Mouse-to-mouse transmission of CHIKV.

1 6.5 log10CCID50/ml. 2 As assessed by clinical symptoms. 3 Infection of Recipient C57BL/6 mice was determined by IgG ELISA 17 days after the last Donor IRF3/7 mouse was euthanized. In a separate series of experiments, a mesh divider was placed between Donor and Recipient mice in the same cage (Mesh divider), allowing air circulation, but not physical contact, between Donor and Recipient mice. Donor mice were infected with CHIKV and were then housed in the same cage as naïve Recipient mice. Infection of Recipient IRF3/7-/- mice become apparent at the indicated times (Column 3) by onset of clinical symptoms (hunching, ruffled fur, swollen feet) indicating onset of CHIKV-induced hemorrhagic shock [6]. Samples for viraemia and/or RT-PCR were taken on the days indicated in Column 3.