Читать книгу Surgery of Exotic Animals - Группа авторов - Страница 94

The Class Arachnida is a huge group of animals (over 100,000 species) that includes over 30,000 spiders, and less conspicuous groups such as the harvestmen, mites, ticks, and scorpions. Tarantulas (actually not true spiders) represent an important taxon of commonly kept arachnids that commonly require medical care. Scorpions also appear with some frequency in the pet trade and are common display animals in zoos and museums.

Surgical repair of the fractured exoskeleton can be accomplished with surgical adhesives like methylmethacrylate or cyanoacrylate (Wolff 1993). A fractured abdomen in a tarantula carries a grave prognosis, but if the hemolymph hemorrhage can be contained with the use of a topical adhesive, the animal can survive. Another common problem that may require intervention is dysecdysis (difficulty shedding). A tarantula or other arachnid that experiences this life‐threatening problem can be either anesthetized or manually restrained while forceps or other appropriate instruments are used to gently extract the animal from the adhered exoskeleton (Figure 4.8).

Like many arthropods, scorpions can display autotomy (Pizzi 2002), but in the case of some species belonging to the genus Ananteris, they can autotomize their tail (metastoma), including a portion of the gastrointestinal (GI) tract, and survive for up to eight months (Mattoni et al. 2015). Virtually all other arthropods that practice autotomy drop (and can redevelop) limbs. In the case of the Ananteris scorpions, tail autotomy appears to be a defense or escape response practiced most commonly by males. While survivors can no longer defecate or sting, they can live long enough to consume small meals and mate (Mattoni et al. 2015). According to one study, sutures are of little use on spiders (Pizzi and Ezendam 2002). Autotomy can be induced in tarantulas by using forceps to grasp the injured appendage by the most proximal segment (femur) and quickly pulling upward (Zachariah and Mitchell 2008). Another small surgical procedure involves inserting microchips (passive integrated transponder [PIT] tags) into manually restrained tarantulas. To do this, an area on the opisthosoma between the heart and intestines was prepared by gently removing the setae from a 1.5 × 1.5 mm area with a 20‐gauge needle. The needle tip was then used like a scalpel to open the exoskeleton allowing for insertion of the PIT tag with fine sterile forceps. The wound was then dabbed dry and sealed with cyanoacrylate to minimize hemolymph loss (Reichling and Tabaka 2001).

Figure 4.8 This image shows the careful removal of a retained exoskeleton from a tarantula.

Source: Courtesy of Dan Johnson.