Update: “Measures to Minimize Influenza Transmission at ...s3.amazonaws.com/onehealth-wp/content/uploads/2018/... · Influenza A Viruses •Named by surface proteins H and N •Hemagglutinin

Joni Scheftel, DVM, MPH, DACVPMState Public Health Veterinarian

6/21/2018

Update: “Measures to Minimize Influenza Transmission at Swine Exhibitions”

What is the difference between bird flu and swine flu?

With bird flu you need tweet-mentand with swine flu you need oink-ment

Influenza A, a scientific soup

Influenza A Viruses

• Named by surface proteins H and N

• Hemagglutinin (H1-H18)

• Neuraminidase (N1-N11)

• These represent only 2 of 8-10 genes

• Names can be the same, H5N1, H7N7, etc

• But can be very different viruses depending on lineage, for example human seasonal influenza H3N2 vs. swine influenza virus H3N2

Current Naming Convention

• When a person is infected with an animal-origin Influenza A virus, it is termed a variant virus infection

• Denoted with a “v” after the subtype

• H3N2v

• The exact same virus when found in a pig or other animal does not carry the “v”

This is what started it all

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2005 2006 2007 2008 2009 2010 2011 2012

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U.S. Cases of Variant Influenza A through 2012

Majority of cases were exhibitors and others with H3N2v infection, who reported contact with pigs at fairs prior to onset of illness

This is what happened after 2012

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2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

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U.S. Cases of Variant Influenza A through 2017

Confirmed Human Cases of H3N2v in the US,2012 (N = 309)

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8-Jul 15-Jul 22-Jul 29-Jul 5-Aug 12-Aug 19-Aug 26-Aug 2-Sep

WV

WI

UT

PA

OH

MN

MI

MD

IN

IL

IA

HI

Slide from Dr. Sue Trock

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107

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Date of onset

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H3N2v and H1N2v Cases in Minnesota, 2012

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human H3N2v human probable H3N2v human H1N2v pig H3N2v pig H1N2v

Minnesota State Fair 8/23-9/3Minnesota State Fair 8/23-9/3Minnesota State Fair 8/23-9/3Minnesota State Fair 8/23-9/3

H3

H3

H3 H3

H3

H3H3H1 H1

H1H1

H1H1

H1

Surprises and Things We Learned

• We were looking for H3N2v in swine exhibitors at the fairs and found it first at the Live Animal Markets

• Instead we found H1N2v in pigs and people at the fair

• These were the first human cases of H1N2v with the pandemic M gene identified in the US

Surprises and Things We Learned

• All the pigs with influenza were hold-over pigs

• Came for the 4H show and stayed for the Open Show or the FFA show

• Came for the Open Show and stayed for the FFA show

• Pigs were likely exposed to influenza at the fair and then stayed beyond the 2-4 day incubation period

Outcomes of MN 2012 Experience

• Great working relationships between BAH, MDA, MDH, State Fair, 4H, U of MN, and the communications people at all entities

• Developed a protocol for influenza surveillance in State Fair swine and 4H exhibitors that we follow today

• Hold-over pigs prohibited at the State Fair

• Agreement on consistent messaging for signage for all state fair buildings

Swine Exhibitions Group

• Regional H3N2v meeting Oct. 9, 2012

• Supported and organized by NPB

• Swine Exhibitions group met Jan. 15 and 16, 2013

• Supported and organized by CSTE/CDC

• NASAHO and NASPHV Co-leads

• AASV, CDC, IAFE, USDA, 4H, NPB, Ohio State U, U of MN, Swine Registry, NASAHO, and NASPHV

2013 “Measures” Document

• Basic structure of the document was established

• Suggested measures to minimize transmission of influenza A viruses before, during , and after swine exhibitions

• Premise: Because of the nature of influenza viruses, preventing transmission from pigs to people at exhibitions is heavily dependent upon preventing infection in pigs

• Very different from enteric pathogens with direct and indirect contact transmission

2013 “Measures” Document

• More questions than answers:

• Efficacy of screening pigs on entry?

