The Central Nevada Health District has confirmed the state’s first human case of highly pathogenic avian influenza (HPAI) H5N1 in an adult who was exposed to infected dairy cattle while working at a dairy farm in Churchill County. The person had conjunctivitis with no other reported symptoms and is recovering.1
Separately, but related, the USDA Animal and Plant Health Inspection Service (APHIS) National Veterinary Services Laboratories (NVSL) confirmed by whole genome sequence the first detection of avian influenza clade 2344b, genotype D11 in dairy cattle in Nevada.2
"Ensuring the safety of the industry is our utmost priority, and the NDA is working with industry members," NDA State Veterinarian Peter Rolfe, DVM, said in a statement. "It is critical that animal health biosecurity practices are enhanced to help prevent the spread of disease and protect animal and worker safety."3
Avian influenza has been detected in dairy cattle in 16 states throughout the US since March 2024. Livestock owners are encouraged to practice good biosecurity and monitor animals for signs of illness. HPAI presents mild symptoms in cows, including reduced milk production, decreased feed consumption or coughing or sneezing. If an animal shows any signs of illness, owners are advised to contact their local veterinarian.3
Protecting Yourself and Others from H5N1 Infection
According to the CHD here are some strategies to consider:
- Do not touch sick or dead animals or their droppings and do not bring sick wild animals into your home.
- Keep your pets away from sick or dead animals and their feces.
- Do not eat uncooked or undercooked food. Cook poultry, eggs and other animal products to the proper temperature and prevent cross-contamination between raw and cooked food.
- Avoid uncooked food products such as unpasteurized raw milk or cheeses.
- If you work on poultry or dairy farms, talk to your provider about getting your seasonal flu vaccination. It will not prevent infection with avian influenza viruses, but it can reduce the risk of coinfection with avian and flu viruses.
D11 Genotype
D11 is commonly found in wild birds and has previously been linked to severe cases in regions like Canada and Washington state. Unlike the B313 strain, which has caused milder symptoms in dairy workers exposed to infected cattle, the D11 genotype appears to be more serious.4
Read more: The First Patient in US With Severe Case of Avian Influenza Dies
Back in January, a person in Louisiana who died from avian influenza had the D11 genotype. Prior to that, cases of H5N1 were reported to be the B313 genotype in farm workers exposed to infected cattle and poultry and caused milder symptoms and no hospitalizations.
Number of US Cases
As of February 10, there has been 68 human cases in the US, according to the Centers for Disease Control and Prevention. The federal agency said data shows D11 last year likely infected a total of 15 people in Iowa, Louisiana, Oregon, Washington and Wisconsin, and were all related to poultry.5
References
1. The Central Nevada Health District is Actively Monitoring for Spread of H5N1 in Northern Nevada. CHD. February 10, 2025. Accessed February 11, 2025.
https://www.centralnevadahd.org/press-release/
2. APHIS Confirms D11 Genotype in Dairy Cattle in Nevada. Animal and Plant Health Inspection Service. Accessed February 11, 2025. https://www.aphis.usda.gov/news/program-update/aphis-confirms-d11-genotype-dairy-cattle-nevada-0
3. Highly Pathogenic Avian Influenza detected in dairy cows in northern Nevada. Nevada Department of Agriculture press release. January 24, 2025. Accessed February 11, 2025.
https://agri.nv.gov/News/2025/Highly_Pathogenic_Avian_Influenza_detected_in_dairy_cows_in_northern_Nevada/
4.CDC Confirms First Severe Case of H5N1 Bird Flu in the United States. CDC press release. December 18, 2024. Accessed February 11, 2025.
https://www.cdc.gov/media/releases/2024/m1218-h5n1-flu.html
5. Stobbe M. Aleccia J. Nevada dairy worker contracted newer strain of bird flu, CDC says. PBS News. February 10, 2025.
https://www.pbs.org/newshour/health/nevada-dairy-worker-contracted-newer-strain-of-bird-flu-cdc-says
