Experimental & Applied Acarology

, Volume 25, Issue 8, pp 661-674

First online:

Salivary fluid secretion in the ixodid tick Rhipicephalus appendiculatus is inhibited by Thogoto virus infection

  • W. Reuben KaufmanAffiliated withDepartment of Biological Sciences, University of Alberta
  • , Alan S. BowmanAffiliated withDepartment of Zoology, University of Aberdeen
  • , Patricia A. NuttallAffiliated withInstitute of Virology and Environmental Microbiology

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Adult Rhipicephalus appendiculatus ticks, infectedwith Thogoto (THO) virus or control, were fed on guinea pigs and removed atintervals throughout the feeding cycle. Salivary fluid secretion was measuredbyan in vitro technique. The salivary glandsof infected, partially-fed ticks secreted fluid in vitro at about 75% the rateof controls, but the difference between infected and controls among engorgedticks was not statistically significant. Basal and DA-stimulated levels ofcyclic AMP (cAMP) were determined in isolated glands and were significantlyaffected by THO virus infection. The differences in secretory rate amongcontroland infected ticks could not be explained in terms of altered cAMP levels.Haemolymph volume was measured by a tracer-dilution technique using3H-inulin. The mean haemolymph volume for both THO-infected andcontrol groups was between 23–24% body weight throughout the feedingcycle, indicating that infection by this arbovirus did not influence salivaryfluid secretion via altered haemolymph volume. The mechanism by which THO virusaffects secretory activity of its tick vector remains unknown.

Arbovirus Cyclic AMP Rhipicephalus appendiculatus Thogoto virus Tick salivary glands