’re going to catch diseases from them, instead of trying to mitigate the threats that we humans present to them. This kind of attitude is very, very damaging to bat conservation.”
Dr. Aziz explaining flying fox pollination to Mak Long, owner of the durian orcharad where her Ph.D. rhesis research was conducted. MTBC photos are playing a vital role in educating islanders to a better appreciation of flying foxes.Sheema using a light microscope to look for pollen grains in flying fox droppings.
Dr. Aziz is one of a very few researchers in her part of the world dedicated to helping people understand the economic and ecological importance of conserving flying foxes. Her research titled, “Pollination by the locally endangered island flying fox (Pteropus hypomelanus) enhances fruit production of the economically important durian (Durio zibethinus),” recently appeared in the journal Ecology and Evolution.
In her paper, she provides information critical to convincing islanders to protect flying foxes, namely that they are playing a key role as pollinators of one of Southeast Asia’s most valued crops, not causing damage as previously believed. She used camera and video traps to document that island flying foxes (Pteropus hyomelanus) do not damage durian flowers, as even some researchers had suspected. Video traps clearly absolved the bats. Island flying foxes and cave nectar bats (Eonycteris spelaea) are major pollinators. The damage was caused by plantain squirrels (Callosciurus notatus) who often ate immature flowers.
Aziz also notes that flying foxes sometimes can become a nuisance when roosting too near people, causing both noise and odor problems. She hopes to find a way to harmlessly convince these bats to move farther away, so they will be more welcome. There is an urgent need for education to minimize negative biases while solving legitimate nuisances. Aziz emphasizes the need to find solutions to real problems instead of needlessly scaring people about rare threats.
Large flying foxes (Pteropus vampyrus) have wingspans of nearly six feet, the largest of any bat. They are widespread in Southeast Asia, Borneo and the Philippines, but are in alarming decline due to over-harvesting for human food, and are often needlessly killed when entering orchards.
She reports, “I have been using your [Merlin Tuttle’s] photos, especially the amazing shots of P. vampyrus, in all the presentations I give. It’s enormously helpful because the only shots I have of that species are the poor dead ones shot by a hunter, and it’s not a very nice picture at all. I think it would be almost impossible for me to get a good photo of P. vampyrus here in Malaysia! Your close-up shots of Pteropus pollinating and feeding on fruit are also particularly useful for illustrating bat ecosystem services – I used these in a public talk I gave, at an event organized by the Malaysian Heritage and History Club, which was very well received. And of course, I also used your photos in the awareness video! I now use them anytime I want to talk about bat ecosystem services.”
An island flying fox (Pteropus hypomelanus), the focus of Dr. Azizes’ primary research.
Aziz is devoting her career to helping people solve problems while benefiting from the essential contributions of flying foxes. If bats are to survive in sufficient numbers to fulfil their critical environmental and ecological roles, Aziz, and many more like her will need all the help they can get. Just saving a few endangered remnants is not enough!
Alexis Valentine won the 2nd Place award at the 14th Annual Jr. Foresters Science/Research Competition in Moscow, Russia.
We first met Alexis Valentine and her mother Amy, when Merlin spoke at an annual Discover Life in America conference in Gatlinburg, Tennessee in 2014. We’ve kept in touch ever since, encouraging her research and competition in local and regional science fairs. We were thrilled to hear that she had been awarded a full scholarship to represent the U.S. at the 14th Annual Jr. Foresters Science/Research Competition in Moscow, Russia. Forty-five participants from 28 countries and five continents presented projects, September 2-10 and Alexis won second place out of 40 awards. At 15, she was the youngest competitor to win an award, and also was the highest ranking American contestant in the competition’s history.
Ian Agranat, Alexis Valentine and Merlin Tuttle at the Wildlife Acoustics display.
Last week, she did a fine job of presenting her research on the impact of white-nose syndrome on bats in the Great Smoky Mountains National Park at the annual teacher’s workshop held in conjunction with the NASBR 47th Annual Symposium on Bat Research in Knoxville, Tennessee.
Knowing Alexis had long dreamed of owning her own ultrasonic bat detectors for her research and public presentations, Merlin took the opportunity to introduce her to Ian Agranat, President of Wildlife Acoustics, the worlds’ largest producer of wildlife monitoring devices. Their Echo Meter Touch 2 Pro bat detector is one on Merlin’s favorite tools for introducing the public to bats, and he was delighted when Ian made Alexis’ long-time dream of owning her own equipment come true through his generous gifts which covered all her needs.
I wholeheartedly applaud Atlantic Monthly’s defense of bats at a time when so many other publications are spreading grossly exaggerated stories attempting to link bats to some of the world’s rarest but also scariest diseases. Bats have never needed help more, nor have we needed them more! As the one who persuaded the citizens of Austin to protect instead of eradicating its now world-famous colony, I’m proud to report that none of millions of tourists who come to enjoy their spectacular emergences has ever been harmed. By simply leaving bats alone (not attempting to handle them), we have exceedingly little to fear and much to gain. Our bats eat tons of crop and yard pests every summer night and attract millions of tourist dollars each year.
Thanks to people who increasingly understand and help bats, even those species most devastated by WNS are gradually beginning to recover. The only cure will come from improved protection and restoration of key bat habitats, especially their hibernation caves. It’s far too late, as well as impractical, to find a cure for WNS. Going forward, all resources should be devoted to recovery.
We invite everyone to share praise and encouragement via email or leaving a comment on the article page.
Photo caption: Tourists observing the emergence of 1.5 million Brazilian free-tailed bats from crevices beneath the Congress Avenue Bridge in Austin, Texas.
This summer saw the worst avalanche of grossly exaggerated disease speculation ever launched against bats. While seemingly countless publications world-wide needlessly frightened millions of readers, Mongabay journalist, John Cannon, investigated and bravely countered the tide in his article, “Bats and viruses: Beating back a bad reputation,” published August 29.
Mongabay is one of the world’s leading environmental websites. It reaches 28 million readers in nine languages annually, making its defense of bats especially helpful at a time when bats are facing so much scary misinformation. We’ve listed actions you can take to share your thanks at the end of this post.
Lesser long-nosed bats (Leptonycteris yerbabuenae) are primary pollinators of agave plants essential to annual production of tequila and mescal worth billions of dollars to the Mexican economy. But thousands at a time have been burned in their caves due to unfounded fear.
