County and State Fair season is underway in the northern states and will continue across the nation well into fall. One of the highlights for many visitors are the agricultural exhibits, including livestock exhibitions. While educational, entertaining, and financially lucrative, there are admittedly some downsides.
Bringing together animals from farms all over the region provides unique opportunities to swap pathogens amongst themselves, and potentially spread them to handlers and the public.
In years past, the concern has centered primarily on swine flu, but the recent emergence of two new swine coronaviruses – PEDV & PDCoV (see SECD: Another Emerging Coronavirus Threat) have complicated matters as well. Unlike the swine influenzas, however, SECDs - or Swine Enteric Coronavirus Diseases – are not known to transmit to humans.
While they generally cause mild symptoms in adult pigs, among piglets, the mortality rate can run close to 100%.
In some regions, fair administrators have implemented a terminal show policy – where pigs exhibited at the fair must be sent to market at the show’s end, rather than back home (or worse, to another fair) to prevent the potential spread of porcine diseases.
This report (and video) from a local Wisconsin TV station.
Terminal show policy in place to control swine virus
Published On: Jul 25 2014 05:44:58 PM CDT
PORTAGE, Wis. -
While most pig exhibitors attend county fairs with the expectation their animal will be sold to market, it is now becoming a certainty. Because of concerns about the spread of a deadly virus, Porcine Epidemic Diarrhea or PED, county fairs have adopted a terminal show policy. That means a pig shown at a county fair must be sold to market at the shows end and cannot be taken back to a farm.
Beyond the opportunities for porcine diseases to spread between pigs, fairs also provide lots of human-animal contact, which can lead to the spread of infections from humans-to-pigs, and from pigs-to-humans.
Illustrating the two-way nature of disease sharing - shortly after the 2009 H1N1 virus emerged in the human population - it began showing up in pig herds around the world (see Study: Reassortants of H1N1pdm & Swine H1 & H3 Viruses in Japan)
With the emergence of several swine variant influenza viruses in the past few years (H1N1v, H1N2v, H3N2v) – all able to jump to humans (albeit, not able to transmit efficiently) - we are seeing a greater emphasis on fair biosecurity than ever before (see CDC: Measures to Minimize Influenza Transmission at Swine Exhibitions, 2014).
Last week, in EID Journal: H3N2v Swine To Human Transmission At Agricultural Fairs – 2012, we looked at what was the most active year for swine variant transmission to humans, where the authors cautioned:
Swine-to-human transmission and human-to-swine transmission of influenza A virus are known to occur at fairs (28), highlighting the fact that swine in this setting are potentially exposed to multiple lineages of influenza A viruses simultaneously, making fairs ideal locations for genomic reassortment and novel virus formation.
Swine are highly susceptible to a variety of flu viruses (human, swine, avian) - and are viewed as excellent `mixing vessels’, allowing viruses to reassort into new hybrid strains. This is how the 2009 H1N1 pandemic virus was created, after bouncing around swine herds for a decade or more.
State & local fairs have instituted inspections for any signs of illness in livestock – but as we’ve discussed previously (see Asymptomatic Pigs: Revisited) - pigs can sometimes carry these viruses without showing any outward signs of infection.
While we’ve not seen any reports of human infection with swine variant influenza this summer, fair officials and health departments are understandably on heightened alert, and are taking steps to try to prevent that from happening. All of which serves as prelude to this announcement (yesterday) by North Dakota’s Department of Health.
Influenza A H3N2v is a non-human influenza virus that normally circulates in pigs. In 2011, a small number of humans were found to be infected with this virus. From 2011 to 2013, a total of 340 cases of H3N2v was identified in 13 states, resulting in 17 hospitalizations and one death. Most of these cases occured in the summer months, and most reported contact with pigs. Symptoms and severity of H3N2v infections in humans resemble that of seasonal influenza, and include fever, cough, sore throat, body aches, and headache. No cases have been identified at this time for 2014, and no cases in North Dakota have ever been reported.
On July 31, 2014 it was reported that three pigs at the 2014 North Dakota State Fair had been removed for illness and had tested positive for an H3N2 virus. The North Dakota Department of Agriculture put out the following news release:
North Dakota Department of Agriculture
July 31, 2014
For immediate release
Precautions advised regarding influenza
BISMARCK – The North Dakota Department of Agriculture (NDDA) and North Dakota Department of Health (NDDoH) received results from the National Veterinary Services Laboratory confirming that three pigs exhibited at the state fair in Minot have tested positive for an influenza A H3N2 virus strain. Although influenza can be passed from swine to people, there is no evidence at this time that any people have become ill as a result of exposure to these pigs.
NDDA animal health division staff inspects all animals displayed at the North Dakota State Fair. The pigs appeared healthy when they arrived at the fair and became ill thereafter. After being tested, they were removed from the fairgrounds by their owners at the recommendation of veterinarians. This is the first time that an influenza virus has been confirmed in swine at a fair in North Dakota.
“Fairs and exhibits are an excellent way to showcase livestock and expose the public to animal agriculture production,” said Agriculture Commissioner Doug Goehring. “When appropriate precautions are taken, there is minimal risk of spreading disease to the public.”
However, some influenza viruses can spread from pigs to people and from people to pigs. Spread from infected pigs to humans is thought to happen in the same way that seasonal influenza viruses spread between people; mainly through infected respiratory droplets created when an infected pig coughs. Swine influenza has not been shown to be transmissible to people through eating properly handled and prepared pork or other products derived from pigs.
According to the NDDoH, appropriate precautions to prevent the spread of influenza from pigs to people include the same types of measures used to prevent the spread of influenza between people; frequent hand washing and avoiding contact with those that are ill. Other precautions include not eating or drinking around animals and avoiding contact with material, such as bedding material, which has been in contact with pigs. Any exhibitor or visitor at high risk of serious flu complications, who is planning to attend a fair where pigs will be present, should consider avoiding pigs and swine barns. The NDDoH also encourages those who work with pigs to take precautions to avoid the spread of illness. Use masks and gloves when you work with ill animals to protect yourself against transfer of the virus.
“Washing hands prior to working with or handling animals and likewise after working with animals is a good practice,” State Veterinarian, Dr. Susan Keller said. “Swine producers should contact their veterinarians if they have any questions about influenza-like illnesses in their pigs. Vaccines are available that may prevent illness.”
According to the NDDoH, if you experience symptoms of influenza (fever, cough, sore throat, body aches, headache) after contact with animals, report that contact to your primary health care provider. Conversely, if you have influenza, avoid contact with pigs during your illness and for another week after symptoms have disappeared.
For more information about influenza, including the H3N2v flu, visit the health department’s influenza website at www.ndflu.com or call the North Dakota Department of Health at 701-328-2378. For recommendations for swine producers, visit the NDDA website at www.nd.gov/ndda/disease/h3n2-influenza or call the State Veterinarian’s office at 701-328-2655.
Although only 19 swine variant flu infections were reported last year, in 2012 more that 300 cases were reported, with nearly all linked to fairgoers, mostly in Indiana & Ohio. Given the limits of surveillance, and the likelihood that some number of mild or asymptomatic cases went undetected, both numbers probably under represent the true incidence of the disease.
Nevertheless, these swine variant viruses do no yet appear ready for prime time, as they have yet to show signs of sustained and efficient transmission in the community.
They do, however, bear watching as research has shown only limited community immunity to these variant strains (see CIDRAP: Children & Middle-Aged Most Susceptible To H3N2v).