Brian J McCluskey DVM MS PhD Dip ACVPM Chief Epidemiologist USDA Animal and Plant Health Inspection Service Veterinary Services Secreatarys Advisory Committee on Animal Health ID: 678223
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Swine Enteric Coronavirus Diseases
Brian J. McCluskey, DVM, MS, PhD, Dip. ACVPMChief EpidemiologistUSDA, Animal and Plant Health Inspection Service, Veterinary Services
Secreatary’s
Advisory Committee on Animal Health
April 2015Slide2
Novel Swine Enteric CoronavirusesPorcine Epidemic Diarrhea virus (PEDv)
Porcine deltacoronavirus (PDCoV)
Picture from Wikipedia of Corona Virus Slide3
PEDv History
1969 - Large outbreaks in European swine herdsDiarrhea associated with weaning or feeder pigsSuckling pigs not always affected1976 - Affecting swine of all ages1978 - Coronavirus-like agent was identified as cause - Porcine Epidemic Diarrhea Virus2010-2012 – Outbreaks of high morbidity and mortality in China
Distribution:Asia, Canada, Columbia, Dominican Republic, Europe, United StatesSlide4
From: Huang et al.,
mBio 2013Slide5
SECD Clinical Signs
Clinical signs:Primary signs are acute watery diarrhea and vomitingAcute, naïve herd: vomiting, diarrhea, loss of appetite in all pigs. Morbidity approaches 100%Suckling pigs: diarrhea, dehydration, acidosis. Mortality between 50-80+%.Feeder/Grower pigs: diarrhea, anorexia depression.
Low mortality (1-3%).Endemic herd: persistent diarrhea in recently weaned pigs.Severity depends on epidemiological status of the herdClinical picture almost indistinguishable from TGESlide6
SECD Differential Diagnosis
DifferentialsTGE (coronavirus)RotavirusOther bacterial diarrheal diseaseParasitismSlide7
SECD Transmission Transmission – fecal/oral route
Pig to pigFomitesVehiclesFeedPeopleSlide8
Epidemiology – Observational Study
Question topic
Type of Variable
Odds Ratio
p value
Interpretation
How many pelleted rations were fed to sows during the last 90 days
Continuous
0.45
0.001
When the number of pelleted rations fed to sows goes up by 1, the odds of being a case goes down 55%.
Origin of sow feed used in the last 90 days
Categorical
2.33
0.002
When sow feed was custom mixed off farm compared to being purchased complete, the odds of being a case goes up 2.3X.
What grain was mixed with in sow feed in the past 90 days.
Categorical
0.44
0.002
When grain was mixed with an amino acid source, salt, calcium, phosphorus and a premix in sow feed compared to only an amino acid source and a base mix, the odds of being a case goes down 56%
How many meal/mash rations were fed to nursery pigs during the last 90 days
Continuous
1.65
0.05
When the number of meal/ mash rations fed to nursery pigs goes up by 1, the odds of being a case goes up 65%.
How many meal/mash rations were fed to finishers during the last 90 days
Continuous
1.51
0.004
When the number of meal/ mash rations fed to finishing pigs goes up by 1, the odds of being a case goes up 51%.
Total number of rations fed to finishers during the last 90 days
Continuous
1.36
0.04
When the total number of rations fed to finishing pigs goes up by 1, the odds of being a case goes up 36%.
What grain was mixed with in finisher feed in the past 90 days.
Categorical
0.50
<0.001
When grain was mixed with a supplement in finisher feed compared to with an amino acid source and a base mix, the odds of being a case goes down 50%
Contents of premix in the most recent finisher diet
Categorical
3.50
0.02
When vitamin and trace mineral premix was in the same premix in the most recent finisher diet the odds of being a case goes up 3.5X.Slide9
Epidemiology – Experimental Study
Cluster, in space and time, of PEDv positive production sitesThree different companies owned the sitesHypothesis of airborne spread was tested by air sampling
Distance from known
PEDv
positive site
Number of PCR
positive samples/Number of samples collected
30
ft
0/1
60
ft
3/6
300
ft
0/6
¼ mile
0/5
½ mile
1/5
1 mile
3/13
2 miles
0/4
3 miles
3/7
5 miles
0/8
10 miles
1/3
15 miles
0/4Slide10
Epidemiology – Experimental Study
A hotspot analysis (
Getis-Ord Gi*) wasperformed to identify statistically significant
geographic clusters of positive PEDv cases.
