Investigators from California and the Centers for Disease Control and Prevention (CDC) have released findings concerning unexplained H5N1 infections in children within the state. Their research was inspired by a recent good news story, involving a positive test for the H5N1 virus in a Texas dairy herd. This underscores existing worries about the virus jumping between species.
The U.S. Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed the positive H5N1 test involving a herd located in Texas. This detection has brought the total of herds infected with this zoonotic disease nationwide to 1,079. These cases have originated in 17 different states since early 2024. The outbreak in Texas is the first H5N1 detected in the state since May. This is a grave reminder of the virus’s ongoing threat in the region.
Ongoing Surveillance and Research
Researchers emphasize the importance of continued surveillance and real-time subtyping at public health laboratories for tracking novel flu viruses, particularly H5N1. New discoveries underscore that the virus is still circulating in species that are most vulnerable to infection. Birds and mammals are especially prone to this problematic phenomenon.
In one case in Beadle County, South Dakota, H5N1 was found at a farm with 52,600 birds. Furthermore, the disease has spread to commercial turkey flocks in Faulk County, South Dakota, and Dickey County, North Dakota. These recent events highlight the urgent need for close monitoring of avian influenza and for a better understanding of its implications for public health.
Child’s Infection Traced to Raw Poultry
That’s when health officials in San Francisco reported that a child who had recently returned from Asia tested positive for influenza A, H5N1. The team immediately sent the child’s nasopharyngeal sample to the San Francisco Department of Public Health’s lab. This move serves to prop up their surveillance spree at public expenses. The first test was positive for influenza A on Dec. 13, 2024, with additional subtyping detected as H5N1 on Jan. 9.
Throughout the investigation, it was revealed that a family member had purchased live poultry from an Asian live-bird market. This purchase took place over two weeks before the child started displaying any symptoms. The child is symptomatic for 1 week, requiring two healthcare encounters within that week. Subsequent reverse-transcription nested PCR genotyping demonstrated that the H5N1 virus belongs to the B3.13 genotype. This genotype has been circulating among dairy cattle, other mammals, poultry, and wild birds.
Implications for Public Health
The persistent global spread of the H5N1 virus is creating grave concern among public health experts. Experts emphasize that knowing how a virus can be transmitted is key to preventing outbreaks and further infection. The results from California serve to highlight just how interconnected animal health and human health truly are. That is particularly the case in states where livestock and poultry markets are robust.
