Sunday, April 26, 2015

On "the nocebo effect" and spraying for gypsy moths



This week my inbox has been flooded by emails about the decision by our Ministry of the Environment to spray for gypsy moths in parts of Surrey and Delta. For those of you outside the British Columbia lower mainland you might not know about gypsy moths. As a province dependent on the export of both agricultural and forest products British Columbia is particularly sensitive to the presence of European and Asian gypsy moths. Both are invasive species that can devastate deciduous trees (read destroy fruit trees) and the presence of gypsy moths can result in our wood products being banned for export. Based on these concerns our government has an integrated program including ministries ranging from the Ministry of Agriculture, to the Ministries of Forests and Environment. This program includes trapping moths, identification of outbreaks and, if necessary, spraying. While the gypsy moth can cause devastation to our economy, it is possible to control it using a safe and effective, non-toxic, aerial spray called Btk. The best thing about Btk is it is the essence of a directed, organic response to infestations. You see Btk is not a chemical pesticide but rather is a formulation of naturally occurring bacteria mixed in a non-toxic solution appropriate for aerial dispersal. As anyone familiar with our environment knows bacteria exist throughout our environment. Each and every one of us carry three to four pounds of bacteria in and on our bodies. Without our natural gut bacteria we would be unable to digest certain foods and people who lose these bacteria either need a transplant or they become extremely ill and in rare cases can die. Due to our interactions with bacteria, our bodies are well suited to their presence and bacteria are similarly adapted. While some bacteria can make you sick, other bacteria (like Btk) cannot. There are literally thousands of studies demonstrating that Btk is harmless to people and pets. More details here. Ironically Btk can’t even hurt adult gypsy moths, their eggs or their pupae. It only works when ingested during the caterpillar stage of their life cycle at which point it gets into their guts, infects them and kills them. I simply lack the space to write about how safe this spraying is which brings us to the topic of this post: The nocebo effect.

So what is the “nocebo effect”? Well let’s start with something everyone knows: the “placebo effect”. The placebo effect is a long understood effect where, in the absence of an active ingredient, a “placebo” (often a sugar pill) has the same effect as if an actual pharmaceutical had been used. The placebo effect has been long understood, heck I first saw it discussed in a MASH episode back in the late 1970’s. Research on the placebo effect is both thorough and extensive. In a review article from 2012 over 2200 studies were identified (ref) demonstrating or discussing trials demonstrating the existence of the effect. The scientific basis of the placebo effect is also well-understood. Human perceptions are driven by our neurochemistry and human neurochemical responses are understood to vary with mood and perceptions. Interestingly enough even the simple act of smiling can cause a biochemical response improving one’s mood (ref). Convince a person with a minor illness that the sugar pill you are giving them will make them feel better and often that is all it takes. As everyone knows, the placebo effect does not work on everyone, nor does it work every time. All that is certain is that on a small percentage of people, in a small number of circumstances, it can have a real effect.

Let’s get back to the “nocebo effect”, it is essentially the placebo effect’s less attractive younger sibling. You could say it is Stephen Baldwin to the placebo effect’s Alec Baldwin. In keeping with the Baldwin theme, while Alec Baldwin is well known for being a liberal-Democrat Stephen is known as an ardent Republican. So while the placebo effect has the ability to help you feel better in the absence of any active ingredients, the nocebo effect has the ability to make a person feel poorly in the absence of any active stimuli. As described in this review paper the nocebo effect is not as well studied as the placebo effect but it has been demonstrated to be real. It is important to recognize a couple things about the nocebo effect. First and foremost, people who “feel bad” or claim to be “sick” via the nocebo effect are neither lying nor are they fakers, rather they are doing one of two things. They are either associating actual symptoms from other causes to the “nocebo” or they are having phantom symptoms based on their minds playing tricks on them. Think about this in your daily lives. Every parent of young children dreads the arrival of the “pink sheet” from your elementary school. For those of you without young children, the “pink sheet” is the warning announcement the schools send home to tell families that one of the children in their child’s class has been diagnosed with lice. The sheet asks parents to check their kids for lice. Try watching a group of parents when their kids hand them the “pink sheet” and watch as virtually every parent in the group starts itching their heads. You would think someone had spread a dose of itching powder into the group. This is the nocebo effect in action. An itchy head is no longer just something you get from life; it is now all about lice. Until you have had a chance to check your kids and yourselves every itch is a sign that you are one of the unlucky ones. There are any number of celebrated cases where people have be shown that their “illnesses” were all in their minds but by far the most entertaining one is described in this article from Daily Tech. In that case a community complained about health issues associated with radio towers even though the radio towers had been turned off during the time the community members claimed they were being made ill by the towers. I have neither the time, nor the space to talk about fears of WiFi in this article, but I think we can all agree that any case where a transmission tower is turned off and people still complain it is making them sick is an example of the nocebo effect.

