[CDHC] Syndrome vs. disease revisited
Eric Borneman
eborneman at uh.edu
Wed Jun 9 19:05:57 EDT 2004
Esther:
Great post. Thank you so much for taking the time to write it.
In preparing my poster on "impairments" from the Flower Garden Banks
for Okinawa, I took care to try and abide by the progress made at the
recent meeting. However, I want to make sure that I am using proper
terminology. If I have found an abnormal condition with characteristic
and consistent identifiable VISUAL signs, but without a known
etiological agent, what is the proper term? It seems as though two
criteria have been met and syndrome/disease is warranted.
And yet, a "birth mark" or a "freckle" has an identifiable group of
signs and consistent anatomical alterations, yet would this be a
syndrome or a disease?
When would the terms condition, or impairment be appropriate? My
Dorland's medical dictionary does not define either term.
On another note, I have been meaning to write to the list and suggest
the following reference which also brings up another set of terms and
which I thought was quite well done, especially since it deals with
invertebrates.
Thomas, Stephen R., and Joseph S. Elkinton. 2004. Pathogenicity and
virulence. J Invert Path 85: 146-151.
This might be something to upload to the site or have available with
permission from Elsevier?
Eric Borneman
On Jun 8, 2004, at 11:48 AM, Esther Peters wrote:
> Dear CDHC List Members,
>
> The Coral Disease and Health Workshop: Developing Diagnostic Criteria
> that was held in Madison, WI, at the end of April, was an excellent
> forum in which scientists with diverse backgrounds in the study of
> corals and diseases came together for many fruitful discussions. I
> think we made a lot of progress that week, but I heard about something
> that happened during the workshop and I felt I should address this
> topic and express my concerns. I did not participate in either of the
> Tuesday afternoon discussion sessions to develop a process to name new
> coral diseases because I was preparing for the Pathologists' Colloquy.
> I understand that in both sessions, use of the terms "disease" and
> "syndrome" were discussed. Apparently in both sessions, coral
> biologists proposed using the term "syndrome" when naming health
> impairments or lesions when first noticed, i.e., no pathogen
> (microbial or otherwise) had been identified as the causal agent; then
> change the name to "disease" when pathogen(s) were identified.
> Veterinarians noted that both "disease" and "syndrome" are used
> interchangeably in the biomedical literature for other organisms; if
> the coral biologists insisted on this naming convention, they would be
> the first to do so and pathologists would not necessarily recognize
> this convention.
>
> I came into the study of diseases of corals and other organisms from
> the perspective of a biologist/marine scientist, but I have also had
> the advantage of studying under comparative histopathologists, taking
> courses in pathology taught by veterinarians (e.g., comparative
> pathology of laboratory animals at the Armed Forces Institute of
> Pathology) or human pathologists (at the Foundation for Advanced
> Education in the Sciences, NIH), I have worked with veterinarians on
> projects (Registry of Tumors in Lower Animals), and I have had the
> pleasure of having some of these pathology specialists in my disease
> courses and slide reading workshops. They have a lot to teach us and
> we need to listen.
>
> I was at a professional meeting a couple of years ago and a
> comparative pathologist came up to me and mentioned reviewing some NSF
> proposals and journal manuscripts on coral diseases. This pathologist
> was appalled at the lack of knowledge of pathology terminology,
> disease mechanisms, and misuse of terms in the description of coral
> lesions and diseases. "Why don't they get it?" I was asked. This
> pathologist noted that it was difficult for the scientific community
> to take the coral biologists seriously when they seemed to be
> incapable of applying the body of knowledge of pathology and its
> terminology to the study of another group of animals.
>
> Why not? Having become trained in field and laboratory investigative
> techniques and terminology so that we can explore coral
> biology/ecology, perhaps we are not aware that disease investigations
> require additional understanding of the field of pathology. Or
> perhaps we don't have time to pick up a pathology text or medical
> dictionary. As an educator in diseases of corals and other organisms,
> I emphasize to my students that we must learn new definitions and
> explore the non-coral pathology literature. I am guilty also: when I
> first started out, I used the term "symptoms" in a published paper
> because I did not know that only humans can report these subjective
> feelings, in animals we note signs of disease. But I was informed by
> others as to that error and joined in trying to make others aware of
> this (see "Epidemic misuse," E.H. Williams, Jr., L. Bunkley-Williams,
> J.M. Grizzle, E.C. Peters, D.V. Lightner, J. Harshbarger, A.
> Rosenfield, and R. Reimschuessel, 1993, Nature 364:664).
>
> So, I ask the coral biologists, since we have had a wonderful
> opportunity to interact with and learn from veterinary pathologists
> through this CDHC workshop, that we take the time to listen and apply
> their knowledge to our studies. This will help others accept and
> understand our work. The terms "syndrome" and "disease" are used
> interchangeably (check any medical dictionary). Criteria for disease
> include any two of the following: recognized etiologic agent(s);
> identifiable group of signs; or consistent anatomical alterations
> (gross or microscopic). Thus, we have Alzheimer's disease, when we
> have no known agent(s); Down's syndrome, caused by triplication or
> translocation of chromosome 21; or toxic-shock syndrome, caused by
> toxin-producing staphlococci. Because many of the impairments and
> lesions we are examining in the corals consist of an "aggregate of
> signs...constituting together the picture of disease" using the term
> "syndrome" is fine. But, they can also be termed "disease."
>
> In e-mail discussions with Pam Parnell and Cheryl Woodley, it was
> noted that field biologists want to be able to give a name to an
> observation made on the reef and apply a disease/syndrome diagnosis
> based only on visual signs. It is important to have identifiers of
> health impairments seen in the field, but describing a condition is
> not the same as diagnosing a condition (presumptive or definitive).
> It is rare in veterinary/human medicine that a set of signs clearly
> identifies a single disease/syndrome; these are pathognomonic signs,
> such as those for smallpox. Most signs of disease can be similar for
> two or more diseases/syndromes, which require application of
> appropriate diagnostic tests and procedures before the
> diseases/syndromes can be differentiated. Thus, the Public Health
> Service Web site on case definitions
> (http://www.cdc.gov/nchstp/od/tuskegee/case_def.htm) defines these
> categories of disease: suspected case, probable case, clinically
> compatible case, epidemiologically linked case, supportive or
> presumptive laboratory results, laboratory-confirmed case confirmed
> case. When we report diseases/syndromes based on field signs only, we
> need to be aware that we are identifying "suspected" or "probable"
> cases, not "confirmed." Only with more diagnostic work
> (histopathology, microbiology, biomarkers, etc.) will we be able to
> confirm cases as this or that. As Pam said "The dream of being able
> to discriminate/differentiate diseases based solely on visual signs in
> the field is one that has not proven to be attainable in
> human/veterinary medicine and I believe that with the exception of the
> RARE few select conditions, the same will hold true for diseases of
> corals and other invertebrates."
>
> What will be important is to develop case definitions for the signs of
> impairment we see in the field under whatever "field condition"
> disease/syndrome name is assigned, realizing these can change as more
> knowledge from definitive diagnostic tests becomes available.
> Preliminary work on the "white syndromes" suggests that these are
> going to require microbiological and histopathological examinations to
> distinguish them (white pox, white plague, white band). Let's listen
> and learn.
>
> Esther Peters
>
>
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>
Best,
Eric Borneman
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