Confluent monolayers of human microvascular endothelial cells (HMECs) cultured at 37°C or 34°C or Amblyomma americanum cells (AAE2) cultured at 34°C were infected with R. prowazekii for 0.5h, 3h, and 24h. Total RNA was extracted using Trizol, DNaseI treated, and reverse transcribed for RT-PCR (n≥3). AAE2 and HMEC expression were baselined to 0.5h and normalized to 16S rRNA. The data is presented as mean±SEM for four trans-acting Rp_sRs, namely, Rp_sR76, Rp_sR83, Rp_sR86, and Rp_sR159. Asterisks indicate *p<0.05, **p<0.01 and ***p<0.001.