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Internet Supplements for VM 585P - Epidemiology 1998
Last Updated February 14, 2000 Began August 24, 1998
Contents:
Purpose:
The purpose of this list is to provide additional information and hot links to Internet
materials for VM 585P - Epidemiology, 1998, for third year veterinary students.
[Return to Contents List]
Course RoadMap
Introduction to Epidemiology
Definitions of epidemiology.
Why epidemiology is important to the clinician.
For further reading for this section see:
Thrusfield Veterinary Epidemiology
Torrence Understanding Epidemiology
Steiner & Norman PDQ Epidemiology
- Chapt. 1:Introduction to Epidemiology
Chapt. 2: Classical Epidemiology
Epidemiology of Disease in Animal Groups
Concepts for understanding the epidemiology of diseases in
populations.
For further reading for this section see:
Thrusfield Veterinary Epidemiology
Torrence Understanding Epidemiology
The Logic of Outbreak Investigation
For further reading for this section see:
Reingold, AL (1998). Outbreak Investigations—A Perspective. Emerging
Infectious Diseases 4(1)
(on-line paper on CDC human outbreak investigations at http://www.cdc.gov/ncidod/EID/vol4no1/reingold.htm
Lessard, PR, BD Perry (1988). Investigation of disease outbreaks and
impaired productivity. Vet Clin North Am Food Anim Pract. 1988 Mar; 4(1): 1-212.
(VMR)
- Chapt. 1: Investigation planning and data gathering, pp. 1-15.
- Chapt 2: The characterization of disease outbreaks. Pp. 17-32.
The Science of Diagnosis
For further reading for this section:
Thrusfield Veterinary Epidemiology
Steiner & Norman PDQ Epidemiology
Fletcher Clinical Epidemiology [Best concise description of
logic]
Sackett, Haynes & Tugwell Clinical Epidemiology (on
VetMed Reserve - best description and examples of the clinical diagnostic process from the
clinician's perspective)
- Chapt. 1: Clinical Diagnostic Strategies
- Chapt. 2: The Clinical Examination
- Chapt. 3: The Selection of Diagnostic Tests
- Chapt. 4: The Interpretation of Diagnostic Data
Smith, RD Veterinary Clinical Epidemiology: A Problem-oriented
Approach
- Chapt. 3: Evaluation of Diagnostic Tests
- Chapt. 4: Use of Diagnostic Tests
Papers the discuss this material from a clinician's perspective:
Tyler, JW, J Schumacher (1992). Problem-oriented diagnostics,
statistical inference, and clinical decisions. Comp Cont Edu Pract Vet
14:1009-1014.
Tyler, JW; JS Cullor (1989). Titres, tests, and truisms: Rational
interpretation of diagnostic serologic testing. JAVMA 194:1550-1558.
On-line Materials:
Glossary of Terminology Specific to Clinical Testing
http://www.vetmed.wsu.edu/courses-jmgay/GlossTesting.htm
How to read a paper: Papers that report diagnostic or screening tests
http://www.bmj.com/archive/7107/7107ed.htm
Evaluating the Veterinary Clinical Literature
The following sections have not been completely mapped (i.e., the
notes completed and assembled in sequence) yet. The content sequence will look something
like this.
Evidence-based medicine - Assessing the strength of evidence
Definition of evidence-based medicine
On-line papers for a preview:
Evidence-Based Medicine: What it is and what it isn't.
http://cebm.jr2.ox.ac.uk/ebmisisnt.html
Evidence-based Medicine: A New Approach to Teaching the Practice of Medicine
http://www.cche.net/ebm/overview.htm
Types of primary, secondary, tertiary literature
Forms of evidence
Empirical evidence vs. anecdotal vs. dogma
Scientific publishing and the refereeing process
The literature evaluation process
Problems with the veterinary literature
The Nature of Science
The Scientific Process and the Scientific Method
Scientific Laws, Theories, Hypotheses
Establishing Cause
Association vs. cause
Hills-Evans Postulates
The basic epidemiology measures
Prevalence, incidence, risk
Critical appraisal of the primary clinical literature
Components of a primary paper
Steps of assessment
External validity / internal validity / assessment of effects of chance
Bias vs. imprecision
Forms of Bias
Selection / Observation / Allocation
Interpreting statistical conclusions
Statistical significance / insignificance vs. clinical significance /
insignificance
Clinical Study Designs
Missing components and what their missing means about the study
Important components of clinical study designs
Observational vs. experimental
Randomization
Blinding
Concurrent comparison
Types of clinical study designs
Case series
Case-control studies
Cross-sectional study
Cohort studies
Randomized controlled clinical trials
Strength of evidence of study designs
Inherent strengths and weaknesses of study designs.
