The following discussion is an archived debate of the proposed deletion of the article below. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review). No further edits should be made to this page.

The result was no consensus. There is no consensus for deletion at this point in time. Further discussion about the couple of proposals for a "merge", may take place at the article's talk page. -- Cirt (talk) 07:29, 27 May 2011 (UTC)[reply]

List of human diseases associated with infectious pathogens[edit]

List of human diseases associated with infectious pathogens (edit | talk | history | protect | delete | links | watch | logs | views) – (View log)
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Entirely built on poorly chosen sources and obviously promulgating the view that particular diseases are caused by infections. We already have List of infectious diseases, which serves this task well. JFW | T@lk 15:55, 19 May 2011 (UTC)[reply]

This new article is categorically different to the extant List of infectious diseases article. This new article is the only resource on Wikipedia that provides a list of pathogens associated with diseases (which is categorically different to pathogens that cause disease, the latter being provided in the List of infectious diseases article). This information cannot be found anywhere else on Wikipedia. The List of infectious diseases page does not, and cannot, provide this information, as it covers different subject matter.
This new article does not particularly promulgate the view that the diseases listed are caused by pathogen infections; such a view could not be based on fact. In fact, the article explicitly states that "association does not imply causation", just to make it clear that many associations may turn out to be spurious. It is only rigorous scientific research that will determine, for each listed disease, whether its associated pathogens play a causal role in the disease, or not. Research of this nature often takes decades. Some disease-pathogen associations may well turn out to be spurious; others may turn out to be causal (or conditionally causal). This new article simply details the current state of knowledge of this area of research. I am not sure why there is so little coverage of this area on Wikipedia.
Important discussion and comments further explaining the categorical differences between this new article on disease-associated pathogens, and the extant List of infectious diseases article, can be found HERE. Drgao (talk) 22:02, 19 May 2011 (UTC)[reply]
Hi SDY. Thanks for your comments. AIDS would not need to be included in this list, as AIDS has an established cause, namely HIV. This article/list will generally only contain diseases that satisfy the two conditions that they are: (1) diseases currently unknown cause, and (2) diseases which have a number of known associated infections, that may conceivably play a causal role in the disease. This is probably not explained sufficiently clearly in the article; I will have to reword it to make this clearer.
You raise a very valid point that the article/list could be very easily misunderstood. Perhaps the intro to the list should be worded with greater clarity to ensure that people appreciate that association is not the same as causation, in other words, innocent until proven guilty. Having said that, the article should be understood as precisely as "infections that might cause disease". That is the reason that these infections are studied, as they might (or might not) be the cause of their associated disease. There would be little point in studying these disease-associated infections, if not for the purpose of finding a possible cause for the disease. Drgao (talk) 02:50, 20 May 2011 (UTC)[reply]
I have changed the page introduction to hopefully address some of your concerns. More emphasis has been placed on the fact that we are only generally concerned with diseases of currently unknown etiology. Also, the potential for misunderstanding the nature of the page has reduced by incorporating the following sentences as the last paragraph of the introduction: "Nevertheless, in the following list of diseases of currently unknown etiology associated with infectious pathogens, there is no proof that the associated pathogens do play a causal role in the disease, only a possibly that they might. Only further medical research will determine whether the associated pathogens do play a causal role or not." Drgao (talk) 03:48, 20 May 2011 (UTC)[reply]
Note: This debate has been included in the list of Lists-related deletion discussions. — • Gene93k (talk) 23:26, 20 May 2011 (UTC)[reply]
Part of the problem is that the sources don't support the content. For example, the "sudden cardiac death" section blames enteroviruses, and the source talks about identifying infections in viral myocarditis. This has nothing to do with the list's supposed inclusion criteria, which is that these are common comorbidities that might have a causative link. This is very, very speculative stuff, and we need a lot better sourcing than "here's one paper that suggests it might be" to get real verification. There are some interesting concepts discussed here that are worth talking about, but the article as written is a disaster. Maybe not a reason to delete it, but maybe a reason to put it back into user space until it's ready for primetime. SDY (talk) 05:35, 21 May 2011 (UTC)[reply]
I have to admit that the reference provided is a little weak, in that the study was more concerned with identifying infections in viral myocarditis, than in studying sudden cardiac death. Nevertheless, viral myocarditis is responsible for 20% of sudden death, according the Myocarditis Wikipedia article, so it occurred to me that this study might provide some useful evidence of enteroviral involvement in sudden cardiac death; and that this might be a useful scientific clue for someone somewhere.
However, I will defer to your judgement, and remove this particular entry in the article's list, if you think this is below the threshold level of acceptance as evidence. I hope the reference I provided for enteroviral involvement in myocardial infarction is of better quality.
I am not sure why you say the article is a disaster. Much of my focus was on the pedagogic quality of the article, trying to give the reader not only a list of diseases that are associated with infectious microorganisms, but also some inkling of the complex causes and mechanisms which may precipitate disease, and the difficulties involved in uncovering these mechanisms. For example, I thought that this inclusion in the article was pedagogically very rich: "In a murine model, Crohn's disease is precipitated by the norovirus CR6 strain, but only in combination with a variant of the Crohn’s susceptibility gene ATG16L1, and chemical toxic damage to the gut in other words, through a virus–gene-toxin interaction)." It shows how it may require three very different causal factors to coincide before the disease appears. I found that fascinating, anyway. This sort of information hopefully gives the reader a better feel and sense of the complexities involved in hunting down the causes of disease.
If it is just that you think some references are below the threshold level for acceptance as evidence, or are too "creatively" used, I would be most grateful if you would point these out, so that they can be addressed, or removed if it comes to that. Drgao (talk) 08:27, 21 May 2011 (UTC)[reply]
Quote: "In the absence of any context, statements like these have no value." If you read the introduction to the article, you will notice that a precise context is very clearly provided. The article is not a random list of any microbial associations of diseases, and the article is not interested in diseases where immune deficiencies are the explanation for the associated infections. Drgao (talk) 14:10, 23 May 2011 (UTC)[reply]
The problem here is that the list may run into problems of original research if we start arbitrarily including and excluding things based on a carefully constructed definition. The concept of "diseases associated with but not necessarily caused by infectious agents" is a useful idea to kick around, but narrowing the list down to speculation about the cause of diseases puts far more editorializing into the content than the sources really support. Honestly, it sounds like the article's content is currently List of an arbitrary group of diseases that might be caused by these pathogens but we can't prove it. It's really more of a cleanup issue than a deletion issue, the idea of the list is valid but it's going to have to include the broader concept, not just specific speculations. SDY (talk) 14:20, 23 May 2011 (UTC)[reply]
I appreciate what you are getting at: that there is the potential that editorial policy might play a greater role in shaping the article that the sources actually dictate (and if this were the case, it would make me feel uneasy as well). In practice, however, you find that no editorial decisions are called for, as a study's content does quite clearly determine whether that study should be included or not. This is because when a study is examining the prevalence of a given pathogen in a certain disease, the authors generally make it clear that the study was gathering this prevalence data for the express purpose of highlighting a possible causal connection. For example, the abstract of this study, which examined the association between HHV-6B infection in the brain and mesial temporal lobe epilepsy (MTLE), ends with the sentence: "Our results suggest a potential etiology and pathogenic mechanism for MTLE". So it is quite clear here that the context is of HHV-6B as a potential causal agent of the disease.
Thinking about Axl's comment: it may be a concern that the context of the article is not immediately obvious from a quick glance; this may be something that needs to be improved in the article, in order to make its contextual background more obvious. Drgao (talk) 15:29, 23 May 2011 (UTC)[reply]