So let’s go back to the gypsy moth spraying. When a mother on television claims that following the spraying for gypsy moths she felt a sore throat, it could be that she didn’t look at the pollen count for the morning and woke up with a sore throat from exposure to high levels of pollen or it could be that she simply had a dry throat that on any other day would be solved with a glass of water. In either case once the “sore” throat is associated with the Btk spraying in a person’s mind, it will be that factor that makes it the cause of the “illness” thereafter. Regardless of the amount of research that shows otherwise, every time a community is told that there is going to be aerial spraying you will get a dozen or so people who claim to have symptoms of various indistinct illnesses all of them “caused” by the spraying. Ironically, the illnesses are indeed associated with the spraying but not in the way you would expect. It is not the spray itself but rather by the simple fact that spraying is occurring that caused people to display their symptoms.

This brings us back to a topic of a previous post “On Science Communication and the Difficulty Relaying Scientific Information to the Public” which introduced the concept of “dread risk”. As I describe in my previous post: dread is a term used by Dr. Paul Slovic in his seminal article on risk communication called "Perceptions of Risk". For those of you without access to journal articles Dr. Roger Pielke discusses the topic in a blog posting. I have previously suggested that any reader who wants a non-technical but compelling read on the subject of Risk should get the book by Dan Gardner of the same name. For those of you not interested in too long a read, dread risks are risks associated with factors that cannot be seen or felt using our normal senses and can have serious or life-threatening consequences, often a long time after the initial exposure. In this the aerial spraying for Btk has features associated with dread risk. The spray, once released, is invisible to the touch, cannot be smelled [author's correction: the Foray 48B formulation has a very minor odour associated with one of the ingredients used to hold the Btk in suspension] but can sometimes leave a minor residue on surfaces. This makes it an ideal source of dread risk. The problem is that based on all the existing science Btk does not cause any short-term, medium term or long-term risk to humans, animals or anything that is not a caterpillar. Unfortunately, as is the case in many other endeavours, a solid basis in science is never enough to calm all the fears in a population that is mostly science-blind. All our regulators can do is to continue spraying, all the time trying to educate the population about the fact that the spraying does not represent a real risk to human health.

18 comments:

  1. You seem to use BTK and "the spray" interchangeably; however, BTK is just one ingredient of "the spray".

    ARTICLE: "The spray, once released, is invisible to the touch, cannot be smelled"
    FACT: The spray does smell and the smell lasts for several hours.

    ARTICLE: "Btk is not a chemical pesticide but rather is a formulation of naturally occurring bacteria mixed in a non-toxic solution appropriate for aerial dispersal."
    FACT: Perhaps BTK may be a safe naturally occurring bacteria... but more than 80% of the ingredients are listed as "other". The actual ingredients used for aerial dispersal are not listed.

    What are the "other" ingredients Blair? Perhaps something that smells? Or are people making that up too?


    ReplyDelete
  2. This comment has been removed by a blog administrator.

    ReplyDelete
  3. This comment has been removed by the author.

    ReplyDelete
  4. Adapted to new systems and processes well and seeks out training to enhance knowledge, skills and abilities.무료야설

    ReplyDelete
  5. I want to to thank you for this great read!! I certainly enjoyed every little bit of it. I have you bookmarked to check out new stuff you post… 출장안마

    ReplyDelete
  6. You are my inhalation, I have few web logs and very sporadically run out from to post .안마

    ReplyDelete
  7. Before Commenting, I wanna say thank you for providing this great information. I feel too good to read it this awesome blog. Keep sharing this type of content. 토토사이트

    ReplyDelete
  8. We have read your blog. It was really informative and we have collected much knowledge that has assisted me a lot. People can also visit our website…
    경마
    온라인경마

    ReplyDelete
  9. I was very interested in the article. it’s quite inspiring I should admit. I like visiting you site since I always come across interesting articles like this one. 카지노

    ReplyDelete
  10. I am for the first time here. I found this board and I in finding It truly helpful & it helped me out a lot. I hope to present something back and help others such as you helped me bitmain antminer s19j pro

    ReplyDelete
  11. youre so cool! I dont think ive read anything which includes this prior to. So first-class to discover anyone with many original ideas on this problem. Realy thank you for starting this up. This fantastic website may be some thing this is required on the net, somebody with a little originality. Valuable problem for bringing something absolutely new on the net . Quality with your permission permit me to seize your feed to preserve updated with imminent post. Thanks a million and please keep up the pleasurable paintings 먹튀신고

