EVP Module 1 – October 2014
Case 2:
CASE DISCLOSURE #1
You are a swine vet who works with very progressive producers. You have deep relationships
with your customers and know a great deal about their systems. One day in October you get a
panicked phone call from a production manager in one of the systems that you work with.
 He has a 5000 sow farm that has 100 sows that are 10 days from farrowing and off feed
this AM. He is worried about PRRS and wants you come out right away. You jump in
the truck and head out.
 The farm is located in an area with others farms in Central Illinois but all are in the same
system. No other pigs are in the area and all farms owned by this system are breeding
herds or gilt development units.
 The farm is well managed with current production at 28 PSY. Gilts are delivered as
weaned pigs every 4 weeks and isolated in an attached nursery that the previous group is
still in (separate rooms).
 They are tested for PRRS and PEDV prior to releasing the older group.
 The gilts grow in a continuous flow GDU prior to breeding.
 The farm is known to be Mhp positive but the source farm in negative for Mhp, PRRS and
PEDv.
The vaccine schedule is as follows:
 Gilts: Weaning - PCV/Mhp; Development- LI and Ery; Prebreeding- 2 doses PLE, kIAV
(commercial), PCV/Mhp
 Gestation: 5 weeks LE; 12 and 14 weeks Ecoli to gilts only.
You arrive to the farm and shower in. This is what you see:
 Watch video
 Sow temps range from 101-106 with higher temperatures in sows that are more
depressed.
1. Construct a problem list includes (across all animals), including an estimate of the
number of animals with each problem:
Problem
No. of animals
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EVP Module 1 – October 2014
Case 2:
2. Based on your problem list you have to identify which organ systems are involved with
each problem. Please list the organ system that is involved with each problem on your
case summary worksheet
Even at a herd level you have to apply Occum’s Razor to determine which effected organ system
is primary and which are secondary.
3. On your case summary worksheet list which organs systems are primary and which are
involved as secondary in the disease process.
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EVP Module 1 – October 2014
Case 2:
CASE DISCLOSURE #2
4. Based on what you know about the case create a series of case definitions that could
capture all of the animals that you observe. The goal is to create unique descriptions that
are general enough to allow you to categorize all of the affected animals in 2-6 groups.
Case Definition
Number of head
1
2
3
4
5
6
5. You know enough to start your quizzical quadrangle. THINKING ABOUT THE
PROBLEMS at the POPULATION/HERD level… what to do you know?
6. How do each of the following impact the next step of your data gathering inquiry?
a. Your organ system prioritorization
b. Your case definition
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EVP Module 1 – October 2014
Case 2:
CASE DISCLOSURE #3
7. The level of depression in these animals bothers you. Which is the best statement about
their depression:
a. The mentation change is due to a systemic inflammatory response arising from activation
of the adaptive immune response
b. The mentation change is likely due to hypoxemia
c. The mentation change is due to a systemic inflammatory response arising from activation
of the innate immune response
d. The mentation change is likely due to the stress of pain
8. Sketch out a timeline of the inflammatory response, placing the animals that you have
observed on the timeline
9. The following is the best statement about normal adaptive immune response:
a. Individual B cells are poly-clonal.
b. CD8+ cells up regulate CD4+ cells and B Cells
c. T-cell receptors (TCR) are polymorphic.
d. Low levels of cortico-steriods down regulate adaptive immune responses.
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EVP Module 1 – October 2014
Case 2:
CASE DISCLOSURE #4
Before you leave you decide to collect some diagnostics and give the herd some direction on a
go forward plan. You have a preliminary herd level case definition based on your observations.
10. The most logical statement about your go forward plan is:
a. The innate immune system is compromised and control of bacterial respiratory infection
is mandatory.
b. The innate immune system is fully intact and antibiotics are not needed.
c. The innate immune system is functioning but we still should treat them with antibiotics.
d. Co-morbidities in individuals and in the herd will determine my course forward.
