The outbreaks of swine H3N2 influenza in pigs at several Maryland County Fairs, and the spillover of H3N2v infections to fair goers we've been following for the past 6 days (see Monday's report Maryland Dept. of Ag.: 11 Pigs At Frederick County Fair Test Positive For Influenza A) continues to expand with the announcement tonight from the Maryland Department of Health that 20 human cases have been detected and a 3rd county fair has been involved.
Tonight's announcement effectively doubles this year's swine variant infection count to 40, cementing 2017 as the second most active year on record (albeit far below 2012's record 307 cases).While swine variant infections are generally either mild or of moderate severity, the CDC takes these outbreaks seriously. The CDC's Risk Assessment on H3N2v and other swine variant viruses reads:
Sporadic infections and even localized outbreaks among people with variant influenza viruses may occur. All influenza viruses have the capacity to change and it's possible that variant viruses may change such that they infect people easily and spread easily from person-to-person. The Centers for Disease Control and Prevention (CDC) continues to monitor closely for variant influenza virus infections and will report cases of H3N2v and other variant influenza viruses weekly in FluView and on the case count tables on this website
We may get more details on Friday when the newest CDC FluView report is released. In the meantime, we have the following press release from the Maryland Department of Health.
Flu virus detected in guests at Anne Arundel, Frederick fairs
Five individuals presumptively positive for H3N2v strain, none hospitalized
Baltimore, MD (September 27, 2017) – The Maryland Department of Health has presumptively identified the influenza virus strain H3N2v (variant flu) in five individuals who had close contact with pigs at the Anne Arundel County Fair and The Great Frederick Fair. None of the five infected people has developed serious illness or has been hospitalized. The investigation into variant flu is ongoing. Updated case count information can be found on the Department of Health’s website.
Test results from sick pigs at the Great Frederick Fair have been confirmed as the subtype H3N2, according to the Maryland Department of Agriculture. Ninety-five pigs remain in isolation at the fairgrounds. Additionally, three farms in Frederick County have been placed on a hold order in relation to this outbreak. The effected farms had pigs at the Great Frederick Fair that were discharged prior to the detection of the virus. Nasal swabs from those pigs have been sent out for further testing.
Officials have lifted the hold order at Charles County Fair. The swine barn at the fairgrounds will be completely broken down to allow thorough cleaning and disinfection. The Anne Arundel County fair ran concurrently, and there were no reports of pigs displaying illness at those fairgrounds.
The Calvert County Fair is the last of the Maryland county fairs scheduled for the season. Swine exhibits at this event were cancelled last week by order of the Secretary of Agriculture out of an abundance of caution.
Health officials recommend that people with influenza-like illness contact their healthcare provider and inform them if they have had pig contact within the past seven days. Providers are advised to contact their local health departments if they suspect variant flu in their patients to coordinate appropriate testing with their local health department.
Influenza is an infection caused by an influenza virus that can affect people and other animals, including pigs and birds. Symptoms for the H3N2v influenza strain are the same as for those of seasonal flu, and they include fever and respiratory symptoms, such as sore throat and cough. Historically, there is limited human-to-human transmission from this strain of variant flu. The treatment recommendations for this strain of influenza are the same as for seasonal flu.
Certain people are at higher risk for complications of influenza, including children under 5, the elderly, pregnant women and those with chronic heart, lung, liver, kidney and neurologic conditions or immunosuppression. The spread of influenza, including the possible spread of H3N2v, between humans can be prevented by:
The spread of influenza between pigs and humans can be prevented by:
- Avoiding close contact with sick people;
- Limiting contact with others as much as possible if you are sick to keep from infecting them and staying home from work or school if you are sick until you are fever free for 24 hours without fever reducing medicines;
- Covering your nose and mouth with a tissue when you cough or sneeze and dispose of the tissue immediately after use;
- Washing your hands often with soap and water or alcohol-based hand rub, if soap and water are not available;
- Avoiding touching your eyes, nose and mouth;
- Cleaning and disinfecting surfaces and objects that might be contaminated with such germs as the flu; and
- Getting the seasonal influenza vaccine when it becomes available. Although it is not effective against H3N2v, it is protective against other common strains of influenza.
Washing your hands frequently with soap and running water before and after exposure to pigs;
Never eating, drinking or putting things in your mouth while occupying areas where pigs are present;
Additional information from the Centers for Disease Control and Prevention regarding Swine Influenza/Variant Influenza Viruses is available here.
- Considering avoiding exposure to pigs and swine barns this year, especially if sick pigs have been identified and if you are high risk of complications from influenza;
- Watching your pig for signs of illness and calling a veterinarian if you suspect it might be sick;
- Avoiding close contact with pigs that look or act ill; and
- Avoiding contact with pigs if you are experiencing flu-like symptoms.
Influenza viruses do not affect the safety of properly cooked pork. As with any raw meat, pork should always be properly handled and cooked to eliminate a range of food safety concerns.
Last month, in EID Journal: Transmission Of Swine H3N2 To Humans At Agricultural Exhibits - Michigan & Ohio 2016, we looked at the risks of novel flu transmission in these types of venues, including from healthy-looking pigs.
In an attempt to better quantify the size of this outbreak, the Maryland Department of Health issued a letter to clinicians on Friday with guidance for testing and reporting.While not everyone who catches the flu will seek medical attention or be tested, this could result in additional cases being uncovered in the days ahead. And while Maryland's fair season is coming to an end, it would not be entirely surprising if we see reports from other states in the weeks to come.