LPAI (low path avian influenza) viruses generally pose little risk to human health (LPAI H7N9 being a notable exception), and usually cause only mild, transient symptoms in birds.
Low path viruses are commonly found in wild and migratory birds, and despite biosecurity measures, occasionally find their way into poultry operations.
The concern is that once in a commercial flock, some LPAI subtypes (H5 & H7) have been known to spontaneously mutate into HPAI (highly pathogenic) strains.
HPAI viruses have been generated in the lab by repeated passage of LPAI viruses through chickens (cite FAO) but exactly how and why this occurs naturally is poorly understood (see JVI Emergence of a Highly Pathogenic Avian Influenza Virus from a Low Pathogenic Progenitor).
While only rarely reported, last year we saw an unusual number spontaneous conversions in the UK, Germany, and France (see You Say You Want An Evolution?) and again earlier this year in Indiana with H7N8 (see APHIS: Epidemiology Report On Indiana H7N8 Outbreak).
Hence the need to act quickly to contain, and eradicate, LPAI outbreaks whenever they are detected.
Since Friday's announcement (see CFIA Statement On LPAI H5 Discovered On Ontario Farm) we've learned that the outbreak in Ontario is LPAI H5N2. Below you'll find the CFIA (Canadian Food Inspection Agency) statement on quarantines imposed in and around the affected farm.
The Canadian Food Inspection Agency Establishes Avian Influenza Control Zone
July 10, 2016
The Canadian Food Inspection Agency (CFIA) has established an Avian Influenza Control Zone in Ontario to control the movement of animals, products and equipment in the area to minimize disease spread.
The boundary of the Avian Influenza Control Zone covers a 3km radius from the single premises confirmed to be infected with avian influenza, located near St. Catharines, Ontario.
All premises located within this zone will be placed under quarantine; however, only the initial infected premises has confirmed positive for avian influenza. The Agency is monitoring all premises within the zone for any signs of disease.
The Avian Influenza Control Zone is part of an internationally accepted practice to allow trade to continue from non-infected areas of a country. We continue to work very closely with industry and our international partners as this situation develops.
Avian influenza does not pose a risk to food safety when poultry and poultry products are properly handled and cooked. Avian influenza rarely affects humans that do not have consistent contact with infected birds.
Poultry farmers are reminded to practice a high level of biosecurity to reduce the risk of disease spread, and report any suspicious symptoms in their flocks to the CFIA.
For more information on avian influenza and measures poultry farmers can take to protect their flocks, please visit the Notifiable Avian Influenza page on the CFIA website.