11. The manager asks you to give a prognosis. The best description is:
a. This is the tip of the iceberg, it will get worse before it gets better. Tomorrow will be
much worse but 3 days from now it will all be behind you.
b. I expect some additional severe cases but everybody is going to cough. 3 days from now
this will all be behind you.
c. I expect some additional severe cases but everybody is going to cough. I would expect
the coughing to last for 3-4 weeks.
d. This is the tip of the iceberg, it will get worse before it gets better. Tomorrow will be
much worse. I would expect the coughing to last for 3-4 weeks.
PLEASE STOP HERE. DO NOT PROCEED UNTIL DIRECTED TO DO SO.
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EVP Module 1 – October 2014
Case 2:
CASE DISCLOSURE #5
You have decided, based on your interpretation of the information that you have assimilated so
far, that there is a potential risk to other farms. You decide that you require additional data to
inform the prophylactic quartile of your Quizzical Quadrangle.
You choose to collect swabs from the upper respiratory tract and blood from 10 affected animals.
You submit them based on your initial case definition and the manager’s concerns for IAV
(Swabs) and PRRS ORF 6-7 (Serum) PCR and IAV and PRRS Idexx ELISA antibodies (Serum).
These are the results you get: 1-5 are gilts, 6-10 are sows. All are 100 days of gestation.
Temp
PRRS PCR
PRRS ELISA
IAV PCR (Ct
from Screen)
IAV ELISA
1
105.5
Neg
Neg
H1 32
Neg
2
104.1
Neg
Neg
Neg
0.52
3
106.5
Neg
Neg
H1 35
0.55
4
107.0
Neg
Neg
H1 28
0.60
5
107.5
Neg
Neg
Neg
Neg
6
103.0
Neg
0.45
H1 25
0.65
7
107.0
Neg
Neg
H1 36
Neg
8
105.5
Neg
Neg
H1 36
Neg
9
106.2
Neg
Neg
Neg
Neg
10
101.0
Neg
Neg
Neg
Neg
Pig
12. The following in the best statement about the results:
a. PRRS not involved, H1infecton of less than 21 days, IAV vaccine failure.
b. PRRS not involved, H1infecton of less than 10 days, Variant H1 infection.
c. PRRS not involved, H1 infection of more than 5 days, IAV vaccine mismatch
d. PRRS not involved, H1 infection of more than 10 days, novel H1 infection.
13. Which is the best statement about the IAV Screening PCR:
a. The HA gene is targeted.
b. Primers are directed at the NP gene.
c. Highly conserved genes increase specificity.
d. Single primer sets are used to increase sensitivity.
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EVP Module 1 – October 2014
Case 2:
CASE DISCLOSURE #6
14. Based on these findings, how do you modify your prognosis and intervention strategy?
15. The best statement about the herd prognosis is:
a. There is little herd immunity, the IAV outbreak will get worse before it gets better.
Tomorrow will be much worse but 3 days from now it will all be behind you.
b. Herd immunity is high, I expect some additional severe cases in compromised
individuals, 3 days from now this will all be behind you.
c. There is little herd immunity to this new virus, I expect some additional severe cases but
everybody is going to cough. I would expect the coughing to last for 3-4 weeks.
d. The herd immunity is high to IAV but this new virus will wreak havoc. This is the tip of
the iceberg, it will get worse before it gets better. Tomorrow will be much worse. I
would expect the coughing to last for 3-4 weeks.
16. The data most useful data to make a more informed prognosis are:
a.
b.
c.
d.
e.
f.
g.
h.
HA gene sequences from this isolate and the vaccine isolates
HA gene sequences from this isolate and previous herd isolates
HI titers against this isolate with herd serum
HI titers against vaccine isolates with herd serum
HI titers against previous isolates with herd serum
HI titers against this isolate with vaccine serum
Off feed incidence on day 2
Response to treatment with antibiotics in effected animals
17. The most effective long term prevention strategy would be:
a.
b.
c.
d.
Close the herd to new introductions, mass vaccinate quarterly
Close the herd to new introductions, increase people downtimes
Continue to vaccinate gilts pre-breeding and vaccinate sows pre-farrowing.
Stop all vaccination in the breeding herd, increase caregiver skills.
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EVP Module 1 – October 2014
Case 2:
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