Highly pathogenic avian influenza virus (HPAIV) H5N1 clade 2.3.4.4b (goose/Guangdong) was first detected in wild waterfowls in the United States in December 2021. It was a result of a transatlantic introduction of the virus into the Atlantic flyway. Since early 2022, there have been a large number of HPAI outbreaks reported from the United States from backyard and commercial poultry affecting more than 90.86 million birds from 484 commercial flocks and 646 backyard flocks spread across forty-eight states.

Recent reports demonstrate that HPAI is an emerging disease in some mammalian species mainly causing encephalitis and death in young animals. So far, more than two hundred mammalian HPAI cases covering more than twenty distinct species have been reported from the United States. In March 2024, HPAI was reported from goat kids showing neurological symptoms in Minnesota. These goats were associated with a poultry farm infected with HPAIV.

HPAI in dairy cattle:

The most recent development in the ongoing and devastating HPAI outbreaks is the detection of HPAI in dairy cattle. On March 25, 2024, APHIS announced the detection of HPAI in dairy cattle in Texas and since then the disease has spread to dairy cattle in other states. So far, nine states (Texas, Kansas, New Mexico, Michigan, Idaho, North Carolina, Ohio, South Dakota, and Colorado) have reported outbreaks in dairy cattle affecting more than thirty-six herds. Virus transmission to dairy cattle has been reported to be due to a single spill-over event from wild birds followed by lateral spread of disease. Cattle to cattle and cattle to poultry transmission of the virus from infected dairy herds have been indicated based on genetic and epidemiological data analysis. Cats and peridomestic animals associated with infected dairy herds were also reported to be affected by HPAI. Death of domestic cats fed on raw colostrum and milk from infected cows was reported from Texas in March 2024. Unpasteurized or spilled milk can act as a source of infection to susceptible animals. Though the risk of human infection is generally low, people exposed to infected birds or animals could be at a greater risk.

What to look for:

The infection in dairy cattle could be asymptomatic, or symptomatic with mild illness. The incubation period varies from 12 to 21 days. The main clinical signs are decreased feed intake or anorexia, reduced rumen motility, drop in milk production, changes in milk quality (thicker or colostrum-like milk or no milk), decreased rumination, and occasional fever. Other clinical signs may include respiratory signs, abnormal sticky or loose feces, dehydration, and lethargy.

Who to contact:

If you suspect HPAI in a dairy herd or in any other animals or birds, please contact the GDA Animal Health team at 404-656-3667.

For movement testing, milk samples are to be collected by a Georgia licensed, accredited veterinarian. If you need assistance with sample collection, please contact GA Milk Producers at 229-221-3906 or the GDA Animal Health team at 404-656-3667.

Where to send sample for testing: The Georgia Veterinary Diagnostic Laboratories at Athens and Tifton location are committed to assisting the dairy industry with HPAI testing for interstate movement and clinical diagnostic testing.

Samples can be submitted to the Athens Lab at:

501 D.W. Brooks Dr.

Athens, Georgia 30602

Or the Tifton Lab at:

43 Brighton Rd./P.O. Box 1389

Tifton, GA 31793

For questions related to HPAI laboratory testing including dairy cattle movement testing, please contact: Athens Lab – call 706-542-5568 or email athndlab@uga.edu or Tifton Lab – call 229-386-3340 or email dlab@uga.edu

Federal Mandate for Interstate Premovement Testing – Main Points): On April 24, 2024, USDA APHIS issued a federal order mandating premovement testing of lactating dairy cattle moving interstate for HPAI and reporting of positive test results.

• Dairy cattle are required to be tested negative for HPAI prior to interstate movement.
• Samples are to be collected by an accredited veterinarian or a state licensed veterinarian or a sample collector authorized by the state animal health official.
• Testing must be done within 7 days of movement.
• Milk samples from all functioning quarters should be combined into one tube for submission. Samples should be collected from individual animals and submitted to a National Animal Health Laboratory Network (NAHLN) laboratory (E.g.: UGA Athens and Tifton Diagnostic Labs).
• Samples from thirty animals must be tested for a group or lot with more than 30 animals. If the number of animals per lot is less than 30, all animals from the lot must be tested.

Laboratory Testing Guidelines: It is critical that samples are submitted to the labs properly packaged with thoroughly completed paperwork to mitigate any potential delays in testing.

The Georgia Veterinary Diagnostic Laboratories in Athens and Tifton recommend all dairy samples submitted for movement testing meet the following criteria to assist in timely accessioning and testing:

• Collect and combine the milk from each quarter into one sample for submission to the laboratory.
• For each animal, collect 5-10 mL of milk in a milk collection tube or a red top tube with no additives.
• Submitters must include the Submission Form with all fields completed, including all signalment and the Premises ID.
• Specify the submission is for required movement testing by writing “movement” at the top of the form or in the history section.
• For testing, request: Influenza Type A under “PCR”
• For accessions with multiple animals (maximum 30), please include all animal IDs either in the history, back of the accession sheet or on a separate sheet of paper.
• For shipping, bag labeled samples, place in a Styrofoam container with ample absorbent and cushioning material and cold packs. Place paperwork in a separate Ziploc bag. Place the Styrofoam container in a larger cardboard container.
• Discounted UPS shipping labels can be requested from both labs ahead of time.
• Samples received at the laboratories are expected to have a turnaround time of 3 days.

For more information on HPAI detections in livestock and other HPAI related news and updates, please click here.

Recent articles on HPAI in cattle

https://www.biorxiv.org/content/10.1101/2024.05.01.591751v1