In recent years - when we've seen large die offs of wild and migratory birds due to avian flu - it has nearly always been due to an HPAI H5 virus. Some major events include Qinghai Lake in 2005, and again in 2009, and last year at Sanmenxia reservoir in Henan Province China.
While HPAI H7 viruses can certainly cause mortality in wild and migratory birds, it is generally less virulent than its H5 cousins. Both HA subtypes can cause substantial mortality and morbidity in gallinaceous birds (poultry).
Which makes the OIE announcement overnight of a large die off of birds (n=892) at a park in Algeria due to the HPAI H7N1 virus a bit unusual. This is the first report of HPAI H7N1 in that country.
The report lists:
Source of the outbreak(s) or origin of infection
- Unknown or inconclusive
- Animals in transit
- Contact with wild species
Given we are in the midst of the yearly fall migration of birds from Eurasia to Africa, we'll need to be alert for additional outbreaks along their migratory routes.