Update: H5N1 in Dairy Cattle. July 17, 2024

As we all know, the H5N1 outbreak in dairy cattle is an evolving situation.  Here is a summary of important updates from the past week:

* Interactive map showing the status of all states.

Going to fair?  See last week’s blog post which includes HPAI Fair Regulations for lactating dairy cattle.

Summary of what HPAI has looked like in dairy herds so far:

*Note, the above information was shared by Dr. Michael Capel in the webinar that can be viewed here. 

Of herds affected:

90% report abnormal milk

80% report decreased feed or milk production

70% develop fever

70% dehydrated

60% report some respiratory signs

Within affected herds:

10%  of herd gets clinical signs

2% of cattle are sold or die

100% of farms had 3^rd and greater lactation affected, 90% had 1^st and 2^nd lactation affected, 30% had disease in dry cows and 4% had disease in bred heifers.

Risk factors:

Introduction of cattle (20% of herds)

Exposure from employees is now thought to be a bigger risk in disease spread:

• 20% had employees visit other diaries within 30 days
• 20% of dairy employees own livestock and poultry
• 30% of dairies employees work at another farm with livestock- mostly dairy
• 20% of dairies employees have family members who work at another farm with livestock

Other species on farm:

• 80% of affected farms had cats and half of these had cats with clinical signs of HPAI
• 20% of affected farms had poultry on farm – ALL got disease and all were depopulated

Human Health– a world summary of HPAI in humans from USDA:

An avian origin H5N1 HPAI virus emerged in Asia during 1996 and was first reported to infect humans during 1997. The virus re-emerged during 2003, and as of May 16, 2017, a total of 859 laboratory-confirmed human cases have been reported to the World Health Organization; 453 of these cases were fatal. Most of these infections have been reported from Asia and Egypt, and a few cases have also been confirmed in other African countries, Azerbaijan, the Middle East, and Turkey. Limited person-to-person transmission has been identified, and this virus lineage is closely monitored for pandemic potential by animal and public health officials around the world.