Experimental Studies on the Transmission Cycle of Thogoto Virus, a Candidate Orthomyxovirus, in Rhipicephalus appendiculatus

Reassortment of Thogoto Virus (a Tick-borne Influenza-like Virus) in a Vertebrate Host

“…The amount of virus delivered by ixodid ticks is difficult to determine because they feed for several days and may deliver virus for most of the feeding period (Kemp et al, 1982;Davies et al, 1986). Results of direct inoculation of hamsters indicated that the process of reassortment is dependent on dose and time of infection.…”

“…The virus was grown in BHK-21 cells, maintained in Eagle's MEM (EMEM) and supplemented with3~ newborn calf serum (NBCS). Plaque assays were performed in Vero cells as described by Davies et al (1986).…”

“…In sheep, the virus induces pyrexia (Haig et al, 1965) and abortions (Davies, 1978). THO virus was selected for studies on reassortment because it produces high titre viraemia in laboratory-bred hamsters and can be transmitted to hamsters by infected ticks (Davies et al, 1986).…”

“…The ability of an arbovirus to reassort in a vertebrate host was examined using Thogoto (THO) virus, a tick-borne virus (Davies et al, 1986) that appears similar to the influenza viruses (Orthomyxoviridae) in structure, morphogenesis and pathogenesis (Clerx et aL, 1983;Filipe et al, 1986). The virus possesses a segmented genome of single-stranded RNA (Clerx et al, 1983).…”

The Effect of Host Resistance to Tick Infestation on the Transmission of Thogoto Virus by Ticks

“…Although THO virus is structurally and morphogenetically similar to the orthomyxoviruses, it is an arbovirus transmitted biologically by the African brown ear tick, Rhipicephalus appendiculatus (Davies et al, 1986). The virus was originally isolated from ticks collected from cattle in Kenya and has subsequently been detected throughout Central Africa, and in certain areas of the Middle East and Southern Europe, with evidence to suggest that it is of veterinary and medical significance (Haig et al, 1965;Moore et al, 1975 ;Davies et al, 1984).…”