1a.Objectives (from AD-416):
There are over 65 million dogs in the US and Rhipicephalus sanguineus is one of the most important vectors of diseases in dogs worldwide. Viral, bacterial and parasitic infections are among the greatest challenges affecting companion animals and ticks are involved in the spread of a number of these problems. In the U. S., R. sanguineus vectors the canine diseases canine ehrlichiosis and canine babesiosis and can also transmit Rocky Mountain spotted fever in humans. An anti-tick vaccine for companion animals is not currently available and the objective of this collaboration is to evaluate a tick protein for its utility as an antigen in an anti-tick vaccine formulated for use in canines against R. sanguineus.
1b.Approach (from AD-416):
Two study groups of 6 canines of similar age per group (randomly assigned) are to be vaccinated at the start of week 1, 4, and 7 of the study. Group 1, and 2 are to be vaccinated with ARS Antigen 1 plus Adjuvant, or Adjuvant alone, respectively. Blood samples are to be drawn from each animal prior to each vaccination and every 4 weeks following the third vaccination for 24 weeks. Each animal will be infested with R. sanguineus following the administration of the third vaccination. Adult female ticks will be collected from each animal and efficacy will be determined by comparison of adult tick counts from the two groups.
Blood is to be collected (10 ml) from each canine into 12.5-ml sterile serum separator tubes (Corvac, Mansfield, MA) or other appropriate collection tubes compatible with serum fraction isolation. Serum is collected after centrifugation (3,400 RPM for 1 h at 25 deg C) and stored at -80 deg C. Serum antibody titers are to be determined using an antigen-specific ELISA to determine specific response to ARS Antigen 1.
The objective of this collaboration is to evaluate a tick protein for its utility as an antigen in an anti-tick vaccine formulated for use in canines against the brown dog tick, R. sanguineus. This collaboration has recently been initiated, and necessary materials and canine hosts are being prepared for the vaccination trial.