Treatment of Equine Sarcoid in Seven Cape Mountain Zebra (Equus Zebra Zebra)
Total Page:16
File Type:pdf, Size:1020Kb
Journal of Wildlife Diseases, 47(4), 2011, pp. 917–924 # Wildlife Disease Association 2011 TREATMENT OF EQUINE SARCOID IN SEVEN CAPE MOUNTAIN ZEBRA (EQUUS ZEBRA ZEBRA) Hendrik J. Marais1,2 and Patrick C. Page1 1 Department of Companion Animal Clinical Studies, Private Bag X04, Faculty of Veterinary Science, Onderstepoort, University of Pretoria, South Africa 2 Corresponding author (email: [email protected]) ABSTRACT: Equine sarcoid has been diagnosed in endangered Cape mountain zebra (Equus zebra zebra) in at least two game reserves in South Africa, with prevalence as high as 53% in Bontebok National Park. Seven Cape mountain zebras with sarcoids were treated with either Downloaded from http://meridian.allenpress.com/jwd/article-pdf/47/4/917/2239705/0090-3558-47_4_917.pdf by guest on 01 October 2021 surgical excision, 5-fluorouracil, allogenous vaccine, or a combination of 5-fluorouracil and allogenous vaccine. One of the two sarcoids on one of the 5-fluorouracil–treated zebras was left untreated. The microscopic features of the tumors evaluated showed either all or most of the typical epidermal and dermal histologic features of equine sarcoid. The zebras were examined 2 yr posttreatment to determine outcome. All sarcoids had resolved except on the zebra on which one of the sarcoids was left untreated. The efficacy of the three treatment methods in Cape mountain zebra is encouraging. Key words: Allogenous vaccine, Cape mountain zebra, 5-fluorouracil, sarcoid, surgical excision. INTRODUCTION Equine sarcoid affects horses of all ages, The term equine sarcoid was introduced types, and colors worldwide without obvi- in 1936 in South Africa to describe a ous sex predilection. The prevalence of unique tumor occurring in the skin of sarcoid in horses ranges from 0.5% to horses (Equus ferus caballus)andto 2.0% (Marti et al., 1993; Goodrich et al., distinguish them from other fibroblastic 1998). Sarcoid prevalence in two separate skin tumors such as fibromas, fibrosarco- populations of Cape mountain zebra has mas, and papillomas (Jackson, 1936). Sar- been reported to be 53 and 25%, respec- coid means fibrosarcoma-like and refers to tively in South Africa (Marais et al., 2007). the characteristic behavior of these tumors The treatment of sarcoids may represent in that they are locally invasive, recur after a considerable expense to horse owners surgical excision, and do not metastasize (Nasir and Reid, 1999). In zebras, the (Goodrich et al., 1998). It is widely ac- expense is increased due to the cost of cepted that bovine papillomavirus (BPV) capture and follow-up treatment or exami- types 1 and 2 are associated with the nations. Should an animal require repeat pathogenesis of equine sarcoid. Although treatments or be monitored after surgery, it sarcoids do not produce infectious virions, must be kept in a sheltered enclosure, with they contain detectable viral DNA and additional cost and risk of injury or mortality RNA and express BPV type 1 and 2 major due to stress and anxiety. In addition, equine transforming protein E5 (Marchetti et al., sarcoid poses a threat to the genetic diversity 2009). Although sarcoids in horses occur of these rare mammals. All currently primarily on the legs, head, and ventral available treatment options have limitations abdomen (Brostrom, 1995; McConaghy concerning their effectiveness in horses or et al., 1996), the most common site for arising from the practical difficulties in sarcoids in Cape mountain zebra (Equus treating wild animals. zebra zebra) is the ventral abdomen and Reports of neoplastic growths in wild legs (Marais et al., 2007). Despite their zebras are sparse and few discuss treat- characteristic anatomical distribution and ment (Lohr et al., 2005; Nel et al., 2006; gross appearance, a biopsy specimen is Marais et al., 2007). Sarcoids are complex required for definitive diagnosis. and many treatments have been described 917 918 JOURNAL OF WILDLIFE DISEASES, VOL. 47, NO. 4, OCTOBER 2011 in horses, including surgical excision sarcoid. Animals were immobilized from a (Martens et al., 2001), Bacillus-Calmette- helicopter using a combination of etorphine hydrochloride (M99, Novartis Animal Health, Guerin immunotherapy (Lavach et al., Johannesburg, South Africa), azaperone 1984, 1985), cryotherapy (Lane, 1977; (Stresnil, Bayer Animal Health, Johannesburg, Martens and De Moore, 1996b), intersti- South Africa), and hyaluronidase (Hyalase, tial brachytherapy (Turrel et al., 1985; Kyron Laboratories, Johannesburg, South Theon and Pascoe, 1995), hyperthermia Africa). Once animals were recumbent, a ground team covered their eyes and blocked (Hoffman et al., 1983), intralesional cis- their ears to reduce stimulation. All animals