Figure 4

MERS-CoV loads in alpaca tracheal explants (ATE). (A) MERS-CoV genomic (left) and subgenomic (right) RNA was determined by microfluidic RT-qPCR assays (Sheet A in Additional file 1). Each line represents the mean Cq value and error bars display standard deviation intervals of ATE from 3 animals sampled at 0, 24, 48 and 72 hpi, respectively. Blue, purple, and red dots indicate ATE infected with 10², 10³ and 10⁴ TCID₅₀/mL MERS-CoV, respectively. (B) Tissue tropism of MERS-CoV in ATE. At 72 hpi, MERS-CoV N protein (brown staining) was detected by immunohistochemistry in the epithelium of ATE that were infected with 10³ and 10⁴ TCID₅₀/mL doses respectively; original magnification: × 200 for both tissues. ATE, alpaca tracheal explants; 1/3 and 2/3 indicate the detection of viral RNA in one out of three or two out of three explants, respectively.