Problems and Pitfalls of study designs.
[Return to Contents List]
VM 585P Epidemiology
Take-Home Midterm (Due by 5 PM,
November 5)
Section for Epidemiology of Disease in Animal Groups (Dr.
Gay)
The purpose of this section is to provide you the opportunity to apply the concepts of
the epidemiology of disease in animal groups to a common disease problem. It is also
intended to provide you the opportunity to search the clinical literature databases and to
use the primary veterinary literature as your source of evidence. This is a prelude to the
next component of the course, evaluating the strength of evidence in clinical papers.
Scenario:
You are an infectious disease consultant retained by the veterinary practice serving an
animal unit with a current or potential disease problem (see below). You are contracted to
provide them with a concise summary review of the basic information on how to control and
to prevent this particular disease. Your task is to review and select the best relevant primary
veterinary literature pertaining to the epidemiology of this disease in animal groups and
to synthesize it into a paper that they can use as the basis for their recommendations for
controlling and for eliminating the disease from that group.
Procedure:
1) Assemble your group: To maximize the group learning experience and
to spread the workload, your group should have at least three members but can not have
more than seven. You do not have to use the same group as that for Dr. Hancock's
section.
- Each phase of the following tasks (searching, reading, synthesizing, drafting) should be
split up equitably among group members. Thus everyone should be involved in the search for
evidence in the primary literature, in the synthesis of this evidence and in the drafting
of the final paper.
- Once you join a group, please stay with it and turn in ONE COMPLETE PAPER for
the entire group by 5 PM, November 5, in the box labeled VM 585P
above the McCoy Hall faculty mailboxes. Keep a copy on disk for safe-keeping. All group
members will receive the identical grade (except as below).
- ALL members of a group must participate in the development of all
aspects of the response. Failure to participate, as assessed by group members, will result
in failure of this examination. The only exception will be unforeseeable serious
extenuating circumstances.
2) Select a Disease: Each of the following diseases, with the current
name of the agent in parenthesis, has a brief scenario to provide you with a context
(general husbandry and housing situation) for thinking about the disease and for deciding
which papers are relevant for your purposes and which aren't. Select one as the focus for
your paper.
Note: You cannot use one of these three diseases or their tests for Dr.
Hancock's section.
Bovine leptospirosis (L. interrogans serovar hardjo
var. bovis and serovar pomona; note that L. interrogans is now
called L. borgpetersenii in some of the recent literature.)
Scenario: The client herd is an expanding 1,500-cow dairy herd located in Washington's
central basin. The herd is housed in free-stall barms flushed daily with recycled lagoon
water. Their heifer calves are raised on a custom heifer raising operation that serves 14
other dairies and returns them after breeding. The calf raiser feeds the waste milk from
the dairy. Springing heifers are purchased from cattle dealers as needed to maintain herd
numbers.
Canine parvoviral enteritis (canine parvovirus-2)
Scenario: The client is a large shelter run by the local chapter of the Humane Society
in a large urban area of western Washington. Because the shelter serves as the official
pound for county animal control, it also houses captured strays as well as unwanted
animals given up for adoption or for euthanasia. The shelter's goal is to place as many
healthy animals as they can and they count on their reputation for providing healthy
animals to maximize this placement.
Equine strangles (Streptococcus equi subspecies equi)
Scenario: The client is a large (150-mare) broodmare farm located in western
Washington. The farm also provides stud and boarding services as well as maintaining a
large indoor arena for events. The housing is a mixture of large barns with individual
stalls and, during the summer, outside paddocks for groups. On a regular basis, off-site
horses are brought to the arena for dressage and horsemanship lessons.
