Friday, July 21, 2017

Second Ohio County Fair Closes Hog Barn Over Swine Flu

Franklin County - Credit Wikipedia


Last Friday we saw Clinton Co. Ohio Fair Close Hog Barn Over Swine H3N2, sending 200 market hogs to slaughter early.  Yesterday it was announced (h/t Shiloh on FluTrackers) that two hogs at the Franklin County Fair (Columbus, Ohio) had tested positive for swine H1N1, and that their exhibit had been closed as well. 
While swine influenza can sometimes jump to humans (where it is then dubbed a `swine variant' virus), so far, we've no reports of human infections from either of these two outbreaks.  
Two reports, then I'll return with a bit more on why we monitor outbreaks like these so closely.  First, from the Columbus Dispatch:

Influenza outbreak leads to slaughter of pigs at Franklin County Fair

By Marion Renault

After at least two hogs tested positive for swine influenza, almost 50 pigs on exhibit at the Franklin County Fair were removed Wednesday evening for slaughter.

Livestock areas have been disinfected and no swine flu is present on the fairgrounds, the Franklin County Agricultural Society said in a Facebook post Thursday afternoon. The fair will continue as planned through Saturday. 

“The Ohio Department of Agriculture was contacted immediately and every protocol was followed,” the post said. “Anyone coming to the fairgrounds can feel comfortable that the grounds are safe.”

(Continue . . . )

 And this statement from the Franklin County Agricultural Society:

The Ohio Department of Agriculture has confirmed two hogs tested positive for influenza at the Franklin County Fair.

Thanks to the proactive communication from of our Fair leadership and 4H advisors, our exhibitor was able to quickly identify an issue with his hogs and report it to the attending veterinarian. The Ohio Department of Agriculture was contacted immediately and every protocol was followed.

On Wednesday evening, out of an abundance of caution, all hogs were removed from the fairgrounds for harvest. All 48 were what we call market pigs, meaning they were already slated for market – to be processed.

The livestock areas were again disinfected, and the Fair will continue through Saturday, July 22. We do not presently have swine flu on the fairgrounds. Anyone coming to the fairgrounds can feel comfortable that the grounds are safe.

The 4H exhibitors showing the hogs will still participate in the livestock auction on Saturday, July 22, rewarding months of hard work and dedication.

“We followed, and continue to follow, every protocol per the Ohio Department of Agriculture to ensure the health of our animals, and most importantly, our exhibitors and fairgoers” says David Fleshman, president, Franklin County Agriculture Society. “We are grateful to everyone for exercising caution and acting in the best interest of our Fair and our community.”

Anyone who visited the Franklin County Fair and experiences flu-like symptoms, should contact a medical professional.

As a reminder to those visiting our livestock areas for the remainder of the Fair, we ask the following:
– Wash and/or sanitize hands thoroughly and often, particularly after handling animals and always before eating meals or touching your mouth (Hand washing/sanitizing stations can be found throughout the livestock barn, for convenience)
– No food or drink is allowed in the livestock barns
– No strollers, sippy cups or pacifiers are allowed in the livestock barns

Influenza viruses (primarily swine H1N1, H3N2, and H1N2) circulate commonly in swine herds, and while there is always a concern that one of these viruses could someday evolve  into a more `humanized' strain (as happened with H1N1 in 2009) - most of the time these infections are mild, and don't pose much of a threat to the pigs or the public.

But when infected pigs are brought into agricultural exhibits at county fairs, they can share flu viruses with other pigs (with a risk of reassortment) and are placed into a public venue where hundreds, even thousands, of visitors could be potentially exposed. 
Hence the closure, out of an abundance of caution, of these two exhibits.
Most years fewer than a dozen `swine variant' infections are reported  in the United States, mostly involving farm or livestock workers. Most are mild, but many others probably go undiagnosed.

During the summer of 2012 we saw our largest outbreak to date, with 10 states reporting more than 300 confirmed cases, nearly all linked to county or state fair attendance (see H3N2v Update: CDC Reports 52 New Cases, Limited H2H Transmission).
Indiana reported the most cases (n=138), followed by Ohio (n=106).  While the H3N2v virus was the most commonly reported strain, H1N1v and H1N2v were also detected.
While most of these infections were mild, 16 people were hospitalized and 1 died (see MMWR: H3N2v Related Hospitalizations In Ohio – Summer 2012). Two years later, during a far less active swine flu year, FluView Week 17 reported A Fatal Swine Variant (H1N1v) Case In Ohio. 
And over this past winter, we looked at two severe swine variant flu infections in Europe (see here and here).  While rare, serious, even fatal infections can occur. 
Last August, over a period of several weeks, we followed reports of 18 people - all fair attendees - who were diagnosed with a swine variant (H3N2v) influenza virus in two states; Michigan and Ohio.  Among those blogs:
CDC FluView: 7 More H3N2v Cases (4 Michigan, 3 Ohio) In Week 33
Ohio: More Reports Of H3N2 In Exhibition Swine
CDC: Interim Guidance for Clinicians on Human Infections with Variant Influenza Viruses
Last October, from the MMWR: Investigation Into H3N2v Outbreak In Ohio & Michigan - Summer 2016, we learned that that 16 of the 18 cases analyzed belonged to a new genotype not previously detected in humans. From the report's summary:
What is already known about this topic?

Sporadic human infections and outbreaks with influenza viruses that normally circulate in swine have occurred in the past. The largest known outbreak of H3N2v virus infections occurred in 2012.

What is added by this report?

In August 2016, 18 laboratory-confirmed infections with H3N2v virus were reported among persons who had attended agricultural fairs in Michigan and Ohio. Sixteen of the 18 cases occurred in persons who were infected with a reassortant H3N2v virus that contained a hemagglutinin (HA) gene previously not detected in variant viruses.

The HA gene was likely introduced from humans into swine in 2010 or 2011, and viruses with this gene have circulated and evolved in swine to be genetically and antigenically different from both previous and currently circulating human seasonal influenza A(H3N2) viruses.

What are the implications for public health practice?

To minimize transmission of influenza viruses from swine to humans and from humans to swine, agricultural fair organizers should consider measures such as shortening the time swine are on the fairgrounds to ≤72 hours, immediately isolating ill swine, maintaining a veterinarian on call for the duration of the swine exhibition, providing prominent handwashing stations, and prohibiting food and beverages in animal barns. Persons at high risk for influenza-associated complications should be discouraged from entering swine barns.

The CDC maintains a comprehensive Swine/Variant Influenza page where you'll find the latest case counts, safety and prevention information, and guidance for health care providers.

Some information for exhibitors at county and state fairs include:
And for some earlier blogs on the evolution of swine viruses, you may wish to revisit:
PNAS: The Pandemic Potential Of Eurasian Avian-like H1N1 (EAH1N1) Swine Influenza
Eurosurveillance: Seroprevalence Of Cross-Reactive Antibodies To Swine H3N2v – Germany
JID: Evolutionary Dynamics Of Influenza A Viruses In US Exhibition Swine
Live Markets & Novel Flu Risks In The United States