Non-viraemic transmission of Thogoto virus: vector efficiency of Rhipicephalus appendiculatus and Amblyomma variegatum.
Jones LD., Davies CR., Williams T., Cory J., Nuttall PA.
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 a detectable viraemia. Furthermore, tick to tick transmission is potentiated by factors associated with the salivary glands of ticks (saliva activated transmission). The vector efficiency of 2 ixodid tick species, Rhipicephalus appendiculatus and Amblyomma variegatum, for Thogoto virus was assessed using this model. The number of uninfected recipient ticks that acquired Thogoto virus when co-feeding with virus-infected ticks (donors) on uninfected guinea-pigs was determined. When nymphs of either tick species were employed as donors, there was no significant difference in the number of infected recipient nymphs. In contrast, a significant difference in the vector efficiency of adults ticks was observed: 77.0% of recipient ticks which co-fed with R. appendiculatus donor adults acquired Thogoto virus compared to 44.7% of recipient ticks which co-fed with A. variegatum donors. No significant difference in susceptibility to Thogoto virus infection was observed between recipient ticks of the 2 species. Thus, adults of R. appendiculatus are more efficient than A. variegatum in mediating non-viraemic transmission.