Update on The Wildlife Society’s Misleading Bat Story, 9/21/15

Second Round of Supporting Documentation of the Wildlife Society’s Misleading Bat Story of September 9, 2015

Thank you very much for your prompt response and offer of possible collaboration in gaining perspective on this controversial issue. I don’t think anyone involved in these stories is deliberately attempting to deceive us or harm bats, though I am amazed at the extent to which scientifically unproven speculation is becoming headline news as though it were well documented fact.

In an extensive literature review Ricardo Moratelli and Charles Calisher (2015, Mem. Inst. Oswaldo Cruz, Rio de Janeiro, 110(1):1-22) raised the question, “Can we confidently link bats with emerging deadly viruses?” Their answer was, “No, or not yet.” They noted that “the supposed connections between bats, bat viruses and human diseases have been raised more on speculation than on evidence supporting their direct or indirect roles in the epidemiology of diseases (except for rabies).”

I read the entire paper published by Angela Luis et al. in Ecological Letters [The basis for the Wildlife Society story]. The research and conclusions seem to reflect a great deal of naiveté regarding the world beyond current virology. Also, they cited Calisher et al. 2006 while ignoring Calisher et al.’s 2015 paper cited above, with which they apparently disagreed.

Furthermore, Luis et al. based their comparisons on 78 years of publications dating from (1934-2011). I can scarcely even imagine the amount of taxonomic confusion this would create, given that just since 1980, we’ve gone from roughly 800 recognized species of bats to over 1,300. Many that were considered distinct were lumped with others, and even more were split to be recognized as distinct, especially following the arrival of DNA analyses. Also, I assume there likely have been many similar changes in rodent taxonomy. And on top of that, let’s consider the extent of viral taxonomic change over such a long period, not to mention that less than 1% of viruses have been described even now and that we know almost nothing of the ecological circumstances under which most exist! Finally, bats that form the largest colonies in caves are far more easily sampled than others, adding a clear additional bias. I’m betting you wouldn’t wager much on any conclusion based on such shaky data.

Bat species that form large colonies in caves are the easiest mammals on earth to sample in large numbers, followed by flying foxes that form conspicuous colonies in trees. As the inventor of the bat trap now standardly used by virologists to catch bats, as one who has extensively caught them on every continent where they exist, and as one who in his youth collected many thousands of mammals, from tapir, primates and large carnivores to rodents and bats for the Smithsonian, I fully understand how much easier it is to sample colonial bats.

The search for a reservoir for Ebola provides a great example of this and other biases. A quick check of the literature will show that while large numbers of bats were sampled at the focal point of the most recent outbreak, none were found to be infected. Other animals of the area remained mostly unsampled. That was deemed unnecessary because they weren’t reported to be sick. Of course if they were actually carriers we wouldn’t expect them to be sick! Based on what is known of dog ability to host similar viruses, it might have at least made sense to sample a few jackals or hyenas, perhaps even a few leopards or lions. But who wants to tackle that, or even trapping large numbers of rodents, civets, ungulates or small primates when bats are so much easier, and everyone is in a race to publish?

Worse yet, despite the absence of confirming data, The National Institutes of Health announced on August 29, 2014 that the Ebola outbreak could now be traced back to a straw-colored fruit bat and a two-year-old boy. Nevertheless, if this boy had been in contact with one of these roughly three-foot wingspan bats, it certainly seems that someone would have known about it. Also, this species does not enter buildings.

Even more amazing, while this story was making headline news worldwide, another research team (Saezet al., 2015, EMBO Molecular Med., 7(1):17-23) visited the same village and home and reached a completely different conclusion. They, after also failing to find evidence of the virus in sampled bats, concluded that “the index case may have been infected by playing in a hollow tree housing a colony of insectivorous free-tailed bats (Mops condylurus).” This further speculation also made headlines, including on BBC NEWS (Dec. 30, 2014). Though the research team, in its journal publication, cautioned that such bats are valuable and shouldn’t be killed, their hollow tree roost was burned with the bats inside. People do kill what they fear regardless of what else we may say.

Since you also seemed impressed with the CDC’s opinion on disease in bats, I suggest you read my well documented account of that entity’s long-standing and continuing misguidance on the issue of bats and rabies (Tuttle, 2013; pp 363-366 In Bat Evolution, Ecology and Conservation, Adams and Pedersen, eds., Springer). There you will see how the CDC claimed a special exemption for continued use of DDT against bats well after it was outlawed for all other use. And after multiple research papers concluded that such use dramatically increased risks of human and pet exposure to rabies and reduced bat resistance to infection, they still attempted to continue. Even now their potential bat exposure policy for rabies flies in the face of studies in Oregon and Canada who found the policy not efficacious. Neither entity follows CDC’s bat policy.

Three final points: 1) It isn’t the number or prestige of proponents that counts, but rather the credibility of scientific data; 2) Authors shouldn’t be the only reviewers of their own work; and 3) How can bats be headlined as high risk while dogs are considered safe despite inflicting far higher rates of human mortality?

If you can accept the kinds of facts I have here presented, I would be delighted to collaborate with you on putting this issue in perspective. I am well aware of how easy it must be to become confused when so many otherwise credible people all seem to agree that bats are dangerous. However, the story hasn’t changed much—Just follow the money. Scary headlines sell media and get big grants.

https://www.merlintuttle.org/resources/exaggerated-disease-warnings/