1. Dr. Watson “This note is indeed a mystery. What do you imagine that it means?” Sherlock Holmes: “ I have no data yet. It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.” From (1887): A Scandal in Bohemia Sir Arthur Conan Doyle EVIDENCE-Based- Medicine...or Diagnosis…or “decisions” Diagnosing DISEASE in a Vaccinated Population 2010 BIVI Pre-AASV Conference KJ Schwartz

3. Disease Abnormal structure ….remember anatomy / pathology OR abnormal function …remember physiology / clinical Observable or measurable With some clinical significance

7. EXAMPLE

9. Look for what we know

11. Why are two “identical” farms not the same? Because they are not: perceptions and limits of detection We see the summation of risk factors interacting with endemic agents

12. Need an understanding of biology; it’s the basis for “thinking” Are we educated or are we trained ? Diagnostic Testing: What are you looking for? How is it detected? Analyte Type Test types Basis for Testing Visualize agent microscopy, electron microscopy you can "see it" Detect viable agent bacterial isolation, virus isolation, bioassay it grows Detect Antigen IHC, agELISA, FAT uses specific antibody Detect Nucleic acid PCR, ISH Uses very specific short chunk of nucleic acid Detect Antibody ELISA, FFN, CF, IFA, Agglutination, HI, VN uses known antigen Detect Chemical/element/toxin GC, AA, ICPMS, ELISA analytical chemistry

15. Generalities: Diagnosis in VACCINATED (Agent and vaccine dependant: assuming killed)

16. Thorough and Objective Assessment

19. Liver What effect? Kidney How do we know if lesions / staining elsewhere is important? We don’t…………but maybe the pig does. How much lesion or staining is enough? Was the pig sick?...diarrhea? / wasting? Did we do a thorough workup? Did we find other potential causes? Agents can have subtle, yet real, effects PRRSV  increase in pre-weaning diarrhea

20. How much lesion or staining is enough? -Was the pig sick?...diarrhea? / wasting? -Did we do a thorough workup? -Did we find other potential causes? Agents can have subtle, yet real, effects PRRSV  increase in pre-weaning diarrhea

23. Diagnosis of PCVAD in Vaccinated

25. M hyo Diagnosis (DX code) from ISU VDL 2003 2004 2005 2006 2007 2008 2009

26. Diagnosis by Mhyo by month

27. Sorting out agents Do you expect to find endemic agents? Lesions? Tests? Impact on individual? Herd? Most common answer in biology: “It depends”