Larval Gnathostoma hispidum detected in the red banded odd-tooth snake, Dinodon rufozonatum rufozonatum, from China

Abstract

A total of 205 larval gnathostomes were collected from 18 (22.5%) of 80 red banded odd-tooth snakes, Dinodon rufozonatum rufozonatum, which had been smuggled from China and confiscated at Customs in Busan, Republic of Korea. In order to identify the species, some of the larvae were observed by a light microscope and a scanning electron microscope (SEM). The larvae were 2.18 x 0.29 mm in average size, and had a pair of lips at the anterior end, a muscular esophagus, 2 pairs of cervical sacs, and brownish intestines. The head bulb was characteristically equipped with 4 rows of hooklets; the average number of hooklets in each respective row was 38.6, 40.5, 41.5, and 43.7. In SEM views, the mouth evidenced a pair of lateral lips of equal size in a half-moon shape. Each lip featured a couple of labial papillae and a small amphid located between the 2 papillae. The hooklets on the head bulb had single-pointed, posteriorly-curved tips. The cuticular spines were larger and more densely distributed on the anterior part of the body, and decreased gradually in size and number toward the posterior body. On the basis of these morphological characteristics, the larvae were identified as the third stage larvae of Gnathostoma hispidum.

Fig. 1

Gnathostome larvae collected in the red banded odd-tooth snakes, D. rufozonatum rufozonatum, smuggled from China. Bar is 1 mm.

Fig. 2

The advanced third-stage larva of Gnathostoma hispidum recovered from the muscles of snakes. Bar is 300 µm.

Fig. 3

The head bulb of the larva bearing 4 transverse rows of hooklets. Bar is 50 µm.

Figs. 4-11

Scanning electron microscopic (SEM) view of the advanced third-stage larvae of G. hispidum from the red banded odd-tooth snake, D. rufozonatum rufozonatum. Fig. 4. Whole body showing a head bulb, numerous transverse striations with cuticular spines and an anus.

Fig. 5

The head bulb of larva bearing 4 transverse rows of hooklets. Each hooklet with a sharp point somewhat curved posteriorly.

Fig. 6

Frontal view of the head bulb, which is somewhat retractable into the body.

Fig. 7

Anterior part of a larva with a head bulb, numerous transverse striations with cuticular spines, a cervical papilla (arrow head) located between 10th and 11th transverse striations and a body papilla (arrow mark) between 19th and 20th transverse striations.

Fig. 8

Posterior part of a larva with numerous transverse striations has smaller cuticular spines, and an anus.

Fig. 9

Body surface of the anterior part consists of a highly wrinkled cuticle and has shape-pointed cuticular spines on the transverse striations.

Fig. 10

Body surface of the middle part has transverse ridges and smaller cuticular spines on the transverse striations. Bar is 10 µm

Fig. 11

Body surface of the posterior part consists of smooth cuticle of which spines are more sparsely distributed on the transverse striations.