Highly pathogenic avian influenza virus of the H5N1 subtype has been infecting U.S. dairy cattle and spreading among dairy operations since March 2024. H5N1 surveillance systems for dairies are needed, but information on whether environmental sampling can inform these systems is lacking. To guide a surveillance framework, we determined the environmental sites with Influenza A virus (IAV) detection on H5N1-affected dairies (n = 25) in four states (California, Colorado, Michigan, and Ohio) and explored sample characteristics that may have influenced detection. A total of 581 samples from dairy environmental sites were characterized for IAV RNA via rRT-PCR, and classified into six categories. A total of 94 samples (16.2%) had IAV detected, and the Ct values measured from these samples were typically higher than those measured in bulk tank milk from a subset of sampled herds. A majority of IAV detections were made from the following site categories: milking equipment/personal protective equipment, parlor surfaces, and wastewater/lagoons/manure. These results suggest that environmental sites most likely to be contaminated with IAV on dairies are those with exposure to milk. Meanwhile, mixed effect logistic modeling showed that days into an outbreak that samples were collected was associated with IAV detection. These results provide a framework within which to continue the assessment of environmental sampling as a surveillance tool for dairy H5N1. This framework can be strengthened by studies that perform further IAV viral characterization and collect samples from sites prior to, during, and after H5N1 outbreak periods.

Background: Brucella melitensis is considered one of the most widespread zoonotic pathogens worldwide. Vaccination remains the most cost-effective strategy for controlling B. melitensis infection in small ruminants. Methods: In this study, we evaluated the immunologic responses and protection against experimental challenge in 18 goats vaccinated with either lipopolysaccharide (LPS) from B. melitensis strain 16M (LPS alone), LPS of B. melitensis strain 16M and MONTANIDE™ ISA 61 VG adjuvant (Seppic; 50 Bd national, 92250 La Garenne-Colombes, France) (LPS + ISA 61 VG), or saline as a control. Results: Goats (n = 6) vaccinated with LPS + ISA 61 VG had greater (p < 0.05) antibody responses than those that were nonvaccinated. Our data demonstrate that goats vaccinated with LPS + ISA 61 VG exhibited greater lymphocyte proliferative responses (p < 0.05) to the LPS antigen than those vaccinated with LPS alone at week 12 after vaccination. However, proliferative responses of peripheral blood mononuclear cell (PBMC) from goats vaccinated with LPS + ISA61VG did not differ (p > 0.05) from responses of PBMC from control goats. CD4+, CD8+, and γδ T cells from all vaccinated goats had negligible proliferation and failed to induce antigen-specific IFN-γ production. Control and vaccinated goats did not differ (p > 0.05) in their protection against abortion, uterine, fetal, mammary, or maternal infection. Conclusions: Our data suggests that LPS + ISA 61 VG induces a robust humoral response but negligible cellular responses. Our data also suggest that LPS + ISA 61 VG or LPS alone would not be efficacious for use as a vaccine in goats, but the LPS + ISA 61 VG inoculum may be beneficial as a booster. Additional trials would be necessary to evaluate the vaccine’s efficacy as a booster inoculation for small ruminants.