Last week I came across a curious bit of information: There exists an apparent correlation between a bat fungal disease and infant mortality. The correlation has been observed in many areas of North America, where bats are perishing in large numbers from white nose syndrome.
An Obviously Annoyed Little Brown Bat With Symptoms of White Nose Syndrome
University of Illinois/Steven Taylor. US. Fish and Wildlife Used under CC 2.0
White nose syndrome, WNS, is endemic to Europe and Asia. The syndrome wasn't found in North America until 2006, when the fungus, Pseudogymnoascus destructans, was introduced. As a novel pathogen, the fungus had the ability to devastate an immunologically naive bat population. And it did.
In China and Europe, this fungus disease seems to have little impact on the bat population. In North American affected areas, bat populations have declined by as much as 90% (in some cases 100%) of affected communities.
The fungus may be essentially wiping out the bat population in some parts of the U.S., but what does this have to do with human babies?
Bats are an important part of the ecosystem. They're insectivores--they eat insects. According to the U.S. Department of Agriculture, a small bat can eat 1,000 insects in an hour. A mother bat, nursing her young, can eat 4,000 in an hour. Bats can be one of a farmer's best friends.
Leaf Hopper Nymph (Cicadellidae)
Credit: Katja Schulz from Washington, D. C., USA. Used under CC 2.0 license. According to the USDA, bats are one of the most important consumers of night flying insects. Their diet includes mosquitoes, moths, beetles, crickets and leafhoppers (such as the one shown in the picture above).
What happens when there are no more bats? What does a farmer do to control insect pests? Apply pesticides. The deleterious effect of environmental pesticides on maternal health and perinatal health has long been established.
Researchers were recently startled to find this relationship between bat decline and infant mortality, and that relationship, they posited, was established by the use of pesticides.
Farmer Spraying Pesticide on a Field
Credit:Photo by Jeff Vanuga, USDA Natural Resources Conservation Service. Public domain. A 2008 report issued by Farm Worker Justice.org describes the ways in which occupational exposure to pesticide influences fertility/childbirth. The article describes how the pesticide interferes with male fertility. How it affects female fertility, gestational health, breast milk.
After reading about the WNS/infant mortality connection, I was curious: Was this the first time agricultural use of pesticides correlated clearly with infant health/mortality?My answer popped up quickly in a Google search.
There was a study out of Sudan in 1993 which looked at exactly this relationship. In an article entitled "Agricultural Pesticide Exposure and Perinatal Mortality in Central Sudan", the result of studies that looked at the risk of pesticide exposure was clear:
Exposure to any pesticide spraying significantly increased the risk of stillbirth in the hospital population and of perinatal death in the community population
and
Pesticide spraying most significantly affected perinatal deaths in women engaged in farming
Then there was an article published by the Journal for Gestational Education (2008), which did an overview of literature that studied environmental exposure to pesticides and herbicides. The authors of this overview state:
Suggestive evidence associates pesticides and polychlorinated biphenyls with decreased fetal growth and length of gestation.
and
Evidence suggests dichlorodiphenyltrichloroethane and bisphenol-A could be associated with pregnancy loss
It's not hard to find studies that draw a relationship between insecticide exposure and a number of fetal abnormalities. What's interesting is that some of this exposure is through ingestion, rather than through air.
Here's another study (2021), for example, from the International Journal of Environmental Research, that looks at the effect of pesticide exposure in a variety of countries. The results are similar to those described in the two studies already cited.
Geomyces Destructans Infecting a Bat
Credit:Djspring. Used under CC 3.0 Attribution Share-alike license.
White Nose Syndrome
As researchers look at this fungal disease their understanding of its etiology grows. Pseudogymnoascus destructans is psychrophilic--it is adapted to a low-temperature environment. The implication of this for bat illness is that when a bat is hibernating, its body temperature is reduced. The bat hibernates because of the scarcity of food (insects) during winter. The cold-loving fungus thrives in this reduced body temperature environment. This is also a time at which a bat is most vulnerable.
Hibernating Bat
Brent and Marilynn. Used under CC 2.0. The picture seems to have been taken in Nashville, TN.
Although the fungus disease is called white nose syndrome, the fungus attacks more than the bat's nose. The fungus can grow on the wings, nose and ears of an affected bat. When the bat comes out of hibernation, the white fuzziness may go away, but the fungus invades deep tissue. Not only does the fungus weaken the bat directly, but when the bat is hibernating the fungus causes it to have more frequent periods of arousal.