• Scientific basis for limiting time at the exhibition to 72 hours?

• How does the virus spread pig-to-pig during shows?

• Unknown, hypothesized to be pen-to-pen

Efficacy of Screening Pigs on Entry

Andrew S. Bowman, MS, DVM, PhD, DACVPM

2014: Efficacy of Screening Pigs on Entry: Results

• 3547 snout wipes on day 1 at 9 fairs in IN and OH

• Total of 5.3% of pigs were PCR positive and 1.5% of pigs were positive via virus isolation

• 5 of 9 fairs positive. Among positive fairs: 0.2% to 34% PCR positive and 0.2% to 10.3% positive via virus isolation

Efficacy of Screening Pigs on Entry: Conclusions

• Frequency of Influenza A isolation from exhibition swine arriving at fairs in the Midwest is low, at 1.5%

• Bowman has also found that most infected pigs are not displaying clinical signs at the time of sample collection

• Taking temperatures at entry not effective

• Control efforts should focus on limiting spread during swine exhibitions rather than attempting to prevent entry of influenza-infected swine

Evidence for Limiting Time to 72 Hours


22

UNIT ID HERE IN ALL CAPS

DEPARTMENT OF VETERINARY PREVENTIVE MEDICINE

Sampling Methods

Typical timeline of fairs

Weights Shows Sale

Entry Exhibition Period Departure

4-36 hours 3-10 days 4-36 hours

23



Methods

Sample every pig, every day at 8 fairs in 2014, and

repeat in 2015.

Shorten swine exhibitions

24



Evidence for Limiting Time to 72 Hours: Results

• 6,810 pigs sampled

• 948 (13.9%) were detected as positive during the course of study.

• IAV was detected in the pigs at 7 (44%) of the 16 fairs

• Sustained IAV transmission at 5 of the 7

• Within those 5 events, the proportion of pigs testing positive for IAV at the conclusion of fairs was 49%.

• If the exhibitions had ended at 72 hours, the proportion of positive pigs would have been <18%.

Limiting Time to 72 Hours: Conclusions

• Limiting the time that swine are on the fairgrounds may be the most important factor in preventing human variant influenza infections

• Yet may be the most difficult change to effect

• Swine shows have a long, entrenched history and most county fair swine shows have always been held for 5-7 or more days

How Does Pig-to-Pig Transmission Occur?


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At the fairs with high

initial prevalence, pigs

were first sampled at

weigh-in

29



Lauterbach SE et al. Emerg Microbes Infect. 2017 Feb 22;6(2):e10.

Weigh-in from 8AM

to 1 PM

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Objective:

To document the frequency of IAV contamination of portable fomites at agricultural fairs to identify mitigation strategies for pathogen spread

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Surface Number tested

PCR

positives/No.

direct contact

surfaces

sampled

PCR positives/No.

indirect contact

surfaces

No. of IAV

isolates

(All from direct

contact surfaces)

Tack Box 80 11/55 (20.4%) 5/25 (20%) 1 (H3N2)

Sort Panel 78 10/43 (23.3%) 2/35 (5.7%) 0

Waterer 82 19/82 (23.2%) 0 3 (H3N2)

Feeder 86 20/86 (23.3%) 02 (H3N2)

1 (H1N1)

Chair 65 2/18 (11.1%) 4/47 (8.5%) 0

Feed Container 2 1/1 (100%) 0/1 (0%) 0

Broom 1 1/1 (100%) 0 0

Fan 2 0 0/2 (0%) 0

Cooler 1 0/1 (0%) 0 0

Pick 1 0 0/1 (0%) 0

Wheelbarrow 1 0/1 (0%) 0 0

Watering Can 1 0 0/1 (0%) 0

Total 400 64/288 (22.3%) 11/112 (9.8%)