platin (Theon et al., 1993), topical chemo- were identified by microchip, and the coat therapy (Theon et al., 1993; Martens and patterns were recorded by means of digital Downloaded from http://meridian.allenpress.com/jwd/article-pdf/47/4/917/2239705/0090-3558-47_4_917.pdf by guest on 01 October 2021 De Moore, 1996a), excision by carbon photography. Reversal was done with dipre- dioxide laser (Carstanjen et al., 1997), norphine HCl (M50-50, Novartis Animal Health). mistletoe extract (Christen-Clottu et al., Eight of the 15 animals were diagnosed 2010), and photodynamic therapy (Martens presumptively with sarcoid and seven were and De Moore, 1996a; Giuliano, 2010). treated. Diagnoses were confirmed by histo- These treatments may be costly, technically pathologic examination. Two animals each difficult to administer, or have variable were treated with surgical excision, chemo- therapy, and allogenous vaccine; one was efficacy (Owen and Jagger, 1987; Theon treated with both chemotherapy and alloge- et al., 1993; Theon and Pascoe, 1995; nous vaccine (Table 1). No antimicrobials or Carstanjen et al., 1997). Regardless of the anti-inflammatory drugs were administered. approach decided on, multiple treatments The ethics committee of South African Na- are often necessary for complete regression tional Parks approved this study. of sarcoids (McConaghy et al., 1994, 1996; Biopsy and histopathology Knottenbelt et al., 1995). The Cape mountain zebra has been Biopsies were taken from all sarcoid-like tumors. The sarcoids were either surgically described as one of the rarest mammals in excised or a representative biopsy was taken the world (Penzhorn and Novelli, 1991). using a biopsy punch. Where two or more There are approximately 1,500 animals tumors were present on a zebra, a maximum of remaining worldwide, distributed among two samples was taken from each tumor. The national parks, game reserves, zoos, and tissues were fixed in 10% buffered formalin, trimmed into blocks and routinely processed, private reserves. The Bontebok National stained with hematoxylin and eosin, and Park is in the foothills of the Langeberg examined with a light microscope. Suspected Mountains, in the region of Swellendam. sarcoids were examined for typical epidermal The region has a temperate climate with and dermal histologic features of equine an average annual rainfall of about sarcoid such as epidermal hyperplasia, epider- mal hyperkeratosis, rete peg formation, and 500 mm, occurring mainly during early proliferation of fibroblast-like cells (Martens summer and winter and is also one of the et al., 2000). largest remaining ‘‘renosterveld islands’’ containing several plant species found Treatment nowhere else. Our objective was to Surgical excision: Surgical excision of sarcoids investigate clinical and pathologic find- was performed on two animals. After immo- ings, treatment, and outcome of sarcoids bilization, a tarpaulin was placed under the animal to attain optimal cleanliness under field in a population of free-ranging Cape conditions. The area around the tumor was mountain zebra. washed with water and dried with a clean towel, but not shaved due to time constraints. MATERIALS AND METHODS An elliptical incision was made through the skin and subcutis with a number 20 scalpel The entire population of Cape mountain blade around the tumor. The tumor and zebra (n515) in Bontebok National Park adjacent skin were removed by blunt dissec- (34u04933.70S, 20u27919.30E) was examined tion with Metzebaum scissors. The sarcoids in 2002 and 23 mo later (2004) for equine were excised in totality using a 10 mm margin. MARAIS AND PAGE—TREATMENT OF EQUINE SARCOID IN CAPE MOUNTAIN ZEBRA 919 TABLE 1. Identification, description of sarcoids, and treatment applied for seven Cape mountain zebra (Equus zebra zebra) in Bontebok National Park, South Africa, with equine sarcoid. Zebra Description of sarcoid (location, size, type) Treatment 1 Ventral abdomen, 90360315 mm, verrucous/fibroblastic Surgical excision and ulcerated 2 Ventral abdomen, 85365315 mm, verrucous/fibroblastic Surgical excision and ulcerated 3 Udder, 20320310 mm, verrucous 5-Fluorouracil Left inner medial thigh, 20315315 mm, verrucous 5-Fluorouracil 4 Medial left axilla, 20315315 mm, verrucous 5-Fluorouracil Downloaded from http://meridian.allenpress.com/jwd/article-pdf/47/4/917/2239705/0090-3558-47_4_917.pdf by guest on 01 October 2021 Medial right elbow, 15315310 mm, verrucous No treatment 5 Ventral abdomen, 20320315 mm, verrucous and ulcerated Allogenous vaccine Medial left elbow, 20320310 mm, verrucous 6 Ventral abdomen, 15315310 mm, verrucous Allogenous vaccine 7 Medial right elbow, 30330315 mm, verrucous 5-Fluorouracil and allogenous vaccine Minor bleeding was controlled by application using 15 g minced and filtered sarcoid, 84 ml of mosquito