Anaesthetized females are lined up ventral sides up on microscope slides coated with vaseline and slides are then submerged in 1x PBS. The abdomens are opened up, intestines and ovaries removed, and the number of GFP+ foci along the abdominal cavity is counted using a Leica MZ 16F dissecting microscope with a GFP filter under a 10x magnification. Each experiment is performed in duplicate (n=30 in each replicate). P-values were calculated using Fisher’s exact test with a 4x2 contingency table to assess the four phenotypic classes between two conditions at a time. Background dissemination level in control uninfected and infected flies were 1% and 5–10%.
For pharmacological treatment chemicals in up to 0.5% DMSO or up to 1% ethanol final vehicle concentration are prepared by diluting e.g. a 200-mM stock (in 100% DMSO) in 60oC-heated flyfood using Bloomington’s semi-defined medium recipe and dispensed into standard Drosophila vials (1 ml/vial). After the flyfood solidified, flies were transferred onto flyfood (n=30 flies/vial). Flies were transferred onto fresh compound-treated food every other day until scoring.