3) Do Preliminary Reading: Familiarize yourself with the disease you
selected by reading the tertiary (general textbooks - Smith, Blood and Radostits,
Ettinger) or secondary (reviews) veterinary literature, such as those in Veterinary
Clinics of North America or Compendium on Continuing Education for Practicing
Veterinarians.
With the information that you find in this tertiary and secondary literature, begin
building a general model of how the disease works in groups. Then find the best pertinent
papers in the primary literature that have the empirical evidence supporting (or refuting)
important statements. One of the points of this exercise is for you to compare what stated
in the secondary and tertiary literature to the best evidence contained in the primary
literature
For further definition of tertiary, secondary and primary literature, see:
"Introduction and Background" in "Guidelines for Assessing Professional
Information" at: http://www.vetmed.wsu.edu/courses-jmgay/EvalGuide.htm
4) Search for the Supporting Evidence: Identify the best relevant
primary veterinary literature containing the evidence that you need to construct your
paper. In many cases, by reading the abstract in the database you will be able to
determine if the paper is likely useful for your purposes. In other cases, you will have
to read the original paper.
This literature can be identified at least four ways:
- The references cited by the authors of textbooks (tertiary literature) and review
articles (secondary literature).
Keep in mind that these references are usually a selected few of what is actually
published that may be useful to you. These references may be out of date, depending upon
when the author wrote or updated the section and how thoroughly they searched the
literature at that time. Because of space limitations, publishers discourage authors,
particularly of general texts, from including an extensive list of references.
This is a quick way to identify the set of the dozen or less most recent papers that
Dr. M.E. White, a Cornell clinician, has selected as being the most clinically relevant.
Keep in mind that this selection is biased toward the treatment of individual clinically
ill animals. Consultant has that advantage that it is free to anyone via the Internet.
Keep in mind that only about half of the veterinary literature, primarily the major
journals, is indexed on PubMed but it is free to anyone via the Internet. The key to doing
this efficiently with good sensitivity and specificity is using a well thought out set of
search terms. Use more terms to reduce the number of papers you need to screen and use
fewer terms to increase the number. Use the [See Related Articles] function of PubMed to
identify other articles similar to ones that you find useful.
- Search the Library's CAB VetBeast CD-ROM database through the network.
This is the most complete collection of veterinary literature citations but it is only
available for a fee to practitioners. Also, sometimes a considerable lag occurs between a
paper's publication and its appearance in the database, particularly for the minor
publications.
Suggestions:
- Note the authors of the useful papers that you find or that are listed in
bibliographies. As they may have published other papers on the topic, find these by
searching on their names in PubMed and VetBeast. For example, two names that appear
multiple times in the literature on bovine leptospirosis are SC Hathaway and CA Bolin.
- Note the keywords used to index the papers that you find useful. Using that set of
keywords to search brings up all the papers indexed with those keywords. The
"Medline" format on PubMed will show the major indexing terms used for a paper.
Help for PubMed is under "Help" on the opening screen or under the "?"
on the top bar of search results. If you wish to tackle it, Internet Grateful Med at
http://igm.nlm.nih.gov/ allows more sophisticated search specifications as does WinWillow
from the University of Washington. Handouts and reference librarians in the libraries also
provide advice on constructing search strategies.
- Be wary of evidence appearing only in proceedings of meetings, especially if the
proceedings are more than several years old. Only about half of the research reported in
proceedings abstracts ever maks it into primary papers in the scientific refereed
literature. This likely means that the preliminary findings were not supported by further
work.
5) Find the Papers: Find the papers in the library collection, copy
the best and read them.
You will find some papers more useful than the abstract indicates and others less so.
As a general principle, it is unwise to use only an abstract as the basis for an
evidence-based statement without checking the entire paper.
6) Synthesize the collected evidence:
If, after thorough searching and reading, you cannot identify solid evidence in the
primary literature to support a statement that is important to your paper, clearly
indicate to your reader that the source is a statement from secondary or tertiary
literature without supporting evidence. Do this by including a phrase such as "In a
review, Smith (1996) stated that . . . ". Such statements then remain as dogma rather
than being based on empirical evidence.
