Isolation of spotted fever group rickettsias from triturated ticks using a modification of the centrifugation-shell vial technique

Abstract

A modification of the centrifugation-shell vial technique was used to isolate spotted fever group (SFG) rickettsias from triturated ticks which had previously been stored at −80 °C for up to 7 months. SFG rickettsias were successfully isolated in Vero cells from all 7 haemolymph positive ticks (Amblyomma hebraeum) used in the experiment. Attempts were also made to use these tick triturates to establish SFG rickettsial infections in tissue culture. Vero cells were used for 5 of the tick triturates and human embryonic lung cells (HEL) for the remaining 2. Infections were successfully established in 4 of the 5 Vero cell cultures, but in none of the HEL fibroblast cultures.