Monday, July 31, 2017

Zimbabwe Farm Reports 2nd Outbreak of HPAI H5N8


Two months after Zimbabwe reported their first HPAI H5N8 outbreak, local and international media are reporting overnight that the same farm complex has been hit again.
The original outbreak only affected 1 of 8 separately managed units, which are kept a minimum of 1 km apart. Two weeks later it was reported the outbreak had spread to two other units.  All three were depopulated, sealed, and disinfected.
 While details are scant, Reuters this morning is reporting:
Zimbabwe poultry farm hit again by avian flu outbreak
Reuters Staff

HARARE, July 31 (Reuters) - A Zimbabwean poultry farm has reported a second outbreak of highly pathogenic H5N8 bird flu, two months after it first occurred, the state-owned Herald newspaper said on Monday
       (Continue . . . )

HPAI H5N8 is a recent arrival to Africa, showing up for the first time last fall in both Egypt and Nigeria (see OIE Report). In January it caused a major die off of waterfowl on the shores of Lake Victoria in Uganda (see Ugandan HPAI H5 Outbreak Confirmed As H5N8). It was then confirmed in Cameroon in February, and two months later in the DRC.
While reports remain sporadic and widely scattered, H5N8 has made far greater inroads into sub-Saharan Africa over the last six months than H5N1 managed to do over the last decade.
Last year's reassortment of H5N8 (see last November's EID Journal: HPAI A(H5Nx) Viruses With Altered H5 Receptor-Binding Specificity) appears to have created a more aggressive virus with a greatly increased avian host range; one that includes (at last count) 78 species of migratory and wild birds.
These genetic changes may help explain last winter's record setting epizootic in Europe, the rapid spread of H5N8 across Europe, the Middle East, and Africa, and even its persistence this summer in Europe (see here, here, and here), long after their bird migration season has ended.
Given the migratory pathways between the Northern and Southern Hemispheres - particularly those linking Africa to Europe and Asia - we'll need to keep watch to see if H5N8 becomes established in Southern Africa, and how that might affect its evolution and spread.

Meanwhile we are less than 90 days away from the start of this fall's return of migratory birds across much of the Northern Hemisphere (see Sci Rpts.: Southward Autumn Migration Of Waterfowl Facilitates Transmission  Of HPAI H5N1).

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