Overview: The U.S. Department of Agriculture (USDA), Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC), as well as state veterinary and public health officials, are continuing to investigate an illness among dairy cows that is causing decreased lactation, low appetite, and other symptoms. To date no similar illness, nor H5N1 detections, have been reported in Canadian dairy cattle.
Over the past weeks, H5N1 has also been detected in the U.S. in one dairy worker on an affected farm, cats on affected farms, and goats in one farm in MN (without reported links to affected dairy herds). Our understanding of H5N1 in North American mammals continues to grow. LINK

26 April 2024. Most recent detection of 34th infected dairy herd, in Colorado, in addition to previously reported detections in Texas, Kansas, New Mexico, Idaho, Michigan, Ohio, North Carolina, and South Dakota. LINK

2 April, 2024 Influenza A detection in Idaho Dairy Cattle  LINK

1 April, 2024 Influenza A detection in New Mexico Dairy Cattle LINK

March 29, 2024 HPAI detection in Michigan dairy cattle LINK

                           HPAI detection in Idaho dairy cattle LINK 

March 25, 2024  HPAI detection in Texas and Kansas dairy cattle LINK

The clinical case presentation that has been reported is:

1. Sudden reduction in feed intake with decreased ruminations evident on physical exam and rumination monitors.

2. Sudden decrease in milk production on a herd level. Individual cows that are more severely affected have milk that is yellow and concentrated with the appearance of colostrum.

3. Variations in manure consistency with the most common finding being tacky to dry manure, although some cows appear to have diarrhea.

4. Secondary infections such as pneumonia and mastitis.

The affected cases appear to be in lactation 2 or greater animals that are more than 150 days in milk. Calves, heifers, and dry cows appear not to be affected. Morbidity is around 10% of the animals. Cases present over a 7-10 day time period and the first herds report a return to near normal production in 3 weeks.

These symptoms have been reported by the American Association of Bovine Practitioners and the USDA-APHIS.

1st May 2024: Update on FDA testing of U.S. retail milk: "The FDA is announcing an additional set of results from our national commercial milk sampling study underway in coordination with USDA. The study includes 297 total retail dairy samples. New preliminary results of egg inoculation tests on a second set of 201 quantitative polymerase chain reaction (qPCR)-positive retail dairy samples, including cottage cheese and sour cream, in addition to fluid milk, show that pasteurization is effective in inactivating HPAI. This additional preliminary testing did not detect any live, infectious virus." LINK

April 26 2024 Preliminary culture results from retail milk samples testing qPCR positive for Avian influenza H5N1. The FDA has received additional results from an initial limited set of geographically targeted samples as part of its national commercial milk sampling study underway in coordination with USDA. The FDA continues to analyze this information; however, preliminary results of egg inoculation tests on quantitative polymerase chain reaction (qPCR)-positive retail milk samples show that pasteurization is effective in inactivating HPAI.    LINK

April 25 2024. Initial results from FDA's nationally representative commercial milk sampling study. The agency continues to analyze this information; however, the initial results show about 1 in 5 of the retail samples tested are quantitative polymerase chain reaction (qPCR)-positive for HPAI viral fragments, with a greater proportion of positive results coming from milk in areas with infected herds. As previously noted and outlined in our summary below, qPCR-positive results do not necessarily represent actual virus that may be a risk to consumers. Additional testing is required to determine whether intact pathogen is still present and if it remains infectious, which would help inform a determination of whether there is any risk of illness associated with consuming the product. The FDA is further assessing any positive findings through egg inoculation tests, a gold-standard for determining if infectious virus is present. Early work by NIH-funded investigators indicates an absence of infectious virus in their studies of retail milk. To date, the retail milk studies have shown no results that would change our assessment that the commercial milk supply is safe. Epidemiological signals from our CDC partners continue to show no uptick of human cases of flu and no cases of H5N1, specifically, beyond the one known case related to direct contact with infected cattle. LINK

27 April 2024

Clarification Regarding Movement of Cattle Through Markets or Auctions to Slaughter, Under the April 24 Federal Order LINK

26 April 2024
APHIS Requirements and Recommendations for Highly Pathogenic Avian Influenza (HPAI) H5N1 Virus in Livestock For State Animal Health Officials, Accredited Veterinarians and Producers LINK     

Testing Guidance for Labs for Influenza A in Livestock LINK tps://www.aphis.usda.gov/sites/default/files/hpai-livestock-testing-recommendations.pdf

Federal Order on Interstate Movement FAQs  LINK 

25 April 2024. Federal Order on Interstate Movement in U.S. Dairy Cattle LINK 

Canada

Update on Guidance on biosecurity measures for farm visits (2nd note)

proAction: Canadian Dairy Quality Assurance Program Biosecurity Module LINK

Canadian Food Inspection Agency Biosecurity for Canadian Dairy Farms: National Standard LINK

U.S.

Dairy Biosecurity Recommendations – HPAI and More_AABP LINK  

USDA-APHIS Secure Milk Supply (SMS) Dairy Biosecurity Resources LINK

Canadian Food Inspection Agency: Highly pathogenic avian influenza (HPAI) in livestock LINK

USDA-APHIS: Detection of Highly Pathogenic Avian Influenza in Dairy Herds: Frequently Asked Questions LINK

USDA-APHIS: Questions and Answers Regarding Milk Safety During Highly Pathogenic Avian Influenza (HPAI) Outbreaks   LINK