Evaluation of four manual tick‐removal devices for dogs and cats

DESPITE the large number of parasiticidal products available, manual removal of ticks remains a useful technique, and can be used in dogs and cats at low risk of tick infestation (Garris 1991, Zenner and Drevon-Gaillot 2003). A number of tick-removal devices are commercially available, which provide an alternative to the use of conventional forceps. The removal of ticks can be divided into two stages; prehension (grabbing and holding the tick) and removal. The tick can be grabbed and held by using a device with apposing jaws resembling forceps, or by using a device with a slit that slides around the mouthparts of the tick. Tick removal can be carried out by use of traction in a direction perpendicular to the skin surface, or via rotation around the axis of the tick’s body. The latter technique allows dissociation of the mouthparts of the tick from the host tissue and avoids resistance exerted by the numerous rows of backward-facing denticles that comprise the hypostome. This short communication compares the use of a tickremoval device (with a slit for tick prehension and rotation) with surgical forceps, in the hands of a trained operator (veterinarian). In addition, the report compares three commercial tick-removal devices that use different methods of tick prehension and removal, in the hands of pet owners. All cats and dogs with a tick infestation brought to 18 participating veterinary clinics in eastern France between April 2001 and May 2002 were included in the study. Four different tick-removal devices that work in different ways were assessed (Fig 1). A device that uses apposing jaws and traction (AT) was represented by small surgical forceps with straight, very sharp jaws (Adson forceps). With this device, the operator must grab the tick as close as possible to its implantation site in the skin and pull the tick in a direction perpendicular to the skin. A device that uses apposing jaws and rotation (AR) was represented by a commercial product, Pen-Tweezers (Buster). This device has two apposing jaws that open when a button is depressed and close when it is released. After prehension of the tick, the operator must rotate the device to extract the tick. A device that uses a slit and traction (ST) was represented by a commercial product, Pro-Tick Remedy (SCS). This device consists of a metal spatula with a pointed end that has a slit of 9 mm that narrows progressively. With this device, the operator must place the slit around the mouthparts of the tick and apply traction at 90° to the surface of the skin to extract it. A device that uses a slit and rotation (SR) was represented by the commercial product, Crochet O’Tom (H3D), which consists of a hook with a slit at the end. After placing the slit around the mouthparts of the tick, the operator must rotate the device to extract the tick. Five aspects of tick removal were objectively evaluated and the results were recorded: time required to remove the tick ( 60 seconds); ease with which the tick was grabbed and held by the device (very easy, easy, awkward or difficult for both grabbing and holding); force needed to extract the tick (none, gentle, moderate or considerable); and reaction of the animal (1 None, 2 Animal turned its head, 3 Whined or growled once, or 4 Whined or growled several times or attempted to bite). The outcome of the manipulation was simply classified as a success or failure. Correct or incorrect use of the instrument when tick removal was carried out by the owner was also recorded. Veterinarians could also add their own comments. The veterinarian was responsible for obtaining owner consent for the animal to be included in the study. The veterinarian used an intervention grid (Schwartz 1989) that randomly selected the operator (veterinarian or owner) and tick-removal device to be used. Veterinarians used the SR device or Adson forceps only. Owners used one of the three commercial devices. When the owner was selected to remove the tick the veterinarian instructed the owner in the use of the device. In these instances, the veterinarian assessed correct or incorrect use of the device and completed the report forms according to the owner’s assessment of the tick-removal procedure. When the veterinarian was selected to remove the tick, he or she also completed the report form in terms of the tick-removal procedure. Ticks were individually placed in tubes filled with 70 per cent ethanol and were sent to the authors’ laboratory with the report forms for data analysis and examination. Ticks were examined by use of a binocular magnifier by an observer blinded to the device used to remove the tick. Type, species, sex and developmental stage (Bourdeau 1993) were recorded. The size of the tick and the condition of the mouthparts were recorded: 1 Mouthparts intact with possible traces of tickorigin cement, host epidermis or both, 2 Hypostome partially severed, 3 Hypostome torn or severed at the base, or 4 Mouthparts totally severed. For each characteristic of the comparison, a chi-squared test was performed, with P<0·05 considered significant. Veterinarians and owners removed 236 ticks from 178 dogs and 46 cats. The ticks were identified as 193 long hypostome species (Ixodes ricinus) and 43 short hypostome species (30 Dermacentor reticulatus and 13 Rhipicephalus sanguineus). Female ticks predominated for each species identified (91 per cent of I ricinus, 77 per cent of D reticulatus and 85 per cent of R sanguineus). Comparison of the SR device and the AT device used by a veterinarian demonstrated that the SR device was significantly quicker for removal of the tick (P<0·05), was easier to use to grab the tick (P<0·05), required less force for extraction (P<0·01) and caused less damage to the mouthparts of the tick (P<0·01) (Fig 2). There were no significant differences between the two devices in terms of success or failure of the removal.