While the spread of H5N8 across Europe and into the Middle East has gotten most of the press, we continue to see signs of its intrusion into West and Central Africa as well.
Last November the virus was first detected in Nigeria (see OIE Report), and in January it caused a major die off of waterfowl on the shores of Lake Victoria in Uganda (see OIE: Ugandan HPAI H5 Outbreak Confirmed As H5N8).
Today we can add Cameroon to the list, where the virus infected peacocks, ducks, and chickens in the north of the country, according to the following OIE Notification.
Within the framework of the epidemiological surveillance of avian influenza in Cameroon, Veterinary services from the Extreme North region notified an important mortality of peacocks in an exotic poultry farm located in the Makilingaye township, Tokombéré district, Mayo-Sava department, close to the border with Nigeria. Samples were taken and analyzed by the National veterinary laboratory (LAVANET) of Garoua. H5 serotype was confirmed on January 16th, 2017 and H5N8 on January 19th, 2017.
Provisional measures were taken according to Law 006 of 16 April 2001 on animal health standards applying to livestock diseases legally considered as contagious and notifiable and according to the OIE Terrestrial Animal Health Code. Three-kilometers protection zones and ten-kilometers surveillance zones were established and the appropriate control measures were implemented accordingly. The samples were sent to an international reference laboratory. According to the Director General’s letter from December 26th, 2016, any case of highly pathogenic avian influenza in birds other than poultry, including wild birds, detected from January 1st, 2017, is notified to the OIE through WAHIS under the new disease name: Highly pathogenic influenza A viruses (infection with) (non-poultry including wild birds).
Surveillance and reporting from much of Africa is severely limited, and it seems likely - given how readily HPAI H5 has spread in Europe and the Middle East - that H5N8 is far more widespread in Sub-Saharan Africa than has been reported.
While H5N8 poses a direct threat to African poultry in its current form, clade 18.104.22.168. H5 viruses have also shown a remarkable ability to reassort with local LPAI viruses - having recently spun off HPAI H5N5 in Europe, and novel H5N2 and H5N1 subtypes in North America two years ago.
Yesterday's FLI: Updated Risk Assessment On HPAI H5 warned specifically that `Generation of reassortants always must be expected when different high and low pathogenic influenza viruses are circulating in one population.'
In the map of migratory bird flyways above, you'll see that West Africa sits at the southern intersection of no fewer than three major migratory flyways. Routes that begin each fall in the northern climes of Russia, Mongolia, and China where H5N1, H5N8, H5N6 and H7N9 are known to circulate in wild birds – and that funnel birds south into Europe, the Middle East, and points south.
As spring approaches, the millions of birds now overwintering in Africa will begin the northbound leg of their yearly migration cycle, re-crossing much of the Middle East, Europe and Asia as they head for their summer roosting ground.
How all of this will play out is anyone's guess, but the risk of seeing a spring wave of outbreaks along these migratory routes - potentially even involving new reassortments - cannot be dismissed.