Mickey Leonard

Proactive disease transmission pathway analyses break complex transmission routes into simpler steps, making risks and uncertainties easier to identify. This approach is especially valuable for African Swine Fever (ASF), a difficult-to-control disease in low-biosecurity settings or when biosecurity practices are inconsistently applied. To support targeted biosecurity planning, a pathway analysis was conducted that is specific to pork harvest facilities in the United States. The analysis focused on two federally inspected plants that slaughter market hogs and produce primal cuts. Inputs, outputs, and potential transmission pathways were identified through a literature review, site visits, and facility personnel interviews. Because ASF virus remains stable at low temperatures and in many pork products, particular attention was given to pathways involving storage conditions, waste materials, and processing steps such as heating or pH modification. Processing steps were evaluated against existing process control plans and ASF inactivation thresholds to determine mitigation status. Of 42 identified pathways, 39 were classified as unmitigated or of unknown mitigation status. These unmitigated or unknown pathways—broadly involving pigs, people, vehicles, and waste—represent the highest priorities for further risk assessment work and for exploring ways to develop or strengthen biosecurity protocols that reduce ASF transmission.

Vaccination is commonly used to minimize disease impacts on birds and promote sustainable poultry production. Vaccination against highly pathogenic avian influenza (HPAI) differs because HPAI is classified as a foreign animal disease in the US and disease control falls under federal jurisdiction. Vaccination for HPAI could negatively affect the nation’s ability to export poultry and poultry products, representing the largest barrier to implementation. However, the continued burden of global HPAI cases requires a reevaluation of the cost of ongoing outbreaks and the need for new mitigation strategies, including HPAI vaccine use.

During highly pathogenic avian influenza (HPAI) outbreaks, the United States Department of Agriculture response requires infected egg production premises to discard on-site poultry products, including eggs that have been processed and stored prior to infection of the site. The disposal of these eggs contributes to global food insecurity through market disruptions, industry revenue loss, and federal indemnity paid. Further, rural farming communities are economically destabilized and farmer health and well-being challenged. To support continuity of business movement decisions during HPAI outbreaks, the Secure Poultry Supply team at the University of Minnesota along with an egg sector stakeholder workgroup has been examining the risk of moving to market processed, segregated, and stored eggs from an infected premises that were laid by uninfected flocks (i.e., a group of egg-laying hens kept in one house/barn during their entire lay cycle). Three important criteria for achieving both acceptable risk and confidence for movement were identified: identification and removal of potentially contaminated eggs from the cooler; protection of cooler eggs from recontamination; and science-assessed egg truck disinfection protocols for exiting an infected premises. The science behind biosecurity and biocontainment practices and risk determination for moving eggs off infected premises are discussed. Confidence in movements determined to be low risk may provide a means for farm and food–protein sustainability.

Oral fluid sampling has been widely adopted in swine health surveillance, offering an effective and cost-effective method for monitoring endemic and emerging diseases. This study characterized oral fluid sampling practices within U.S. pig production systems. An online questionnaire was conducted between June and October 2023, targeting swine practitioners, to collect data on implementation, usage, sampling protocols, and handling procedures. A total of 67 valid responses were received, representing an estimated 58M growing pigs and 3.9M sows. Nearly all respondents (99%) reported being familiar with or using oral fluid sampling for diagnostic purposes. The median of ropes hung per barn was two (interquartile range [IQR]: 1; 4), with 68% using one rope per two pens. The median of pens sampled per barn was six (IQR: 4; 10). Pigs typically accessed the rope for a median of 20 min (IQR: 17.5; 30). Sampling frequency varied by farm types. Half of gilt-development-unit (GDU) respondents collected samples monthly. When submitting samples to the veterinary diagnostic laboratories, pig age (91%) was the most frequently included information. This study reveals the widespread and varied adoption of oral fluid sampling, highlighting the need for standardized collection procedures to support consistent interpretation and improve reliability for detecting emerging pathogens.