If you find good, pertinent primary papers with significantly disparate evidence and
conclusions, present all sides but indicate your resolution of the disagreement. For
example, you might conclude some of the papers present weaker evidence than others. Or if
all are excellent papers presenting strong but disparate evidence you might conclude that
the disagreement indicates that further research are needed in this area. Or you may
conclude that the papers are from significantly different settings so you indicate that
you have selected the ones that are most applicable to that of the initial disease
scenario stated above.
7) Write the Paper:
Because your clients are busy veterinarians, write concise but specific
information in paragraphs of complete sentences to provide the information required. Use
the six bold headings below to divide your paper into sections.
Cite the reference upon which the information in the sentence is based by using the
"(author last name, year)" format at the end of the sentence. Use the "all
authors names (year). Article title. Abbreviated italicized journal name volume:start page
- end page" format for the citation in the reference section at the end of your
paper. The following is an example of an in text citation and the reference in the
bibliography:
The Sentence: In an endemically infected dairy herd, salmonella may be shed in the
feces of up to twenty-five percent of clinically normal cows presented for breeding (Gay
and Hunsaker, 1993). (use (first author name "et al. (year) for more than two
authors)
The Reference: Gay, JM, ME Hunsaker (1993). Isolation of multiple Salmonella serovars
from a dairy two years after a clinical salmonellosis outbreak. JAVMA 203:1314-1320.
Type the paper with 1" margins, 11 or 12 point font, with 1.5 line spacing.
Be prepared to provide an electronic copy. I expect that a thorough coverage will require
at least 4 typed pages plus references and that at least 10 references from the primary
literature will be required to cite sufficient supporting evidence. I also expect that
more than 8 pages and 25 references is approaching excessive. Attach a coversheet with the
names of your group members listed alphabetically.
The Guiding Questions and Paper Structure:
The following questions focus on the background information that is needed to develop
strategies to prevent a group of animals from acquiring an infectious disease (primary
prevention) and to control or eliminate such an infection in a group of animals once it is
present (secondary prevention) on a specific premises.
Group Disease Manifestation:
- How does this disease typically manifested in a group of animals in an outbreak
situation? In an endemic situation? What are the typical proportions of animals that are
in the categories of the disease severity spectrum (e.g., uninfected vs. infected,
subclinical vs. clinical) in these situations?
- What are the reservoir(s) of the agent? What is the potential for susceptible animals to
be exposed to this reservoir in a closed and disease-free group (e.g., other animal
species in the farm or building ecosystem, imported feeds, flowing water)? In an open
group (one in which animals regularly are added)? In a group that already has the disease
in it?
- What is the typical incubation period? What is the range (shortest to longest) of
incubation period that should be taken into account when developing prevention and control
practices?
- What is the typical period of communicability for infected animals? For clinical cases?
What proportion of infected animals become chronic or latent carriers?
- What are the sensitivity and specificity of the available tests in this population of
animals? What is the best test to use in screening situations (testing clinically normal
animals)? In diagnostic situations (testing clinically ill animals)?
- Carriers:
How can subclinical carriers best be detected? Incubating or latent carrier carriers?
What is the diagnostic performance of each of the available tests across the spectrum of
infection and the stages in the natural history of the disease?
How can the shedding of chronic carriers be reduced or cleared? What events increase
the level of shedding? Reduce the level of shedding?
Disease Transmission:
- What is the primary mode of transmission? Secondary modes? What are the relative
importance of these? What vehicles (fomites) and vectors are important in this
transmission? What procedures can practitioners use to determine which routes are likely
involved in a given group of animals?
- If aerosol transmission is involved, what environmental factors influence this? How can
these be manipulated?
- If a mechanical or biological vector transmission is involved, what factors influence
the vector's survival and transmitting ability? How can contact between the vector and
susceptible animals be reduced or prevented?
- What is the typical level of shedding (e.g., colony forming units (CFU) per gram of
discharge) by clinical cases? By subclinical cases? Can shedders be detected by practical
means?
- What are the environmental survival characteristics of the agent?
Is it significantly affected by freezing? By desiccation? By sunlight (UV)? How long
does it typically survive in biological materials associated with infected animals (e.g.
feces, urine, saliva, nasal discharge, cadavers)? In soil? In water? On surfaces?
