USDA Animal and Plant Health Inspection Service Shares Update on H5N1 Detection in Oregon Swine, Bovine Vaccine Candidate Progression

Today, the U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) is sharing key updates regarding the detection of HPAI H5N1 in a backyard farm operation in Crook County, Ore., as well as additional information about the agency’s proactive efforts to protect livestock, farms and communities from avian influenza.  

On Wed., Oct. 30, USDA APHIS announced that H5N1 avian influenza was detected in one of the pigs at this backyard farm, that two pigs tested negative, and tests were pending for two additional pigs.  The USDA National Veterinary Services Laboratories (NVSL) has completed testing on the two remaining pigs and has confirmed that one tested positive and met the clinical case definition for HPAI H5N1. Sequencing from this positive sample, while incomplete due to the low level of the virus, indicates infection from the D1.2 genotype of H5N1.  

Because the amount of virus from the infected pigs was very low, only partial genomic sequences could be extracted from one of the two samples and these sequences indicate infection with the D1.2 genotype of H5N1. APHIS and the Oregon Department of Agriculture had previously also shared that H5N1 had been detected in poultry on the same farm; the samples from the poultry were also found to have the D1.2 genotype.  

Genomic sequencing of samples from migratory birds in the area showed very similar sequences, which increases the probability that the pigs and poultry on this farm became infected after coming into contact with infected migratory birds, not dairy cattle or other livestock.   

This farm is a non-commercial operation, and the animals were not intended for the commercial food supply. There is no concern about the safety of the nation’s pork supply as a result of this finding.    

Additionally, over the past week APHIS has approved field safety trials for two additional vaccine candidates for H5N1 in cattle, bringing the total number of candidates approved for field trials to four. USDA continues to support the rapid development and timely approval of an H5N1 vaccine for dairy cows, in addition to other species. 

Last week, as part of USDA’s broader efforts to combat the spread of H5N1, APHIS announced plans to partner with State and animal health officials to enhance testing and monitoring for H5N1, building on measures taken by USDA since the beginning of the avian influenza outbreak. This strategy builds on measure taken by states, as well as national risk mitigation measures including the Federal Order requiring testing of lactating cattle prior to interstate movement, which was announced in April 2024. The state of Colorado’s bulk milk testing program has been highly successful, with no herds currently containing cattle infected with H5N1 and has helped inform the design of this new milk testing strategy.