Bats ordinarily are aroused periodically during hibernation. Those periods of arousal are costly, in terms of energy and resources (stored fat) used. The fungus therefore weakens the bat systemically and also by causing exhaustion of fat reserves.
Tri-colored Bat With Visible WNS Symptoms: Wings, Ears and Nose
Credit: Darwin Brock. US Fish and Wildlife. Used under CC 2.0 license
According to the U.S. Fish and Wildlife, white nose syndrome has spread rapidly, and continues to spread. It is in 40 U. S. states, and in Canada. There are teams of researchers and interested individuals who are working to combat the disease. It is believed the fungus must have been introduced by a human who visited a cave in Europe. It could have been carried in on a shoe, or boot.
However, (as mentioned previously) bats in Europe seem to have built up immunity to the syndrome. According to an article in BMC Zoology, " We hypothesised that WNS exerted historical selective pressure in Palearctic bats, resulting in genomic changes that promote infection tolerance." Palaeactic refers to Old World regions; Nearctic refers to New World regions.
Below is a relatively current distribution map of white nose syndrome's spread in Nearctic regions. If you click on the link, you will find yourself at an interactive map that shows the rapid spread of the disease since 2006.
Credit: U. S. Fish and Wildlife Service. Public domain.
White nose syndrome has not infected humans. This fungus likes cold temperatures. Human bodies are simply too warm for it to thrive.
Conclusion
When I write a blog I first of all look for a subject that interests me. The association between white nose syndrome and infant mortality I found fascinating. Also, when I write, I like my blog to have some significance. In this case, we see once again how different parts of nature cannot be walled off. Everything is connected. The association between bat disease and human infants is a pretty dramatic illustration of that connection.
Thank you for reading my blog. Hive on!
Some Resources Used in Writing This Blog
https://en.wiktionary.org/wiki/immunologically_naive
https://www.britannica.com/science/Holarctic-region
https://www.usda.gov/peoples-garden/pollinators/bats
https://www.msn.com/en-us/health/medical/how-a-bat-disease-may-have-led-to-the-death-of-more-than-1-000-kids/ar-AA1q4bmn?ocid=winp1taskbar&cvid=d0ec4ec2cf484a11acd6379ea70a00ef&ei=41
https://pubmed.ncbi.nlm.nih.gov/8324850/
sudan report on infant mortality and pesticide use
https://voxdev.org/topic/health/herbicides-widely-used-agriculture-increase-infant-mortality
Brazilian agriculture and pesticide use correlation with infant mortality
https://www.nps.gov/articles/what-is-white-nose-syndrome.htm
https://www.biologicaldiversity.org/campaigns/bat_crisis_white-nose_syndrome/Q_and_A.html
https://www.bats.org.uk/about-bats/threats-to-bats/white-nose-syndrome/white-nose-syndrome-in-europe
https://news.ucsc.edu/2015/11/bat-disease-china.html
https://www.nature.com/articles/srep19829
https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fseprd476773.pdf
https://www.americanfarmlandowner.com/post/helping-the-bats
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4833532/
https://journals.sagepub.com/doi/
https://www.science.org/doi/10.1126/science.adg0344
https://journals.sagepub.com/doi/10.1177/1933719108322436
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8471259/
https://bmczool.biomedcentral.com/articles/10.1186/s40850-018-0035-4
https://academic.oup.com/jmammal/article/93/2/497/922002
https://www.science.org/doi/10.1126/science.adq5157
https://wdfw.wa.gov/species-habitats/diseases/bat-white-nose#wns
https://www.sciencedirect.com/science/article/abs/pii/S0306456521002758
https://bmczool.biomedcentral.com/articles/10.1186/s40850-018-0035-4
https://www.britannica.com/science/Holarctic-region
Fascinating piece. We're such a destructive species us humans, so great is our hubris and so poor our ability to join the dots. Much of what we do makes little logical sense at all. I think we need a great reset:)
😄
If things keep going the way they are, we going to get one of those.
Thank you! Not everyone is finds that interesting. I'm glad you did.
Interesting blog! I never imagined bats could suffer from such a disease, and it might go that far to affect, indirectly, humans. Bats haven't been on a good streak lately.
