H5N1 Avian Influenza Detected in Texas Dairy Herd; Sick Child Source Investigation in California Remains Unclear
The USDA Animal and Plant Health Inspection Service (APHIS) confirmed H5N1 avian influenza in a Texas dairy herd, marking the state’s first detection since May 2025. This brings the total number of infected herds in the U.S. since early 2024 to 1,079 across 17 states, emphasizing the ongoing spread of the virus in both livestock and wildlife.
In addition to the Texas dairy herd, APHIS reported a new H5N1 outbreak at a commercial turkey operation in Beadle County, South Dakota, housing over 52,000 birds. Recent cases in poultry have also been documented in Faulk County, South Dakota, and Dickey County, North Dakota. These outbreaks highlight the continued risk of H5N1 in both commercial and backyard avian populations.
Human Case Investigation Highlights Need for One Health Awareness
Meanwhile, California and CDC investigators recently published findings in the Morbidity and Mortality Weekly Reportregarding one of two unexplained pediatric H5N1 cases. A school-age child developed fever, myalgia, abdominal pain, and conjunctivitis in December 2024. Diagnostic testing confirmed H5N1 (B3.13 genotype), a strain circulating in dairy cattle, poultry, wild birds, and other mammals.
Epidemiologic investigation suggested that the child’s infection was not linked to poultry consumption. The family lived in an urban environment and had minimal contact with live poultry. Testing of close contacts showed no evidence of human-to-human transmission, though environmental exposure during outdoor activities at school was considered a possible source.
Investigators emphasized that real-time surveillance, subtyping, and genomic sequencing remain critical for understanding virus transmission across species. The case underscores the importance of a One Health approach, integrating animal and human health monitoring to detect and mitigate emerging zoonotic threats.
Implications for Veterinary Practice
Veterinarians should remain vigilant for H5N1 in dairy, poultry, and other susceptible species, even in regions without recent detections. Monitoring for unusual mortality, respiratory signs, or neurologic symptoms in livestock is essential. In addition, veterinary professionals play a critical role in biosecurity, outbreak response, and communication with public health authorities to limit interspecies transmission and safeguard both animal and human health.
