A case study of biosafety considerations and solutions for work with highly pathogenic avian influenza virus with large scale equipment in high biocontainment

Authors: Chaplinski, Nick; Haley, David; Mead, Nancy; Spackman, Erica

Submitted to: Applied Biosafety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Bird flu is a serious and deadly disease for poultry and in March of 2024 was found to have infected dairy cattle in the US. Although disease in cows was much more mild than in poultry, the virus that causes bird flu was found in raw milk and could occur at high concentrations. Therefore, it was crucial to confirm that current pasteurization methods in the US were sufficient to inactivate the virus. To accomplish this a pilot scale continuous flow pasteurizer was needed to simulate actual practices in the dairy industry. This is a large piece of equipment which presents challenges because of its large size. First, all proposed work and safety risk assessment were reviewed by the Institutional Biosafety Committee and the chief Biosafety Officer of the Agriculture Research Service. All work was conducted in a airtight high containment room with double HEPA exhaust filtration, heat treated effluent, incinerated waste, and required personnel to shower to exit. Then, to address logistical challenges within the contained space the safety team developed numerous innovative approaches including application specific sealed, HEPA filtered buckets with valved connectors to completely contain all the test material. Completely sealed tubing with valved connections were utilized throughout the testing process. Viability based safety testing to confirm the complete disinfection of the equipment was also conducted at the completion of the work. The result was safe and successful completion of the research while mitigating all safety concerns.

Technical Abstract: Introduction. Highly pathogenic avian influenza virus (HPAIV), a potential pandemic pathogen (PPP), was discovered in a new species, cattle, in March 2024 in the U.S. Soon thereafter it was discovered that infectious virus could be present in milk at very high titers (up to 10 log10 50% egg infectious doses per ml). Therefore, “emergency” testing to confirm that current milk processing methods used to reduce bacterial pathogens were sufficient to inactivate HPAIV was needed. Continuous flow pasteurization (CFP) is the industry standard and conditions defined in the Pasteurized Milk Ordnance of the US Food and Drug Administration needed to be validated with HPAIV. To accomplish this, biosafety procedures for a pilot scale CFP with high volumes of HPAIV contaminated milk needed to be developed. Methods. Numerous information sources, including subject matter experts, were utilized to acquire information for risk assessments and to develop procedures for a new, large-scale piece of equipment that required 5L of a PPP at a high titer per test. Results. Application specific equipment such as sample and waste vessels with sealed ports, tubing with valved connection, and HEPA filtered vents were designed with corresponding safety procedures, such as seal integrity testing of the sample vessels. Conclusions. The use of high-volumes of infectious material, the scale of the equipment, and time constraints presented unique challenges to balance biosafety and research objectives. Innovative engineering and procedural approaches allowed the research to be completed successfully in a time-sensitive manner while mitigating biosafety risk.