Pig-to-Pig Transmission: Key Findings

• IAV was detected with PCR on 18.75% of inanimate surfaces

• ≥1 surface tested positive at 50% of the fairs (8 Indiana and 2

Ohio fairs)

• Within positive fairs, frequency of IAV detection ranged from

5% to 90%; mean = 37.5%

• Viable IAV was recovered from 7 surfaces across 4 fairs

• 85% of virus isolation positive surfaces were plastic

Pig-to-Pig Transmission: Conclusions

• Corralling pigs for weighing, tagging, and other activities, with contamination of chutes and other equipment, likely enhances spread of influenza at exhibitions

• Better explains observed pattern of infection than pen-to-pen

• Cleaning and disinfection of surfaces and equipment during an exhibition is very important

Measures to Minimize Survey



• Approximately 150 surveys were collected from jackpot swine exhibitors regarding their perceptions and behaviors related to recommendations in the “Measures to Minimize Influenza Transmission at Swine Exhibitions” document

• 18 states represented

• Average number of shows respondents plans to attend in 2017 = 11

36



Good

Recommendation

Could

Implement

Already Has

Implemented

Clean and disinfect all tack, feeders, waterers, and show supplies between

shows98% 93% 51%

Wash your hands with soap and water when you leave the barn. 96% 92% 75%

No food or drink in animal areas. 67% 66% 21%

Allow at least 7 days of “down time” (i.e. on-farm quarantine) after

returning from a previous show before showing a pig or pen-mates, to

reduce the risk of spreading influenza. - DOWNTIME80% 65% 58%

Allow at least 7 days of “down time” (i.e. on-farm quarantine) after

returning from a previous show before showing a pig or pen-mates, to

reduce the risk of spreading influenza. - ISOLATION

85% 69% 50%

Discuss the use of swine influenza vaccines with a veterinarian and check

the show rules for any requirements. 95% 92% 83%


37



Good

Reccomendation

Could

Implement

Already Has

Implemented

Consult a veterinarian to help outline and implement applicable biosecurity

and swine health practices at home.96% 92% 89%

Sick pigs and sick people need to stay home so they do not risk infecting

other pigs or people.98% 92%

77% -Pigs

60% - People

Avoid sharing tack with other exhibitors, but if you must, clean and disinfect

in-between uses.87% 83% 53%

No sleeping in animal areas. 75% 66% 53%

Report sick pigs to exhibition organizers. 89% 84% 43%

Become familiar with the clinical signs of influenza and other illnesses in

pigs.

99% 94% 71%


Measures to Minimize Survey: Results

• No-one had heard of the document

• Not surprising!

• Most of the recommendations were considered “Good” and could be implemented, but hadn’t yet been implemented

• Public health recommendations had the least uptake

Measures to Minimize Checklist New in 2018

• Developed to increase accessibility

• Maintains the before/during/after the exhibition format

• Includes checklist of actions to take in case of an outbreak

Measures to Minimize: New in 2018

• Reorganized and shortened

• Stronger language around measures for which there is supporting evidence

• 72 hours

• Efforts to limit spread of influenza during the fair

• Cleaning and disinfection guidance

• Biosecurity measures

• More emphasis on exhibitor meetings and dissemination of information

Measures to Minimize: New in 2018

• Enhanced “Measures to Consider if there is an Outbreak in Pigs or People”

• Limit access to pigs and the barn area to people at high risk

• Additional signage should warn people about the occurrence of influenza and the increased risk of serious illness for persons in high risk groups

• Personal protective equipment guidance

• Section for state animal and public health officials

• Human and pig testing guidance

Questions?

Documents

Update: “Measures to Minimize Influenza Transmission at ...s3.amazonaws.com/onehealth-wp/content/uploads/2018/... · Influenza A Viruses •Named by surface proteins H and N •Hemagglutinin