This method is suitable for maintaining hard colonies, studying tick biology or host-vector pathogen interactions or evaluating different control measures of these medically important attributes. The main advantages of these techniques are its simplicity and short duration. and most importantly ability to be modified, according to the experimental needs of the study.
Although this method can be used for feeding the different life stages of hard ticks on laboratory rabbits. It can also be adapted to other host systems such as sheep. Begin by cutting an appropriately-sized capsule frame from a sheet of EVA Foam rounding the outer corners to minimize accidental detachment during gluing.
Cut four eight millimeter wide strips of self-adhesive hook tape and attach the strips to the sides of the frame. Cut the same size strips from the self-adhesive loop tape and bind them to the hook tape on the frame. Next, cut a piece of pine mosquito mesh big enough to cover the frame and stick the mesh to the self-adhesive loop strips, trimming any overhanging material as necessary.
When the capsule is ready, manually restrain the rabbit and shave the experimental regions on the back and sides of the animal. Apply fast-drying non-irritating latex glue to the entire surface of the prepared capsule and after one minute, gently pressed the capsule to the skin. The most critical step of the protocol is the field attachment of the capsule to the skin.
Therefore, constant pressure of the capsule onto the rabbit skin especially at the corners for at least three minutes is required. After three minutes, slightly lift the capsule to visually confirm its attachment using a spatula to apply glue to any non-attached parts. When the capsule is secured, apply protective tape to the rear paws to prevent jacket damage and place the front legs through the front jacket openings tightening the neck of the jacket to one finger width between the animal and the jacket.
To initiate the tick infestation, first add the ticks into the plunger end of a plastic cotton plug to syringe with a cut-off tip. Next, lift the mesh from one corner of the capsule and place the syringe deep into the capsule through the opening. Insert the plunger all the way into the syringe to infest the animal with the ticks.
Then slowly twist the plunger toward the skin to remove any remaining ticks while simultaneously pulling the plunger out of the capsule. When all the ticks have been delivered, refasten the hook and loop tape. Close the jacket by zipping the backside of it and insert the rear legs of the rabbit into the rear elastic enclosures.
Then return the rabbit to its cage. At the appropriate experimental time point, transfer the rabbit to the bench and unzip the jacket. Gently restraining the rabbit, open the capsule and use forceps to collect the fully engorged adults and a tick twister to collect the partially fed adults.
Engorged larvae and nymphs can be collected by brushing them into the dish. Then re-close the capsule if experimentally appropriate. At the end of the experiment, remove the mosquito mesh completely from the capsule without removing the jacket.
Three to four weeks later, gently trim one of the corners to try to remove the capsule. Once the capsule has been removed, remove the jacket and allow the rabbit to recover in its cage. If the protocol and experiments allow, the recovered rabbit can be reused or offered for adoption.
This protocol is suitable for various types of experiments including mass rearing of multiple tick groups on the same host. The EVA Foam capsule system has been proven to be highly successful when feeding different developmental stages of various hard tick species. It may also be adapted for other type of laboratory hosts such as sheep.
In addition, this versatile method facilitates the creation of a variety of different experimental settings based on the modifiable number, shape and composition of the capsules on the host. The procedure also allows a complete recovery of the rabbit hosts after the experiments. This protocol is not laborious and no intensive training is required to become familiar with the technique.
In addition, a minimal amount of materials, steps and stress to the experimental animals is required.
