#17,998
The USDA has added 5 more outbreaks of HPAI H5 to their list (2 in Texas, 2 in New Mexico, 1 in Michigan), although the number of states reporting outbreaks remains at 6. Since testing remains on a voluntary basis - and currently only symptomatic dairy cows are recommended for testing - we've no idea how widespread the virus really is.
Nor do we know if the HPAI H5 virus is infecting livestock in other regions of the world. Or if it is affecting other livestock beyond cattle (e.g. goats, pigs, alpacas, etc.).
While there are legitimate logistical problems inherent in widespread testing (see discussion here), this is a situation where ignorance is far from bliss. We can hope that cows are a dead-end host, and that dairy cows will clear the virus in a few weeks and return to production, but no one really knows what the long-term impact of HPAI in cattle will be.
Over the weekend, the The American Association of Bovine Practitioners (AABP) announced in an open letter that they would now refer to the disease in cattle as BIAV (Bovine Influenza A Virus), and would encourage others to do the same.
From a public relations standpoint, I understand their motivation, but simply calling is something `less scary' doesn't change the threat. Somewhat surprisingly, I'm seeing some state agriculture departments already adopting this nomenclature.
As far as I know, it is still the purview of WOAH to name animal diseases, so unless or until they change their naming conventions, I'll continue to use HPAI.
Yesterday, OFFLU - the WOAH/FAO joint network of expertise on avian influenza - published a brief update on HPAI in cattle (see below). While it doesn't add a lot we haven't already seen, it illustrates how seriously they take these developments.
OFFLU statement on high pathogenicity avian influenza in dairy cows
April 9th
Since its inception in 2005, OFFLU (WOAH-FAO network of expertise on animal influenza) has been closely monitoring the global impacts of high pathogenicity avian influenza (HPAI), including working with multiple countries affected by the current H5N1 HPAI panzootic. Field veterinarians and OFFLU scientists in influenza Reference Centres play a key role in responding to novel outbreaks and characterising avian influenza viruses, including those that spillover to livestock or new and aberrant hosts.
There has been much attention around recent reports of confirmed detection of H5N1 clade 2.3.4.4b in dairy cows in the USA (the first such spillover to bovine species). This virus is a Gs/Gd lineage, clade 2.3.4.4b, 4 gene reassortant with the PB2, PB1, NP and NS segments of North American wild bird origin. This B3.13 genotype has previously been detected initially in wild and later in domestic birds affected by HPAI but to current knowledge has not been detected outside the USA.
The situation is rapidly unfolding; genetic sequences of these viruses from dairy cattle have been shared and further information on these events is being shared and updated daily by the USDA, FDA and CDC. Answers to frequently asked questions are also available on their websites.
OFFLU, the WOAH and FAO are closely monitoring the situation as it unfolds and will share further information through the OFFLU website as it becomes available, especially risk assessments, surveillance and diagnostics advice, guidance for veterinary health professionals. Potential socioeconomic impacts and health and wellbeing of farm workers and veterinarians may be additional considerations as outbreak investigations continue.
OFFLU strives to share information with stakeholders and partners and has created a page specific for the HPAI detections in livestock, where new information will be updated regularly. OFFLU urges the scientific community to continue to:
1. Monitor HPAI events in animals and report to WOAH.
2. Timely deposit and share genetic sequence data in publicly available databases.
3. Coordinate studies to better understand pathogenesis, transmission and adaptation of virus lineages and share the results with OFFLU.
4. Provide support to national risk managers.
OFFLU (www.offlu.org) will continue to support the activities of its parent organisations (FAO and WOAH) and partners (WHO) in ensuring that scientifically sound information is available on strains of virus that are detected in poultry and in aberrant hosts.
While it isn't clear yet how big of a deal HPAI in cattle really is, we are obviously entering new territory. If cattle, and goats can be infected, then there is reason to believe other types of livestock may be at risk as well.
And the longer HPAI circulates in livestock, the better the chances that it will accrue host adaptations, which could conceivably increase its threat over time.
Which means we need to be willing to test far more aggressively, across a wider range of susceptible animals, if we hope to stay ahead of this evolving threat.