What specific sanitation procedures will eliminate it? If a disinfectant is involved,
what are the minimums for concentration, contact time and temperature for effective
disinfection with that particular compound?
Susceptible Hosts:
- What is the minimum dose that will typically cause infection or disease in normal
animals? How does this compare to the typical level of exposure?
- What host factors increase susceptibility? What host factors increase resistance? How
can these be manipulated practically?
- What forms of vaccine or bacterins are available? What is the relative effectiveness of
these forms of vaccination (e.g., killed vs. live)? What level of herd immunity is
required to prevent an outbreak?
- What is the typical incubation period? What is the range (shortest to longest) of
incubation period that should be taken into account when developing prevention and control
practices?
Key Recommendation Summary:
What are the crucial factors for control and prevention programs? List the ten or so
key points for controlling and preventing this disease in a group of animals.
Optional: If economic decisions are involved (they almost always are), what are
the relative costs of the infection in groups and the costs of prevention and control
measures?
Literature Identification Process and Sources:
Your clients also wish to periodically update this review on their own.
- How did you identify the papers you used? What search methods and search terms did you
use?
- What specific search strategies (e.g., sets of key words) were the most useful,
producing the most relevant papers with the least amount of chaff for the different
components of this problem?
- How do you recommend that your practitioner clients identify new findings that have a
bearing on these aspects of this disease? Provided sufficient information for them to do a
thorough search
References:
Use the "author's names (year). Article title. Abbreviated journal name
volume:start page - end page" format. Place the references in alphabetical order by
the first author's last name.
If you have any questions during this process, please do not hesitate to contact me. My
e-mail and phone are jmgay@vetmed.wsu.edu and
335-0785. I will announce any clarifications if they are needed.
[Return to Contents List]
Question Responses:
This section is for my response to selected student questions that were submitted in
class, via e-mail or wherever.
9/13/98 Question: Following your lectures on the "iceberg
phenomenon" and the erroneous decisions which are made based on the misunderstanding
of this phenomenon, I began to wonder about the designation of states as "Brucella
free". What is the likelihood that a state designated as "Brucella free" is
in actuality free of Brucella abortus?
Good question and one that drives regulatory authorities nuts. In an absolute sense, it
is logically impossible to prove that a state is "free" of Brucella abortus. One
can only establish that the level of infection in a state is likely below a certain level
and from there estimate a likelihood of freedom. With increasing international trade of
livestock and associated commodities, this is problem is being addressed more from a risk
assessment perspective than from a "black or white" present or absent
perspective.
Part of the problem is the surveillance system. Each state relies on some sort of
surveillance program, this surveillance being more intense in areas where herds having
active infection are known to exist. However, there are many weak spots in this. For
example, females meeting certain criteria are blood tested at slaughter. A state
veterinarian once told me that of the positive serums identified at this point, only about
one-half can be traced back to a herd of origin so that a determination can be made
whether or not active infection exists in that herd. A historical problem has been the
problem with vaccinal titers; which may have been solved by the development of the RB51
vaccine.
Part of the problem is cattle movement. Although movement of cattle, particularly from
positive states, is supposed to be closely monitored with varying requirements that are to
be met prior to transport, and in some cases forbidden, human nature is active in this
area. When a buck is involved, someone will figure out how to make it by bending if not
ignoring the law. For example, say Minnesota forbids the movement into the state of dairy
heifers originating in Florida. Animal dealers who want to disguise the herd of origin of
a bunch of Florida-purchased heifers that they intend to sell in Minnesota can move them
to an intermediate that allows their import, say Tennessee, hold them, and then apply to
move them from Tennessee to Minnesota since import from that state is not forbidden. That
is for legal movement. And illegal movement occurs. The smaller livestock trailers are
seldom stopped at most state boundaries. I know of people loading up dairy cattle in a
trailer pulled by a pickup and hauling them to Minnesota, no one the wiser. Monitoring for
livestock being moved illegally is a secondary responsibility of most of the people
directly involved in detecting this movement, the highway patrols and the GVW people.
