Monday, September 25, 2017

Maryland Dept. of Ag.: 11 Pigs At Frederick County Fair Test Positive For Influenza A

CDC Safety Poster


Yesterday, in Updating The Maryland Swine Variant H3N2v Outbreak, we looked at reports from the Maryland Health Department that the number of human H3N2v infections reported since the middle of last week had increased to 10, and a media report that a Sick Pig and Child Causes Shut Down Of Frederick Co. Fair Pig Exhibit.

While the child's illness has yet to be identified as swine variant influenza, 11 pigs have at the Frederick County Fair have tested positive for influenza A (subtype pending), and their hog barn has been put under quarantine.
Since the influenza subtypes that commonly circulate in swine (H1, H2 & H3) are also the same HA subtypes as have caused all of the human pandemics going back 130 years (see Are Influenza Pandemic Viruses Members Of An Exclusive Club?), swine influenza viruses are watched carefully for signs of jumping to humans.

Up until about six years ago the CDC only received 1 or 2 swine variant human infection reports each year. In 2010, that number jumped to 8, and in 2011 to 12. In 2012 we saw more than 300 casesmostly mild - and nearly all associated with exposure to pigs at state and local agricultural fairs.
This year - up until a week ago - 20 cases had been reported, mostly over the summer from Ohio. 
Since then Maryland has reported 10 presumptive positive cases, and the epidemiological investigation - and testing - continues. At this point we only have confirmed human infections linked to the Charles County Fair.

While more details will likely emerge over the next 24 to 48 hours, late yesterday the Maryland Department of Agriculture posted the following statement.

Influenza A Detected in Swine Exhibited at The Great Frederick Fair 

September 24, 2017

ANNAPOLIS, MD – The Maryland Department of Agriculture, Maryland Department of Health and the Frederick County Health Department are investigating 11 cases of influenza in pigs recently exhibited at The Great Frederick Fair. Preliminary tests show that the pigs are infected with influenza A, but it is not yet known if this strain is potentially transmissible to humans. Additional testing and investigation is underway by the Department of Agriculture.

All swine at the Frederick County fairgrounds are under a quarantine order from the Department of Agriculture and will not be released until seven days after the last pig shows signs of influenza illness. To report sick pigs, or if you have questions about pigs and influenza, please call the Department of Agriculture at 410-841-5810 or after hours at 410-841-5971.

It is rare for influenza viruses that normally infect pigs – often called “swine flu” – to spread to people, but it is possible. Most commonly, human infections with swine flu occur in people who have been exposed to infected pigs (e.g., children handling pigs at agricultural fairs or workers in the swine industry). Limited human-to-human spread of swine flu has been detected previously, but no sustained or community spread has been identified.

The symptoms of swine flu in humans are similar to non-swine influenza and can include fever, cough and sore throat. Prescription influenza antiviral drugs can treat swine flu infections in people, especially when started early. 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 swine flu in their patients to coordinate appropriate testing with their local health department. The Frederick County Health Department can be reached at 301-600-1733.

In accordance with the Secretary of Agriculture’s Hold Order (September 19, 2017), all swine exhibitions and any other activities involving swine will remain closed at the St. Mary’s and Calvert county fairs. All other movement or activities involving swine, including slaughter and butchering can proceed as usual.

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.

The CDC's Risk Assessment on H3N2v and other swine variant viruses reads:
CDC Assessment
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

For more information on swine variant viruses, and how to protect yourself when in contact with farm animals, the CDC provides the following guides.

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