NEW REPORTS ON PARASITISM BY Haplometroides buccicola (DIGENEA, PLAGIORCHIIDAE) IN BRAZILIAN SNAKES

The occurrence of Haplometroides buccicola (Digenea, Plagiorchiidae) in the esophagus of two Brazilian snakes is reported in the present study. The trematodes were collected from one Micrurus corallinus (Elapidae) and one Phalotris lativittatus (Colubridae); both snakes were found in Botucatu city, São Paulo State, Brazil. Morphological and morphometric analyses of the trematodes are presented. For the first time Micrurus corallinus has been recorded as a host for H. buccicola and this is the second time that P. lativittatus has been reported as a host for this trematode species.


INTRODUCTION
The current study aimed to report the occurrence of Haplometroides buccicola (Digenea, Plagiorchiidae) in a new host, Micrurus corallinus (Serpentes, Elapidae), and also the second case of infection by this trematode species in Phalotris lativittatus (Serpentes, Colubridae).
The host snakes were captured in the municipality of Botucatu, São Paulo State, and were donated to the Center for the Study of Venoms and Venomous Animals (CEVAP) of São Paulo State University (UNESP).In both snakes trematodes were found in their esophagus.Three helminthes were collected in M. corallinus and nine in P. lativittatus.The trematodes were fixed in AFA (alcohol-formol-acetic acid) under slight pressure of a coverslip for 10 minutes, and then transferred to 70% alcohol for further processing.The specimens were stained with carmine and cleared in creosote.
Morphological and morphometric analyses were accomplished in a computerized imaging system (Qwin Lite 3.1®, Leica, Germany).Measurements for the specimens are reported as the mean and range (minimum-maximum).
The trematodes were deposited in the Reference Helminthological Collection (CHIBB) of the Department of Parasitology, Botucatu Biosciences Institute, UNESP.
The trematodes (Figure 1, Table 1) presented: tegument covered with spines; oral subterminal sucker; prepharynx not evident; muscular pharynx; short and narrow esophagus; slightly sinuous intestinal ceca (distributed until the testicular region); pre-equatorial acetabulum; preacetabular, postbifurcal, submedian genital pore, opening near the right cecal branch; small cirrus pouch positioned behind the acetabulum and presenting an opposed curvature beside the ovary; ovoid testes with irregular contours, in a diagonal, postacetabular and intercecal position; ovoid ovary just behind the acetabulum, with regular contours, pre-testicular, intercecal; a Mehlis' gland located below and on the right ovary portion; a seminal receptacle posterior to the Mehlis' gland; vitellaria consisting of few bunched developed follicles, in a lateral and extracecal position, distributed from the zone slightly anterior to the genital pore to the testicular zone; a well-developed uterus, occupying most of the post-testicular zone; a long and narrow vagina; ovoid, operculated and thick shelled eggs with two small, apical lateral protuberances; terminal excretory pore.
The Haplometroides species found in M. corallinus and P. lativittatus was identified using the identification key proposed by Silva et al. (7).The genus Haplometroides is included in the family Plagiorchiidae (9) and only three snake parasite species have been described for this genus: H. buccicola (2), H. odhneri (4) and H. intercaecalis (7).
The present study reports the first case of infection by H. buccicola in M. corallinus.
Elapid snakes have been reported as hosts for this trematode (2,3,4,6).However, despite the large geographic distribution of M. corallinus (1), this is the first report on the helminth fauna of this snake in Brazil.
With regard to P. lativittatus, only one case of infection by the trematode exists in the literature.Silva et al. (5) reported the occurrence of H. buccicola in a P. lativittatus specimen deposited in the Herpetological Collection of CEVAP.The trematodes were collected from the mouth and esophagus of the snake, but the helminthes were in inadequate conditions for the morphometric analysis since they were fixed incorrectly inside the snake organs.In the in toto preparations, the worms were bent, crooked or kneaded, which hindered not only the measuring, but also the illustration of the trematodes.The present study is the second report of H. buccicola occurrence in P. lativittatus, thus confirming this species as a host.In this study, the trematodes were processed correctly and the prepared material permitted appropriate illustrations and morphometric analysis, thereby contributing to the knowledge of the species.

Table 1 .
Morphometric data of Haplometroides buccicola found in the esophagus of Micrurus corallinus (Elapidae) and Phalotris lativittatus (Colubridae) from the municipality of Botucatu, São Paulo, Brazil Reference Helminthological Collection, Department of Parasitology, Botucatu Biosciences Institute, UNESP, Botucatu, São Paulo State, Brazil; Dist OS-AC: distance between oral sucker and acetabulum; Dist IC-PE: distance between intestinal ceca and posterior end of the body.