" If you read the introduction to the article, you will notice that a precise context is very clearly provided. "

— Drgao
I have read the introduction to the article. The opening sentence is "The following is a list of human diseases of currently unknown etiology that have been associated with infectious pathogens." On what basis have the editors of this article decided that a disease is "of unknown etiology"? Does "not well understood" count? How about "probably due to"? "Possibly due to"? Some specific examples I have major concerns about: asthma, atherosclerosis, autoimmune diseases, cancers, chronic obstructive pulmonary disease, dementia, etc.. The article's scope fails at the first clause. Axl ¤ [Talk] 18:58, 23 May 2011 (UTC)[reply]

" The article is not a random list of any microbial associations of diseases. "

— Drgao
Yes, it is. As Graham Colm mentions below, each "association" is based on its own primary source. Axl ¤ [Talk] 19:00, 23 May 2011 (UTC)[reply]

" The article is not interested in diseases where immune deficiencies are the explanation for the associated infections. "

— Drgao
On what basis have you decided this? Does IgG deficiency have "known etiology"? If so, how is it any different from autoimmune diseases or cancers in this respect? If not, it is indeed "a human disease of currently unknown etiology that has been associated with infectious pathogens". Axl ¤ [Talk] 19:01, 23 May 2011 (UTC)[reply]
If a disease were of a known etiology, there would be generally no need to investigate the microbial associations of that disease with the view to determining which microbes may potentially play a causal role in the disease, as the cause is established. So this is why an unknown etiology is stipulated.
Similarly, an immune deficiency disease like AIDS, where it is known that the co-infections do not play a causal role (since HIV in both the necessary and sufficient cause of AIDS), there is also no need to investigate the microbial associations for etiological purposes, as the cause is established.
Review sources were used whenever they could be found. There are lots of primary sources employed, admittedly, but many of these sources are also used in the existing main articles for each disease. Drgao (talk) 21:20, 23 May 2011 (UTC)[reply]
You have failed to address my concern regarding the definition of "unknown etiology". Axl ¤ [Talk] 21:49, 23 May 2011 (UTC)[reply]

