SIV Surveillance and Recent Fair Human Infections - Dr. Dave Pyburn, USDA, APHIS, VS, from the 2012 Allen D. Leman Swine Conference, September 15-18, St. Paul, Minnesota, USA.

1. SIV Surveillance and Recent
Fair Human Infections
(“Spill Over”)
Dr. Dave Pyburn
USDA APHIS VS
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2. Swine Influenza Virus
Surveillance
• Voluntary Program / Anonymous
• Objectives
 Monitor genetic evolution and ecology
 Provide isolates for research activities
 Provide isolates for progressive development of
 Diagnostic reagents
 Diagnostic assays
 Vaccines
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3. Swine Influenza Virus
Surveillance
• Surveillance streams
 Case compatible
accessions to diagnostic
laboratories
 First point of contact or
commingling events
 Swine linked to a human
case of SIV
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4. SIV Surveillance Results
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5. SIV Surveillance Results
Number of accessions with each subtype present
Total Accessions
Accessions Accessions with H3N2 H3N2 with
with with H3N2 with North Matrix family
H3N2 Pandemic American not yet
Month reported Matrix Matrix reported H1N1 H1N2
Oct 2011 10 5 4 1 14 13
Nov 2011 15 9 3 3 21 11
Dec 2011 10 7 2 1 11 13
Jan 2012 9 9 0 0 11 11
Feb 2012 12 7 3 2 10 4
Mar 2012 3 3 1 1 13 4
Apr 2012 16 7 8 1 13 10
May 2012 11 2 8 1 14 7
Jun 2012 30 7 1 29 16 24
Jul 2012 22 1 0 21 18 25
Aug 2012 … … … … … …
Sep 2012 … … … … … …
FY 2012 YTD
Total 138 57 30 60 141 122
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6. SIV Surveillance Numbers
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7. Human Infections
• Recent H3N2v findings:
 Humans linked to exposures through exhibitions
(county and state fairs) - Multiple states involved
 >300 people (in 10 states) have documented
sickness; many were traced to exposure to swine
at exhibition events (state and county fairs)
Most cases have occurred in pig exhibitors and have
occurred after very close contact with pigs over a
relatively long period of time
16 hospitalizations and one death associated with H3N2v
• Also human infections (4) with H1N2v linked
with swine exposure in one state (+H1N1v)
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8. Human Infections
• Limited human-to-human transmission of
H3N2v virus is thought to have occurred in
the fall and winter of 2011
 2012 H3N2v very similar to the H3N2v viruses
found in 2011
 No sustained community transmission of this virus
taking place at this time but some human to
human looks likely
 CDC is monitoring for changes in the virus and
potential person-to-person transmission of H3N2v
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9. H3N2v
• Influenza A (H3N2) viruses with genes from
avian, swine, and human viruses that
normally circulate in swine
• When human infections with these viruses
occur, these viruses are called “variant”
viruses (thus the “v”)
• When these viruses are found in swine, they
are called swine influenza A (H3N2) viruses.
• M gene from 2009 pH1N1
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10. H1N2v
• Prolonged contact with pigs at a fair
 First time this virus has been found in humans
• Two of the people had underlying health
conditions that placed them at high risk of
serious flu complications
 One of the two people with high risk factors was
hospitalized
 All recovered
• Susceptible to antiviral drugs oseltamivir
(Tamiflu®) and zanamivir (Relenza®)
• M gene from 2009 pH1N1
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11. Public Guidance
• CDC recommends annual seasonal influenza
vaccination for all persons aged 6 months
and older to protect against seasonal
influenza viruses
 Unlikely to protect against variant influenza
viruses
• For high risk persons (age and medical
factors) - avoiding or minimizing exposure to
pigs or pig barns at fairs
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12. Public Guidance
Recently, CDC and 4-H issued a fact sheet titled “Influenza H3N2v: Key Facts
For People Exhibiting Pigs at Fairs .” (Available at
http://www.cdc.gov/flu/swineflu/h3n2v-key-facts-exhibiting-pigs-at-
fairs.htm.)
CDC and USDA have issued a fact sheet titled “Issues for Fair Organizers to
Consider When Planning Fairs.” (Available at
http://www.cdc.gov/flu/swineflu/h3n2v-fairs-planning.htm.)
Additionally, CDC has issued a fact sheet for fair goers entitled “Take Action
to Prevent the Spread of Flu Between People and Pigs at Fairs.” (Available at
http://www.cdc.gov/flu/swineflu/h3n2v-fairs-factsheet.htm.)
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13. Take Home Thoughts
• Influenza A viruses have been isolated from many
species including humans, pigs, horses, marine
mammals, and birds
• One notable commonality between
H1N2v, H1N1v, and H3N2v influenza viruses is that
all have the M gene from the 2009 pH1N1 virus
 Does the M gene confer easier transmissibility to humans?
 Between humans?
• Surveillance in swine can help to target surveillance
in humans – geographically and for a specific virus
 Effective surveillance not possible without industry
willingness and participation
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