Description of Gastrointestinal Parasite From a Red-footed Tortoise (Geochelone
carbonaria) in Brazil
Karin Werther1; Joaquim Júlio Vicente2; Cláudia Brigagão de
Petta1
1Universidade Estadual Paulista (UNESP) – Campus de Jaboticabal, Department
of Veterinary Pathology, Via de Acesso Prof. Paulo Donato Castellane s/nº, 14870-000
Jaboticabal/SP/Brazil; 2Laboratório de Helmintos Parasitos de Vertebrados, Departamento de
Helmintologia do Instituto Oswaldo Cruz, Rio de Janeiro/RJ/Brazil
Abstract: This paper describes and classifies a nematode parasite found in the
gastrointestinal tract of a red-footed tortoise (Geochelone carbonaria)
from Brazil. The parasite ultimately was identified as Labiduris irineuta.
Key Words: endoparasites, reptiles, Labiduris irineuta, red-footed tortoise, Geochelone carbonaria.
Introduction
Free-ranging and captive reptiles are infected and infested with a great diversity of
endo- and ectoparasites (Jacobson, 1986). The diagnosis of the parasitism can be made
antemortem by routine fecal examinations with microscopic visualization of the ova or
postmortem in dead animals.
In the tortoise of this report, parasitism was diagnosed at necropsy.
Case History
A captive, pet, juvenile red-footed tortoise (Geochelone carbonaria), weighing
155g was bitten by a dog. The tortoise was examined at the Veterinary Hospital of the
Universidade Estadual Paulista/Campus de Jaboticabal. Both the plastron and the carapace
had profound lesions. In some foci the carapace was absent. The bony plates were bleeding,
the peritoneum was ruptured, and some organs, such as liver, were injured. The lesions
were cleaned with sterile saline solution and covered with a sterile compress. The
tortoise also was treated with systemic antibiotics (Enrofloxacin 10 mg/kg).
Despite intensive treatment, the tortoise died two days later and was necropsied.
During the necropsy, numerous white nematodes were observed within the large intestines.
These parasites were submitted for identification to the Instituto Oswaldo Cruz, Rio de
Janeiro/RJ, Brazil, Department of Endoparasites / Helminthes. Based upon the morphologic
and anatomical characteristics of the nematodes, they were classified as members of the
Hyperfamily Cosmocercoidea, Family Atractidae Travassos, 1919, Genus Labiduris Schneider, 1866, species Labiduris irineuta Costa, 1961. Representative
specimens of the nematodes subsequently were deposited in the Oswaldo Cruz
Helminthological Collection (CHIOC) n°. 33,892 (alcohol 70°GL).
Three different species of the genus LabidurisSchneider 1866 had been
described until the present parasite was discovered in this red-footed tortoise in Brazil.
The following description is from the nematode Labiduris zschokkei Linstow, 1899,
the unique until describe species in Brazil. These species differ from the other species
of the same genus by there total length, length of the tail, form of the spicules and by
the papillae pre and ad-anais. This parasite habitue the large intestine from the
tortoise, Chelonoidis denticulata L. 1766 (COSTA, 1961).
The same author (COSTA, 1961) described Labiduris zschokkei as having a
thin cuticle with transverse striations. The excretory pore was 0.975 mm distant from the
anterior extremity. The mouth was a complex structure with the presence of lips and one
structure resembling a brush. This brush-like structure began at the apex of the cephalic
region and extended to the anterior part of the pharynx. A laminar part of the cuticle
formed a thin, concave band that encompassed the entire body and ended with a fringe. The
mouth was composed of an inferior platform and a superior platform with a structure
resembling a tooth. Long vestibules, measuring 0.052 mm in length, were located posterior
to the mouth.
The pharynx measured 0.135 mm in length and was immediately followed by the first part
of the oval esophagus. This initial portion of the esophagus resembled a club and measured
0.504 mm in length. Additional cells also formed a 0.52 mm long isthmus. This structure
had a spherule dilatation that was 0.078 mm in diameter. The dilatation was followed by a
bulb, measuring 0.185 to 0.210 mm in diameter, that had valves. The intestines were
rectilinear and separated from the esophageal bulb by well marked valves.
The female nematodes were 4.5 – 5.5 mm long and had a vulva near the anus. These
orifices were separated by a distance of 0.23 mm. The anus was located 0.3 mm from the
anterior extremity. These female nematodes were viviparous; a small number of larvae (6 at
most) were observed inside the uterus. The larvae were released without rupture of the
vulva.
The male nematodes were 5.3 mm long and 0.32 mm wide at the region of the esophageal
bulb. Two spicules were present that measured 0.323 to 0.352 mm in length. These spicules
were reinforced at the posterior extremity by a structure that resembled a nail. This
structure also was responsible for the curvature of the spicules.
The male nematodes also had 3 pairs of papillae in the pre-anal region and one pair of
papillae posterior to the anal region. Two globular papillae also were located at the
cloacal region; one of these papilla was twice the size of the other papilla. The
post-anal papillae were difficult to see because they formed four little peduncles that
were united by a membrane. These peduncles could only be observed by the anterior view of
the parasite. On the lateral view, two fixed papillae were present adjacent to the
peduncular papillae. The tail measured 0.120 to 0.140 mm in length.
Using the descriptions above and information from the literature concerning the
parasite Labiduris irineuta Costa, 1961, the following line drawings present the
morphological features of this parasite as observed in our red-footed tortoise from
Brazil.
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| Figure 1. Labiduris irineuta Costa, 1961, anterior extremity. The nematode was recovered from a red-footed tortoise (Geochelone
carbonaria). |
Figure 2. Labiduris irineuta Costa, 1961; ventral view of the tail of the male nematode. |
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| Figure 3. Labiduris irineuta Costa, 1961; lateral view of the tail of the male nematode. |
Figure 4. Labiduris irineuta Costa, 1961; lateral view of the tail of the female nematode. |
References
1. Jacobson, E. Parasitic Diseases of Reptiles. In: Fowler (ed.) Zoo and Wild
Animal Medicine. 2. Edition, W.B. Saunders, Philadelphia, 162-181, 1986.
2. Costa, SCG. Nota prévia sobre um novo nematódeo do gênero Labiduris
Schneider, 1866 (Atractoidea). Atas da Sociedade de Biologia do Rio de Janeiro, 4:17-18,
1961.
3. Vicente, J., Rodrigues, H.O., Gomes, D.C., Pinto, R.M. Nematóides do Brasil.
Parte III: Nematóides de répteis. Revista Brasileira de Zoologia. 10 (1):19-168, 1993
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