With the North American county and state fair season just recently underway, on Monday I wrote A Reminder About The `Other' Novel Flu Threat, which looked at the risks posed by swine influenza viruses.
When swine flu viruses jump to humans, they are called swine variant viruses (e.g. H3N2v, H1N1v, H1N2v).Last summer we saw a significant cluster of human infections in the Midwest - all connected to attendance of county fairs - with a new genotype of the H3N2v virus (see MMWR: Investigation Into H3N2v Outbreak In Ohio & Michigan - Summer 2016).
While human infection with swine influenza generally produce mild or moderate illness, in 2015 the CDC's FluView reported a Fatal Swine Variant (H1N1v) Case In Ohio, and over the winter we looked at two swine flu infections in Europe where patients required extended ECMO support in the ICU.
Prior to that, in September of 2012, after a record outbreak of H3N2v that infected at least 305 people across 10 states, the CDC's MMWR released a report on H3N2v Related Hospitalizations In Ohio – Summer 2012, that looked at 11 patients that required hospitalization, including the nation’s only H3N2v related fatality.
Exactly how many people contract swine variant flu viruses each year is unknown, but a study published in 2013 (see CID Journal: Estimates Of Human Infection From H3N2v (Jul 2011-Apr 2012) - estimated that the number of infections could be 100 to 200 times greater than is reported.Since county fairs bring millions of people into close contact with livestock, and flu viruses can jump both from pigs-to-humans and from humans-to-pigs (reverse zoonosis), we pay particular attention to reports like the following, which comes out of Clinton, Ohio.
Swine flu found at Clinton Co. Fair
July 14, 2017
A case of H3N2 Swine Flu has been lab confirmed in one hog at the Clinton County Fair. There are no human cases at this time. The Clinton County Fair Board is working with the Ohio Department of Agriculture, the Clinton County Agricultural Society along with local and state health officials to stop further spread of this virus in the animal population. By Friday morning, July 14, 2017, all swine will have been removed from the Clinton County Fairgrounds.
“July 12, a pig at the Clinton County fair tested positive for H3N2, a zoonotic disease that can be transferred between animals and humans,” said Ohio Department of Agriculture (ODA) Spokesman Mark Bruce. “July 13th, additional animals in the barn showed clinical signs of illness and out of an abundance of caution to the general public and Ohio’s livestock population, ODA placed a quarantine on the hog barn. Only exhibitors and their parents were allowed into the building.”
The Clinton County Health Department has issued the following statement:
Clinton County Health District
For Immediate Release 13 July 2017
Clinton County Agricultural Society and Clinton County Health District
Report One Case of H3N2 Swine Flu at the Clinton County Fair
Clinton County, OHIO – A case of H3N2 Swine Flu has been lab confirmed in one hog at the Clinton County Fair. There are no human cases at this time. The Clinton County Fair Board is working with the Ohio Department of Agriculture, the Clinton County Agricultural Society along with local and state health officials to stop further spread of this virus in the animal population. By Friday morning, July 14, 2017, all swine will have been removed from the Clinton County Fairgrounds.
Swine Flu, like any flu virus can be spread, although rare, from pigs to people. Spread of swine flu viruses from pigs to people is thought to happen the same way that human flu viruses are spread; mainly through droplets when infected pigs cough or sneeze.
What to do if you get sick:
- Flu symptoms usually include fever, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, fatigue, and sometimes vomiting or diarrhea.
- If you are at high risk and you get the flu symptoms, call your health care provider. Tell them about your high risk factors and your symptoms. If you have had recent exposure to pigs, tell them that too.
- If you are not at high risk and you get flu symptoms after exposure to pigs, seek medical care as you normally would.
- A health care provider can decide whether influenza testing or treatment is needed.
- These drugs work better the sooner you start them, so seek medical treatment promptly if you get symptoms and are at high risk.
“If you have been in contact with swine and are experiencing signs and symptoms of flu-like illness, please consult your medical provider,” said Dr. Terry Holten, Clinton County Health District Medical Director. “Especially if you are high risk which includes children under 5 years, those with long term health conditions, like asthma and other lung diseases, diabetes, heart disease, weakened immune systems, as well as pregnant women and people 65 years and older.”(Continue . . . )
The Clinton County Fair remains open to the public. As with any pet or livestock contact, visitors should continue to wash their hands after petting animals and before eating. Sanitizer stations are available throughout the Clinton County Fairgrounds.
The 2009 H1N1 pandemic was caused by a swine variant H1N1 virus that had kicked around swine herds for a decade or more before it adapted well enough to humans to transmit easily in the community.
While pandemic viruses are very rare, we have ample and recent precedent to justify monitoring swine viruses closely.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.
For more on swine as potential `flu factories’, you may wish to revisit:
Live Markets & Novel Flu Risks In The United States
Keeping Our Eyes On The Prize Pig
EID Journal: Influenza A Viruses of Human Origin in Swine, Brazil