An Aberrant Acephalic Metacestode and Other Parasites of Masticophis Flagellum (Reptilia: Serpentes) from Texas

Home , Masticophis, Masticophis flagellum, Psammophis, Zamenis

J. Helminthol. Soc. Wash. 57(2), 1990, pp. 140-145

An Aberrant Acephalic Metacestode and Other Parasites of Masticophis flagellum (Reptilia: Serpentes) from Texas

DAVID BRUCE CONN' AND CHRIS T. McALLiSTER2'3 1 Department of Biology, St. Lawrence University, Canton, New York 13617, 2 Renal-Metabolic Lab (151-G), Veterans Administration Medical Center, 4500 South Lancaster Road, Dallas, Texas 75216, and 3 Department of Biological Sciences, University of North Texas, Denton, Texas 76203

ABSTRACT: Two of 12 (17%) western coachwhip snakes, Masticophis flagellum testaceus, from Texas were found to be infected with parasites. Several aberrant metacestodes occurred free in the pericardial cavity of 1 snake. Each lacked a scolex and possessed a disorganized body musculature and a highly vacuolated parenchyma. These aberrant metacestodes were structurally similar to metacestodes reported as Sparganum proliferum (Stiles, 1908) from various mammalian hosts, but asexual proliferation could not be confirmed in the present case. This snake also harbored numerous tetrathyridia of Mesocestoides sp. Vaillant, 1863, which were encapsulated in the intestinal wall. The tetrathyridia showed no sign of deformity or asexual activity. Other parasites infecting this snake included Eimeria zamenis Phisalix, 1921, Ochetosoma georgianum (Byrd and Denton, 1938), and Physa- loptera sp. Rudolphi, 1819. The only other parasitized snake harbored Sarcocystis sp. Lankester, 1882. New host and locality records are reported herein. KEY WORDS: Cestoda, coachwhip snake, Eimeria zamenis, Masticophis flagellum, Mesocestoides, metacestode, Ochetosoma georgianum, Physaloptera, Reptilia, Sarcocystis, Sparganum proliferum, tetrathyridium.

A large amount of information is available on (1937) reported a coccidian, Eimeria zamenis the natural history and ecology of the coachwhip Phisalix, 1921, from a single M. f. flagellum from snake, Masticophis flagellum (Shaw, 1802). Wil- Iowa. To our knowledge, the only other report son (1973b), in a species account, summarized of parasites of M. flagellum was by Hilman and data on the biology of the various taxa of this Strandmann (1960), who reported an intraery- snake; however, little is known regarding its par- throcytic hematozoan, Hepatozoon serpentium, asites. from 4 M. flagellum in Texas. The first report of parasites from coachwhips During a survey of parasites of various reptile appears to be that of Leidy (1856), who described species in Texas, we found 1 M. flagellum that Physaloptera abjecta in Psammophis flagellifor- harbored a remarkable infection of aberrant ace- mis Holbrook, 1842 (=M. flagellum} from an phalic metacestodes. These worms were similar unknown locality in the southern United States. to some occasionally reported from mammals, Later, Nicoll (1911) reported Neochetosoma but they have not been reported previously from (=Ochetosoma Braun, 1901) formosus in Za- nonmammalian hosts. This report provides data mensis flagelliformis (=M. flagellum). Harwood on the morphology and histology of these (1932) described a nematode, Kalicephalus ag- metacestodes and documents the occurrence of kistrodontis flagellus, from a single Coluber other parasites in 2 of the 12 M. flagellum ex- (=Masticophis} flagellum in Texas, and Reiber amined. et al. (1940) reported Physaloptera variegata (=P. abjecta Leidy, 1856) (see Morgan, 1943) from a Materials and Methods coachwhip from Georgia. Schad (1962), in a re- Between May 1986 and May 1988, 12 (6 male, 6 vision of Kalicephalus, reported Kalicephalus female) juvenile and adult western coachwhips, Mas- (Kalicephalus} costatusparvus Ortlepp, 1923 and ticophis flagellum testaceus (Say, 1823), were collected K. (Inermiformis} inermis coronellae (Ortlepp, from Hood (N = 3), Johnson (N = 5), Somervell (N = 3), and Palo Pinto (N = 1) counties in north-central 1923) Lichtenfels, 1980 from M. flagellum. Hub- Texas. Snakes were taken either alive or as fresh road bard (1938) reported over 1,000 unidentified ces- kills, measured (snout-vent length [SVL]: x ± SD = tode plerocercoids from a single specimen of Col- 838.3 ± 298.6, range = 430-1,300 mm), and examined uber (^Masticophis} flagellum flavigularis for parasites. Road-killed snakes were placed on ice and examined within 8 hr of collection; live snakes (Hallowell) from Oklahoma. Loomis (1956) re- were killed within 24 hr with an overdose of sodium covered 3 species of ectoparasitic chigger mites pentobarbital. A midventral incision was made, and from coachwhips from Kansas. Roudabush the gastrointestinal tract, heart, liver, spleen, lungs, and

