Epidemiologists Acknowledge Virus Hunting as a Costly Waste

By Merlin Tuttle
6/15/18

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.

Morrison, J. 2018. Can virus hunters stop the next pandemic before it happens? SmithsonMag.com. https://www.smithsonianmag.com/science-nature/how-to-stop-next-animal-borne-pandemic-180967908/.

Tuttle, M.D. 2017. Give bats a break. Issues in Science and Technology 33, (Spring 2017):41-50.

Tuttle, M.D. 2018. Fear of bats and its consequences. J. Bat Research and Conservation, 10(1).  https://doi.org/10.14709/ BarbJ.10.1.2017.09.

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Bats and Chocolate Production

By Merlin Tuttle
6/6/18

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.

Maas, B. and T. Tscharntke, A. Tjoa, S. Saleh, N. Edy, A. Anshary and M. Muhammad Basir. 2018. Effects of Ecosystem Services Provided by Birds and Bats in Smallholder Cacao Plantations of Central Sulawesi. Gottingen Univ. Press.

 

 

 

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Success in Panama!

During both weeks of our workshops, we encountered periodic rain showers, keeping the normally hot, dry-season temperatures far more comfortable than anticipated. The downside was that we had poor netting results on three nights during the second week. We shared the forest with some interesting characters, such as a black jaguar, which fortunately left us alone, though it likely observed our activities. This one was photographed on a trail camera near one of our netting sites.

 

We set up a triple-high mist net almost every night, both weeks.

Departing to net bats over the nearby river. Daniel Hargreaves is carrying the triple-high net rig in the red bag. His team of skilled instructors from the U.K., Steve and Fiona Parker and Daniel Whitby, were superb.

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More Bats from Cocobolo

During our two-week stay in Panama’s Cocobolo Nature Reserve, we recorded more than 600 bats of 53 species, more than half the total number known for the entire country. Additional species were netted nearly every night, including two on our final evening. Over our two-weeks of workshops, common vampire bats (Desmodus rotundus) and greater fishing bats (Noctilio leporinus) were participant favorites, though an incredible variety of fruit-, nectar-, and insect-eating species were seen. The hardiest of our group members often worked till dawn, bringing in a steady stream of species for portrait photos, especially during the first week. By the second week much more time was devoted to training bats to come on call, especially to locations where Merlin could photograph natural behavior, such as catching katydids.

Merlin Tuttle training a hairy big-eared bat (Micronycteris hirsuta) to come on call to a leaf to catch katydids (its natural prey) in front of bright video lights needed for high speed video shooting.

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MTBC’s Bat Adventures continue: Panama – Week 2!

The new group arrived successfully and with bells on for Week 2.

We have three bats in training. Merlin trained a hairy big-eared bat (Micronycteris hirsuta) for photography. Within 15 minutes it was flying to his hand on call, rewarded with meal worms. Janell Cannon, the famous author of  Stella Luna, trained a white-throated round-eared bat (Lophostoma silvicolum) to eat from her hand. Her bat has a very calm temperament. Alexis and Amy trained a Niceforo’s big-eared bat (Trinycteris nicefori) for photography, a very sweet and eager gal.

Merlin guiding Janell in training the Lophostoma silvicolum in a small tent provided for this purpose.
Merlin guiding Janell’s bat training.
Merlin guiding Alexis in training a Trinycteris nicefori.

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Bats from Cocobolo

We’re just finishing up an incredible first week at Cocobolo and already caught 44 species of bats, everything from fishing bats to vampires, not to mention a wide variety of fruit, nectar, and insect eaters. Merlin added 10 additional species to his collection! Pygmy fruit-eating bats were found roosting in leaves they had cut to form “tents”.

Pygmy fruit-eating bat (Artibeus phaeotis)

Chestnut short-tailed bats were all around camp, feeding on piper fruit.

Chestnut short-tailed bat (Carollia castanea)

We caught more than 20 Common vampire bats. Frontier campesinos keep a few livestock not too far away, explaining the presence of so many vampires. Most of these seem to have lots of personality, enabling Merlin to get this cool photo. The trip participants had loads of fun shooting videos of the vampires running around on the ground on all fours.

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Hike to the Continental Divide and back!

MTBC’s Bat Adventures in Panama Week 1 group started out from our base camp for an energetic hike to the top of the mountain ridge. Some did it in 3.5 hours, some 6.5 hours, and everything in between. My GPS said I hiked 19,190 steps (about 10 miles!) and burned 2,701 calories. Some will go back at night to net for bats in this cloud forest where they hope to find different species than the ones found at the Cocobolo Nature Reserve banana plants, and along the lower river forest.

Merlin in the lead for our hike from camp straight up the vertical climb to the ridge top of the Continental Divide, about halfway between the Pacific and Caribbean.

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Off to a great start!

34 species, over a third of Panama’s 100+ bat species have been captured by our intrepid bat enthusiasts in just three nights!

Rebecca Edwards and Melissa Donnelly are raising the triple-high, while Fiona Parker looks on. This is a special rig to catch the freetail bats (high flyers) coming in to drink.

 

Fieldwork is teamwork! Melissa Donnelly and Daniel Hargreaves upright the triple-high net pole, while Fiona Parker and Baptiste Chadeyron open a mist net.

 

 

 

Processing team trio: Mary Smith weighs the bats, Karen Slote measures the bats’ forearm, and Mindy Vescovo enters all the data.

 

 

 

Melissa Donnelly has lots of experience catching bats and processing them. Here she trains Gretchen VanCleave, Maria Serrano, and Mindy Vescovo how to process the bats caught.

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MTBC’s Bat Adventures: Panama-Week 1

MTBC’s Panama Bat Workshop Week 1 Jonathan Duward, Fiona Parker, Steve Parker, Teresa Nichta, Daniel Hargreaves, Daniel Whitby, Mindy Vescovo, Rebecca Edwards, Michael Roy, Melissa Donnelly Maria Serrano, Karen Slote, Baptiste Chadeyron, and Mary Smith.

Merlin and Daniel Hargreaves, co-founder of Trinibats, have teamed up to co-lead two weeks of bat workshops at the Cocobolo Nature Reserve in Panama. The reserve is over 1,000 acres located about halfway between the Pacific and the Caribbean on the narrow Isthmus of Panama, about 35 miles wide.

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Bat Flash! Encouragement for Positivity in Cambodia

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.

 

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