| the effect of host resistance to tick infestation on the transmission of thogoto virus by ticks. | tick-borne virus transmission was examined using guinea-pigs and hamsters previously infested with ticks. guinea-pigs developed immunity to rhipicephalus appendiculatus after a single exposure to the ticks. nymphal and adult stages that fed on resistant guinea-pigs had increased mortality during feeding, and reduced engorged weights. egg production from female ticks fed on resistant hosts fell by at least 50%. guinea-pigs maintained high levels of immunity to tick infestation for at least 210 da ... | 1990 | 2345364 |
| anatomical basis of thogoto virus infection in bhk cell culture and in the ixodid tick vector, rhipicephalus appendiculatus. | infection by thogoto (tho) virus, a tick-borne virus related to the orthomyxoviruses, has been compared in vertebrate cell culture and in rhipicephalus appendiculatus ticks using infectivity titrations, immunofluorescence, and immune electron microscopy with colloidal gold markers to detect cell surface and intracellular antigens. morphogenesis of tho virus in cell culture was similar to that of influenza virus, with polymorphic virus particles budding at the plasma membrane. in the tick, tho vi ... | 1989 | 2543769 |
| the effect of virus-immune hosts on thogoto virus infection of the tick, rhipicephalus appendiculatus. | thogoto (tho) virus infections of rhipicephalus appendiculatus ticks were examined using tick hosts immune to the virus. in the first set of experiments, ticks were infected by feeding on viraemic hamsters. inter-stadial infection of tho virus was not affected when ticks ingested a virus-immune bloodmeal but there was an effect on persistence of the virus. the incidence of intra-stadial infection was reduced by at least 40% when nymphs partially fed on viraemic hamsters and completed their blood ... | 1989 | 2558460 |
| viral interference in the tick, rhipicephalus appendiculatus. i. interference to oral superinfection by thogoto virus. | interference between arboviruses in a naturally infected tick vector is reported for the first time. rhipicephalus appendiculatus nymphs were dually infected with thogoto (tho) virus, a tick-borne virus, similar to members of the family orthomyxoviridae. in the first series of experiments examining 'inter-stadial' interference, larvae were orally infected with a temperature-sensitive (ts) mutant, and after moulting the nymphs were superinfected with the wild-type (wt) virus. in the second series ... | 1989 | 2778441 |
| intra-stadial tick-borne thogoto virus (orthomyxoviridae) transmission: accelerated arbovirus transmission triggered by host death. | haematophagous insect vectors of arthropod-borne viruses (arboviruses) feed repeatedly. consequently, they can transmit arboviruses to more than one host during the same developmental stage (intra-stadial transmission). by contrast, ixodid ticks generally feed only once at each parasitic stage (larva, nymph, and adult) and hence they have only one opportunity for tickborne virus transmission per stadium (inter-stadial transmission). under natural conditions, tick-infested hosts may die (from dis ... | 2001 | 11315177 |
| heterogeneity in the effect of different ixodid tick species on human natural killer cell activity. | tick saliva plays a vital role in blood-feeding, including manipulation of the host response to tick infestation. furthermore, a diverse number of tick-borne pathogens are transmitted to vertebrate hosts via tick saliva, some of which exploit the immunomodulatory activities of their vector's saliva. we report that salivary gland extracts (sge) derived from dermacentor reticulatus adult ticks induce a decrease in the natural killer (nk) activity of effector cells obtained from healthy human blood ... | 2002 | 11856443 |
| susceptibility of mosquito and tick cell lines to infection with various flaviviruses. | the genus flavivirus consists of more than 70 virus species and subtypes, the majority of which are transmitted by mosquitoes or ticks, although some have no known vector (nkv). the ability of these viruses to infect cultured cells derived from mosquito or tick species offers a useful insight into the suitability of such vectors to harbour and replicate particular viruses. we undertook a comparative study of the susceptibility of mammalian vero cells, a clonal mosquito cell line (c6/36) and rece ... | 2004 | 15347394 |