Exaggerated Disease Warnings

Fear of Bats and its Consequences
By Merlin Tuttle
5/2018

Merlin’s Opinion Letter, “Fear of Bats and its Consequences,” was published in the Journal of Bat Research and Conservation. This is a thoroughly documented report on how exaggerated disease claims against bats have harmed bats and efforts to conserve them over the past 47 years—something all who care about bats should know.

 

Merlin’s Response to Reuters News Release Blaming Bats for New Ebola Outbreak
By Merlin Tuttle
5/15/18

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.

 

A Terrifying Time for Bats
By Merlin Tuttle
7/2/17

Sensational speculation has become widely cited as fact, with spin-off damage that will be exceedingly difficult to reverse. All who truly care about bats have cause to be deeply concerned.
A far more meaningful analysis should have considered the historic rarity of viral spillover from bats to humans. Many media stories now claim bats to be the primary source of so-called “emerging infectious diseases” like Ebola, though most of these speculations remain unproven.

 

How A Witch Hunt for So-Called Emerging Diseases in Bats
Threatens Both Public and Environmental Health
By Merlin Tuttle
10/10/16

So-called emerging diseases are not new. They’ve been around for millions of years, only recently being discovered due to their rarity. In the past 20 years, SARS, Hendra, Nipa, Marburg, Ebola and MERS combined have accounted for fewer than 20,000 human deaths worldwide.

Many efforts to link scary diseases to bats as reservoirs are based on little more than premature speculation under misleading titles. Unfortunately, often repeated speculation is rapidly becoming widely accepted as fact, implying bats to rank among our planet’s most dangerous animals. This has diverted unprecedented funding from far higher public health and bat research priorities, simultaneously reversing decades of conservation progress in helping people overcome unfounded fear of bats.

Contrary to sensational, grant-getting speculation, in reality bats have one of our planet’s finest track records of living safely with humans.

 

For documented details please read this overview of what’s behind exaggerated disease warnings.

Read more about Ebola

Read more about bats and viruses

Read about rabies

Millions of Brazilian free-tailed bats emerging from Frio Cave Texas.
Millions of Brazilian free-tailed bats emerging from Frio Cave Texas.

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