Part of the problem is cultural. Compared to attitudes of livestock owners in other
countries that enable more thorough surveillance, in general livestock owners in this
country do not want the government to know how many cattle they have. Some, particularly
in the south where Brucella remains a problem in cattle, do not cooperate at all with
regulatory veterinarians trying to control the infection. Some have calculated that for
less than the annual investment in the brucellosis control program by the state and
federal governments (excluding the costs to the others involved, such as the animal
owners), the farms having known Brucella-infected herds could be purchased and plowed
under. It won't happen.
And then there is the problem of brucellosis in captive as well as free-ranging bison
and elk.
And it is a huge political issue. An organization called the United States Animal
Health Association that brings together all interested (private veterinarians, state and
federal regulatory veterinarians, commodity groups, and researchers in the area) to hammer
out the policy issues for most of the major livestock diseases. They meet annually
(jointly with the diagnostic lab vets) and publish a proceedings. The 1997 proceedings is
on the web.
The 1997 USAHA brucellosis committee report is at http://www.usaha.org/reports/bruc97.html
The USAHA website is at http://www.usaha.org/index.html
Good question.
=====================
9/3/98 Questions:
What can we do in 4 years of education to lower our diagnostic failure rate? How do
we get better so not so many misdiagnoses are made?
- First step - Recognize the problem's existence and magnitude. This is probably the
single biggest step.
- Second step - Incorporate the principles from this class into your thinking. Be
aware of what kinds of clinical procedures tend to cause problems. Be aware of what is the
root of the problems.
- Third step - Develop the habit of looking for well-validated clinical procedures in the
literature. Develop the habit of evaluating how well those diagnostic procedures are were
validated. We will take up how to do this later in the course.
- Fourth step - In your area of interest, obtain as much experience as you can where there
is feedback available. Then commit yourself to your findings before you know the results.
We often do this backwards in a teaching environment - students often know the diagnosis
before they get the clinical experience from the case. Read films before you know
the diagnosis, do clinical exams in the clinical teaching environment before you
know the diagnosis (with the clinician's permission!). Then follow cases that you have
examined to autopsy. Palpate and call ovarian and uterine findings before you know
the breeding date or previous findings.
(Surprising) that veterinary medicine has continued for so long with so many
inherent problems.
No, the easy stuff is still easy. It's the hard stuff where the problems lie. Rather
than looking at it as a glass half empty, look at it as a glass that is half full and that
is filling because more of the profession is understanding these problems and is doing
something about them. The profession will become stronger over time if we collectively
appreciate these problems and develop ways to compensate for them.
Surprising how much epidemiology is based on human medicine models.
For two reasons, I have shown you evidence from human medicine on the difficulty of the
diagnostic process. The main one is that because of resource limitations, very few if any
similar studies have been done in veterinary medicine. Most of those in veterinary
medicine that I have found I have included. If you find one I've overlooked, please let me
know. In the absence of evidence from veterinary medicine, I believe that veterinary
medicine is sufficiently similar to human medicine that it is reasonable to apply that
available from human medicine and to act accordingly. Second, since we or our loved ones
are all likely to have been or likely to be patients at one time or another, this material
then has direct relevance to us.
How should we apply the concept of N / 3? Isn't the 3/N rule still subjective as to
where you decide an acceptable success rate lies?
Yes. It depends on the relative costs and benefits involved - the cost of the disease
condition, the cost of the procedure, the cost of failure and the benefit of success.
Regarding 3/N, what is the failure rate? If I do the procedure someone who's done
it five times (discounting all other factors) will I fail in the procedure 60% of the
time? Why? If the procedure is sound, the teacher just hasn't done it a lot, it doesn't
make intuitive sense that I would fail 60% of the time. I would expect a higher
number to be required.
We have no basis to judge what percent of the time you will fail with this procedure at
this point. This rule of thumb is intended to provide a basis for estimating what the long
run failure rate may be for the person presenting the procedure when they have had nothing
but successes.. If the person has done it 5 times successfully, that person could still
have a 60% long run failure rate when they repeat it a bunch more times.
