Honey bees were collected from a San Francisco, CA (U.S.A.) colony previously identified to be Crithidia positive by microarray and PCR testing. Honey bees were immobilized by chilling at 4uC for 20 minutes, briefly washed in 70% ethanol, and decapitated prior to dissection. The SF strain was isolated from honey bee intestines dissected in a sterile environment, minced and placed in a T25 flask and cultured in BHT medium composed of Brain Heart Infusion (BHI) 28.8 g/L (DIFCO), tryptose 4.5 g/L (DIFCO), glucose 5.0 g/L, Na 2 HPO 4 0.5 g/L, KCl 0.3 g/L, hemin 1.0 mg/L, fetal bovine serum (heat inactivated) 2% v/v, pH 6.5, and containing penicillin G sodium (10 6 units/L) and streptomycin sulfate (292 mg/L) at 27uC [101] . Free active Crithidias were observed 24 hours post inoculation. Parasites were maintained by subculture passage every 4 days; stable liquid nitrogen stocks were archived. Light microscopy of live parasites was performed using a Leica DM6000 microscope equipped with Hamamatsu C4742-95 camera and Volocity Software (PerkinElmer). Imaging fixed parasites (4% paraformaldehyde, 20 min) facilitated visualization of DAPI (49,6-diamidino-2-phenylindole) stained nuclear and kinetoplast DNA. Images of fixed Crithidia mellificae were obtained using both the Leica DM6000 microscope and a Zeiss LSM 510-M microscope equipped with both a 636 objective numerical aperture 1.4, and a 1006 objective numerical aperture 1.4.