" If a disease were of a known etiology, there would be generally no need to investigate the microbial associations of that disease with the view to determining which microbes may potentially play a causal role in the disease. "

— Drgao
So the list is actually about diseases that might possibly have an infectious cause that hasn't been confirmed yet? That isn't what the title of the article or the article's opening sentence say. Axl ¤ [Talk] 21:50, 23 May 2011 (UTC)[reply]
Quote: So the list is actually about diseases that might possibly have an infectious cause that hasn't been confirmed yet? – Axl
Yes, that in a nutshell is exactly what the article is about. I'm not quite sure why I didn't think of putting it like that in the first place. I will definitely edit the article to place this phrasing as the first sentence in the introduction.
Regarding the various shades of unknown etiology ("not well understood", "probably due to" and "possibly due to"):
First of all, it seems that there are two classes of etiology behind a disease: what might be called a metabolic etiology, which relates to the system(s) of metabolism that are malfunctioning in a given disease; and then there is what might be called a primal etiology, which relates to what caused that malfunction in the first place. For example, in type 1 diabetes a malfunction of the beta cells results in insufficient insulin - and this aspect, the disease's metabolic etiology (and how to compensate for it), is well understood; however the primal etiology of type 1 diabetes is not known, but is possibly due to a noncytolytic enterovirus infection of the beta cells.
In asthma, as another example, the metabolic etiology involves inflammation, swelling, and excess mucus production in the airways of the lungs, again something that is reasonably well understood, I believe; however the primal etiology (or etiologies) of asthma are not known, but various risk factors and have been identified, so we might describe this primal etiology as "not well understood". By contrast, adult-onset asthma has primal etiology that we might stretch to describing as "probably due to" Chlamydia pneumoniae.
In the case of myalgic encephalomyelitis (ME), "almost clueless" may be an appropriate way to describe the current understanding of the metabolic etiology of this disease; but the primal etiology of ME perhaps warrants a "possibly due to" chronic infection with Coxsackie B viruses, and/or echoviruses, and/or herpes family viruses, as well as various toxic contributory causes.
In general, a specific disease will presumably generally have only one metabolic etiology (the areas of metabolism that are malfunctioning), but potentially many primal etiologies that may precipitate the metabolic etiology.
Some primal etiologies may be able to singularly precipitate a disease (for example, HIV singularly causes AIDS); other primal etiologies might only precipitate a disease when there is a concurrence of two or more necessary causal factors (herpes simplex 1, plus a specific allele of the gene APOE, in combination lead to a higher risk of contracting Alzheimer's)
Anyway, this article is generally concerned with primal etiologies that comprise microbial infections, or microbial infections in conjunction with one or more other necessary causal factors (like additional microbes, genes or toxins).
Most primal etiologies presently listed in this article are "possibly due to" cases. I am still classing this as an "unknown etiology", since "possible" (or even "probable") is still not a fully proven cause.
However, sometimes a disease of fully known primal etiology is included in the article, but is listed because the disease also appears to have other separate possible primal etiologies that are still unknown (for example myalgic encephalomyelitis has a proven primal etiology of Chlamydia pneumoniae, but may also have additional distinct primal etiologies that are possibly due to Coxsackie B viruses and so forth). Drgao (talk) 04:41, 24 May 2011 (UTC)[reply]
Thank you for your detailed reply, clarifying some important points. I remain concerned by the subjective nature of "unknown etiology", the speculative implication of the associations, and "sometimes a disease of fully known primal etiology is included in the article", which is contrary to the declared aim of the article. Axl ¤ [Talk] 08:53, 25 May 2011 (UTC)[reply]
Well, if as you suggest, the article is renamed as:
List of diseases that may possibly have an infectious cause that has not been confirmed yet
which is an excellent suggestion, then the "unknown etiology" clause can be dropped entirely, because this new title succinctly and completely prescribes the intended scope of the article. My use of the clause "unknown etiology" was just an effort to try to capture and pin down the scope, as the present title of this article does not fully capture the aim of the article. Hence I made an awkward effort in the article's introduction to try to describe the article's scope - but that effort is now redundant, as the scope perfectly encapsulated in your suggested title.
Other variations of your new article title suggestion include:
List of diseases in which infectious microbes might play a casual role
List of diseases that possibly have an infectious cause not yet confirmed
List of diseases with possible (but unconfirmed) infectious etiologies
List of diseases with possible (but unproven) infectious etiologies
Of course, this article remains one of speculative implications, not proven ones, and I do appreciate SDY's comment (copied from the discussion page of the article) that, quote: "Wikipedia really hasn't made a habit of publishing speculative material, especially on medical topics. "It could be true" is not the level of verification we're looking for". I would not like this article to be a blot on the landscape of Wikipedia's high quality of medical coverage, if it was generally felt that the type of medical research in progress covered by this list ought not to be included in Wikipedia.
