Specificpathogenfree

Specific-pathogen-free (SPF) refers to a designation for populations of laboratory animals that are guaranteed to be free from defined pathogens. SPF status is achieved through barrier housing, controlled husbandry, quarantine of new arrivals, and ongoing health monitoring. The objective is to reduce or eliminate infections that can confound experiments or compromise animal welfare.

Implementation involves barrier systems such as dedicated rooms, HEPA-filtered caging, sterile equipment, and strict personnel procedures. New animals undergo quarantine and acclimation before joining the main colony. Health monitoring uses sentinel animals and periodic testing of the colony by serology, PCR, and culture for a defined panel of pathogens. The panel and testing frequency are determined by the species, facility, and research needs.

Pathogens and scope of SPF programs vary by institution and species. Pathogens commonly monitored include certain viruses, bacteria, and parasites known to affect the species. SPF status can be maintained for mice, rats, rabbits, and other laboratory animals, but the exact list of excluded pathogens is defined by the facility’s health program.

Benefits of SPF housing include increased experimental reliability, reduced biological variability, and improved reproducibility of results, along with enhanced welfare by preventing disease outbreaks. Limitations include that SPF does not guarantee freedom from all microorganisms, as some infections may be latent or undetected, and maintaining SPF requires ongoing surveillance, investment in infrastructure, and dedicated personnel.

Related terms include germ-free (axenic) conditions, which are completely free of microorganisms, and conventional colonies, which are not specifically screened for defined pathogens.