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Copyright © 2011, The Helminthological Society of Washington 141 oral cavity were examined for helminths. Fecal and parentheses in jum unless otherwise stated): body intestinal contents were removed and placed in indi- 3.3mmx 1.1 mm (2.9-3.6 mm x 1.0-1.2 mm); vidual vials of 2.5% (w/v) aqueous potassium dichro- oral sucker 322 x 348 (274-340 x 329-388); mate solution and examined for coccidian oocysts following methods of Upton and McAllister (1990). acetabulum 426 x 455 (404-450 x 433-488); Trematodes were placed in distilled water to allow for pharynx 163 x 170 (141-199 x 125-198); ovary ejection of eggs and then transferred onto glass slides 174 x 184(131-197 x 140-254); testes 279 x and, with gentle coverslip pressure, fixed in alcohol- 265(187-370 x 168-387); eggs 42 x 28(36-50 formalin-acetic acid (AFA). They were stained with Semichon's acetocarmine and mounted whole in Per- x 20-33). mount. Nematodes were killed in hot AFA, transferred Histologic sections of the small intestine of to glycerine, and examined as temporary mounts. ASUMZ 8419 revealed nodules that were situ- Metacestodes from the pericardial cavity of 1 host ated in the intestinal wall on each side of the were removed and fixed in 10% neutral-buffered for- muscularis layer. Each contained a tetrathyrid- malin (NBF) and prepared as whole mounts by staining in acetocarmine, dehydrating in ethanol, clearing in ium of Mesocestoides sp. (Fig. 1). These meta- methyl salicylate, and mounting in damar. Others were cestodes were morphologically typical for the ge- embedded in JB-4 methacrylate plastic, sectioned at 2 nus, possessing a solid hind body, highly /urn, stained with Harris' hematoxylin and eosin (H&E), organized musculature, well-developed unarmed and mounted in damar. The small intestine of the same snake appeared to be infected by encapsulated hel- tetraacetabulate scolex, and deep invagination minths and was fixed in NBF, embedded in Paraplast, canal. None showed any sign of asexual activity. sectioned at 10 pm, stained in H&E, and mounted in Several metacestodes occurred in the pericar- damar. dium and pericardial cavity of ASUMZ 8419. Voucher specimens of parasites were deposited in the U.S. National Parasite Collection, Beltsville, Mary- These worms lacked scolices and primary lacu- land, with the following accession numbers: Ocheto- nae (Figs. 2-4). They had various body forms, soma georgianurn (80820), Physaloptera sp. (80821), always with a poorly organized musculature and aberrant metacestode (80835), Mesocestoides sp. tetra- a highly vacuolated parenchyma. Some con- thyridium (80836). Host voucher specimens were de- tained unidentified parenchymal inclusions that posited in the Arkansas State University Museum of Zoology (ASUMZ). stained intensely with acetocarmine (Fig. 3). Some of the worms were asymmetrically branched, but Results no attempt was made to determine whether they were reproducing asexually. Histologic sections Of the 12 snakes examined, only 2 (17%) har- revealed that the parenchymal vacuoles were bored parasites. One of the infected snakes (AS- lined by a homogeneous eosinophilic layer. The UMZ 7659), a female (SVL = 730 mm) collected vacuoles appeared to be extensive anomalous di- in Somervell County on 18 April 1987, was in- verticula of the excretory system, with the eo- fected with sporocysts of an unknown species of sinophilic lining conforming to the structure of Sarcocystis Lankester, 1882 (see Upton and the syncytial excretory epithelium (Figs. 5, 6). McAllister, 1990). No gross pathology of the heart was noted in The other infected snake (ASUMZ 8419), a association with the worms' presence. These male (SVL = 1,300 mm) collected from Palo metacestodes did not occur in any other part of Pinto County on 18 July 1987, harbored several the host's body. parasite species. This snake was moribund and malodorous when collected, but still alive. Spor- ulated coccidian oocysts recovered from the feces Discussion and gall bladder were identified as Eimeria za- The present study establishes a host record for menis Phisalix, 1921 (see Upton and McAllister, Sarcocystis sp. Most of the parasites reported 1990). Two spirurid nematodes, Physaloptera sp. here have been reported previously from M. fla- Rudolphi, 1819, were found in the stomach. Be- gellum, although some of those reports are ques- cause only male worms were present, species tionable. The ubiquitous E. zamenis has been identification was not possible. reported previously from other North American Eight ochetosomatid flukes matching the de- colubrid snakes, including M. f. flagellum from scription of Ochetosoma georgianurn (syn. Neo- Iowa (Roudabush, 1937; Upton and McAllister, renifer georgianus) (Byrd and Denton, 1938) were 1990). Nematodes of the genus Physaloptera are found in the oral cavity and upper esophagus of common helminths of various colubrid snakes ASUMZ 8419. Measurements were as follows in North America (Baker, 1987) and were re- (mean length x width followed by the range in ported from M. flagellum by Leidy (1856).