    ReplyDelete
  12. superb information! I lately got here across your blog and had been reading along. I thought i might go away my first comment. I don’t realize what to mention except that i have. You may additionally test my blog . An sd card or a protection digital card is one that is going to shop extra amounts of records for you. It’s used for cell devices along with cameras and smartphones,recommendations. I should say you're an first-rate writer, i like the manner which you describe the matters. Please preserve sharing i'm upbeat to find out this put up rather beneficial for me, as it contains part of data. I typically want to peruse the excellent substance and this issue i discovered in you put up. A debt of gratitude is so as for sharing. That is this kind of exceptional resource which you are imparting and you provide it away without cost. I love seeing weblog that understand the cost of imparting a first-class resource without spending a dime. Terrific statistics in your internet journal, thank you for putting aside a great possibility to impart to us. Stunning expertise you've got in this modern, it is respectable to discover a website that subtle factors any such notable amount of statistics about numerous specialists. I really enjoying each little bit of it. It is a top notch website and pleasant percentage. I need to thank you. Desirable task! You men do a exceptional weblog, and feature some fantastic contents. Preserve up the best work . I'm interestingly right here. I discovered this board and that i in discovering it really accommodating and it helped me out a extremely good deal. I need to offer some thing back and assist other human beings, as an example, you helped me . Top website! I virtually love how it is simple on my eyes it's miles. I am wondering how i might be notified whenever a new put up has been made. I've subscribed in your rss which may additionally do the trick? Have a excellent day! I’ve suffered with a listening to trouble all my lifestyles and the usage of the internet to speak to people has changed my existence, i revel in many blogs and plan to begin my personal within the near destiny. I found your web site from a publish i read, i although i’d take a glance and i’m glad i did. Thank you for sharing quality data with us. I like your post and all you share with us is uptodate and quite informative, i would like to bookmark the page so i will come right here again to study you, as you have got finished a exquisite process. This precise papers excellent, and my spouse and that i revel in each of the perform that you have located into this. I’m certain that you will be creating a truly useful vicinity. I has been additionally pleased. Excellent carry out! Extraordinarily fascinating on-line magazine. Alot of on line journals i see nowadays don't typically give some thing that i'm keen on, but i'm maximum definately intrigued with the aid of this one. Lately felt that i might put up and can help you recognise. Thank you for taking the time to talk about this, i sense strongly approximately it and love learning more in this subject matter. If feasible, as you benefit information, might you mind updating your blog with greater statistics? It is extremely helpful for me. Thank you so much for the submit you do. I like your submit and all you percentage with us is up to date and quite informative, i would like to bookmark the web page so i'm able to come here again to examine you, as you've got executed a outstanding job . When you have a secret recipe that no one knows and also you want to share it so everyone can see, we're more than satisfied to lend a hand for you! Sure i'm completely agreed with this article and i just want say that this text could be very nice and very informative article. I can make sure to be reading your blog more. You made a good point but i can't help but marvel, what approximately the alternative aspect? !!!!!! Thank you 메이저사이트홍보

    ReplyDelete
  13. that is an tremendous motivating article. I am almost glad along with your brilliant work. You positioned surely extraordinarily supportive facts. Hold it up. Continue running a blog. Hoping to perusing your subsequent submit . I without a doubt enjoy sincerely analyzing all of your weblogs. Absolutely wanted to tell you which you have people like me who recognize your work. Honestly a tremendous post. Hats off to you! The information which you have furnished may be very helpful. I’m excited to uncover this web page. I need to to thanks for ones time for this mainly terrific study !! I without a doubt genuinely preferred every part of it and that i also have you stored to fav to observe new information to your site. 토토사이트

    ReplyDelete
  14. i really taking part in every little bit of it. It is a terrific website and first-rate percent. I need to thanks. Suitable project! You guys do a excellent weblog, and have a few superb contents. Hold up the good paintings. What a superb submit i've come upon and agree with me i have been seeking out for this similar kind of put up for beyond in keeping with week and infrequently got here across this. Thanks very tons and will look for more postings from you. You've got completed in splendid work. T propose to my frtends ind personilly wtll certitnly dtgtt. T'm conftdent they will be gitned from thts internet website. Took me time to read all the remarks, however i definitely enjoyed the item. It proved to be very useful to me and i'm certain to all the commenters here! It’s usually notable while you cannot simplest be knowledgeable, but additionally entertained . Outstanding internet site, in which did u offer you with the statistics in this posting? I'm thrilled i found it even though, sick be checking once more quickly to find out what more posts . I discovered your this put up on the equal time as trying to find some associated information on weblog search... Its a fantastic placed up.. Preserve posting and update the facts . It was a first-rate danger to go to this sort of internet site on line and i am glad to apprehend. Thank you a lot for giving us a chance to have this opportunity . I found your this submit whilst attempting to find a few associated information on blog seek... Its a excellent positioned up.. Maintain posting and replace the information 사설토토추천

    ReplyDelete