Non-viraemic transmission of Thogoto virus: influence of time and distance.

Previous studies have demonstrated that Thogoto virus is transmitted from infected to uninfected ticks when co-feeding on uninfected guinea-pigs, even though the guinea-pigs do not develop detectable viraemia. The dynamics of this 'non-viraemic transmission' were investigated. The percentage of nymphs (recipients) that acquired virus increased from zero, when co-feeding with infected adults (donors) for 3 d, to 80% for a co-feeding period of 5 d. No statistically significant difference was detected when infected donors and uninfected recipients were separated physically up to a maximum distance of approximately 160 mm. These results indicate that the temporal, but not the spatial, relationship affects the number of recipient ticks that become infected.