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Update: HPAI/H5N1 (avian influenza)

(Updated, as of April 15, 2024/4p CT)

The virus known as H5N1 or highly pathogenic avian influenza (HPAI) was confirmed by USDA March 25th to be found in cattle in the United States. Initial positives came from samples of unpasteurized milk from sick cattle at two farms in Kansas and one in Texas and an oropharyngeal swab at another dairy in Texas. Later testing demonstrated similar findings in other states. Cornell University virologists reported that samples from cats, birds, and cattle from Texas were tested and found positive. University of Minnesota also recently reported cases in goats exposed to infected poultry. As is well known, avian flu has impacted poultry for the past several years and the virus is currently detected in mammals in 20 states


As of April 15, 2024, the following 28 herds in eight states have tested positive for H5N1/HPAI:

(BIO-ISAC is following state-level reports of herds with pending confirmations and will update this inventory with confirmation from the APHIS/USDA map tool/lists started April 4, 2024 with typically a 3+ day delay. To access our closed alerts, email

Transmission is also confirmed from the cows to at least one human in Texas. Humans have had avian flu before, with more than 900 cases reported all time.

Note! Information about case fatality rates vary for H5N1 in humans when all 20 years are observed. The individual in the April 2024 US case connected to H5N1 in dairy cows, has recovered fully.

The Centers for Disease Control and Prevention has published a technical review of the tested human specimen, from that sequencing report, “The genome of the virus identified from the patient in Texas is publicly posted in GISAID and has been submitted to GenBank.” This report details the samples sequenced from the human demonstrating a unique mutation. At this time, it does not appear to have spread to other humans from this individual. 


APHIS has published recommendations related to this incident.

As of today, it is STRONGLY RECOMMENDED to minimize the movement of cattle and the depopulation of cattle is not thought to be necessary.

APHIS also requests that farms: 

  1. Expedite testing for HPAI (H5N1) via milk samples or nasal swabs. APHIS will reimburse for initial testing of suspect animals at NAHLN labs, a FAD/EP number is required (the Wisconsin Veterinary Diagnostic Laboratory).

  2. Monitor the herds for signs of sickness (one sign: discolored milk or decreased production)

  3. Heighten protocols to control disease and prevent it (tips at Secure Milk Supply)

  4. Have workers wear PPE and avoid contact or activities around those confirmed or suspected to have HPAI (H5N1)

  5. Anyone exposed to the virus should be monitored for symptoms for 10 days and be tested if any new symptoms are experienced

The Animal Health Diagnostic Center at Cornell University is also encouraging veterinarians to send samples from cows and other animals for any disease outbreak for testing.  

Note! 17 states have restricted cattle importations from states where the virus is known to have infected dairy cows: Alabama, Arizona, Arkansas, California, Delaware, Florida, Hawaii, Idaho, Kentucky, Louisiana, Mississippi, Nebraska, North Carolina, Pennsylvania, Tennessee, Utah, and West Virginia (via AVNMA).

BIO-ISAC has been in contact with individuals at several farms nationwide and offered support connecting to state and federal resources and for reporting animal safety and human health concerns. If you require assistance or support for disclosure, please contact


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