The case I would put forward to argue for inclusion of this article in Wikipedia is that: in recent decades, an increasing number of possible (but unproven) infectious etiologies have been discovered in connection with common chronic illnesses; and this has surprised many researchers. There appears to be a new school of thought in medical research that is beginning to accept the idea that infectious etiologies are likely behind many diseases of currently poorly understood etiology. So as well as providing some definite references, this article also reflects this new school of thought to a degree.
It must be pointed out, though, that some of the inclusions in this article's list of microbe-disease associations go back a long way: breast cancer's association with mouse mammary tumor virus (MMTV) goes back to the 1930's, and yet amazingly, after all this time, MMTV remains a possible but still unproven cause of human breast cancer (even though MMTV is a proven cause of murine breast cancer). So this article covers an old area of medical research, but one that has recently come much more to the fore. The main problem with obtaining proof in the case of humans always comes back to the fact that, for obvious ethical reasons, you cannot inoculate infectious pathogens into humans to see if these pathogens do cause the disease or not. So these possible (but unproven) infectious etiologies may retain their state of limbo for many years to come.
Another argument for inclusion of this article is that many of these listed possible but unproven microbial causes of disease are already included in the main Wikipedia article for each particular disease. So there is very little new information in this article; just a juxtaposition of information already existing in Wikipedia - arranged in a way that allows readers to better examine and compare various possible but unproven microbial causes of disease. Drgao (talk) 16:32, 25 May 2011 (UTC)[reply]
The article does not presume that infectious pathogens are the only potential cause of disease; it's just that the article's focus is diseases with microbial associations.
I am not entirely sure this article does contravene WP:Weight, as WP:Weight says "In articles specifically about a minority viewpoint, such views may receive more attention and space. However, these pages should still make appropriate reference to the majority viewpoint wherever relevant and must not represent content strictly from the perspective of the minority view". The next edit of the article will include appropriate references to the majority viewpoint, ie, that there are several other potential causes of disease, including: toxins, radiation, dietary and lifestyle factors, stress, genetics, epigenetics. The article tries hard to make it clear that "association" is not the same as "cause", and I hope to make this distinction even clearer in the next article edit. Drgao (talk) 21:20, 23 May 2011 (UTC)[reply]
This isn't clearly about a minority viewpoint, though. Association of any disease with infectious pathogens is extremely, extremely common, and this is a tiny subset. If the list covered the whole concept instead of just the wild mass guessing that happens to have some evidence of correlation, it'd be fine, but carefully defining the limits of an article to limit it to a single point of view is... well, let's just say that it's not what we do here. The WP:WEIGHT exclusion there is so that we can have articles on conspiracy theories and such, which are always very explicit, usually from the title of the article, that they are not mainstream thought, and treat the subject matter with suspicion and doubt. This article appears to endorse the subject matter, and that's essentially a WP:NPOV problem because reliable sources don't make these links. There's an article here, but it's not the article (not a list) that's being written. SDY (talk) 14:18, 24 May 2011 (UTC)[reply]
Of course it should be kept. I do agree with Axl and some others that "the list is never-ending" and some of the specific associations have been challenged in scientific literature. So, what? The subject is widely discussed in literature (more than a hundred of valid references already). Let's expand and improve. Hodja Nasreddin (talk) 17:45, 24 May 2011 (UTC)[reply]
(1) The article is now much more clearly described as: a list of diseases with possible (but unconfirmed) infectious etiologies - as per Axl's suggestion.
(2) Removed the unnecessary stipulation of the diseases being of "unknown etiology" - as per Axl's concern.
(3) Included the statement that there are other potential causes of disease (toxin exposure, radiation exposure, dietary and lifestyle factors, stress, genetics, and epigenetics) - as per Doc James's suggestion.
(4) Added text to make it very clear that the terms linked and associated are used in a strict technical sense (meaning a frequent co-occurence of certain pathogens in certain diseases, and not be read that linked and associated imply that there is a causal relationship between pathogen and disease), as per SDY's concern.
(5) Removed some of the "hype" that potentially unbalances the article's neutrality, as per SDY's concern. Drgao (talk) 23:49, 25 May 2011 (UTC)[reply]
The above discussion is preserved as an archive of the debate. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review). No further edits should be made to this page.
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