A better context in which to think how the 3/N rule works is that of the rate of side
effects for a new drug. In this case, N is the number of times that a new drug has been
administered without any side effects. Under this scenario, the rate of side effects could
be as high as 3/N. Administering this drug more times will provide a increasingly certain
estimate. This context removes the complex issue of clinical skill in performing a new
clinical procedure.
With today's methods of communication and computers, why does it still take so long
to get new procedures or knowledge to the practitioners?
Several reasons. The following are a rough estimate of the lag times inherent to the
process of scientific information generation, dissemination and verification using the
conventional paper publishing system:
- Researcher finds something and verifies their findings - 1 year
- Prepares, submits paper that is published - 1 year
- Other scientists notice these new findings - 1 year
- Other scientists submit grants for funding experiments to verify them - 1 year.
- Scientists run independent experiments to verify them - 1 year
- Those are submitted and published - 1 year
- Scientists begin developing the applied aspects of these findings - 1 year
- People preparing reviews begin noticing the new findings and submitting these - 1 year.
- Textbook authors begin noticing these reviews and incorporating them into textbooks - 3
years. Total of 11 years
Note: Acting on new information too soon (before it is independently verified) is the
problem opposite of that of not adopting new findings soon enough. For an interesting
presentation on adoption lag in human medicine, see JAMA 268:240-248 (1992). For
information on the failure of initial findings, such as those presented at conferences, to
be supported see JAMA 272:158-162 (1994).
Tell us how to objectively evaluate articles that describe techniques for use in
practice.
That is a later part of this course.
What can I do as a student to help prepare me for the change both now and in 5
years to keep me on top of the info that is ever changing?
Develop the skills and habits of scanning for and critically evaluating new information
in your area of interest. Regularly:
- Use Cornell Consultant and PubMed to identify new papers
- Regularly critically read a selected set of them.
- Annually attend at least one national veterinary conference in your area of interest.
- Subscribe to a listserve of veterinary professionals that covers your area of interest.
[Return to Contents List]
Lecture Links:
Evidence-based Medicine
Documents:
Evidence-Based Medicine: What it is and what it isn't. (BMJ (1996)
312:71-2)
http://cebm.jr2.ox.ac.uk/ebmisisnt.html
Evidence-based Medicine: A New Approach to Teaching the Practice of Medicine
http://www.cche.net/ebm/overview.htm
Levels of Evidence and Grades of Recommendations
http://cebm.jr2.ox.ac.uk/docs/levels.html
Major Evidence-based Medicine CentersWeb Sites:
McMaster University Health Information Research Unit
http://www.cche.net/
Evidence Based Medicine: Bridging Evidence to Practice
http://www.cche.net/ebm/default.htm
NHS Research and Development Centre for Evidence-Based Medicine
http://cebm.jr2.ox.ac.uk/index.extras
Extensive on-line index to EBM materials and websites:
Netting the Evidence: A ScHARR Introduction to Evidence Based Practice
on the Internet
http://www.shef.ac.uk/uni/academic/R-Z/scharr/ir/netting.html
On-line Tutorials for EBM:
The Wisdom Project
http://www.shef.ac.uk/uni/projects/wrp/seminar.html#EBP
main site http://www.shef.ac.uk/uni/projects/wrp/index.html
SUNY Health Sciences Evidence Based Medicine Course
http://courses.hscbklyn.edu/ebm/ebmtoc.htm
PubMed http://www.ncbi.nlm.nih.gov/PubMed/
Bovine Spongiform Encephalopathy
Institute of Food Science & Technology BSE Statement
http://www.easynet.co.uk/ifst/hottop5.htm
Problems of Visual Perception:
Visual Illusions due to vague subjects (source of the class overheads; Cal Tech - This
site also explains why some of these illusions occur)
http://www.illusionworks.com/html/hall_of_illusions.html
Introduction to Seeing (Richard Gregory, Professor of Neuropsychology, University of
Bristol)
http://www.grand-illusions.com/gregory1.htm
The Visual Image - (Links to more materials on this subject)
http://www.aber.ac.uk/~dgc/image05.html
A visual illusion involving colors
http://www.grand-illusions.com/square.htm
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Specific Links from Class Notes:
Introduction to Epidemiology
Main Sites Useful to Veterinarians
Main Link Sites for Epidemiology:
CDC-related sites listed:
Debate on incorporation of alternative medicine treatment modalities into the
veterinary profession
Evidence-based Medicine major websites
USDA-related sites listed:
Veterinary Listservers listed:
Note: NetVet ( http://netvet.wustl.edu/vmla.htm)
contains a much longer list of e-mail listserves of interest to veterinarians and links to
lists of others.