* I

Figures 1-6. Metacestodes from Masticophis flagellum. 1. Longitudinal section of Mesocestoides sp. tetrathyridium encapsulated between the mucosa and muscularis of the small intestine. Note prominent scolex, deep

Ochetosoma georgianum has been reported and Berntzen, 1963), an anomalous hymenolep- previously from the northern black racer, Col- idid cysticercoid (Lucas et al., 1980), or some uber constrictor constrictor, in Georgia (Byrd and other cyclophyllidean (McAllister et al., 1989). Denton, 193 8) and Tennessee (Parker, 1941)and The aberrant worms reported in the present from the speckled kingsnake, Lampropeltis ge- study lacked a primary lacuna, but their other- tulus holbrooki, and the Florida kingsnake, L. g. wise solid bodies possessed large vacuoles, ap- jloridana, in Tennessee and Florida, respectively parently resulting from deformation of the ex- (Parker, 1941). Ochetosoma formosus was re- cretory canals. Similar abnormalities were ported previously from Leptodira annulata and reported in metacestodes tentatively identified M. flagellum in South America (Nicoll, 1911). as Sparganum proliferum by Mueller (1938) and However, it is likely that the latter host was mis- in unidentified metacestodes by Beaver and Ro- identified because M. flagellum ranges no farther lon (1981). Other reports have tentatively iden- south than northern Veracruz and Queretaro, tified aberrant acephalic metacestodes from Eu- Mexico (Dixon et al., 1972). Only Masticophis ropean (Neumann, 1896; Sendrail and Cuille, mentovarius is known to range as far south as 1906; Ssolonitzin, 1933) and North American northwestern Colombia and northern Venezuela (Orthoeferetal., 1974;Barsantietal., 1979;Greve (Wilson, 1973a). Thus, the present report prob- et al., 1979) dogs as Mesocestoides tetrathyridia. ably represents a new host record from the genus However, the true identity has not been con- Ochetosoma. firmed in any of the reported cases. The only This is the first definite report ofMesocestoides verified report of aberrant tetrathyridia from a sp. from M. flagellum. The unidentified plero- naturally infected host was that of Specht and cercoids reported by Hubbard (1938) were tet- Voge (1965), who collected asexually prolifera- raacetabulate when large but lacked suckers when tive (and thus aberrant) forms from a single liz- small. In 2 reviews, Hughes et al. (194la, b) sug- ard population; however, these forms differed gested that the plerocercoids reported by Hub- from the other aberrant metacestodes reported bard (1938) might be Mesocestoides tetrathyrid- above in having well-developed scolices and ia, although they expressed some reservations. lacking extensive vacuolation. Hubbard's (1938) written report and drawings Solid-bodied metacestodes, such as pseudo- do not provide enough information to identify phyllideans, proteocephalideans, and Mesoces- the worms, but they were undoubtedly a cyclo- toides spp., are difficult to distinguish without phyllidean or proteocephalidean. the scolex. The organization of the body mus- As far as we can determine, this is the first culature allows differentiation of pseudophyllid- report of an aberrant acephalic metacestode from ean plerocercoids from Mesocestoides tetrathy- a naturally infected nonmammalian host. The ridia in normal specimens (Andersen, 1983), but worms reported here were structurally similar to such distinctions break down in aberrant speci- many such metacestodes that have been reported mens such as those reported here. Thus, the iden- from mammals throughout the world (see review tity of the present aberrant worms is unknown. by Beaver and Rolon, 1981). Because the scolex It is possible that they are plerocercoids of a is lacking, it is impossible to obtain adults from pseudophyllidean or proteocephalidean or tetra- such worms for definitive identification. How- thyridia of Mesocestoides. The co-occurrence of ever, certain morphological hallmarks allow some the aberrant metacestodes and normal tetra- narrowing of possibilities. For example, the pres- thyridia in the same host does not argue for or ence of a primary lacuna would suggest that against any of these possibilities. The snake was a metacestode is either a taeniid cysticercus (Voge obviously exposed to infection by numerous par- invagination canal, and solid hindbody parenchyma. 2-6. Unidentified aberrant metacestodes from the pericardial cavity. Note well-developed tegument and absence of scolex in all specimens. 2. Whole mount showing typical plerocercoidlike body form with solid hind body. 3. Whole mount showing vacuolated parenchyma and unidentified acidophilic bodies. 4. Whole mount showing highly vacuolated parenchyma. 5. Transverse section showing clusters of large and small vacuoles in the parenchyma. 6. Transverse section showing a high magnification of the thin uniform eosinophilic lining of the parenchymal vacuolations, resembling excretory duct epithelium. B, unidentified acidophilic bodies; C, host capsule; E, intestinal epithelium of host; I, invagination canal; L, eosinophilic lining of parenchymal vacuole; M, smooth muscle of host intestine; P, parenchyma; S, sucker of tetraacetabulate scolex; T, tegument; V, parenchymal vacuole.