Thanks for sharing :)
Hello @gabmr,
So nice to see you here. Thank you for reading that long blog. I'm very happy you found it interesting. Bats are really important. They don't just eat insects but they are also significant pollinators. They are even better than bees because they fly greater distances (that's what I've read, anyway).
Hope your summer was tops. Regards, AG
Very interesting post @agmoore, I was unaware of this case of fungal attacks on bat populations. A very important point is when you mention that “everything is connected”, since everything is part of a balance that must be maintained for ecosystems to function in a good way, the lack of any natural component can trigger very serious problems.
On the other hand, the issue of agrochemicals applied to crops is another serious problem and even more so when applied excessively, many of these products wear out the soil, making it infertile over time and bring health complications. In turn, the birth rate and also human fertility can be compromised, you already made a good mention of what can happen to babies in your post with the lack of bats that forces to use even more chemicals for pest control.
In my country there was a case study where in a village used for agriculture many young people under the age of 20 were already infertile, it was discovered that the river they used for water supply was contaminated with the chemicals they used for crops. The issue was that the products applied were very residual and stayed in the soil, then when it rained the rains washed all these chemical residues to the natural water sources, so everything was contaminated.
A pleasure reading you, hope you have a good week 🤗.
There are 'cancer villages' in China - over 400 last time I checked, where maybe 5% might die from cancer in a single year... Toxic water supply mostly
There must be several contaminated villages in China. I would say that in more developed or more populated countries, the contamination rates due to agricultural practices are higher, since they require very high production levels to satisfy the needs of their population, without adding what is exported. The fastest and "safest" way to achieve this is by using chemical products to fight pests, diseases, improve yields, etc.
Because of all this, soil and water contamination rates will be very high, hence cancer and other health complications.
over 400 stats was years ago and I don't expect they have done much to reduce so yeah, for the same reasons you describe, and a whole lot of 'good enough' mentality for the tiny pay check people are being given to provide health & safety
That is tragic. I'm sure there are cases all over the world. Surprisingly hard to find them. I don't think the companies and governments want us to know.
Here (on Long Island) we have the issue of nitrogen runoff and herbicide runoff. People want green lawns so they use chemicals to induce that look. Crazy! Every time we have a storm, the chemicals are washed off the lawns and into our surrounding bodies of water. Just to get a greener lawn!!!!
Thank you for your informative and perceptive comment, my friend @abneagro. I hope you and your family are enjoying a peaceful end of summer.
This is one thing I love about humanity - whenever I end up diving deep into some geeky thing, there's always some really detailed, usually interactive map displaying all the research in one place, things most normal humans wouldn't even consider thinking about as an issue.
I'm always fascinated by the chain of causality in so many things, and just how incomprehensibly complex it can be, like, to make up an example that could probably be true: We stop using plastic straws --> We use paper straws --> The straw paper is made in a particular country --> The increase in demand increases water demand --> drains the lakes --> keystone locust-eating species gets wiped out --> overpopulation of locusts --> they wipe the... wheat production from several countries during their migration --> a country 8,000 miles away ends up with food insecurity and malnourishment.
This kinda thing really happens! And it's wild that smart people are keeping track of it all while we go about our day
I was sure nobody would look at that map. I'm so glad you did. It's the kind of thing that gets my attention.
Causality. Can be scary and powerful. Butterfly effect.
Good or bad? Who knows. As we move through the universe we matter in more ways than we realize, even the least of us.
Thanks very much for reading, and commenting, @mobbs. Hope all the butterflies in your life are good ones :))
Ohhh despite it killing the bat, the whiteness of the nose does add a bit of pizzazz to its look.
Like it's a wizened elder bat or something.
This is an intriguing piece though. It's no news that pesticides are more harm than good yet not using them leaves farmers at the risk that their crops are decimated.
I hope America bats win this battle...
😇
I think bats in North America will follow the pattern of European and Asian bats. The few that survive will be immune to the fungus (they will adapt) and over time the population will rebuild. The bats have a lot of friends--a lot of teams of human helpers who are trying to get them over this rough patch.
And, the problem with pesticides is not restricted to farmers. Even in our own homes, when faced with an insect infestation many of us resort to insecticides. We know they are bad, but we have a hard choice to make.
Thank you for reading and commenting, @seki1. Nice to see you back on Hive (feeling better 😃)
I never knew animals also suffer from diseases and not just bats alone this time
So you mean that there are times when bats don’t feel so well as suffer from diseases?
I’m shocked
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