Evidence-based Medicine
Documents:
Evidence-Based Medicine: What it is and what it isn't. (BMJ (1996)
312:71-2)
http://cebm.jr2.ox.ac.uk/ebmisisnt.html
Evidence-based Medicine: A New Approach to Teaching the Practice of Medicine
http://www.cche.net/ebm/overview.htm
Major Evidence-based Medicine CentersWeb Sites:
McMaster University Health Information Research Unit
http://www.cche.net/
Evidence Based Medicine: Bridging Evidence to Practice
http://www.cche.net/ebm/default.htm
NHS Research and Development Centre for Evidence-Based Medicine
http://cebm.jr2.ox.ac.uk/index.extras
Extensive on-line index to EBM materials and websites:
Netting the Evidence: A ScHARR Introduction to Evidence Based Practice
on the Internet
http://www.shef.ac.uk/uni/academic/R-Z/scharr/ir/netting.html
On-line Tutorials for EBM:
The Wisdom Project
http://www.shef.ac.uk/uni/projects/wrp/seminar.html#EBP
main site http://www.shef.ac.uk/uni/projects/wrp/index.html
SUNY Health Sciences Evidence Based Medicine Course
http://courses.hscbklyn.edu/ebm/ebmtoc.htm
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General Resources:
The following are on-line materials that you may find very useful to help you
understand and apply the concepts of this class.
Veterinary Epidemiology - An Introduction (1998) (Dirk Pfeiffer,
veterinary epidemiologist, Massey University, 56 page booklet)
(Note-this Acrobat PDF file is sized for A4 paper. To print on US 8.5x11, select
"Shrink to Fit" on the "Print" menu from Adobe Reader. Otherwise,
margin printing will be obscured and printer memory overflow may occur.)
http://epicentre.massey.ac.nz/files/Pfeiffer/epinotes.pdf
To download a free copy of Adobe Acrobat to your home machine: http://www.adobe.com/prodindex/acrobat/readstep.html
Epidemiology for the Uninitiated, 4th ed. (1997) (This is a brief
introductory epidemiology text)
http://www.bmj.com/collections/epidem/epid.shtml
Supercourse: Epidemiology, the Internet and Global Health (an on-line
course in human epidemiology)
http://www.pitt.edu/~super1/
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Text Books (Updated
8/25/98 from Spring98 list)
Note: In reading through the class notecards, I noticed that a number
of you are interested in careers in some aspect of wildlife. The following book covers the
basic epidemiologic principles, investigation and management of wildlife diseases.
Wobeser, GA (1994). Investigation and Management of Disease in Wild Animals.
Plenum, New York. ISBN 0-306-44703-7. VET SF 996.4 W63 1994.
Thrushfield MV (1995). Veterinary Epidemiology, 2nd ed.
This book covers classical epidemiology very thoroughly and very well. Its disadvantage
is that it is expensive.
Torrence, ME (1997). Understanding Epidemiology. Mosby, St. Louis.
The strength of this book is its focus on concise definitions and explanations of
epidemiological concepts. It is part of Mosby's Biomedical Science series, which is
intended to be "the identification and terse statement of the first principles."
Streiner, DL, GR Norman (1996). PDQ Epidemiology. 2nd ed. Mosby Year
Book.
A concise, humorous and somewhat irreverent guide to the important concepts of clinical
epidemiology. Human oriented.
Books available from the Bookie (used in Med Sci 530, WAMI program)
Morton, RF, JR Hebel, RJ McCarter (1996). A Study Guide to Epidemiology and
Biostatistics. Aspen.
Concise coverage of 45 learning objectives over 17 chapters in a self-instructional
format with self-assessment exercises.
Hennekens, CH, JE Buring, SL Mayrent (1987). Epidemiology in Medicine.
Little, Brown and Co.
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