Copyright © 2011, The Helminthological Society of Washington 144 JOURNAL OF THE HELMINTHOLOGICAL SOCIETY asite species, and the 2 types of metacestodes their ecto-congeners observed by the author. Pro- could have been acquired at different times. ceedings of the Academy of Natural Sciences of Philadelphia 8:42-58. Loomis, R. B. 1956. The chigger mites of Kansas (Acarina, Trombiculidae). University of Kansas Acknowledgments Science Bulletin 37:1195-1443. We thank B. D. Earle and R. T. Howell for Lucas, S. B., O. Hassounah, R. Muller, and M. J. assistance in collecting snakes, S. J. Upton for Doenhoff. 1980. Abnormal development of Hy- menolepis nana larvae in immunosuppressed mice. identifying coccidian specimens, G. Roberts for Journal of Helminthology 54:75-82. allowing C.T.M. to collect on his properties, and McAllister, C. T., S. J. Upton, and D. B. 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Editor's Acknowledgment

In addition to the members of the Editorial Board, I thank the following persons for their valuable help in reviewing manuscripts for the Journal: Lawrence R. Ash, Ian Beveridge, Brian Boag, Burton J. Bogitsh, Albert O. Bush, Janine N. Caira, Ronald A. Campbell, Patrick W. Carney, Allen W. Cheever, David J. Chitwood, William H. Coil, David B. Conn, A. P. Dobson, Donald W. Duszynski, William G. Dyer, Evelyn M. Ernst, Gerald W. Esch, Donald J. Forrester, Bernard Fried, Eugene G. Hayunga, Eric P. Hoberg, Jane E. Huffman, John Janovy, Jr., Kevin R. Kazacos, Delane C. Kritsky, Dennis E. Kyle, Omer R. Larson, David A. Leiby, Norman D. Levine, David S. Lindsay, Jeffrey M. Lotz, Eugene T. Lyons, Sharon E. Maclean, William C. Marquardt, Chris T. McAllister, Lena Measures, Donald A. Munson, Kenneth D. Murrell, Patrick M. Muzzall, Ronald C. Neafie, David W. Reduker, Marcia L. Rhoads, Michael D. Ruff, Thomas K. Sawyer, Gerald D. Schmidt, Wesley L. Shoop, Robert D. Specian, Dennis A. Thoney, Kenneth L. Tiekotter, John E. Ubelaker, Eugene C. Weinbach, P. L. Wong, Gary L. Zimmerman, and Bert M. Zuckerman.