Is the mouse LD50 unit here to stay?

Investigators adopted the mouse LD50 unit for quantifying botulinum neurotoxin (BoNT) in the early 1900s, and through a combination of necessity and tradition, public health agencies, laboratory researchers, clinicians and manufacturers of BoNT have continued to use the mouse LD50 unit as the gold standard for expressing toxin quantity and potency.A recent article by Pickett (2011) questions whether there is still a need in the botulinum community to continue to use this bioassay and raises issues regarding a lack of standardisation in the reporting of toxin preparations.