A neighborhood search radius of 11.5
miles
was selected for this cluster
analysis
based on the results of the
Global
Moran’s I statistic
.
The resulting surface shows geographic
areas
with significant clusters of
positive
sites in red and areas without
significant
clustering of positive sites
in
blue.
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Epidemiology – Experimental StudySlide12
Epidemiology – System/herd investigations
Investigations are being conducted on operations that are isolated geographically, have no known link to other
PEDv
positive operations, experienced simultaneous clinical signs in multiple sites within a distinct system or for other epidemiologically significant reasons.
The objectives of these investigation are:
To investigate the potential pathways of introduction of the virus into the system. This objective requires completion of a standardized investigation form and in most cases a personal interview with the person most knowledgeable about the practices and procedures of the operation and a site visit.
To assess the current biosecurity practices on the operation and to determine their role in the initial introduction of virus or in the spread of virus.Slide13
Investigation Results
Two investigations with feed the most likely introductory pathway (spray dried plasma implicated and feed pellets implicated)One investigation with pig additions most likely (very small scale producer)Three investigations with biosecurity breaches most likely (large, highly integrated systemsSlide14
Initial Response
NonregulatoryNo mandatory reportingNo movement controlsEpidemiological studies to investigate inter-herd transmission
Epidemiological investigations and assessments to discover introductory pathwaysIndustry and Academia led research efforts to understand viral ecology and disease dynamics
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15National Animal Health Laboratory Network Accession ReportingSlide16
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Federal Order
Impact of disease called for greater Federal and State roleRequired reporting allows:Determination of disease incidenceImproved tracking of disease spreadRapid detection of new viruses
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From: National Hog Farmer, August 2013Slide18
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Users: VS area offices
Owner: APHIS IT
Ag Connect®
ERSS, BFES, LCEM, BCOP
COGNOS
®
IBM Cognos
®
Business Intelligence
USDA FIREWALL
Purpose:
Response system to collect and manage resources, disease mitigation data
and operations activities
Users:
IMTs, AVIC and state animal health officials.
Customer:
NCAHEM
Purpose:
Visualizing data and providing a common operating picture
User:
APHIS National Incident Coordinator, NAHLN
Viewers
:
IMTs;
AVICs, SAHO, I
ndustry
Owner:
IIAD
Purpose:
Collecting surveillance
d
ata on a PDA
Users:
Field disease diagnosticians
Owner:
APHIS VS IT
Purpose:
Messaging
lab results
Users:
Field disease diagnosticians
Owner:
NVSL / NAHLN
Purpose:
Query/Report Results
User:
VS area offices
Purpose:
System for sharing surveillance data
Users:
State and Fed animal health officials
Owner:
APHIS VS IT
LMS
Laboratory Messaging System
EMRS
Emergency Management Response System
SCS
Surveillance Collaboration Services
MIM
Mobile Information Management
Purpose:
Collecting surveillance data from 3
rd
party providers
Users:
State and VS animal health officials
3
rdSlide22
Herd Management PlansRequired for herds meeting the definition of a confirmed positive
Developed with a veterinarianInclude biosecurity measures
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Funding
$26.1 million including:$3.9 million for vaccine development$2.4 million for laboratory testing$1.4 million for sequencing
$11 million for biosecurity support
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Epidemiology
Pathways of introduction being examined:
Intentional introduction
Circulating in Feral swine
Clothing/shoes contaminated
on
trip to China
Human nasal passages
Escape from laboratory or diagnostic sample
Contaminated biological
Antibiotic filler; e.g., rice hulls
Pet food/treats used in swine
rations
Vitamin/mineral
premixes
Amino acid supplements
Complete feed swine base mixes/premixesSlide26
Information and Resources
National Pork Board
Website: www.pork.org
American Association of Swine VeterinariansWebsite: aasv.orgUSDA, APHIS, Veterinary ServicesWebsite: aphis.usda.gov
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