Avian influenza consistent with genotype D1.1, unrelated to Nevada strain, found in dairy cattle in Maricopa County On February 11, 2025 the Arizona Department of Agriculture (AZDA), working in conjunction with the United States Department of Agriculture (USDA), confirmed Arizona’s first identified H5N1 avian influenza detection in milk produced by a dairy herd in Maricopa County. As a protective measure, the facility is currently under quarantine. Unlike other detections involving B3.13 H5N1, cattle have not yet displayed signs of illness with this particular D1.1, but if clinical symptoms become evident, cattle will be isolated from the main herd. This detection stemmed from AZDA’s implementation of the National Milk Testing Strategy initiated in January focusing on farm-level bulk tank testing. This detection of avian influenza is consistent with a D1.1 genotype and unrelated to the recent Nevada detection of this virus. This D1.1 genotype bears no features that would make it more likely to infect humans. Every dairy in Arizona has been tested at least once since January; thus far only a sample from this dairy has tested positive. Milk and other dairy products that have been pasteurized are safe to consume. The health and safety of dairy workers and the public are AZDA's top priority. AZDA is working closely with the Arizona Department of Health Services and the Maricopa County Department of Public Health to provide worker safety guidance, monitor staff at the affected site, and prevent spread among livestock. Overall, the risk to the general public remains low. Individuals in close contact with dairy cattle may be at increased risk due to contact with potentially affected animals.
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Survey of bovine veterinarians at US conference for HPAI antibodies, conducted September 2024 Public health officials conducted a serosurvey among 150 bovine veterinary practitioners at a U.S. conference in September of 2024. Three U.S. practitioners had evidence of recent infection with HPAI A(H5) virus, including two without exposures to animals with known or suspected HPAI A(H5) virus infections and one who did not practice in a U.S. state with known HPAI A(H5) virus–infected cattle. What are the implications for public health? These findings suggest the possible benefit of systematic surveillance for rapid identification of HPAI A(H5) virus in dairy cattle, milk, and humans who are exposed to cattle to ensure appropriate hazard assessments.
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USDA Confirms D1.1 Genotype of H5N1 in Dairy Cattle in Nevada, January 2025
On January 31, 2025, the USDA Animal and Plant Health Inspection Service (APHIS) National Veterinary Services Laboratories (NVSL) confirmed by whole genome sequence the first detection of highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b, genotype D1.1 in dairy cattle. This confirmation was a result of State tracing and investigation, following an initial detection on silo testing under the USDA’s National Milk Testing Strategy (NMTS) in Nevada. USDA APHIS continues to work with the Nevada Department of Agriculture by conducting additional on-farm investigation, testing, and gathering additional epidemiological information to better understand this detection and limit further disease spread. This is the first detection of this virus genotype in dairy cattle (all previous detections in dairy cattle have been HPAI H5N1 clade 2.3.4.4b, genotype B3.13). Genotype D1.1 represents the predominant genotype in the North American flyways this past fall and winter and has been identified in wild birds, mammals, and spillovers into domestic poultry.
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Beef surveillance in western Canada
Poultry surveillance in western Canada
Dairy surveillance in western Canada
Smallholder livestock production surveillance in western Canada
Companion animal surveillance in western Canada
Small ruminant surveillance in western Canada
Equine surveillance in western Canada
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